The Controversial Role of Homocysteine in Neurology: From Labs to Clinical Practice

Analysis of risk factors for the development of cognitive dysfunction in patients with cerebral small vessel disease and the construction of a predictive model

Background

Cognitive dysfunction in cerebral small vessel disease (CSVD) is a common cause of vascular dementia. The purpose of this study was to find independent risk factors for the development of cognitive dysfunction in patients with CSVD and establish a risk prediction model, in order to provide a reference for clinical diagnosis and treatment of such patients.

Methods

In this study, clinical data of patients with CSVD admitted to the Department of Neurology in Gansu Provincial Hospital from December 2019 to December 2021 were collected, and 159 patients were finally included after strict screening according to the inclusion and exclusion criteria. There were 43 patients with normal function and 116 patients with cerebral small vessel disease cognitive impairment (CSVDCI). The logistic multivariable regression model was used to screen out the independent risk factors of cognitive dysfunction in patients with CSVD, and the nomogram of cognitive dysfunction in patients with CSVD was constructed based on the results of the logistic multivariable regression analysis. Finally, the accuracy of the prediction model was evaluated by C-index, calibration curve, receiver operating characteristic (ROC) curve, and decision curve analysis (DCA).

Results

The results of multivariable logistic regression analysis showed that hypertension (OR = 2.683, 95% CI 1.119–6.432, P = 0.027), homocysteine (Hcy) (OR = 1.083, 95% CI 1.026–1.143, P = 0.004), total CSVD MRI Score (OR = 1.593, 95% CI 1.025–2.475, P = 0.039) and years of schooling (OR = 0.883, 95% CI 0.798–0.978, P = 0.017) were independent risk factors for the development of cognitive dysfunction in patients with CSVD. The C-index of this prediction model was 0.806 (95% CI 0.735–0.877), and the calibration curve, ROC curve, and DCA curve all showed good predictive power in the nomogram.

Conclusions

The nomogram constructed in this study has high accuracy and clinical utility in predicting the occurrence of cognitive dysfunction in patients with CSVD. For patients with CSVD with the above risk factors, active clinical intervention and prevention are required during clinical consultation and disease management to avoid cognitive impairment as much as possible.

Study of the value of homocysteine levels in predicting cognitive dysfunction in patients after acute carbon monoxide poisoning

PURPOSE

The purpose of this research was to assess the value of homocysteine (HCY) levels in predicting cognitive dysfunction in patients after acute carbon monoxide (CO) poisoning.

METHODS

A total of 115 patients who were admitted to the emergency department of Yinzhou NO. 2 Hospital after CO poisoning between January 2017 and December 2021 were enrolled in this retrospective study. All patients were followed up for 1 month. According to the Mini-Mental State Examination (MMSE) scores, patients were divided into two groups. The demographic and clinical characteristics and magnetic resonance imaging (MRI) results were gathered and statistically analysed.

RESULTS

Twenty-six and 89 patients were ultimately enrolled in the cognitive dysfunction and control groups, respectively. There were significant differences between the groups in terms of age, coma duration, and carboxyhaemoglobin (COHB), lactate and HCY levels (p < 0.05), but there were no significant differences in white blood cell (WBC) counts or aspartate transaminase (AST), alanine transaminase (ALT), creatinine, troponin T, creatinine kinase (CK), or creatinine kinase muscle and brain (CK-MB) levels (p > 0.05). Univariate and multivariate analyses identified that a higher HCY level (OR 2.979, 95% CI 1.851-5.596, p < 0.001) was an independent risk factor for patient cognitive dysfunction after acute CO poisoning. Linear regression analysis showed a negative correlation between MMSE scores and HCY levels (r = - 0.880, P < 0.001). According to the MRI results, the most common lesion site was the globus pallidus, and the central ovale, diffuse white matter, corona radiata, basal ganglia (other than the globus pallidus) and cerebral cortex were also involved.

CONCLUSIONS

Higher HCY levels were associated with cognitive impairment and were independent risk factors for cognitive impairment after acute CO poisoning. The level of HCY was negatively correlated with the degree of cognitive impairment.

Maternal Mental Health in Late Pregnancy and Longitudinal Changes in Postpartum Serum Vitamin B-12, Homocysteine, and Milk B-12 Concentration Among Brazilian Women

Background

Little is known regarding the association between mental health distress during pregnancy and postpartum maternal serum biomarkers of vitamin B-12 status and milk B-12 concentration.

Objective

To evaluate the association between depressive and anxiety symptoms in the third trimester of pregnancy and changes in postpartum serum B-12, homocysteine, and B-12 milk concentration.

Methods

A total of 101 women (18–40 years) were studied in a prospective cohort with data at the third trimester of pregnancy (baseline) and three postpartum time-points (TPs): 2–8 days (TP1), 28–50 days (TP2), and 88-119 days (TP3) postpartum. B-12 concentrations in milk were measured by competitive chemiluminescent enzyme immunoassay at TP1, TP2, and TP3. Serum B-12 and homocysteine concentrations were evaluated at baseline, TP1, TP2, and TP3 by chemiluminescent immunoassays. Depressive and anxiety symptoms were measured with the Edinburgh Postnatal Depression Scale and the State-Trait Anxiety Inventory at baseline. Spearman's correlation test and multiple linear mixed-effect models were performed.

Results

The prevalence of depressive and anxiety state symptoms was 35.6 and 39.6% at baseline. High prevalence of low milk B-12 concentration (<310 pmol/L) were observed at TP1 (53.2%), TP2 (71.4%), and TP3 (71.1%). Women with anxiety symptoms at baseline presented higher median concentrations of serum homocysteine at TP1 and lower concentrations of serum and milk B-12 at TP2 compared with women without anxiety symptoms [8 (7; 9) vs. 6 (5; 8) and 266 (188; 369) vs. 332 (272; 413)]. Milk B-12 concentrations were positively and significantly correlated with maternal serum B-12 concentrations at different TP. Women with anxiety symptoms at baseline exhibited a decrease in daily postpartum homocysteine concentrations compared to women without anxiety symptoms (β = −0.002, SE = 0.001, p = 0.024).

Conclusion

Anxiety symptoms at the end of pregnancy were associated with longitudinal changes in maternal serum homocysteine concentrations during the first 3 months postpartum.

Research Progress in Pharmacological Activities and Applications of Cardiotonic Steroids

Cardiotonic steroids (CTS) are a group of compounds existing in animals and plants. CTS are commonly referred to cardiac glycosides (CGs) which are composed of sugar residues, unsaturated lactone rings and steroid cores. Their traditional mechanism of action is to inhibit sodium-potassium ATPase to strengthen the heart and regulate heart rate, so it is currently widely used in the treatment of cardiovascular diseases such as heart failure and tachyarrhythmia. It is worth noticing that recent studies have found an avalanche of inestimable values of CTS applications in many fields such as anti-tumor, anti-virus, neuroprotection, and immune regulation through multi-molecular mechanisms. Thus, the pharmacological activities and applications of CTS have extensive prospects, which would provide a direction for new drug research and development. Here, we review the potential applications of CTS in cardiovascular system and other systems. We also provide suggestions for new clinical practical strategies of CTS, for many diseases. Four main themes will be discussed, in relation to the impact of CTS, on 1) tumors, 2) viral infections, 3) nervous system diseases and 4) immune-inflammation-related diseases.

