Archive for category Pharmacological

[Abstract] Exploratory Randomized Double-Blind Placebo-Controlled Trial of Botulinum Therapy on Grasp Release After Stroke (PrOMBiS)

Background. OnabotulinumtoxinA injections improve upper-limb spasticity after stroke, but their effect on arm function remains uncertain.

Objective. To determine whether a single treatment with onabotulinumtoxinA injections combined with upper-limb physiotherapy improves grasp release compared with physiotherapy alone after stroke.

Methods. A total of 28 patients, at least 1 month poststroke, were randomized to receive either onabotulinumtoxinA or placebo injections to the affected upper limb followed by standardized upper-limb physiotherapy (10 sessions over 4 weeks). The primary outcome was time to release grasp during a functionally relevant standardized task. Secondary outcomes included measures of wrist and finger spasticity and strength using a customized servomotor, clinical assessments of stiffness (modified Ashworth Scale), arm function (Action Research Arm Test [ARAT], Nine Hole Peg Test), arm use (Arm Measure of Activity), Goal Attainment Scale, and quality of life (EQ5D).

Results. There was no significant difference between treatment groups in grasp release time 5 weeks post injection (placebo median = 3.0 s, treatment median = 2.0 s; t(24) = 1.20; P = .24; treatment effect = −0.44, 95% CI = −1.19 to 0.31). None of the secondary measures passed significance after correcting for multiple comparisons. Both groups achieved their treatment goals (placebo = 65%; treatment = 71%), and made improvements on the ARAT (placebo +3, treatment +5) and in active wrist extension (placebo +9°, treatment +11°).

Conclusions. In this group of stroke patients with mild to moderate spastic hemiparesis, a single treatment with onabotulinumtoxinA did not augment the improvements seen in grasp release time after a standardized upper-limb physiotherapy program.

 

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[Abstract] Update on pharmacotherapy for stroke and traumatic brain injury recovery during rehabilitation

Abstract

PURPOSE OF REVIEW:

This article evaluates whether specific drugs are able to facilitate motor recovery after stroke or improve the level of consciousness, cognitive, or behavioral symptoms after traumatic brain injury.

RECENT FINDINGS:

After stroke, serotonin reuptake inhibitors can enhance restitution of motor functions in depressed as well as in nondepressed patients. Erythropoietin and progesterone administered within hours after moderate to severe traumatic brain injury failed to improve the outcome. A single dose of zolpidem can transiently improve the level of consciousness in patients with vegetative state or minimally conscious state.

SUMMARY:

Because of the lack of large randomized controlled trials, evidence is still limited. Currently, most convincing evidence exists for fluoxetine for facilitation of motor recovery early after stroke and for amantadine for acceleration of functional recovery after severe traumatic brain injury. Methylphenidate and acetylcholinesterase inhibitors might enhance cognitive functions after traumatic brain injury. Sufficiently powered studies and the identification of predictors of beneficial drug effects are still needed.

 

via Update on pharmacotherapy for stroke and traumatic brain injury recovery during rehabilitation. – PubMed – NCBI

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[ARTICLE] Pharmacological Therapies for Motor Recovery After Stroke – Full Text

Abstract and Introduction

Abstract

Stroke is the most common serious neurological disorder. To date, the focus for research and trials has been on prevention and acute care. Many patients are left with serious neurological impairments and limitations in activity and participation after stroke. Recent preliminary research and trials suggest that the brain is ‘plastic’ and that the natural history of stroke recovery can be improved by physical therapy and pharmacotherapy. Motor weakness and the ability to walk have been the primary targets for testing interventions that may improve recovery after stroke. Physical therapeutic interventions enhance recovery after stroke; however, the timing, duration and type of intervention require clarification and further trials. Pharmacotherapy, in particular with dopaminergic and selective serotonin-reuptake inhibitors, shows promise in enhancing motor recovery after stroke; however, further large-scale trials are required.

Introduction

This review is a framework around an emerging and exciting area of stroke care – maximizing recovery after stroke. Stroke care is a continuum from prevention to hyperacute care to acute care to rehabilitation to community reintegration and back (Figure 1). The traditional medical model of care artificially divides care across multiple healthcare providers and locations. Prevention is most often in the hands of general and primary care medicine with the goal of maximizing stroke risk reduction strategies such as controlling hypertension. Hyperacute stroke care is in the hands of neurologists with a primary goal of providing thrombolysis to as many patients as possible and as quickly as possible. Acute stroke care is in the hands of neurologists and very often in the hands of internal medicine specialists who manage patients according to best practices on acute stroke units in acute care hospitals. Rehabilitation is under the care of physical medicine and rehabilitation physicians and allied health professionals usually in rehabilitation hospitals. Reintegration into the community is in the hands of home care and out-patient providers in the community. One patient, one neurological disorder and so many different care providers and locations.

Figure 1.The continuum of stroke care.

Recent research suggests that we are at the edge of major advances in post-stroke care. Animal and human studies show that the brain is ready to heal immediately after a stroke. The brain is ‘plastic’ and responds to external influences, such as physical therapy. The timing, the intensity and the exact external influence may all be important factors in maximizing recovery. Pharmacotherapy may influence how the injured brain recovers. This complex array of influences and recent research addressing these areas will be elaborated on in this review (Figure 2).

Figure 2.
Multiple factors may influence recovery after stroke.

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[WEB PAGE] What are the benefits of increased GABA levels in the brain?

Gamma-aminobutyric acid (GABA) is a neurotransmitter, or chemical messenger, in the brain. It blocks specific signals in the central nervous system, slowing down the brain. This provides a protective and calming effect on the brain and body.

