Creatine protects against excitoxicity in an in vitro model of neurodegeneration

Creatine supplementation increases postnatal growth and strength and prevents overexpression of pro-inflammatory interleukin 6 in the hippocampus in an experimental model of cerebral palsy

ABSTRACTObjectives: The aim of this study was thus to evaluate the effect of Cr supplementation on morphological changes and expression of pro-inflammatory cytokines in the hippocampus and on developmental parameters. Methods: Male Wistar rat pups were submitted to an experimental model of CP. Cr was administered via gavage from the 21st to the 28th postnatal day, and in water after the 28th, until the end of the experiment. Body weight (BW), food consumption (FC), muscle strength, and locomotion were evaluated. Expression of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) were assessed in the hippocampus by quantitative real-time polymerase chain reaction. Iba1 immunoreactivity was assessed by immunocytochemistry in the hippocampal hilus. Results: Experimental CP caused increased density and activation of microglial cells, and overexpression of IL-6. The rats with CP also presented abnormal BW development and impairment of strength and locomotion. Cr supplementation was able to reverse the overexpression of IL-6 in the hippocampus and mitigate the impairments observed in BW, strength, and locomotion. Discussion: Future studies should evaluate other neurobiological characteristics, including changes in neural precursor cells and other cytokines, both pro- and anti-inflammatory.

"Heads Up" for Creatine Supplementation and its Potential Applications for Brain Health and Function

There is emerging interest regarding the potential beneficial effects of creatine supplementation on indices of brain health and function. Creatine supplementation can increase brain creatine stores, which may help explain some of the positive effects on measures of cognition and memory, especially in aging adults or during times of metabolic stress (i.e., sleep deprivation). Furthermore, creatine has shown promise for improving health outcome measures associated with muscular dystrophy, traumatic brain injury (including concussions in children), depression, and anxiety. However, whether any sex- or age-related differences exist in regard to creatine and indices of brain health and function is relatively unknown. The purpose of this narrative review is to: (1) provide an up-to-date summary and discussion of the current body of research focusing on creatine and indices of brain health and function and (2) discuss possible sex- and age-related differences in response to creatine supplementation on brain bioenergetics, measures of brain health and function, and neurological diseases.

Smoking, tobacco dependence, and neurometabolites in the dorsal anterior cingulate cortex

Cigarette smoking has a major impact on global health and morbidity, and positron emission tomographic research has provided evidence for reduced inflammation in the human brain associated with cigarette smoking. Given the consequences of inflammatory dysfunction for health, the question of whether cigarette smoking affects neuroinflammation warrants further investigation. The goal of this project therefore was to validate and extend evidence of hypoinflammation related to smoking, and to examine the potential contribution of inflammation to clinical features of smoking. Using magnetic resonance spectroscopy, we measured levels of neurometabolites that are putative neuroinflammatory markers. N-acetyl compounds (N-acetylaspartate + N-acetylaspartylglutamate), glutamate, creatine, choline-compounds (phosphocholine + glycerophosphocholine), and myo-inositol, have all been linked to neuroinflammation, but they have not been examined as such with respect to smoking. We tested whether people who smoke cigarettes have brain levels of these metabolites consistent with decreased neuroinflammation, and whether clinical features of smoking are associated with levels of these metabolites. The dorsal anterior cingulate cortex was chosen as the region-of-interest because of previous evidence linking it to smoking and related states. Fifty-four adults who smoked daily maintained overnight smoking abstinence before testing and were compared with 37 nonsmoking participants. Among the smoking participants, we tested for associations of metabolite levels with tobacco dependence, smoking history, craving, and withdrawal. Levels of N-acetyl compounds and glutamate were higher, whereas levels of creatine and choline compounds were lower in the smoking group as compared with the nonsmoking group. In the smoking group, glutamate and creatine levels correlated negatively with tobacco dependence, and creatine correlated negatively with lifetime smoking, but none of the metabolite levels correlated with craving or withdrawal. The findings indicate a link between smoking and a hypoinflammatory state in the brain, specifically in the dorsal anterior cingulate cortex. Smoking may thereby increase vulnerability to infection and brain injury.