Phloroglucinol, a clinical-used antispasmodic, inhibits amyloid aggregation and degrades the pre-formed amyloid proteins

Amyloid proteins, such as β-amyloid (Aβ) and α-synuclein (α-syn), could form neurotoxic aggregates during the progression of neurodegenerative disorders. Phloroglucinol, a clinical-used drug for treating spasmodic pain, was predicted to cross the blood brain-barrier and possesses neuroprotective potential. In this study, we have found, for the first time, that phloroglucinol inhibited the formation of amyloid aggregates, and degraded pre-formed amyloid aggregates with the similar efficacy as curcumin, a widely known amyloid aggregation inhibitor. Moreover, phloroglucinol decreased the seeding during aggregation process and inhibited the aggregation of Aβ_1-42 with homocysteine (Hcy) seeds. Molecular docking analysis further demonstrated hydrophobic interactions and hydrogen bonds between phloroglucinol and Aβ_1-42/α-syn. Furthermore, phloroglucinol inhibited amyloid aggregates-induced cytotoxicity in neuronal cells and prevented Aβ_1-42 + Hcy aggregates-induced cognitive impairments in mice. All these results suggested that phloroglucinol possesses the ability to degrade pre-formed amyloid aggregates, to inhibit the seeding during amyloid aggregation, and to reduce the neurotoxicity, indicating the reposition possibility of phloroglucinol as a novel drug for treating neurodegenerative disorders.

Serum pyridoxine, folate, cobalamin, and homocysteine levels in children presenting with vasovagal syncope

BACKGROUND

Recent studies confirm the role of B vitamins deficiency and hyperhomocysteinaemia in the development of dysautonomia that has been considered to be the main factor in vasovagal syncope development. The aim of the study was to investigate serum pyridoxine, folate, cobalamin, and homocysteine levels in children presenting with vasovagal syncope and to analyse the correlation between them and main clinical parameters of syncope.

METHODS

We studied 40 children, ages 8-17 years with a history of vasovagal syncope and 24 healthy volunteers. The serum pyridoxine, folate, cobalamin, and homocysteine levels were measured by a quantitative sandwich enzyme immunoassay technique using a commercial kit (Monobind, USA). Twenty-four-hour Holter monitoring and 24-hour ambulatory blood pressure monitoring were conducted for all participated patients.

RESULTS

Serum pyridoxine (9.42 ± 4.87, 16.11 ± 5.53 µg/L) and cobalamin (307.48 ± 95.50, 447.28 ± 108.85 ng/L) levels were reasonably low (p < 0.05) in patients with vasovagal syncope. Although there was no significant change in folate levels between syncope and healthy children (4.00 ± 1.34, 4.71 ± 1.73 µg/L; p = 0.20), we detected low folate-level association with longer duration of syncope (r = -0.42) and post syncope (r = -0.43) symptoms (p < 0.05). Finally, there was increased serum homocysteine level (13.55 ± 5.03, 7.81 ± 1.71 µmol/L; p < 0.05) in patients with vasovagal syncope. It was positively correlated with the average PQ interval (r = 0.35, p < 0.05) and average QTc interval (r = 0.49, p < 0.05).

CONCLUSIONS

The results suggested that pyridoxine, folate, cobalamin, and homocysteine may be involved in the pathogenesis of vasovagal syncope. This might provide a new approach for effective treatment of paediatric vasovagal syncope, requiring further study.

The Roles of Long-Term Hyperhomocysteinemia and Micronutrient Supplementation in the AppNL–G–F Model of Alzheimer’s Disease

A causal contribution of hyperhomocysteinemia to cognitive decline and Alzheimer’s disease (AD), as well as potential prevention or mitigation of the pathology by dietary intervention, have frequently been subjects of controversy. In the present in vivo study, we attempted to further elucidate the impact of elevated homocysteine (HCys) and homocysteic acid (HCA) levels, induced by dietary B-vitamin deficiency, and micronutrient supplementation on AD-like pathology, which was simulated using the amyloid-based App^NL–G–F knock-in mouse model. For this purpose, cognitive assessment was complemented by analyses of ex vivo parameters in whole blood, serum, CSF, and brain tissues from the mice. Furthermore, neurotoxicity of HCys and HCA was assessed in a separate in vitro assay. In confirmation of our previous study, older App^NL–G–F mice also exhibited subtle phenotypic impairment and extensive cerebral amyloidosis, whereas dietary manipulations did not result in significant effects. As revealed by proximity extension assay-based proteome analysis, the App^NL–G–F genotype led to an upregulation of AD-characteristic neuronal markers. Hyperhomocysteinemia, in contrast, indicated mainly vascular effects. Overall, since there was an absence of a distinct phenotype despite both a significant amyloid-β burden and serum HCys elevation, the results in this study did not corroborate the pathological role of amyloid-β according to the “amyloid hypothesis,” nor of hyperhomocysteinemia on cognitive performance. Nevertheless, this study aided in further characterizing the App^NL–G–F model and in elucidating the role of HCys in diverse biological processes. The idea of AD prevention with the investigated micronutrients, however, was not supported, at least in this mouse model of the disease.

Myeloneuropathy induced by recreational nitrous oxide use with variable exposure levels

BACKGROUND

Although several case series have described nitrous oxide-associated neurological disorders, a comprehensive assessment of exposure characteristics (e.g., time to onset, level of exposure) in substance abusers has not been performed. The aim of this study was to describe the onset patterns of recreational use of nitrous oxide-induced neurological disorders.

METHODS

All cases of neurological disorders related to nitrous oxide recreational use reported to the Hauts-de-France addictovigilance center between January 2019 and August 2020 were selected. Only cases requiring hospitalization with informative data to perform the nitrous oxide causality assessment were included.

RESULTS

A total of 20 cases from 5 hospitals were included. The male-to-female ratio was 6:1 and the median age was 19 years (range 16-34). The neurological presentation [myeloneuropathy 64% (7/11), sensorimotor neuropathy 36% (4/11)] included for all patients gait disorders due to proprioceptive ataxia and limb hypoesthesia. The median dose used per occasion was 100 cartridges (range 5-960; n=19). The median time from the start of nitrous oxide use to the onset of neurological symptoms was 6 months (range 0.7-54; n=16). The cumulative dose was significantly higher in patients with damage to all four limbs than in patients with lower limbs symptoms only (p=0.042).

CONCLUSIONS

A low intermittent exposure may be sufficient to cause neurological damage in some subjects, suggesting that, at the population level, there is no safe exposure to nitrous oxide in recreational settings. The severity of neurological impairment could increase once used at high doses and for prolonged durations of nitrous oxide.

Protein S-sulfhydration: Unraveling the prospective of hydrogen sulfide in the brain, vasculature and neurological manifestations

Hydrogen sulfide (H₂S) and hydrogen polysulfides (H₂S_n) are essential regulatory signaling molecules generated by the entire body, including the central nervous system. Researchers have focused on the classical H₂S signaling from the past several decades, whereas the last decade has shown the emergence of H₂S-induced protein S-sulfhydration signaling as a potential therapeutic approach. Cysteine S-persulfidation is a critical paradigm of post-translational modification in the process of H₂S signaling. Additionally, studies have shown the cross-relationship between S-sulfhydration and other cysteine-induced post-translational modifications, namely nitrosylation and carbonylation. In the central nervous system, S-sulfhydration is involved in the cytoprotection through various signaling pathways, viz. inflammatory response, oxidative stress, endoplasmic reticulum stress, atherosclerosis, thrombosis, and angiogenesis. Further, studies have demonstrated H₂S-induced S-sulfhydration in regulating different biological processes, such as mitochondrial integrity, calcium homeostasis, blood-brain permeability, cerebral blood flow, and long-term potentiation. Thus, protein S-sulfhydration becomes a crucial regulatory molecule in cerebrovascular and neurodegenerative diseases. Herein, we first described the generation of intracellular H₂S followed by the application of H₂S in the regulation of cerebral blood flow and blood-brain permeability. Further, we described the involvement of S-sulfhydration in different biological and cellular functions, such as inflammatory response, mitochondrial integrity, calcium imbalance, and oxidative stress. Moreover, we highlighted the importance of S-sulfhydration in cerebrovascular and neurodegenerative diseases.

Elevation of Plasma Homocysteine and Minor Hallucinations in Parkinson’s Disease: A Cross-Sectional Study

Purpose

Minor hallucinations (MHs) are the most common psychotic phenomena in Parkinson's disease (PD), and it has important clinical and prognostic implications in PD. Plasma homocysteine (Hcy) has been reported to predict the outcome of PD; whether or not Hcy is associated with MH is not known. We aim to investigate the Hcy level and related factors in patients with PD and MH.