The body produces GABA, and it may also be present in some fermented foods, such as kimchi, miso, and tempeh. These are not foods that most people include in their daily diets, so some people take GABA supplements to achieve the benefits.

In this article, we examine how increased levels of GABA may impact the brain and body, and whether taking GABA supplements could have the same benefits.

What is GABA?

a couple looking relaxed because of gaba activity.

GABA activity can relieve stress, reduce stress, and improve sleep.

GABA is a neurotransmitter that inhibits or slows the brain’s functions. This activity produces effects such as:

  • relieving anxiety
  • reducing stress
  • improving sleep
  • preventing brain damage

The brain naturally releases GABA at the end of a day to promote sleepiness and allow a person to rest. Some of the medications doctors prescribe to induce sleep and reduce anxiety may also increase the action of GABA.

Medical benefits of increased GABA

Some experts have suggested that increased levels of GABA may have benefits, but the evidence is not clear. According to a 2019 review, GABA has anti-microbial, anti-seizure, and antioxidant properties and may help treat and prevent conditions such as:

Medications to increase GABA

Doctors may prescribe medicines that increase the amount of GABA or stimulate the same neurotransmitters in the brain to treat some medical conditions, such as epilepsy.

For example, benzodiazepines (Valium, Xanax) act on many of the same neurotransmitter receptors as GABA. According to one study, people who have depression may have reduced GABA levels in the brain. The use of benzodiazepines may be beneficial in those instances.

Doctors also prescribe the medication gabapentin (Neurontin), which is chemically similar to GABA to reduce seizures and muscle pain.

However, doctors are not clear whether the therapeutic effects of these medications are related to their effect on GABA receptors or whether they work in other ways.

GABA as a supplement

a woman enjoying the benefits of taurine in an energy drink she is drinking

Many sports drinks contain GABA.

Some people take supplements of GABA for their supposed stress- and anxiety-relieving benefits.

The Food and Drug Administration (FDA) has approved GABA for use as a supplement and as a food additive. Manufacturers may add GABA to:

  • sports drinks
  • snack bars
  • chewing gum
  • candies, and more

Manufacturers produce GABA supplements by fermenting a form of lactic acid bacteria.

However, the FDA do not regulate dietary supplements in the same way as medications. Therefore, consumers should exercise caution as to where they purchase the product from and only buy from reputable vendors and companies.

How to use GABA supplements

Some people may take a supplement in pill form, while others may add it to foods, such as protein drinks.

Researchers have not established a daily recommended intake or a suggested upper limit for GABA. Anyone wanting to take GABA as a supplement should consider talking to their doctor first.

At present, there is not enough research to evaluate the possible side effects of taking GABA supplements. However, if a person does experience side effects that might be GABA-related, they should discontinue the use of the supplement and contact their doctor.

Benefits of taking GABA supplements

Some researchers have voiced concerns about the supposed positive benefits of taking GABA supplements. An article in the journal Frontiers in Psychology notes that experts remain unclear whether GABA offers real benefits or whether the effects that people report experiencing are a placebo response.

Other researchers do not believe that GABA supplements cross the blood-brain barrier, which they would have to do to have any effect on the body.

However, some studies report positive effects from taking GABA supplements. These include:

Enhanced thinking and task performance abilities

study from 2015 found that taking 800 milligrams (mg) of GABA supplementation per day enhanced a person’s ability to prioritize and plan actions. Although the study was small, involving just 30 healthy volunteers, it showed how GABA supplementation might promote enhanced thinking.

Stress reduction

An older study from 2012 found that taking 100 mg of GABA daily helped reduce stress due to mental tasks. Like many other studies related to GABA, the study was small and involved just 63 participants.

Workout recovery and muscle building

a man and a woman working out together outside.

GABA supplements may improve workout recovery and muscle building.

The participants performed the same resistance training exercises twice a week, and the researchers measured the results. The researchers found that the combination of whey protein and GABA increased levels of growth hormone compared to whey protein alone.

Although this was another small study, the researchers concluded that GABA supplements might help to build muscle and assist in workout recovery. They recommended that researchers conduct more studies.

Summary

GABA naturally plays an essential role in promoting sleep, relieving anxiety, and protecting the brain.

Scientists have not been able to prove the positive effects of GABA supplementation on a large scale, and their use may have limited effectiveness.

If a person has received a diagnosis for conditions such as depression, anxiety, or attention deficit hyperactivity disorder, they may wish to talk to their doctor about medically-proven treatment before taking GABA supplements.

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[ARTICLE] Follow-up after 5.5 years of treatment with methylphenidate for mental fatigue and cognitive function after a mild traumatic brain injury – Full Text

Objective: Prolonged mental fatigue and cognitive impairments are common after a mild traumatic brain injury (TBI). This sets limits for rehabilitation and for regaining the capacity for work and participation in social life.

Method: This follow-up study, over a period of approximately 5.5 years was designed to evaluate the effect and safety of methylphenidate treatment for mental fatigue after a mild TBI. A comparison was made between those who had continued, and those who had discontinued the treatment. The effect was also evaluated after a four-week treatment break.

Results: Significant improvement in mental fatigue, depression, and anxiety for the group treated with methylphenidate (p < .001) was found, while no significant change was found for the group without methylphenidate. The methylphenidate treatment group also improved their processing speed (p = .008). Withdrawal produced a pronounced and significant deterioration in mental fatigue, depression, and anxiety and a slower processing speed. This indicates that the methylphenidate effect is reversible if discontinued and that continued methylphenidate treatment can be a prerequisite for long-term improvement. The effect was found to be stable and safe over the years.