Creatine Activity as a Neuromodulator in the Central Nervous System

Creatine is a nutritional compound that potentially influences cognitive processing and neuroprotection. Recent evidence has demonstrated that similar to neurotransmitters, creatine is released in an excitotoxic and action potential-dependent manner and acts as a neuromodulator. Creatine deficiency syndromes are characterized by severe mental and developmental disorders. Studies have reported that brain creatine content could be enhanced with creatine supplementation. Nevertheless, there is still limited knowledge about the effects of creatine on the central nervous system. However, ample evidence has proved the neuroprotective effects of creatine on various mental aspects, such as cognition, memory skills, and spatial memory. The present review aimed to review available experimental data and clinical observations confirming creatine roles in the central transmission process. A systematic search in the literature was performed in PubMed, Scopus, Embase, Cochrane Library, Web of Science, and Google Scholar database using all available MeSH terms for Creatine, Phosphocreatine, Bioenergetics, Nervous system, Brain, Cognition, and Neuroprotection. Electronic database searches were combined and duplicates were removed. Here, first, creatine and its potential influence on cognitive health and performance were briefly reviewed. Next, the existing experimental and clinical evidence was specifically explored to understand how creatine could interact as a neurotransmitter in the nervous system. Studies have revealed that exogenous creatine supplementation decreases neuronal cell loss in experimental paradigms of neurological diseases. It was observed that creatine could interact with the N-methyl-D-aspartate receptor, Na+-K+-ATPase enzyme, GABAA receptor, serotonin 1A receptors, and presumably α1-adrenoceptor and play critical roles in the central transmission process which implies that creatine can be considered a neuromodulator.

Creatine supplementation to improve the peripheral and central inflammatory profile in cerebral palsy

This opinion paper presents a brief review on the potential use of Creatine (Cr) to improve the inflammatory profile in individuals with Cerebral Palsy (CP). CP is a condition that causes muscle atrophy followed by reduced strength and altered muscle tone. The prevalence of chronic diseases is higher in people with CP due to this, which are often associated with peripheral inflammation, but there are no studies that have evaluated central inflammation in this condition. Nevertheless, the anti-inflammatory action of Cr has already been observed in different types of studies. Thus, the use of experimental models of CP to evaluate the expression of the inflammatory markers, especially in the brain, as well as approaches to reduce the impairments already observed becomes essential. Results obtained in these preclinical studies may contribute to the quality of therapeutic strategies offered to children suffering from CP, the most common cause of chronic motor disability in childhood.

The role of nutrients in human neurodevelopment and their potential to prevent neurodevelopmental adversity

Nutritional deficits or excesses affect a huge proportion of pregnant women worldwide. Maternal nutrition has a significant influence on the fetal environment and can dramatically impact fetal brain development. This paper reviews current nutritional supplements that can be used to optimise fetal neurodevelopment and prevent neurodevelopmental morbidities, including folate, iodine, vitamin B12, iron, and vitamin D. Interestingly, while correcting nutritional deficits can prevent neurodevelopmental adversity, overcorrecting them can in some cases be detrimental, so care needs to be taken when recommending supplementation in pregnancy. The potential benefits of using nutrition to prevent neurodiversity is shown by promising nutraceuticals, sulforaphane and creatine, both currently under investigation. They have the potential to promote improved neurodevelopmental outcomes through mitigation of pathological processes, including hypoxia, inflammation, and oxidative stress. Neurodevelopment is a complex process and whilst the role of micronutrients and macronutrients on the developing fetal brain is not completely understood, this review highlights the key findings thus far.

Decision tree distinguish affective disorder diagnosis from psychotic disorder diagnosis with clinical and lab factors

Background

Affective symptoms usually occur at the same time of psychotic symptoms. An effective predictive method would help the differential diagnosis at an early stage of the mental disorder. The purpose of the study was to establish a predictive model by using laboratory indexes and clinical factors to improve the diagnostic accuracy.