Methods

We conducted a cross-sectional study and included 99 patients with PD, 34 with MH, and 65 without any hallucinations. The clinical and demographic data of the patients with and without hallucinations were compared. Hcy-related clinical factors were also analyzed.

Results

The plasma Hcy level was higher in MH patients than in patients without hallucinations, and the result was more pronounced in male patients than in female patients. Differences were also observed when the groups were divided on the basis of levodopa equivalent daily dose and disease duration. The high Hcy concentration was correlated with some symptoms in patients with MH, including motor dysfunction and nonmotor symptoms, such as symptoms of the gastrointestinal tract, angiocarpy, sleep/fatigue, and poor visuospatial/executive function.

Conclusions

Results indicated a higher plasma Hcy concentration in MH patients than in their counterparts and revealed that Hcy is associated with certain motor and nonmotor symptoms in patients with MH. Hcy may be a marker of MH and have important therapeutic implications in PD.

Hyperhomocysteinemia Increases Risk of Metabolic Syndrome and Cardiovascular Death in an Elderly Chinese Community Population of a 7-Year Follow-Up Study

Background

Hyperhomocysteinemia (HHcy) and abdominal obesity are risk factors for metabolic syndrome (MetS) and death from cardiovascular disease (CVD). Recent studies have shown a correlation between HHcy and abdominal obesity, suggesting that they may have a combined effect on the risk of MetS and CVD mortality. However, this suspicion remains to be confirmed, particularly in the elderly population. We explored their combined effects on the risk of MetS and CVD mortality among the community population aged 65 and above in China.

Methods and Results

This prospective study enrolled 3,675 Chinese community residents aged 65 and above in May 2013 with 7-year follow-up of all-cause and CVD mortality. HHcy was defined as the blood homocysteine (Hcy) level >15 μmol/L and abdominal obesity as waist circumference (WC) ≥90 cm for men and ≥80 cm for women (HWC). All participants were grouped into four categories by WC and the blood level of Hcy: NWC (normal WC) /HHcy(–), NWC/HHcy(+), HWC/HHcy(–), and HWC/HHcy(+). The relationship of combined HHcy and abdominal obesity with MetS and metabolic profile was evaluated by logistic regression analysis and the association of combined HHcy and abdominal obesity with CVD and all-cause mortality evaluated by Cox regression analysis. The prevalence of HHcy, abdominal obesity and MetS in elderly Chinese community residents was 40.1, 59.3, and 41.4%, respectively. Using group without HHcy and abdominal obesity [NWC/HHcy(–)] as reference, the participants of other three groups had significantly higher risk of MetS and its component abnormalities, with HWC/HHcy(+) group having the highest risk (OR = 13.52; 95% CI = 8.61–14.55). After a median of 6.94 (±1.48) years follow-up, 454 deaths occurred with 135 CVD deaths. Compared with NWC/HHcy(–) group, the risk of 7-year follow-up CVD mortality (HR = 1.75; 95% CI = 1.02–3.03) and all-cause mortality (HR = 1.23; 95% CI = 1.04–2.18) of HWC/HHcy(+) group increased considerably after adjustment for major MetS and CVD risk factors.

Conclusions

There is high prevalence of HHcy, abdominal obesity, and MetS in the elderly Chinese community population. HHcy increases risk of MetS, CVD, and all-cause mortality, especially in the populations with abdominal obesity.

Neuroprotective Effect of Riboflavin Producing Lactic Acid Bacteria in Parkinsonian Models

Oxidative stress and inflammatory processes might contribute to the cascade of events leading Parkinson disease (PD); and vitamins such as riboflavin can exert protection on vulnerable neurons in neurodegenerative conditions. Previously, it was demonstrated that a mixture of lactic acid bacteria (including a riboflavin-producing strain) improved motor skills in a parkinsonian model. The aim of the present work was to investigate the neuroprotective potential of Lactiplantibacillus (L.) plantarum CRL2130, a riboflavin-producing strain in PD models. In vitro, N2a differentiated neurons were exposed the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) and treated with intracellular bacterial extracts or commercial riboflavin. In vivo, adult male C57BL/6 mice were injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and probenecid, and received orally L. plantarum CRL2130, L. plantarum CRL725 (parent strain that produces low levels of riboflavin) or commercial vitamin. Results showed that when N2a cells were incubated with intracellular extract from L. plantarum CRL2130 maintained the viability, and significantly decreased the release of IL-6 and the formation of reactive oxygen species (ROS), all affected by MPP+. In vivo, the administration of L. plantarum CRL2130 attenuated motor deficits and prevented dopaminergic neuronal death. Decrease of pro-inflammatory cytokines and increase of IL-10 in both serum and brain were observed in samples from mice that received L. plantarum CRL2130 compared to MPTP control group (without treatment). In addition, these beneficial effects were similar or improved when compared with animals that received commercial riboflavin. In conclusion, L. plantarum CRL2130 showed a neuroprotective effect in both PD models through anti-oxidant/anti-inflammatory mechanisms.

Identification and Determination of 1,3-Thiazinane-4-carboxylic Acid in Human Urine-Chromatographic Studies

It is well established that homocysteine (Hcy) and its thiolactone (HTL) are reactive towards aldehydes in an aqueous environment, forming substituted thiazinane carboxylic acids. This report provides evidence that Hcy/HTL and formaldehyde (FA) adduct, namely 1,3-thiazinane-4-carboxylic acid (TCA) is formed in vivo in humans. In order to provide definitive proof, a gas chromatography-mass spectrometry (GC-MS) based method was elaborated to identify and quantify TCA in human urine. The GC-MS assay involves chemical derivatization with isobutyl chloroformate (IBCF) in the presence of pyridine as a catalyst, followed by an ethyl acetate extraction of the obtained isobutyl derivative of TCA (TCA-IBCF). The validity of the method has been demonstrated based upon United States Food and Drug Administration recommendations. The assay linearity was observed within a 1-50 µmol L-1 range for TCA in urine, while the lowest concentration on the calibration curve was recognized as the limit of quantification (LOQ). Importantly, the method was successfully applied to urine samples delivered by apparently healthy volunteers (n = 15). The GC-MS assay may provide a new analytical tool for routine clinical analysis of the role of TCA in living systems in the near future.

Causal effects of homocysteine levels on the components of sarcopenia: A two-sample mendelian randomization study

Background: Currently, it is unclear whether there is a causal association between genetically predicted plasma homocysteine (Hcy) levels and the risk of sarcopenia. We performed a Mendelian randomization (MR) study to assess the association between circulating Hcy levels and the components [grip strength, walking pace, and appendicular lean mass (ALM)] of sarcopenia. Methods: Independent single nucleotide polymorphisms (SNPs) significantly associated with plasma Hcy levels served as instrumental variables. Summary-level data regarding the components of sarcopenia. Were obtained from the UK Biobank. Inverse variance weighted (IVW) as the primary method was used for Mendelian randomization (MR) analysis. We also use four models, weighted median, MR-Egger regression, Maximum likelihood, and Penalised weighted median, as supplementary methods to IVW. The MR-Egger intercept test, Cochran's Q test, and "leave-one-out" sensitivity analysis were performed to evaluate the horizontal pleiotropy, heterogeneities, and stability of the causal association between Hcy levels and the components of sarcopenia. Results: The IVW-MR analysis suggested significant negative associations of increased plasma Hcy levels with grip strength (right: effect = -0.036, SE = 0.032, p = 5.53E-4; left: effect = -0.045, SE = 0.010, p = 1.45E-5), walking pace (effect = -0.038, SE = 0.011, p = 3.18E-4), and ALM (effect = -0.058, 0.013, p = 1.03E-5). However, there were no significant associations of decreased plasma Hcy levels with grip strength (right: effect = 0.005, SE = 0.021, p = 0.82; left: effect = -0.006, SE = 0.014, p = 0.64), walking pace (effect = 0.01, 0.020, p = 0.61), or ALM (effect = -0.034, SE = 0.018, p = 0.06).The accuracy and robustness of these findings were confirmed by sensitivity tests. Conclusion: Increased circulating Hcy levels were associated with lower grip strength, slower walking pace, and decreased ALM.