Conclusion: We suggest methylphenidate to be a possible treatment option for patients with post-TBI symptoms including mental fatigue and cognitive symptoms.

Introduction

Long-term mental fatigue and cognitive impairment are common after a mild, moderate or severe traumatic brain injury (TBI) and these can have a significant impact on work, well-being and quality of life (1). Fatigue and concentration deficits are acknowledged as being one of the most distressing and long-lasting symptoms following mild TBI (1). There is currently no approved treatment (2), although the most widely used research drug for cognitive impairments after TBI is methylphenidate (3). A few studies have used methylphenidate for mental fatigue after TBI with promising results including our own (4,5). Other clinical trials of drugs have reported improvements in mental fatigue ((−)-osu6162 (6)) or none ((−)-osu616, modafinil (79)).

In our feasibility study of methylphenidate (not placebo controlled) we reported decreased mental fatigue, improved processing speed and enhanced well-being with a “normal” dose of methylphenidate compared to no methylphenidate for people suffering from post-traumatic brain injury symptoms (4). We tested methylphenidate in two different dosages and found that the higher dose (20 mg three times/day) had the better effect compared to the lower dose. We also found methylphenidate to be well tolerated by 80% of the participants. Adverse events were reported as mild and the most commonly reported side-effects included restlessness, anxiety, headache, and increased heart rate; no dependence or misuse were detected (10). However, a careful monitoring for adverse effects is needed, as many patients with TBI are sensitive to psychotropic medications (11).

Participants who experienced a positive effect with methylphenidate were allowed to continue the treatment. We have reported the long-term positive effects on mental fatigue and processing speed after 6 months (12) and 2 years (13). No serious adverse events were reported (13)(Figure 1). In a 30-week double-blind-randomized placebo-controlled trial, Zhang et al. reported that methylphenidate decreased mental fatigue and improved cognitive function in the participants who had suffered a TBI. Moreover, social and rehabilitation capacity and well-being were improved (5). Other studies evaluating methylphenidate treatment after TBI have focused only on cognitive function reporting improved cognitive function with faster information processing speed and enhanced working memory and attention span (1421). A single dose of methylphenidate improved cognitive function and brain functionality compared to placebo in participants suffering from post-TBI symptoms (22,23). Most of these have been short-term studies covering a period between 1 day and 6 weeks and included participants suffering from mild or more severe brain injuries.

This clinical follow-up study was designed to evaluate the long-term effect and safety of methylphenidate treatment. We also evaluated the effect after a four-week treatment break and compared the subjective and objective effects with and without methylphenidate. Patients who had discontinued methylphenidate during this long-term study were also included in this follow-up, as it was our intention to compare the long-term effects on mental fatigue in patients with and without methylphenidate treatment.

[…]

 

Continue —->  Follow-up after 5.5 years of treatment with methylphenidate for mental fatigue and cognitive function after a mild traumatic brain injury: Brain Injury: Vol 0, No 0

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[NEWS] Botox is Now Approved for Lower-Limb Spasticity in Children

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FDAapprovedAAA1

The US Food and Drug Administration (FDA) has approved onabotulinumtoxinA (Botox, Allergan) to ease lower-limb spasticity in children and adolescents aged 2 years to 17 years, excluding spasticity caused by cerebral palsy (CP), Allergan announces.

“Lower limb spasticity can impact many aspects of a child’s life and have a drastic influence on their overall development and quality of life,” David Nicholson, Allergan’s chief research and development officer, says in a news release.

The FDA approved Botox for lower-limb spasticity on the basis of safety and efficacy data from a phase 3 study involving more than 300 children aged 2 years or older with lower-limb spasticity.

Participants in the trial had CP, but the approved indication excludes lower-limb spasticity caused by CP, owing to marketing exclusivity by another company, according to Allergan.

The approved recommended dose per treatment session is 4 to 8 units/kg divided among affected muscles of the lower limb. The total dose for pediatric patients should not exceed 8 units/kg body weight, or 300 units, whichever is lower.

When treating both lower limbs or upper and lower limbs in combination, the total dose for pediatric patients should not exceed 10 units/kg, or 340 units, whichever is lower, in a 3-month interval, the company states.

“Pediatric lower limb spasticity inhibits normal muscular movement and function and can result in delayed or impaired motor development, as well as difficulty with posture and positioning,” Mark Gormley, Jr, MD, of Gillette Children’s Specialty Healthcare–St. Paul, comments, in the release.

“Botox has a well-established safety and efficacy profile, and supports children and adolescents successfully manage both their upper and lower limb spasticity,” said Gormley.

Botox was approved for pediatric upper-limb spasticity in June.

[Source: Medscape]

 

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[WEB PAGE] Dysport is Now Approved for Upper Limb Spasticity as Well

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The United States Food and Drug Administration (FDA) has expanded the use of Dysport (abobotulinumtoxinA) for injection to include the treatment of upper limb spasticity in children two years of age and older, excluding spasticity caused by cerebral palsy (CP), Ipsen Biopharmaceuticals, an affiliate of Ipsen, announces in a news release.

This approval makes Dysport the first botulinum toxin approved by the FDA for both pediatric spasticity indications, following the previous approval to treat children with lower limb spasticity aged two and older received in July 2016.

“For physicians, it is reassuring to have a botulinum toxin treatment in Dysport which demonstrated sustained symptom relief for spasticity, which can be physically challenging for children,” says Ann Tilton, MD, study investigator and Professor of Clinical Neurology at the Louisiana State University Health Sciences Center New Orleans, in the release.