Methods

Subjects were patients diagnosed with psychiatric disorders with affective and/or psychotic symptoms. Two patient samples were collected in the study (n = 309) With three classification methods (logistic regression, decision tree, and discriminant analysis), we established the models and verified the models.

Results

Seven predictors were found to be significant to distinguish the affective disorder diagnosis from the psychotic disorder diagnosis in all three methods, the 7 factors were Activities of daily living, direct bilirubin, apolipoproteinA1, lactic dehydrogenase, creatinine, monocyte count and interleukin-8. The decision tree outperformed the other 2 methods in area under the receiver operating characteristic curve, and also had the highest percentage of correctly classification.

Conclusion

We established a predictive model that included activities of daily living, biochemical, and immune indicators. In addition, the model established by the decision tree method had the highest predictive power, which provided a reliable basis for future clinical work. Our work would help make diagnosis more accurate at an early stage of the disorder.

A longitudinal investigation of GABA, glutamate, and glutamine across the insula during antipsychotic treatment of first-episode schizophrenia

Individuals with first-episode schizophrenia (FES) typically present with acute psychotic symptoms. Though antipsychotic drugs are the mainstay for treatment, the neurobiology underlying successful treatment remains largely elusive. Recent evidence from functional connectivity studies highlights the insula as a key structure in the neural mechanism of response. However, molecular contributions to response across insular regions remain largely unknown. We used 7-Tesla magnetic resonance spectroscopic imaging (MRSI) to measure glutamate (Glu), Glutamine (Gln), and GABA from anterior and posterior regions of the insula across antipsychotic treatment. A total of 36 participants were examined, including 15 individuals with FES and moderate to severe psychosis who were scanned at two time points, while starting and after 6 weeks of antipsychotic treatment. Symptoms were carefully monitored across the study period to characterize treatment response. GABA, Glu, and Gln levels were calculated relative to creatine in anterior and posterior insular regions, bilaterally. In relation to psychotic symptom reduction, we observed a significant increase in Glu across all insular regions with (p < 0.001), but no corresponding changes in Gln or GABA. In group analyses, the FES cohort showed lower levels of Glu (p < 0.001) and GABA (p = 0.02) at baseline. Finally, in exploratory analyses, treatment remitters demonstrated a normalization of lower insular Glu levels across treatment, unlike non-remitters. Overall, these findings contribute to our understating of molecular changes associated with antipsychotic response and demonstrate abnormalities specific to the insula in FES.

Immunomodulatory protein from ganoderma microsporum protects against oxidative damages and cognitive impairments after traumatic brain injury

A traumatic brain injury (TBI) causes abnormal proliferation of neuroglial cells, and over-release of glutamate induces oxidative stress and inflammation and leads to neuronal death, memory deficits, and even death if the condition is severe. There is currently no effective treatment for TBI. Recent interests have focused on the benefits of supplements or natural products like Ganoderma. Studies have indicated that immunomodulatory protein from Ganoderma microsporum (GMI) inhibits oxidative stress in lung cancer cells A549 and induces cancer cell death by causing intracellular autophagy. However, no evidence has shown the application of GMI on TBI. Thus, this study addressed whether GMI could be used to prevent or treat TBI through its anti-inflammation and antioxidative effects. We used glutamate-induced excitotoxicity as in vitro model and penetrating brain injury as in vivo model of TBI. We found that GMI inhibits the generation of intracellular reactive oxygen species and reduces neuronal death in cortical neurons against glutamate excitotoxicity. In neurite injury assay, GMI promotes neurite regeneration, the length of the regenerated neurite was even longer than that of the control group. The animal data show that GMI alleviates TBI-induced spatial memory deficits, expedites the restoration of the injured areas, induces the secretion of brain-derived neurotrophic factors, increases the superoxide dismutase 1 (SOD-1) and lowers the astroglial proliferation. It is the first paper to apply GMI to brain-injured diseases and confirms that GMI reduces oxidative stress caused by TBI and improves neurocognitive function. Moreover, the effects show that prevention is better than treatment. Thus, this study provides a potential treatment in naturopathy against TBI.