Insufficient S-Sulfhydration of Methylenetetrahydrofolate Reductase Contributes to the Progress of Hyperhomocysteinemia

Aims: Hyperhomocysteinemia (HHcy) has been considered as a risk factor for cardiovascular disease, Alzheimer's disease, nonalcoholic fatty liver, and many other pathological conditions. Vitamin B6, Vitamin B12, and folate have been used to treat HHcy in clinics. However, at present, clinical therapies of HHcy display unsatisfactory effects. Here, we would like to explore a new mechanism involved in homocysteine (Hcy) metabolic disorders and a novel target for HHcy treatment. The key enzymes involved in Hcy metabolism deserve more insightful investigation. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating the intracellular Hcy metabolism. Until now, the effect of post-translational modification on the bioactivity of MTHFR still remains unclear. This study aimed at exploring the relationship between MTHFR S-sulfhydration and its bioactivity, and at identifying the contribution of an elevated Hcy level on MTHFR bioactivity. Results: By both in vivo and in vitro studies, we observed the following results: (i) The bioactivity of MTHFR was positively associated with its S-sulfhydration level; (ii) MTHFR was modified at Cys32, Cys130, Cys131, Cys193, and Cys306 by S-sulfhydration under physiological conditions; (iii) Hydrogen sulfide (H₂S) deficiency caused the decrease of MTHFR S-sulfhydration level and bioactivity in HHcy, which resulted in further aggravation of HHcy; and (iv) H₂S donors reversed the decreased bioactivity of MTHFR in HHcy, thus reducing the excessive Hcy level. Innovation and Conclusion: Our study suggested that H₂S could improve MTHFR bioactivity by S-sulfhydration, which might provide a candidate therapeutic strategy for HHcy. Antioxid. Redox Signal. 36, 1-14.

Hyperhomocysteinemia and Dementia Associated With Severe Cortical Atrophy, but No Amyloid Burden

We report a case of a 77 years old patient who was admitted to our memory clinic because of progressive gait impairment and amnestic cognitive decline associated with extrapyramidal symptoms and behavioral changes. The clinical picture was consistent with a possible diagnosis of Alzheimer's Disease associated with parkinsonian symptoms or with a Parkinson Plus syndrome. After a complete investigation, she was found to have a high plasma level of homocysteine due to homozygous methylene-tetrahydrofolate reductase (MTHFR) gene C665 T polymorphism, cognitive and motor impairment were associated with a severe cortical atrophy and mild subcortical vascular disease. PET neuroimaging excluded a significant amyloid load. Clinically, she showed improvement of the movement disorder and functional status after folate integration plus levodopa and memantine administration. We concluded for a primary degenerative dementia with movement impairment associated with persistent hyperhomocysteinemia. We hypothesized that neurodegeneration is driven by mechanisms linked to homocysteine metabolism possibly associated with tauopathy.

The Correlations Between Serum Hcy Level and Seizures and Cognitive Function in Patients After Stroke

BACKGROUNDS

Post-stroke cognitive dysfunction (PSCI), a set of illnesses ranging from moderate cognitive impairment to dementia, which is one of the most prevalent consequences following a stroke. Homocysteine (Hcy) has been related to a number of neurological and systemic diseases. It's also a known risk factor for cardiovascular disease and systemic atherosclerosis (CVD). The link between Hcy and PSCI, on the other hand, is unknown.

METHODS

Our hospital evaluated 325 patients with acute cerebral infarction between January 1, 2018 and December 1, 2021. There are biological markers and baseline data available. Patients were divided into two groups based on the results of the Montreal Cognitive Assessment (MoCA). The researchers performed logistic regression analysis to find variables that may be linked to PSCI.

RESULTS

HCY levels were significantly higher in PSCI patients than in non-PSCI patients. Age, education, seizure manifestation, and income level were all shown to be independent risk variables for PSCI in a multivariate logistic analysis. Hcy levels in PSCI patients differed considerably between the high and low groups. The high and low Hcy levels groups had significantly varied hypertension histories and urine levels. Hcy levels in PSCI patients differed considerably between the high and low groups. The high and low Hcy levels groups had significantly varied hypertension histories and urine levels.

CONCLUSION

Serum Hcy levels have been linked to PSCI in post-stroke patients, and researchers believe that serum Hcy levels will diminish PSCI.

Individuals with Bipolar Disorder Have a Higher Level of Homocysteine Than Major Depressive Disorder: A Retrospective Chart Review and Observational Study

PURPOSE

Previous studies suggest that homocysteine (Hcy) may be involved in the pathogenesis of bipolar disorder (BD) and major depressive disorder (MDD) by influencing glutamatergic transmission, inflammation, and other mechanisms. There are no established biomarkers to distinguish BD from MDD. This study aims to compare Hcy levels between BD and MDD.

PATIENTS AND METHODS

We collected medical records of patients aged 14-75 admitted to the hospital from January 1 to July 1, 2022 with a discharge diagnosis of MDD or BD, including all examinations of patients at admission (acute phase) and discharge (non-acute phase). We measured Hcy levels in healthy controls (HC).

RESULTS

The analysis included 104 patients with MDD, 103 patients with BD, and 80 HC. Hcy levels were higher in the MDD and BD group than in the HC group and higher in the BD group than in the MDD group, both in the acute and non-acute phases (all P < 0.05). There was no significant difference in Hcy levels between the psychotropic medication users and non-users in the BD or MDD group (all P > 0.05). Multivariate logistic regression analysis only for the MDD and BD group indicated that the likelihood of BD diagnosis was significantly associated with Hcy levels (in the acute phase: OR = 1.052, P = 0.016; in the non-acute phase: OR = 1.101, P < 0.001) after controlling for gender, age, and metabolic indicators.

CONCLUSION

Our study suggests that Hcy levels were elevated in MDD and BD patients and were higher in BD patients than in MDD patients, which provides evidence for a possible relationship between one-carbon metabolism and the pathogenesis of BD. Besides, Hcy may be one of the potential biomarkers to distinguish BD from MDD.

Relationship between homocysteine levels and post-stroke cognitive impairment in female and male population: from a prospective multicenter study

Background and Objectives:

To investigate the relationship between homocysteine levels and post-stroke cognitive impairment (PSCI) in Chinese female and male populations with minor acute ischemic stroke or transient ischemic attack.

Materials and methods:

A total of 1070 participants with clinically confirmed acute minor ischemic stroke or transient ischemic attack and baseline homocysteine information from a nationwide multicenter prospective registry study in China were included in this study. Of these, 919 patients had cognitive assessments at 3-month follow-ups and 584 participants had cognitive assessments at 12-month follow-ups. The incidence of PSCI was defined as a Montreal Cognitive Assessment score ≤22. The differences in homocysteine levels and the incidence of PSCI were compared between female and male populations. Relationships between homocysteine levels and the incidence of PSCI in female and male populations were analyzed using multiple logistic regression, respectively.

Results:

Females had lower baseline homocysteine levels than males. Compared to males, females had lower education levels, lower rates of smoking and alcohol intake, and higher rates of diabetes and hypertension. No relationship was observed between elevated homocysteine level and 3-month PSCI incidence in either females or males. After adjusting the confounders, elevated baseline homocysteine significantly increased the 12-month PSCI risk (odds ratio 3.28, 95% confidence interval 1.47–7.34, P = 0.004) in females, but not in males (odds ratio 0.86, 95% confidence interval 0.49–1.49, P = 0.586).

Conclusion:

Elevated homocysteine levels increased the 12-month PSCI risk in females, but not in males with minor acute ischemic stroke or transient ischemic attack.