“This FDA decision for Dysport means we now have an approved therapy to offer children and adolescents seeking improvements in mobility in both upper and lower limbs.”

The approval is based on a Phase 3 study with children aged two to 17 years old being treated for upper limb spasticity. Due to Orphan Drug Exclusivity, this approval excludes use in children with upper limb spasticity caused by CP. Dysport demonstrated statistically significant improvements from baseline at Week 6 with doses of 8 Units/kg and 16 Units/kg vs. 2 Units/kg, as measured by the Modified Ashworth Scale (MAS) in the elbow or wrist flexors.

Dysport demonstrated a reduction in spasticity symptoms through 12 weeks for most children for both upper and lower limbs. In the upper limb study, a majority of patients were retreated between 16-28 weeks; however, some patients had a longer duration of response (ie, 34 weeks or more). The most frequent adverse reactions observed were upper respiratory tract infection and pharyngitis, the release explains.

“This approval is a testament to Ipsen’s legacy in neurotoxin research and continued commitment to advancing patient care,” states Kimberly Baldwin, Vice President, Franchise Head, Neuroscience Business Unit, Ipsen. “We believe the data for both pediatric upper and lower limb spasticity underscore the role of Dysport as an important treatment option for patients seeking long-lasting spasticity symptom relief.”

For more information, visit Ipsen.

[Source(s): Ipsen, Business Wire]

 

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[BLOG POST] Benefits Of Magnesium For Traumatic Brain Injury treatment

magnesium tabletMagnesium is a vital nutrient that the human body requires in order to function healthily. It’s important for a range of bodily processes, including regulating nerve functions, blood sugar levels, blood pressure, and making protein, bone, and DNA. It’s one of the 24 essential vitamins and minerals critical for a healthy body.

Magnesium cannot be produced by the body itself – in other words, it needs to be sourced elsewhere, such as from food or supplements. The levels of magnesium needed for each person varies on gender, age and size. However, when a Traumatic Brain Injury occurs, magnesium becomes a nutrient you should strive for with its many mental and physical health benefits.

Many ordinary people today use Magnesium supplements to help with their energy, flexibility, muscle strength, and even sleep or stress management. In particular, people who have a love for fitness or sports take regular Magnesium tablets to assist with recovery and performance.

 

So, what could it do for TBI?

Magnesium For TBI
Following a traumatic brain injury, the side effects of anxiety, stress, brain swelling, cramping and tightening of muscles, stiff muscles, and insomnia are quite possible.

That’s where magnesium comes in to save the day.

Increase Flexibility, Decrease Tone, Reduce
Considering magnesium can assist with flexibility and loosening tight muscles, increasing your magnesium intake after a traumatic brain injury can likely help alleviate your stiff, cramped muscles.

Low magnesium levels can also cause a large build-up of lactic acid, which results in workout pain and tightness.

Taking magnesium for this particular problem allows your muscles to relax correctly before and after exercise.

 

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Stress & Anxiety
Magnesium can also help to control stress hormones. Serotonin, in particular, depends on magnesium for production.

This is responsible for relaxing your nervous system and encouraging positive moods, thus stabilizing you mentally.

Low magnesium levels are linked with anxiety behaviours and heightened stress – all the more reason to ensure you are taking in adequate amounts after your injury.

Brain Swelling
Magnesium is an anti-inflammatory, and as such, it can help to reduce brain swelling from a traumatic brain injury.

It increases cardiac output and cerebral blood flow. When the body has appropriate levels of it circulating throughout the body, people can experience improved neurological and cognitive outcomes.

It has also shown to possibly reduce pain intensity and headache severity.

Insomnia
Serotonin also helps encourage a good night sleep. Low magnesium levels can affect the sleep-regulating hormone melatonin, too.

Insomnia is indeed a common symptom of magnesium deficiency seen in many people today. They experience restless sleep and constant waking during the night, which leads to unhealthy sleep.

By maintaining the correct magnesium levels, people can enjoy deep, undisturbed sleep. Along with the melatonin, magnesium plays a role in maintaining healthy levels of “GABA” which is a neurotransmitter that promotes optimal sleep quality.

How To Take Magnesium

Magnesium can be taken in the form of a tablet supplement, but there are many magnesium-rich foods that can be incorporated into your daily diet, as well.

Try this list of power foods to hit your daily magnesium intake.

Dark leafy green vegetables
Flax seeds and pumpkin seeds
Almonds
Seaweed
Brown rice
Avocado’s
Walnuts, cashews, pecans

 

Other Sources of Magnesium

Magnesium Cream: Magnesium cream delivers the nutrients full spectrum of benefits, soothes muscle tension and increases flexibility in the applied area.

Magnesium Oil: Magnesium oil is  a no mess, easy-to-absorb, form of magnesium that may be able to raise levels of this nutrient within the body when applied topically to the skin.

 

In Conclusion

Ensuring that you have optimal levels of magnesium is the first step towards a healthy recovery following TBI.