Effects of Creatine Supplementation on Brain Function and Health

While the vast majority of research involving creatine supplementation has focused on skeletal muscle, there is a small body of accumulating research that has focused on creatine and the brain. Preliminary studies indicate that creatine supplementation (and guanidinoacetic acid; GAA) has the ability to increase brain creatine content in humans. Furthermore, creatine has shown some promise for attenuating symptoms of concussion, mild traumatic brain injury and depression but its effect on neurodegenerative diseases appears to be lacking. The purpose of this narrative review is to summarize the current body of research pertaining to creatine supplementation on total creatine and phophorylcreatine (PCr) content, explore GAA as an alternative or adjunct to creatine supplementation on brain creatine uptake, assess the impact of creatine on cognition with a focus on sleep deprivation, discuss the effects of creatine supplementation on a variety of neurological and mental health conditions, and outline recent advances on creatine supplementation as a neuroprotective supplement following traumatic brain injury or concussion.

Creatine Metabolism in Female Reproduction, Pregnancy and Newborn Health

Creatine metabolism is an important component of cellular energy homeostasis. Via the creatine kinase circuit, creatine derived from our diet or synthesized endogenously provides spatial and temporal maintenance of intracellular adenosine triphosphate (ATP) production; this is particularly important for cells with high or fluctuating energy demands. The use of this circuit by tissues within the female reproductive system, as well as the placenta and the developing fetus during pregnancy is apparent throughout the literature, with some studies linking perturbations in creatine metabolism to reduced fertility and poor pregnancy outcomes. Maternal dietary creatine supplementation during pregnancy as a safeguard against hypoxia-induced perinatal injury, particularly that of the brain, has also been widely studied in pre-clinical in vitro and small animal models. However, there is still no consensus on whether creatine is essential for successful reproduction. This review consolidates the available literature on creatine metabolism in female reproduction, pregnancy and the early neonatal period. Creatine metabolism is discussed in relation to cellular bioenergetics and de novo synthesis, as well as the potential to use dietary creatine in a reproductive setting. We highlight the apparent knowledge gaps and the research “road forward” to understand, and then utilize, creatine to improve reproductive health and perinatal outcomes.

High serum creatinine is associated with reduction of psychiatric symptoms in female patients with anti-NMDAR encephalitis

OBJECTIVE

Serum creatinine (SCR) has been shown to be associated with many neurodegenerative diseases. In this study, we investigated the relationship between SCR levels and the incidence of psychiatric symptoms in patients with anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis.

METHODS

The SCR levels were tested in 69 patients with anti-NMDAR encephalitis at admission. Clinical characteristics and blood and CSF parameters were compared between the group of patients with psychiatric symptoms (P + group) and the group of those without psychiatric symptoms (P- group). The association between SCR and the incidence of psychiatric symptoms was determined by multivariate-adjusted linear regression analyses.

RESULTS

The SCR levels in the P + group were significantly lower than those in the P- group (P < 0.001). In the female subgroup, the SCR levels in the P + group were significantly lower compared to the P- group (P < 0.001), whereas in the male subgroup, the SCR levels did not differ between the two groups (P = 0.084). Furthermore, the highest SCR tercile overall had a significantly lower incidence of psychiatric symptoms than the lowest tercile (P < 0.001), and a significant negative correlation between the SCR levels and the occurrence of psychiatric symptoms was observed (r = -0.392, P < 0.001). Multivariate logistic regression analysis showed that the association was independent after adjusting for age, cystatin C and the modified Rankin Scale (mRS) score (P = 0.001). A similar result was found in the female subgroup (P = 0.010), but not in the male subgroup (P = 0.225).

CONCLUSION

Our study indicated that the SCR level was negatively correlated with incidence of psychiatric symptoms in female patients, and higher SCR level could be a protective factor for psychiatric symptoms in female patients with anti-NMDAR encephalitis.