Hyperhomocysteinemia: Metabolic Role and Animal Studies with a Focus on Cognitive Performance and Decline-A Review

Disturbances in the one-carbon metabolism are often indicated by altered levels of the endogenous amino acid homocysteine (HCys), which is additionally discussed to causally contribute to diverse pathologies. In the first part of the present review, we profoundly and critically discuss the metabolic role and pathomechanisms of HCys, as well as its potential impact on different human disorders. The use of adequate animal models can aid in unravelling the complex pathological processes underlying the role of hyperhomocysteinemia (HHCys). Therefore, in the second part, we systematically searched PubMed/Medline for animal studies regarding HHCys and focused on the potential impact on cognitive performance and decline. The majority of reviewed studies reported a significant effect of HHCys on the investigated behavioral outcomes. Despite of persistent controversial discussions about equivocal findings, especially in clinical studies, the present evaluation of preclinical evidence indicates a causal link between HHCys and cognition-related- especially dementia-like disorders, and points out the further urge for large-scale, well-designed clinical studies in order to elucidate the normalization of HCys levels as a potential preventative or therapeutic approach in human pathologies.

Homocysteine inhibits pro-insulin receptor cleavage and causes insulin resistance via protein cysteine-homocysteinylation

Elevation in homocysteine (Hcy) level is associated with insulin resistance; however, the causality between them and the underlying mechanism remain elusive. Here, we show that Hcy induces insulin resistance and causes diabetic phenotypes by protein cysteine-homocysteinylation (C-Hcy) of the pro-insulin receptor (pro-IR). Mechanistically, Hcy reacts and modifies cysteine-825 of pro-IR in the endoplasmic reticulum (ER) and abrogates the formation of the original disulfide bond. C-Hcy impairs the interaction between pro-IR and the Furin protease in the Golgi apparatus, thereby hindering the cleavage of pro-IR. In mice, an increase in Hcy level decreases the mature IR level in various tissues, thereby inducing insulin resistance and the type 2 diabetes phenotype. Furthermore, inhibition of C-Hcy in vivo and in vitro by overexpressing protein disulfide isomerase rescues the Hcy-induced phenotypes. In conclusion, C-Hcy in the ER can serve as a potential pharmacological target for developing drugs to prevent insulin resistance and increase insulin sensitivity.

Emerging roles of dysregulated adenosine homeostasis in brain disorders with a specific focus on neurodegenerative diseases

In modern societies, with an increase in the older population, age-related neurodegenerative diseases have progressively become greater socioeconomic burdens. To date, despite the tremendous effort devoted to understanding neurodegenerative diseases in recent decades, treatment to delay disease progression is largely ineffective and is in urgent demand. The development of new strategies targeting these pathological features is a timely topic. It is important to note that most degenerative diseases are associated with the accumulation of specific misfolded proteins, which is facilitated by several common features of neurodegenerative diseases (including poor energy homeostasis and mitochondrial dysfunction). Adenosine is a purine nucleoside and neuromodulator in the brain. It is also an essential component of energy production pathways, cellular metabolism, and gene regulation in brain cells. The levels of intracellular and extracellular adenosine are thus tightly controlled by a handful of proteins (including adenosine metabolic enzymes and transporters) to maintain proper adenosine homeostasis. Notably, disruption of adenosine homeostasis in the brain under various pathophysiological conditions has been documented. In the past two decades, adenosine receptors (particularly A₁ and A_2A adenosine receptors) have been actively investigated as important drug targets in major degenerative diseases. Unfortunately, except for an A_2A antagonist (istradefylline) administered as an adjuvant treatment with levodopa for Parkinson's disease, no effective drug based on adenosine receptors has been developed for neurodegenerative diseases. In this review, we summarize the emerging findings on proteins involved in the control of adenosine homeostasis in the brain and discuss the challenges and future prospects for the development of new therapeutic treatments for neurodegenerative diseases and their associated disorders based on the understanding of adenosine homeostasis.

Improvement of cognitive performance by a nutraceutical formulation: Underlying mechanisms revealed by laboratory studies

Cognitive decline, decrease in neuronal function and neuronal loss that accompany normal aging and dementia are the result of multiple mechanisms, many of which involve oxidative stress. Herein, we review these various mechanisms and identify pharmacological and non-pharmacological approaches, including modification of diet, that may reduce the risk and progression of cognitive decline. The optimal degree of neuronal protection is derived by combinations of, rather than individual, compounds. Compounds that provide antioxidant protection are particularly effective at delaying or improving cognitive performance in the early stages of Mild Cognitive Impairment and Alzheimer's disease. Laboratory studies confirm alleviation of oxidative damage in brain tissue. Lifestyle modifications show a degree of efficacy and may augment pharmacological approaches. Unfortunately, oxidative damage and resultant accumulation of biomarkers of neuronal damage can precede cognitive decline by years to decades. This underscores the importance of optimization of dietary enrichment, antioxidant supplementation and other lifestyle modifications during aging even for individuals who are cognitively intact.

The Role of Vitamins in Neurodegenerative Disease: An Update

Acquiring the recommended daily allowance of vitamins is crucial for maintaining homeostatic balance in humans and other animals. A deficiency in or dysregulation of vitamins adversely affects the neuronal metabolism, which may lead to neurodegenerative diseases. In this article, we discuss how novel vitamin-based approaches aid in attenuating abnormal neuronal functioning in neurodegeneration-based brain diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, and Prion disease. Vitamins show their therapeutic activity in Parkinson's disease by antioxidative and anti-inflammatory activity. In addition, different water- and lipid-soluble vitamins have also prevented amyloid beta and tau pathology. On the other hand, some results also show no correlation between vitamin action and the prevention of neurodegenerative diseases. Some vitamins also exhibit toxic activity too. This review discusses both the beneficial and null effects of vitamin supplementation for neurological disorders. The detailed mechanism of action of both water- and lipid-soluble vitamins is addressed in the manuscript. Hormesis is also an essential factor that is very helpful to determine the effective dose of vitamins. PubMed, Google Scholar, Web of Science, and Scopus were employed to conduct the literature search of original articles, review articles, and meta-analyses.

The Association Between Homocysteine and Memory in Older Adults

BACKGROUND

Identifying modifiable risk factors for cognitive decline can reduce burden of dementia.

OBJECTIVE

We examined whether homocysteine was associated with memory performance, mediated by entorhinal volume, hippocampal volume, total gray matter volume, or white matter lesions, and moderated by APOE ɛ4 allele, B vitamins, creatinine, total cholesterol, or triglycerides.

METHODS

All 204 members of the Czech Brain Aging Study with subjective cognitive decline (SCD; n = 60) or amnestic mild cognitive impairment (aMCI; n = 144) who had valid data were included. Linear regression was used, followed by conditional process modeling to examine mediation and moderation.

RESULTS

Controlling for age, sex, and education, higher homocysteine was related to poorer memory performance overall (b = -0.03, SE = 0.01, p = 0.017) and in participants with SCD (b = -0.06, SE = 0.03, p = 0.029), but less so in aMCI (b = -0.03, SE = 0.02, p = 0.074); though sensitivity analyses revealed a significant association when sample was reduced to aMCI patients with more complete cognitive data (who were also better functioning; b = -0.04, SE = 0.02, p = 0.022). Results were unchanged in fully adjusted models. Neither mediation by markers of brain integrity nor moderation by APOE ɛ4, B vitamins, creatinine, and cardiovascular factors were significant. Memory sub-analyses revealed that results for SCD were likely driven by non-verbal memory. The homocysteine-memory relationship was significant when hippocampal volume was below the median (b = -0.04, SE = 0.02, p = 0.046), but not at/above the median (p = 0.247).

CONCLUSION

Higher homocysteine levels may adversely influence memory performance, which appears particularly apparent in those without cognitive impairment. Results appear to be independent of brain health, suggesting that homocysteine may represent a good target for intervention.