It will help your muscles improve in flexibility, reduce pain, balance hormone levels, encourage positive moods, and sleep more soundly.

via Benefits Of Magnesium For Traumatic Brain Injury – treatment

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[ARTICLE] Therapeutic Potential of Neurotrophins for Repair After Brain Injury: A Helping Hand From Biomaterials – Full Text

Stroke remains the leading cause of long-term disability with limited options available to aid in recovery. Significant effort has been made to try and minimize neuronal damage following stroke with use of neuroprotective agents, however, these treatments have yet to show clinical efficacy. Regenerative interventions have since become of huge interest as they provide the potential to restore damaged neural tissue without being limited by a narrow therapeutic window. Neurotrophins, such as brain-derived neurotrophic factor (BDNF), and their high affinity receptors are actively produced throughout the brain and are involved in regulating neuronal activity and normal day-to-day function. Furthermore, neurotrophins are known to play a significant role in both protection and recovery of function following neurodegenerative diseases such as stroke and traumatic brain injury (TBI). Unfortunately, exogenous administration of these neurotrophins is limited by a lack of blood-brain-barrier (BBB) permeability, poor half-life, and rapid degradation. Therefore, we have focused this review on approaches that provide a direct and sustained neurotrophic support using pharmacological therapies and mimetics, physical activity, and potential drug delivery systems, including discussion around advantages and limitations for use of each of these systems. Finally, we discuss future directions of biomaterial drug-delivery systems, including the incorporation of heparan sulfate (HS) in conjunction with neurotrophin-based interventions.

Introduction

Stroke consistently remains a leading cause of death and disability worldwide (Mozaffarian et al., 2015). While stroke preferentially affects older people, stroke can affect anyone of any age, race, or gender (Feigin et al., 2014). In addition, ethnic disparities are known to exist, for instance, New Zealand Māori, and Pacific Island populations experience a stroke at a much younger age than Europeans (Feigin et al., 2006). With the global population continuing to age, the number of people suffering from a stroke and subsequently living with a lasting disability is also expected to rise. As a result, there is an urgent and unmet need to find treatment options to aid in improving recovery of lost functions.

The central nervous system CNS has a limited capacity to regenerate, which is one of the main causes for why stroke patients recover poorly. In addition, there is a lack of spontaneous recovery seen after stroke, leading to a large personal, and societal burden (Mozaffarian et al., 2015). This burden has led research into investigating neural mechanisms of regeneration and repair, in the hope to restore and improve lost functions following stroke. Depending on the neuronal area affected by the stroke (i.e., motor, speech, or language centers), rehabilitation, mental practice, and music therapies have all been shown to increase the capacity to recover after a stroke (Johansson, 2011). However, in patients who have had a large stroke, rehabilitation is less effective in facilitating an improvement in functional recovery (Johansson, 2011).

Significant work has shown that exogenous administration of GFs can help facilitate the repair of injured CNS tissue via their ability to regulate neuronal growth and survival (Connor and Dragunow, 1998Sofroniew et al., 2001Berretta et al., 2014). In particular, BDNF has been highlighted as being a key regulator of rehabilitation-induced recovery after stroke (Ploughman et al., 20072009). Moreover, activity-driven increases in BDNF have also been shown to promote motor recovery after stroke (Fritsch et al., 2010Clarkson et al., 2011).

The regenerative capabilities of neurotrophin-mediated interventions have already been observed in preclinical models of neurodegenerative diseases. Specifically, systemic administration of BDNF, NGF, and NT-3 have been reported to enhance neurite outgrowth, neurogenesis, and functional recovery in rodent models of stroke (Grill et al., 1997Jakeman et al., 1998Ramer et al., 2000Winkler et al., 2000Schäbitz et al., 20042007). However, the translation of such treatments into a clinical setting has been challenged by poor BBB permeability, off-target effects on the PNS, and short half-life (Chan et al., 2017). Approximately 98 percent of all compounds targeting the CNS have failed to cross the BBB (Pardridge, 2005), creating a need for alternative approaches. As a novel solution to this issue, various biomaterials have been engineered to provide an effective, and sustained drug-delivery system to the injured brain. These systems allow stem cells and/or small drug molecules including neurotrophins to bypass the BBB (Aizawa et al., 2008) and be delivered directly to the site of injury.

Heparan sulfate, as the GAG cleaved from its protein backbone, is thought to provide a novel approach for the delivery of neurotrophins to the injured CNS. HS plays a critical role in coordinating GFs and mediating their biological potential (Xu and Esko, 2014). This highly sulfated biopolymer is ideally suited as a component of a biomaterial therapeutic for brain injury. It is chemically stable, physiologically tolerated, has a demonstrated long-term benefit to wound repair by tunable protein-interactions and has been demonstrated to tolerate the level of γ-irradiation treatment required to sterilize sufficiently medical-device-like materials (Smith et al., 2018). In addition, HS has demonstrated a remarkable propensity to stabilize short-lived GF’s in what appears to be a selective fashion (Wang et al., 2014Wijesinghe et al., 2017).

The effects of BDNF and other GFs have previously been investigated in various stroke models and have shown strong regenerative potential (Berretta et al., 2014). In general, BDNF is believed to have a beneficial effect on stroke recovery via several mechanisms: protection against acute ischemic injury (Schäbitz et al., 2007), increased angiogenesis (Kermani and Hempstead, 2007), neurogenesis (Schäbitz et al., 2007), and neural repair (Mamounas et al., 2000) as well as enhanced synaptic plasticity (Waterhouse and Xu, 2009Clarkson et al., 2011). Whilst the use of BDNF and other GFs to promote neuroprotection and minimize the spread of damage during the acute phase of injury has been extensively studied (Pardridge, 2005Wu, 2005Cai et al., 2014), this work will not be reviewed here. This review instead summarizes past experimental evidence that highlights how neurotrophins have shown potential as a delayed treatment option for aiding in repair and regeneration of neural tissue for stroke and other neurodegenerative diseases. In addition, we discuss novel biomaterial delivery systems that have been utilized to enhance the delivery of neurotrophins to the CNS, as utilizing such delivery systems have resulted in a further improvement in functional recovery when treatment is delayed by days to weeks post injury.