Metabolomic Responses to Manganese Dose in SH-SY5Y Human Neuroblastoma Cells

Manganese (Mn)-associated neurotoxicity has been well recognized. However, Mn is also an essential nutrient to maintain physiological function. Our previous study of human neuroblastoma SH-SY5Y cells showed that Mn treatment comparable to physiological and toxicological concentrations in human brain resulted in different mitochondrial responses, yet cellular metabolic responses associated with such different outcomes remain uncharacterized. Herein, SH-SY5Y cells were examined for metabolic responses discriminated by physiological and toxicological levels of Mn using high-resolution metabolomics (HRM). Before performing HRM, we examined Mn dose (from 0 to100 μM) and time effects on cell death. Although we did not observe any immediate cell death after 5 h exposure to any of the Mn concentrations assessed (0-100 μM), cell loss was present after a 24-h recovery period in cultures treated with Mn ≥ 50 μM. Exposure to Mn for 5 h resulted in a wide range of changes in cellular metabolism including amino acids (AA), neurotransmitters, energy, and fatty acids metabolism. Adaptive responses at 10 μM showed increases in neuroprotective AA metabolites (creatine, phosphocreatine, phosphoserine). A 5-h exposure to 100 µM Mn, a time before any cell death occurred, resulted in decreases in energy and fatty acid metabolites (hexose-1,6 bisphosphate, acyl carnitines). The results show that adjustments in AA metabolism occur in response to Mn that does not cause cell death while disruption in energy and fatty acid metabolism occur in response to Mn that results in subsequent cell death. The present study establishes utility for metabolomics analyses to discriminate adaptive and toxic molecular responses in a human in vitro cellular model that could be exploited in evaluation of Mn toxicity.

The possible beneficial effects of creatine for the management of depression

Depression, a highly prevalent neuropsychiatric disorder worldwide, causes a heavy burden for the society and is associated with suicide risk. The treatment of this disorder remains a challenge, since currently available antidepressants provide a slow and, often, incomplete response and cause several side effects that contribute to diminish the adhesion of patients to treatment. In this context, several nutraceuticals have been investigated regarding their possible beneficial effects for the management of this neuropsychiatric disorder. Creatine stands out as a supplement frequently used for ergogenic purpose, but it also is a neuroprotective compound with potential to treat or mitigate a broad range of central nervous systems diseases, including depression. This review presents preclinical and clinical evidence that creatine may exhibit antidepressant properties. The focus is given on the possible molecular mechanisms underlying its effects based on the results obtained with different animal models of depression. Finally, evidence obtained in animal models of depression addressing the possibility that creatine may produce rapid antidepressant effect, similar to ketamine, are also presented and discussed.

Production, characterization and toxicology assay of creatine pegylated nanoliposome with polysorbate 80 for brain delivery

Creatine acts intracellularly as energy buffer and storage, demonstrating protective effects in animal models of neurodegenerative diseases. However, its permeability throught blood-brain barrier (BBB) is reduced. The aim of the present study was developing a carrier to facilitate the delivery of creatine to the central nervous system. Creatine nanoliposomes were produced, characterized and assayed in models of toxicity in vitro and in vivo. Particles showed negative zeta potential (-12,5 mV), polydispersity index 0.237 and medium-size of 105 nm, which was confirmed by transmission electron microscopy (TEM) images. Toxicity assay in vitro was evaluated with blank liposomes (no drug) or creatine nanoliposomes at concentrations of 0.02 and 0.2 mg/mL, that did not influence the viability of Vero cells. The result. of the comet assay that the nanoliposomes are not genotoxic, togeher with cell viability demonstrated that the nanoliposomes are not toxic. Besides, in vivo assays not demonstrate toxicity in hematological and biochemical markers of young rats. Nevertheless, increase content of creatine in the cerebral cortex tissue after subchronic treatment was observed. Altogether, results indicate increase permeability of creatine to the BBB that could be used as assay for in vivo studies to confirm improved effect than free creatine.