Voluntary Exercise Attenuates Hyperhomocysteinemia, But Does not Protect Against Hyperhomocysteinemia-Induced Testicular and Epididymal Disturbances

The hyperhomocysteinemia (HHcy) is toxic to the cells and associated with several diseases. Clinical studies have shown changes in plasma concentrations of Hcy after physical exercise. This study aimed to assess the effect of HHcy on testis, epididymis and sperm quality and to investigate whether voluntary exercise training protects this system against damage caused by HHcy in Swiss mice. In this study, 48 mice were randomly distributed in the control, HHcy, physical exercise, and HHcy combined with physical exercise groups. HHcy was induced by daily administration of dl-homocysteine thiolactone via gavage throughout the experimental period. Physical exercise was performed through voluntary running on the exercise wheels. The plasma concentrations of homocysteine (Hcy) and testosterone were determined. The testes and epididymis were used to assess the sperm count, histopathology, lipoperoxidation, cytokine levels, testicular cholesterol, myeloperoxidase, and catalase activity. Spermatozoa were analyzed for morphology, acrosome integrity, mitochondrial activity, and motility. In the testes, HHcy increased the number of abnormal seminiferous tubules, reduced the tubular diameter and the height of the germinal epithelium. In the epididymis, there was tissue remodeling in the head region. Ultimately, voluntary physical exercise training reduced plasma Hcy concentration but did not attenuate HHcy-induced testicular and epididymal disturbances.

Identification of Drug-Related Problems in Hypertension Comorbid Type 2 Diabetes Mellitus Patients at Primary Health Care Center Batununggal District Bandung

Many factors can increase the risk of hypertension, one of which is diabetes mellitus. The study aims to provide an overview of Drug-Related Problems (DRPs) in patients with hypertension comorbid type 2 diabetes mellitus at Primary Health Care Center Batununggal District Bandung. This research was an observational study with retrospective data collection and descriptive analysis. Data were taken from patient prescriptions January-December 2019 period. The sample inclusion criteria are patients aged 30-75 years, patients diagnosed with hypertension comorbid type 2 diabetes mellitus, and patients treated in January-December 2019. The number of samples that met the inclusion criteria was 268 patients, of which 69 patients (25.75%) are male, and 199 patients (74.25%) are female. 164 patients (61.2%) are aged 60-75 years old. It is found that 1 case (0.37%) has the drug-related problem of drug overdose and as many as 34 cases (12.69%) have potential drug interactions.

The first Saudi baby with classic homocystinuria diagnosed by universal newborn screening

Classic homocystinuria (CH) is an inborn error of metabolism caused by cystathionine beta-synthase enzyme deficiency. Affected patients present with intellectual disability and other comorbidities. If diagnosed early in infancy and started treatment, inevitable complications can be prevented. Newborn screening (NBS) uses tandem mass-spectroscopy (MSMS) to measure the amino acid levels. In CH, the first-tier screening test is the measurement of methionine by MSMS. If methionine remained elevated in the recall sample, plasma level for homocysteine is performed. A newborn infant underwent routine NBS in our institute that showed elevated methionine in the first and the recall sample. Thereafter, total serum homocysteine was found to be elevated, consistent with the diagnosis of CH. An early medical and dietary management was commenced for this first Saudi baby diagnosed with homocystinuria by universal NBS. This report demonstrates that NBS for CH is feasible and effective in preventing the disease burden.

Research progress of hydrogen sulfide in Alzheimer's disease from laboratory to hospital: a narrative review

Alzheimer's disease is a neurodegenerative disease that mainly occurs in old age and early stages. Its main manifestations are memory impairment, aphasia, apraxia, loss of identity, abstract thinking and impairment of computing power, personality and behavior changes, etc. At present, the treatment of Alzheimer's disease only stays on reducing the disease and delaying the development, which is also a difficult problem to overcome in clinical practice. Hydrogen sulfide, as a third gaseous signal molecule after carbon monoxide and nitrogen monoxide, has become very popular in recent years. It shows very promising prospects in the Alzheimer's disease model. It can protect the nerve function and prevent the progress of the disease by affecting the amyloid precursor protein metabolism, anti-apoptosis, anti-inflammatory, and antioxidant pathways. Therefore, this article summarizes the relevant basic and clinical research of hydrogen sulfide in Alzheimer's disease, and discusses its progress and findings and mechanism characteristics.

Lycium barbarum polysaccharides attenuate cardiovascular oxidative stress injury by enhancing the Keap1/Nrf2 signaling pathway in exhaustive exercise rats

Moderate exercise is beneficial to physical and mental health. When the amount of exercise and exercise intensity exceeds a certain limit and reaches the state of exhaustion, oxidative stress levels in the body increase, which can lead to oxidative stress‑associated damage. Lycium barbarum polysaccharide (LBP) is one of the primary active ingredients extracted from wolfberry. Following exhausting exercise in rats, LBP supplements decrease damage to the myocardium and blood vessels, indicating that LBP exerts a protective effect on the cardiovascular system. The Kelch‑like ECH‑associated protein 1 (Keap1)/NF‑E2‑related factor 2 (Nrf2) anti‑oxidative stress signaling pathway improves total oxidizing ability; anti‑apoptosis and other aspects serve a vital role. In the present study, LBP intervention was performed in vivo and in vitro to observe its effect on the Keap1/Nrf2 pathway and oxidative stress‑associated indicators in order to clarify its protective mechanism. For the in vivo experiments, 60 male Sprague‑Dawley rats were randomly divided into normal control and aerobic, exhaustive and exhaustive exercise + LBP (200 mg/kg/day) groups. For the in vitro experiments, a rat thoracic aortic endothelial cell (RTAEC) oxidative stress model was established using angiotensin II (AngII) and divided into blank control, LBP (3,200 µg/ml), AngII (1x10^‑4 mol/l) and AngII + LBP groups. For in vitro experiments, small interfering (si)RNA (50 nmol) was used to transfect RTAEC and induce gene silencing of Nrf2. ELISA, hematoxylin and eosin staining, TUNEL, immunofluorescence, western blotting, immunohistochemistry and reverse transcription‑quantitative PCR were used to evaluate and verify the effect of LBP on oxidative stress indicators and the expression of Keap1/Nrf2 antioxidative stress signaling pathway. The in vivo experiments showed that LBP decreased the expression of serum malondialdehyde (MDA) and AngII, as well as apoptosis of blood vessels and cardiomyocytes and expression of TNF‑α in rats following exhaustive exercise. Meanwhile, LBP enhanced expression of the Keap1/Nrf2 signaling pathway and downstream associated protein glutamyl‑cysteine synthetase catalytic subunit (GCLC), quinone oxidoreductase 1 (NQO1) and glutamate‑cysteine ligase modified subunit (GCLM) in the thoracic aorta and myocardium of rats following exhaustive exercise. In RTAEC in vitro, LBP decreased the expression of MDA and TNF‑α in the supernatant, promoted the nuclear translocation of Nrf2 and increased expression levels of GCLC, NQO1 and GCLM. Following siNrf2 transfection into endothelial cells, the anti‑inflammatory and antioxidant stress effects of LBP were decreased. LBP was found to enhance the expression of the Keap1/Nrf2 antioxidant stress signaling pathway in endothelial cells, decreasing oxidative stress and the inflammatory response. Moreover, LBP improved the antioxidant stress ability of endothelial cells and alleviated injury of myocardial vascular tissue, thereby protecting the cardiovascular system.