Stroke Pathophysiology and Mechanisms of Endogenous Repair

Stroke occurs when blood flow to the brain is either obstructed by an occlusion (ischemic) or following rupturing (hemorrhagic) of a cerebral blood vessel. Lack of oxygen and glucose, and a build-up of toxic by-products, cause the areas of the brain deprived of blood flow to undergo a chain of pathological events (ischemic cascade), ultimately leading to cell death, and loss of function associated with that region of the brain (Dirnagl et al., 1999). As time passes, a lack of reperfusion to the penumbra (regions surrounding the core infarct) results in further expansion until the stroke is fully formed. Whilst neuroprotective agents have shown preclinical success at restoring reperfusion and minimizing cellular damage, they are only effective when administered within the first few hours following stroke onset and have failed to translate into clinical use, with the exception of thrombolytic compounds (Moretti et al., 2015). As a result, much needed stroke research unraveling the mechanisms associated with neuroregeneration and repair in the days to weeks following a stroke have highlighted a number of targetable treatment options, some of which have already resulted in the establishment of clinical trials.

Whilst the CNS shows limited capacity for regeneration and repair, under pathological conditions such as stroke, axonal sprouting, endogenous neurogenesis, and spontaneous functional recovery appear to be enhanced (Carmichael et al., 2001Benowitz and Carmichael, 2010). In addition, Stroemer et al. (1995) reported that both GAP-43 and synaptophysin, two proteins involved with neurite growth and synaptogenesis; are upregulated throughout the neocortex 2 weeks following a focal infarct in rats. Further, these researchers show a positive correlation between improved locomotor function and stroke-induced elevations in GAP-43 and synaptophysin. It has since been established that enhancing neuronal connections throughout the ischemic brain via pharmacological interventions correlates with an improvement in functional motor recovery after stroke (Lee et al., 2004Overman et al., 2012Clarkson et al., 2013Cook et al., 2017).

Neurogenesis occurs continuously in two areas of the healthy adult CNS: the SVZ of the lateral ventricle, and the subgranular zone (SGZ) of the hippocampal dentate gyrus. In these areas, self-renewing multipotent cells known as NSPCs differentiate into both neuronal, and glial cells (Taupin, 2006). Under physiological conditions these NSPCs migrate to the dentate gyrus or olfactory bulb to replenish the continuously dying granule cells or olfactory neurons, respectively. Following acute injury to the CNS, these resident neural progenitors may also be induced in an attempt to replace damaged neurons (Zhang et al., 2005Greenberg, 2007). Supporting this notion, many animal models of stroke have reported the upregulation of SVZ and SGZ neurogenesis, peaking around 7–10 days post-stroke (Iwai et al., 20022003Parent et al., 2002Carmichael et al., 2005). Furthermore, stroke-induced local changes to the microvasculature has been found to attract neuroblasts generated within the SVZ and facilitate their migration to the ischemic boundary zone (peri-infarct), an area lying lateral to the stroke (Carmichael et al., 2005Yamashita et al., 2006Thored et al., 2007).

Interestingly, preclinical research indicates NSPCs offer the majority of their regenerative potential through bystander effects, specifically by providing a rich source of GFs to the injured tissue rather than contributing to structural reconstruction (Chen et al., 2000). Supporting this, preclinical work has shown that MSCs facilitate an improvement in functional recovery, even though they fail to differentiate into mature neurons or glia when grafted into the ischemic boundary zone of rats exposed to a MCAo (Chen et al., 2000). Moreover, at least a portion of the therapeutic potential of MSCs has been ascribed to their ability to enhance endogenous neurogenesis and protect newborn cells from deleterious environments (Yoo et al., 2008), both of which are mechanisms mediated by neurotrophin signaling pathways. Although explicit evidence directly linking enhanced neurogenesis and functional recovery is sparse, a direct causal relationship seems probable with almost all neuroregenerative agents that improve neurological function following stroke also potentiating neurogenesis (Zhang et al., 2001Wang et al., 2004Schäbitz et al., 2007Cook et al., 2017). Of note, HS has also been demonstrated to support the proliferation (without differentiation) of stem cells ex vivo (Dombrowski et al., 2009Wijesinghe et al., 2017).

In addition to changes in neurogenesis, angiogenesis and axonal sprouting, work over the past few years has highlighted a chronic imbalance in brain excitability following stroke (Clarkson, 2012). Specifically, stroke has been reported to weaken transcallosal inhibition from the ipsilesional hemisphere onto the intact, contralesional hemisphere (Murase et al., 2004Duque et al., 2005). This further exacerbates an increase in tonic GABAergic inhibition onto the stroked hemisphere, limiting its potential for cortical plasticity, and spontaneous recovery after stroke (Clarkson et al., 2010). Indeed, restoring neuronal excitability in the ipsilesional stroke hemisphere via increasing AMPA activity, and/or dampening tonic GABAergic inhibition has shown great promise to enhance recovery of lost function (Clarkson et al., 20102015Orfila et al., 2017). Whilst the above evidence collectively supports an intrinsic capability of the ischemic brain to regenerate and repair itself, it must be reiterated that these mechanisms alone are most often insufficient to cause a complete reversal of the functional impairment (Yamashita and Abe, 2012). Furthermore, age-related decreases in neurogenesis (Cooper-Kuhn et al., 2004Kernie and Parent, 2010) and angiogenesis (Sonntag et al., 1997) have been reported, making it even harder for endogenous repair mechanisms to overcome damage and promote recovery. Accordingly, regenerative interventions have begun to target the potentiation of these endogenous mechanisms to try and maximize functional recovery in animal models of stroke and other neurodegenerative conditions such as SCI and Alzheimer’s disease (Wang et al., 2004Piantino et al., 2006Schäbitz et al., 2007Weishaupt et al., 2014Choi et al., 2018). This has been demonstrated in the case of the endogenous stimulation of key GF’s by addition of HS on a biomaterial support to the wound site (Murali et al., 2013).