Experimental and Clinical Strategies for Treating Spinocerebellar Ataxia Type 3

Spinocerebellar ataxia type 3 (SCA3), or Machado-Joseph disease (MJD), is an autosomal dominant neurodegenerative disorder caused by the expansion of a polyglutamine (polyQ) tract in the ataxin-3 protein. To date, there is no effective therapy available to prevent progression of this disease. However, clinical strategies for alleviating various symptoms are imperative to promote a better quality of life for SCA3/MJD patients. Furthermore, experimental therapeutic strategies, including gene silencing or mutant protein clearance, mutant polyQ protein modification, stabilizing the native protein conformation, rescue of cellular dysfunction and neuromodulation to slow the progression of SCA3/MJD, have been developed. In this study, based on the current knowledge, I detail the clinical and experimental therapeutic strategies for treating SCA3/MJD, paying particular attention to drug discovery.

Potential for use of creatine supplementation following mild traumatic brain injury

There is significant overlap between the neuropathology of mild traumatic brain injury (mTBI) and the cellular role of creatine, as well as evidence of neural creatine alterations after mTBI. Creatine supplementation has not been researched in mTBI, but shows some potential as a neuroprotective when administered prior to or after TBI. Consistent with creatine’s cellular role, supplementation reduced neuronal damage, protected against the effects of cellular energy crisis and improved cognitive and somatic symptoms. A variety of factors influencing the efficacy of creatine supplementation are highlighted, as well as avenues for future research into the potential of supplementation as an intervention for mTBI. In particular, the slow neural uptake of creatine may mean that greater effects are achieved by pre-emptive supplementation in at-risk groups.

Cardiac protection with phosphocreatine: a meta-analysis

Phosphocreatine (PCr) plays an important role in the energy metabolism of the heart and a decrease in its intracellular concentration results in alteration of myocardium energetics and work. We conducted a meta-analysis of all randomized and matched trials that compared PCr with placebo or standard treatment in patients with coronary artery disease or chronic heart failure or in those undergoing cardiac surgery. We systematically searched PubMed/Medline, Embase, Cochrane Central Register of Controlled Trials and Google Scholar up to 1 November 2015, for pertinent trials. The primary outcome was all-cause mortality. Secondary outcomes included inotrope use, ejection fraction (EF), peak creatinine kinase-myocardial band (CK-MB) release and the incidence of major arrhythmias, as well as spontaneous recovery of the heart performance in the subgroup of patients undergoing cardiac surgery with cardiopulmonary bypass. We pooled odds ratio (OR) and mean difference (MD) using fixed- and random effects models. We identified 41 controlled trials, of them 32 were randomized. Patients receiving PCr had lower all-cause mortality when compared with the control group [61/1731 (3.5%) vs 177/1667 (10.6%); OR: 0.71, 95% CI: 0.51-0.99; P = 0.04; I(2) = 0%; with 3400 patients and 22 trials included]. Phosphocreatine administration was associated with higher LVEF (MD: 3.82, 95% CI: 1.18-6.46; P = 0.005; I(2) = 98%), lower peak CK-MB release (MD: -6.08, 95% CI: -8.01, -4.15; P < 0.001; I(2) = 97%), lower rate of major arrhythmias (OR: 0.42; 95% CI: 0.27-0.66; P < 0.001; I(2) = 0%), lower incidence of inotropic support (OR: 0.39, 95% CI: 0.25-0.61; P < 0.001; I(2) = 56%) and a higher level of spontaneous recovery of the heart performance after cardiopulmonary bypass (OR: 3.49, 95% CI: 2.28-5.35; P < 0.001; I(2) = 49%) when compared with the control group. In a mixed population of patients with coronary artery disease, chronic heart failure or in those undergoing cardiac surgery, PCr may reduce all-cause short-term mortality. In addition, PCr administration was associated with improved cardiac outcomes. Owing to the pharmacological plausibility of this effect and to the concordance of the beneficial effects of PCr on several secondary but important outcomes and survival, there is urgent need for a large multicentre randomized trial to confirm these findings.