Homocysteine restrains hippocampal neurogenesis in focal ischemic rat brain by inhibiting DNA methylation

Ischemic stroke represents a major cause of mortality worldwide. An elevated level of homocysteine (Hcy) is recognized as a powerful risk factor of ischemic stroke. We previously reported that Hcy induces cytotoxicity and proliferation inhibition in neural stem cells (NSCs) derived from the neonatal rat hippocampus in vitro. However, the toxic potential of Hcy on NSCs and its underlying mechanisms are not entirely clear in ischemic brain. Since DNA methylation is critical for establishing the diverse cell fates in the central nervous system, we hypothesized that negative effect of Hcy (an intermediate in the one-carbon metabolism) on neurogenesis might be link to DNA methylation in ischemic stroke. In our study, the rats in Hcy intervention group were intraperitoneally injected with 2% Hcy solution (5 mL/kg/d) for 7 consecutive days before MCAO surgery until they were sacrificed. Our study indicated that Hcy inhibited NSCs self-renewal capacity, which was exhibited by lowering the number of DCX+/BrdU+ and NeuN+/BrdU+ in ischemic brain hippocampus. A reduction in the activity of the DNA methyltransferases (DNMTs), total methylation level and the number of 5mC+/NeuN+ and DCX+/5mC+ cells was observed in Hcy-treated ischemic brains. Additionally, Hcy also induced an increase in S-adenosylhomocysteine (SAH), and a decrease in the ratio of S-adenosylmethionine (SAM) to SAH. These results suggest that the alterations in DNA methylation may be an important mechanism by which Hcy inhibits neurogenesis after stroke. Hcy-induced DNA hypomethylation may be mainly caused by a reduction in the DNMT activity which is regulated by the concentrations of SAM and SAH. Maintaining normal DNA methylation by lowering Hcy level may possess therapeutic potential for promoting neurological recovery and reconstruction after stroke.

Homocysteine and Age-Related Central Nervous System Diseases: Role of Inflammation

Hyperhomocysteinemia (HHcy) is remarkably common among the aging population. The relation between HHcy and the development of neurodegenerative diseases, such as Alzheimer's disease (AD) and eye diseases, and age-related macular degeneration (AMD) and diabetic retinopathy (DR) in elderly people, has been established. Disruption of the blood barrier function of the brain and retina is one of the most important underlying mechanisms associated with HHcy-induced neurodegenerative and retinal disorders. Impairment of the barrier function triggers inflammatory events that worsen disease pathology. Studies have shown that AD patients also suffer from visual impairments. As an extension of the central nervous system, the retina has been suggested as a prominent site of AD pathology. This review highlights inflammation as a possible underlying mechanism of HHcy-induced barrier dysfunction and neurovascular injury in aging diseases accompanied by HHcy, focusing on AD.

Methylation as a key regulator of Tau aggregation and neuronal health in Alzheimer's disease

Neurodegenerative diseases like Alzheimer's, Parkinson's and Huntington's disease involves abnormal aggregation and accumulation of toxic proteins aggregates. Post-translational modifications (PTMs) of the causative proteins play an important role in the etiology of disease as they could either slow down or accelerate the disease progression. Alzheimer disease is associated with the aggregation and accumulation of two major protein aggregates-intracellular neurofibrillary tangles made up of microtubule-associated protein Tau and extracellular Amyloid-β plaques. Post-translational modifications are important for the regulation of Tau`s function but an imbalance in PTMs may lead to abnormal Tau function and aggregation. Tau methylation is one of the important PTM of Tau in its physiological state. However, the methylation signature on Tau lysine changes once it acquires pathological aggregated form. Tau methylation can compete with other PTMs such as acetylation and ubiquitination. The state of PTM at these sites determines the fate of Tau protein in terms of its function and stability. The global methylation in neurons, microglia and astrocytes are involved in multiple cellular functions involving their role in epigenetic regulation of gene expression via DNA methylation. Here, we have discussed the effect of methylation on Tau function in a site-specific manner and their cross-talk with other lysine modifications. We have also elaborated the role of methylation in epigenetic aspects and neurodegenerative conditions associated with the imbalance in methylation metabolism affecting global methylation state of cells. Video abstract.

Hyperhomocysteinemia increases susceptibility to cortical spreading depression associated with photophobia, mechanical allodynia, and anxiety in rats

Epidemiological data suggest that elevated homocysteine is associated with migraine with aura. However, how homocysteine contributes to migraine is still unclear. Here, we tested whether hyperhomocysteinemia (hHCY) promotes cortical spreading depression (CSD), a phenomenon underlying migraine with aura, and whether hHCY contributes to pain behavior. hHCY was induced by dietary methionine in female rats while the testing was performed on their 6-8week-old offspring. CSD and multiple unit activity (MUA) induced by KCl were recorded from the primary somatosensory cortex, S1, using multichannel electrodes. In hHCY rats, compared to control, we found: i) higher probability of CSD occurrence; ii) induction of CSD by lower concentrations of KCl; iii) faster horizontal propagation of CSD; iv) smaller CSD with longer duration; v) higher frequency of MUA at CSD onset along with slower reappearance. Rats with hHCY demonstrated high level of locomotor activity and grooming while spent less time in the central area of the open field, indicating anxiety. These animals showed light sensitivity and facial mechanical allodinia. Thus, hHCY acquired at birth promotes multiple features of migraine such as higher cortical excitability, mechanical allodynia, photophobia, and anxiety. Our results provide the first experimental explanation for the higher occurrence of migraine with aura in patients with hHCY.

The role of B vitamins in stroke prevention

Elevated plasma levels of homocysteine (Hcy) are a recognized risk factor for stroke. This relationship represents one aspect of the debated `Hcy hypothesis'. Elevated Hcy may be an independent and treatable cause of atherosclerosis and thrombotic vascular diseases. Further observations indicate that proper dietary supplementation with B-vitamins decreases total plasma Hcy concentrations and may be an effective intervention for stroke prevention. Metabolic vitamin B₁₂ deficiency is a nutritional determinant of total Hcy and stroke risk. Genetic factors may link B vitamins with stroke severity due to the impact on Hcy metabolism of polymorphism in the genes coding for methylenetetrahydrofolate reductase, methionine-synthase, methionine synthase reductase, and cystathionine β-synthase. Several meta-analyses of large randomized controlled trials exist. However, they are not completely in agreement about B vitamins' role, particularly folic acid levels, vitamin B₁₂, and B₆, in lowering the homocysteine concentrations in people at high stroke risk. A very complex relationship exists between Hcy and B vitamins, and several factors appear to modify the preventive effects of B vitamins in stroke. This review highlights the regulating factors of the active role of B vitamins active in stroke prevention. Also, inputs for further large, well-designed studies, for specific, particularly sensitive subgroups are given.

Association of Red Blood Cell Indices with Mild Cognitive Impairment in Chinese Elderly Individuals: A Matched Case-control Study

BACKGROUND

Mild cognitive impairment (MCI) represents an intermediate and modifiable stage between normal aging and dementia. There is an urgent need for simple, non-invasive testing of MCI by blood biomarkers.

OBJECTIVE

This study aimed to retrospectively evaluate the association of red blood cell (RBC) indices with MCI, and select the best hematologic characteristic for detection of MCI in elderly Chinese.

METHODS

Matched case-control study was carried out with 85 pairs of MCI subjects and healthy controls. The matching criteria was age, gender and education attainment. All samples were analyzed for RBC indices, including hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC) and red cell distribution width-standard deviation (RDW-SD). A conditional logistic regression model was used to evaluate the association between RBC indices and MCI. The diagnostic efficacy of the biomarkers was evaluated by receiver operating characteristics (ROC).

RESULTS

Among all RBC indices, there were significant differences in HGB (124.82 ± 7.89 vs. 133.93 ± 4.52, P < 0.001) and RDW-SD (45.29 ± 2.03 vs. 41.34 ± 4.41, P < 0.001) between two groups. In the logistic regression model, after adjustment for lifestyle factors and comorbidities, significant statistically associations have been found between higher HGB and lower risk of MCI (adjusted OR: 0.831; 95% CI: 0.773-0.893), higher RDW-SD and a higher risk of MCI (adjusted OR: 1.575; 95% CI: 1.326- 1.872). ROC analysis suggested that the largest area under the ROC curve (AUC) was found with the combination of HGB and RDW-SD (AUC = 0.842), followed by HGB(AUC = 0.795), and finally by modest RDW-SD (AUC = 0.777). Combination of HGB <131 g/L and RDW-SD >43.4 fL yielded a sensitivity of 92% and a specificity of 89%, overall diagnosis efficiency of which were better than HBG and RDW-SD alone.