Neurotrophins for Repair and Regeneration

Neurotrophins are the predominant mediators of neuronal survival and regeneration throughout the CNS, making them of particular interest in neuroregenerative research. The neurotrophin family consists of several main GFs, including NGF, BDNF, and NT-3. All neurotrophins are initially synthesized as precursor proteins, known as pro-neurotrophins. These pro-neurotrophins can then be cleaved intracellularly by furin or proconvertases, or extracellularly by metalloproteases and plasmin, to form stable mature neurotrophins. Whilst mature neurotrophins selectively bind to their respective Trk to exert neurotrophic effects, pro-neurotrophins have been found to conduct somewhat opposing, pro-apoptotic effects through the p75NTR/sortilin receptor (see Figure 1: further information on neurotrophin signaling pathways can be found below; (Nykjaer et al., 2004Teng et al., 2005). This finding has left the scientific world moving away from the passive function of these pro-domains, and has brought a new level of complexity to the role and function of neurotrophin signaling in the CNS (Zanin et al., 2017).

Figure 1. Neurotrophin signaling through the p75NTR and Trk receptors. This diagram depicts the major intracellular signaling pathways associated through each neurotrophin receptor. Each Trk receptor isoform binds mature neurotrophins and acts through three predominant pathways. Activation of PLC-γ1 results in PKC-mediated promotion of synaptic plasticity. Activation of Ras initiates MAPK-mediated promotion of neuronal regeneration and growth. Activation of PI3-K results in activation of Akt and promotion of NF-κB-mediated cell survival. Each of these pathways are also known to regulate genetic transcription, further promoting pro-survival, and regenerative gene expression. The p75NTR receptor also regulates three main pathways. When a mature neurotrophin binds to an isolated p75NTR NF-κB-mediated cell survival is promoted. If the p75NTR is co-expressed with the sortilin receptor, pro-neurotrophins can bind, and cause activation of JNK-c-Jun mediated cell death and degeneration. A receptor complex consisting of Nogo, p75NTR, and Lingo1 can bind both pro- and mature-neurotrophins to alter neurite outgrowth in a RhoA-dependent manner. NGF, nerve growth factor; BDNF, brain-derived neurotrophic factor; NT-3, neurotrophin-3; Trk, tropomyosin receptor kinase; mNT, mature neurotrophin; ProNT, proneurotrophin; p75NTR, pan neurotrophin receptor 75; PLCy1, phospholipase C gamma one; PKC, protein kinase C; MAPK, mitogen-activated protein kinase; TFs, transcription factors; PI3-K, phosphoinositide 3-kinase; NF-kB, nuclear factor kappa-light-chain-enhancer of activated B cells; JNK, c-Jun N-terminal kinase

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Continue —> Frontiers | Therapeutic Potential of Neurotrophins for Repair After Brain Injury: A Helping Hand From Biomaterials | Neuroscience

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[WEB SITE] Nootropics: Types, safety, and risks of smart drugs

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Nootropics, or “smart drugs,” are a class of substances that can boost brain performance. They are sometimes called cognition enhancers or memory enhancing substances.

Prescription nootropics are medications that have stimulant effects. They can counteract the symptoms of medical conditions such as attention deficit hyperactivity disorder (ADHD), narcolepsy, or Alzheimer’s disease.

Nonprescription substances that can enhance brain performance or focus — such as caffeine and creatine — are also considered nootropics. They do not treat diseases but may have some effects on thinking, memory, or other mental functions.

This article looks at prescription and nonprescription smart drugs, including their uses, side effects, and safety warnings.

Prescription nootropics

a woman taking nootropics at her desk.

A person may take a nootropic to treat ADHD, narcolepsy, or dementia.

Prescription nootropics include:

  • modafinil (Provigil), a stimulant that addresses the sudden drowsiness of narcolepsy
  • Adderall, which contains amphetamines to treat ADHD
  • methylphenidate (Ritalin), a stimulant that can manage symptoms of narcolepsy and ADHD
  • memantine (Axura), which treats symptoms of Alzheimer’s disease

While these can be effective in treating specific medical conditions, a person should not take them without a prescription.

Like any prescription medications, they carry risks of side effects and interactions, and a person should only take them under a doctor’s care.

Common side effects of prescription nootropics include:

Some evidence suggests that people who use prescription nootropics to improve brain function have a higher risk of impulsive behaviors, such as risky sexual practices.

Healthcare providers should work closely with people taking prescription nootropics to manage any side effects and monitor their condition.

Over-the-counter nootropics

The term “nootropic” can also refer to natural or synthetic supplements that boost mental performance. The following sections discuss nootropics that do not require a prescription.

Caffeine

Many people consume beverages that contain caffeine, such as coffee or tea, because of their stimulant effects. Studies suggest that caffeine is safe for most people in moderate amounts.

Having a regular cup of coffee or tea may be a good way to boost mental focus. However, extreme amounts of caffeine may not be safe.

The Food and Drug Administration (FDA) recommend that people consume no more than 400 milligrams (mg) of caffeine a day. This is the amount in 4–5 cups of coffee.

Caffeine pills and powders can contain extremely high amounts of the stimulant. Taking them can lead to a caffeine overdose and even death, in rare cases.

Women who are pregnant or may become pregnant may need to limit or avoid caffeine intake. Studies have found that consuming 4 or more servings of caffeine a day is linked to a higher risk of pregnancy loss.