Creatine affords protection against glutamate-induced nitrosative and oxidative stress

Creatine has been reported to exert beneficial effects in several neurodegenerative diseases in which glutamatergic excitotoxicity and oxidative stress play an etiological role. The purpose of this study was to investigate the protective effects of creatine, as compared to the N-Methyl-d-Aspartate (NMDA) receptor antagonist dizocilpine (MK-801), against glutamate or hydrogen peroxide (H2O2)-induced injury in human neuroblastoma SH-SY5Y cells. Exposure of cells to glutamate (60-80 mM) or H2O2 (200-300 μM) for 24 h decreased cellular viability and increased dichlorofluorescein (DCF) fluorescence (indicative of increased reactive oxygen species, ROS) and nitric oxide (NO) production (assessed by mono-nitrogen oxides, NOx, levels). Creatine (1-10 mM) or MK-801 (0.1-10 μM) reduced glutamate- and H2O2-induced toxicity. The protective effect of creatine against glutamate-induced toxicity involves its antioxidant effect, since creatine, similar to MK-801, prevented the increase on DCF fluorescence induced by glutamate or H2O2. Furthermore, creatine or MK-801 blocked glutamate- and H2O2-induced increases in NOx levels. In another set of experiments, the repeated, but not acute, administration of creatine (300 mg/kg, po) in mice prevented the decreases on cellular viability and mitochondrial membrane potential (assessed by tetramethylrhodamine ethyl ester, TMRE, probe) of hippocampal slices incubated with glutamate (10 mM). Creatine concentration-dependent decreased the amount of nitrite formed in the reaction of oxygen with NO produced from sodium nitroprusside solution, suggesting that its protective effect against glutamate or H2O2-induced toxicity might be due to its scavenger activity. Overall, the results suggest that creatine may be useful as adjuvant therapy for neurodegenerative disease treatments.

Creatine for neuroprotection in neurodegenerative disease: end of story?

Creatine (Cr) is a natural compound that plays an important role in cellular energy homeostasis. In addition, it ameliorates oxidative stress, glutamatergic excitotoxicity, and apoptosis in vitro as well as in vivo. Since these pathomechanisms are implicated to play a role in several neurodegenerative diseases, Cr supplementation as a neuroprotective strategy has received a lot of attention with several positive animal studies in models of Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS). This has led to a number of randomized clinical trials (RCT) with oral Cr supplementation, with durations up to 5 years. In this paper, we review the evidence and consequences stemming from these trials. In the case of PD, the initial phase II RCT was promising and led to a large and well-designed phase III trial, which, however, turned out to be negative for all outcome measures. None of the RCTs that have examined effects of Cr in ALS patients showed any clinical benefit. In HD, Cr in high doses (up to 30 g/day) was shown to slow down brain atrophy in premanifest Huntingtin mutation carriers. In spite of this, proof is still lacking that Cr can also have beneficial clinical effects in this group of patients, who will go on to develop HD symptoms. Taken together, the use of Cr supplementation has so far proved disappointing in clinical studies with a number of symptomatic neurodegenerative diseases.

Diminution of Oxidative Damage to Human Erythrocytes and Lymphocytes by Creatine: Possible Role of Creatine in Blood

Creatine (Cr) is naturally produced in the body and stored in muscles where it is involved in energy generation. It is widely used, especially by athletes, as a staple supplement for improving physical performance. Recent reports have shown that Cr displays antioxidant activity which could explain its beneficial cellular effects. We have evaluated the ability of Cr to protect human erythrocytes and lymphocytes against oxidative damage. Erythrocytes were challenged with model oxidants, 2, 2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H₂O₂) in the presence and absence of Cr. Incubation of erythrocytes with oxidant alone increased hemolysis, methemoglobin levels, lipid peroxidation and protein carbonyl content. This was accompanied by decrease in glutathione levels. Antioxidant enzymes and antioxidant power of the cell were compromised while the activity of membrane bound enzyme was lowered. This suggests induction of oxidative stress in erythrocytes by AAPH and H₂O₂. However, Cr protected the erythrocytes by ameliorating the AAPH and H₂O₂ induced changes in these parameters. This protective effect was confirmed by electron microscopic analysis which showed that oxidant-induced cell damage was attenuated by Cr. No cellular alterations were induced by Cr alone even at 20 mM, the highest concentration used. Creatinine, a by-product of Cr metabolism, was also shown to exert protective effects, although it was slightly less effective than Cr. Human lymphocytes were similarly treated with H₂O₂ in absence and presence of different concentrations of Cr. Lymphocytes incubated with oxidant alone had alterations in various biochemical and antioxidant parameters including decrease in cell viability and induction of DNA damage. The presence of Cr attenuated all these H₂O₂-induced changes in lymphocytes. Thus, Cr can function as a blood antioxidant, protecting cells from oxidative damage, genotoxicity and can potentially increase their lifespan.

In vivo neurometabolic profiling in patients with spinocerebellar ataxia types 1, 2, 3, and 7

Spinocerebellar ataxias (SCAs) belong to polyglutamine repeat disorders and are characterized by a predominant atrophy of the cerebellum and the pons. Proton magnetic resonance spectroscopy ((1) H MRS) using an optimized semiadiabatic localization by adiabatic selective refocusing (semi-LASER) protocol was performed at 3 T to determine metabolite concentrations in the cerebellar vermis and pons of a cohort of patients with SCA1 (n=16), SCA2 (n=12), SCA3 (n=21), and SCA7 (n=12) and healthy controls (n=33). Compared with controls, patients displayed lower total N-acetylaspartate and, to a lesser extent, lower glutamate, reflecting neuronal loss/dysfunction, whereas the glial marker, myoinositol (myo-Ins), was elevated. Patients also showed higher total creatine as reported in Huntington's disease, another polyglutamine repeat disorder. A strong correlation was found between the Scale for the Assessment and Rating of Ataxia and the neurometabolites in both affected regions of patients. Principal component analyses confirmed that neuronal metabolites (total N-acetylaspartate and glutamate) were inversely correlated in the vermis and the pons to glial (myo-Ins) and energetic (total creatine) metabolites, as well as to disease severity (motor scales). Neurochemical plots with selected metabolites also allowed the separation of SCA2 and SCA3 from controls. The neurometabolic profiles detected in patients underlie cell-specific changes in neuronal and astrocytic compartments that cannot be assessed by other neuroimaging modalities. The inverse correlation between metabolites from these two compartments suggests a metabolic attempt to compensate for neuronal damage in SCAs. Because these biomarkers reflect dynamic aspects of cellular metabolism, they are good candidates for proof-of-concept therapeutic trials. © 2015 International Parkinson and Movement Disorder Society.

Inferring metabolic networks using the Bayesian adaptive graphical lasso with informative priors

Metabolic processes are essential for cellular function and survival. We are interested in inferring a metabolic network in activated microglia, a major neuroimmune cell in the brain responsible for the neuroinflammation associated with neurological diseases, based on a set of quantified metabolites. To achieve this, we apply the Bayesian adaptive graphical lasso with informative priors that incorporate known relationships between covariates. To encourage sparsity, the Bayesian graphical lasso places double exponential priors on the off-diagonal entries of the precision matrix. The Bayesian adaptive graphical lasso allows each double exponential prior to have a unique shrinkage parameter. These shrinkage parameters share a common gamma hyperprior. We extend this model to create an informative prior structure by formulating tailored hyperpriors on the shrinkage parameters. By choosing parameter values for each hyperprior that shift probability mass toward zero for nodes that are close together in a reference network, we encourage edges between covariates with known relationships. This approach can improve the reliability of network inference when the sample size is small relative to the number of parameters to be estimated. When applied to the data on activated microglia, the inferred network includes both known relationships and associations of potential interest for further investigation.