L-theanine

L-theanine is an amino acid that occurs in black and green teas. People can also take l-theanine supplements.

A 2016 review reported that l-theanine may increase alpha waves in the brain. Alpha waves may contribute to a relaxed yet alert mental state.

L-theanine may work well when paired with caffeine. Some evidence suggests that this combination helps boost cognitive performance and alertness. Anyone looking to consume l-theanine in tea should keep the FDA’s caffeine guidelines in mind.

There are no dosage guidelines for l-theanine, but many supplements recommend taking 100–400 mg per day.

Omega-3 fatty acids

person at desk holding omega 3 supplements in palm

Studies have shown that omega-3 fatty acids are important to fight against brain aging.

These polyunsaturated fats are found in fatty fish and fish oil supplements. This type of fat is important for brain health, and a person must get it from their diet.

Omega-3s help build membranes around the body’s cells, including the neurons. These fats are important for repairing and renewing brain cells.

A 2015 review found that omega-3 fatty acids protect against brain aging. Other research has concluded that omega-3s are important for brain and nervous system function.

However, a large analysis found “no benefit for cognitive function with omega‐3 [polyunsaturated fatty acids] supplementation among cognitively healthy older people.” The authors recommend further long term studies.

A person can get omega-3 supplements in various forms, including fish oil, krill oil, and algal oil.

These supplements carry a low risk of side effects when a person takes them as directed, but they may interact with medications that affect blood clotting. Ask a doctor before taking them.

Racetams

Racetams are synthetic compounds that can affect neurotransmitters in the brain. Some nootropic racetams include:

  • piracetam
  • pramiracetam
  • phenylpiracetam
  • aniracetam

A study conducted in rats suggests that piracetam may have neuroprotective effects.

One review states that “Some of the studies suggested there may be some benefit from piracetam, but, overall, the evidence is not consistent or positive enough to support its use for dementia or cognitive impairment.” Confirming this will require more research.

There is no set dosage for racetams, so a person should follow instructions and consult a healthcare provider. Overall, studies have no found adverse effects of taking racetams as directed.

Ginkgo biloba

Ginkgo biloba is a tree native to China, Japan, and Korea. Its leaves are available as an herbal supplement.

2016 study found that gingko biloba is “potentially beneficial” for improving brain function, but confirming this will require more research.

Ginkgo biloba may help with dementia symptoms, according to one review, which reported the effects occurring in people who took more than 200 mg per day for at least 5 months.

However, the review’s authors note that more research is needed. Also, with prescription nootropics available, ginkgo biloba may not be the most safe or effective option.

Panax ginseng

Panax ginseng is a perennial shrub that grows in China and parts of Siberia. People use its roots for medicinal purposes.

People should not confuse Panax ginseng with other types of ginseng, such as Siberian or American varieties. These are different plants with different uses.

2018 review reports that Panax ginseng may help prevent certain brain diseases, including Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. It also may help with brain recovery after a stroke.

Panax ginseng interacts with many medications, so consult a doctor before taking it. A typical dosage for mental function is 100–600 mg once or twice a day.

Rhodiola

Some evidence suggests that Rhodiola rosea L., also known as rhodiola or roseroot, can help with cognitive ability.

One review reported that rhodiola may have neuroprotective effects and may help treat neurodegenerative diseases.

Another review found that rhodiola helped regulate neurotransmitters in the brain, having a positive effect on mood.

Rhodiola capsules have varying strengths. Usually, a person takes a capsule once or twice daily.

Creatine

Creatine is an amino acid, which is a building block of protein. This supplement is popular among athletes because it may help improve exercise performance. It may also have some effects on mental ability.

A 2018 review found that taking creatine appears to help with short term memory and reasoning. Whether it helps the brain in other ways is unclear.

The International Society of Sports Nutrition report that creatine supplementation of up to 30 grams per day is safe for healthy people to take for 5 years.

Another 2018 review notes that there has been limited research into whether this supplement is safe and effective for adolescent athletes.

Do nootropics work?

Some small studies show that some nootropic supplements can affect the brain. But there is a lack of evidence from large, controlled studies to show that some of these supplements consistently work and are completely safe.

Because of the lack of research, experts cannot say with certainty that over-the-counter nootropics improve thinking or brain function — or that everyone can safely use them.

For example, one report on cognitive enhancers found that there is not enough evidence to indicate that they are safe and effective for healthy people. The researchers also point to ethical concerns.

However, there is evidence that omega-3 fatty acids can benefit the brain and overall health. In addition, caffeine can improve mental focus in the short term.

Notes on the safety of nootropics

doctor and patient in office discussing adrenal cancer

A person should talk to a doctor about any interactions supplements may have with existing medications.

Also, some supplements may not contain what their labels say. A study of rhodiola products, for example, found that some contain contaminants or other ingredients not listed on the label.

For this reason, it is important to only purchase supplements from reputable companies that undergo independent testing.

BUYING NOOTROPICSA prescription is necessary for some nootropics, such as Provigil and Adderall. Over-the-counter nootropics are available in some supermarkets and drug stores, or people can choose between brands online:

Not all of these supplements are recommended by healthcare providers and some may interact with medications. Always speak to a doctor before trying a supplement.

Summary

Many doctors agree that the best way to boost brain function is to get adequate sleep, exercise regularly, eat a healthy diet, and manage stress.

For people who want to boost their cognitive function, nootropic supplements may help, in some cases. Anyone interested in trying a nootropic should consult a healthcare professional about the best options.

 

via Nootropics: Types, safety, and risks of smart drugs

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