CONCLUSION

Lower HGB and higher RDW-SD alone were significantly found to be associated with increased risk of MCI, and offered modest sensitivity and specificity as a diagnostic marker. The combination of HGB and RDW-SD was more sensitive and had higher classification accuracy for differentiating MCI from healthy controls. Further prospective research is needed to clarify whether HGB in combination with RDW-SD may be a potential diagnostic tool for early diagnosis of AD.

Homocysteine in Neurology: A Possible Contributing Factor to Small Vessel Disease

Homocysteine (Hcy) is a sulfur-containing amino acid generated during methionine metabolism, accumulation of which may be caused by genetic defects or the deficit of vitamin B12 and folate. A serum level greater than 15 micro-mols/L is defined as hyperhomocysteinemia (HHcy). Hcy has many roles, the most important being the active participation in the transmethylation reactions, fundamental for the brain. Many studies focused on the role of homocysteine accumulation in vascular or degenerative neurological diseases, but the results are still undefined. More is known in cardiovascular disease. HHcy is a determinant for the development and progression of inflammation, atherosclerotic plaque formation, endothelium, arteriolar damage, smooth muscle cell proliferation, and altered-oxidative stress response. Conversely, few studies focused on the relationship between HHcy and small vessel disease (SVD), despite the evidence that mice with HHcy showed a significant end-feet disruption of astrocytes with a diffuse SVD. A severe reduction of vascular aquaporin-4-water channels, lower levels of high-functioning potassium channels, and higher metalloproteinases are also observed. HHcy modulates the N-homocysteinylation process, promoting a pro-coagulative state and damage of the cellular protein integrity. This altered process could be directly involved in the altered endothelium activation, typical of SVD and protein quality, inhibiting the ubiquitin-proteasome system control. HHcy also promotes a constant enhancement of microglia activation, inducing the sustained pro-inflammatory status observed in SVD. This review article addresses the possible role of HHcy in small-vessel disease and understands its pathogenic impact.

The close link between the fetal programming imprinting and neurodegeneration in adulthood: The key role of "hemogenic endothelium" programming

The research on neurodegenerative diseases (NeuroDegD) has been traditionally focused on later life stages. There is now an increasing evidence, that they may be programmed during early development. Here, we propose that NeuroDegD are the result of the complex process of imprinting on fetal hemogenic endothelium, from which the microglial cells make to origin. The central role of placenta and epigenetic mechanisms (methylation of DNA, histone modifications and regulation by non-coding RNAs) in mediating the short and long-term effects has been also described. Precisely, it reports their role in impacting plasticity and memory of microglial cells. In addition, we also underline the necessity of further studies for clearing all mechanisms involved and developing epigenetic methods for identifying potential targets as biomarkers, and for developing preventive measures. Such biomarkers might be used to identify individuals at risk to NeuroDegD. Finally, the sex dependence of fetal programming process has been discussed. It might justify the sex differences in the epidemiologic, imaging, biomarkers, and pathology studies of these pathologies. The discovery of related mechanisms might have important clinical implications in both the etiology of disorders and the management of pregnant women for encouraging healthy long-term outcomes for their children, and future generations. Impending research on the mechanisms related to transgenerational transmission of prenatal stress might consent the development and application of therapies and/or intervention strategies for these disorders in humans.

Hyperhomocysteinemia is an emerging comorbidity in ischemic stroke

Hyperhomocysteinemia or systemic elevation of the amino acid homocysteine is a common metabolic disorder that is considered to be a risk factor for ischemic stroke. However, it is still unclear whether predisposition to hyperhomocysteinemia could contribute to the severity of stroke outcome. This review highlights the advantages and limitations of the current rodent models of hyperhomocysteinemia, describes the consequence of mild hyperhomocysteinemia on the severity of ischemic brain damage in preclinical studies and summarizes the mechanisms involved in homocysteine induced neurotoxicity. The findings provide the premise for establishing hyperhomocysteinemia as a comorbidity for ischemic stroke and should be taken into consideration while developing potential therapeutic agents for stroke treatment.

Association between serum non-high-density lipoprotein cholesterol and cognitive dysfunction after acute ischemic stroke: a cross-sectional study

This study aimed to explore the association between serum non-high-density lipoprotein cholesterol (non-HDL-C) and cognitive dysfunction risk in patients with acute ischemic stroke (AIS). This cross-sectional study enrolled 583 AIS patients. Biochemical markers and lipid profile were collected after admission. AIS patients were classified into high group (non-HDL-C ≥3.4 mM) and normal group (non-HDL-C <3.4 mM). Mini-Mental State Examination scale (MMSE), Montreal Cognitive Assessment scale (MoCA), Activities of Daily Living (ADL) scale, Neuropsychiatric Inventory (NPI), and Hamilton Depression scale 21 version (HAMD-21) were applied on the third day after admission. Compared with the control group, patients of the high group had higher body mass index and higher frequency of intracranial artery stenosis, and exhibited higher levels of non-HDL-C, total cholesterol, triglycerides, low-density lipoprotein cholesterol, homocysteine, fasting blood glucose, and glycosylated hemoglobin (HbA1c), and lower levels of high-density lipoprotein cholesterol (all P<0.05). Compared with the control group, patients of the high group had significantly lower MMSE and MoCA scores (MMSE: 26.01±4.17 vs 23.12±4.73, P<0.001; MoCA: 22.28±5.28 vs 20.25±5.87, P<0.001) and higher scores on the NPI and HAMD-21 (both P<0.001). MMSE (r=-0.306, P<0.001) and MoCA scores (r=-0.251, P<0.001) were negatively associated with non-HDL-C level. Multivariate regression analysis revealed that non-HDL-C level (OR=1.361, 95%CI: 1.059-1.729, P=0.016) was independently associated with the presence of cognitive dysfunction after adjusting for confounding factors. High serum non-HDL-C level might significantly increase the risk of cognitive dysfunction after AIS.

Homocysteine Impairs Endothelial Cell Barrier Function and Angiogenic Potential via the Progranulin/EphA2 Pathway

Hyperhomocysteinemia is a well-recognized independent risk factor for cardiovascular disease. To date, the mechanism of pathological plasma homocysteine (Hcy) level elevation remains to be elucidated. We aimed to investigate the levels of progranulin (PGRN), Eph-receptor tyrosine kinase-type A2 (EphA2), vascular cell adhesion molecule-1 (VCAM-1), and Hcy in patients with arteriosclerosis and investigate their functions in Hcy-injured human umbilical vein endothelial cells (HUVECs). EphA2 knockdown was induced in HUVECs by shRNA lentivirus infection with EphA2-RNAi, and bulk RNA-seq assay was performed. Then we investigated the mechanism underlying the effect of recombinant human PGRN (rhPGRN) combined with shRNA interference of EphA2 on cell proliferation, migration, and angiogenesis in Hcy-injured HUVECs. Results showed that serum EphA2, VCAM-1, and Hcy levels in acute coronary syndrome patients were significantly higher than those in chronic coronary syndrome patients (p = 0.000; p = 0.000; p = 0.033, respectively). In vitro, we demonstrated that knockdown of EphA2 significantly impaired cell adhesion and inhibited HUVECs migration and angiogenesis (p < 0.001), which was associated with reduction in VCAM1 and VE-cadherin (p < 0.05). Hcy modulated the expression of PGRN and EphA2 in a time-and dose-dependent manner. However, rhPGRN ameliorated the Hcy-induced reduction in cell viability and migration (p < 0.05). Mechanistically, we found that PGRN/EphA2 and its downstream AKT/NF-κB signaling might be the primary signal transduction pathways underlying Hcy-induced injury. The present study illustrated that PGRN plays a previously unrecognized role in Hcy-induced endothelial injury, which is achieved through its interaction with EphA2 signaling, implying a promising therapeutic target for cardiovascular disease.

The association between retinal vessel abnormalities and H-type hypertension

Background

This study aimed to investigate the relationship between H-type hypertension and retinal vessel abnormalities.

Methods

Hypertensive patients were retrospectively enrolled in this study. According to plasma homocysteine (HCY), patients were divided into isolated hypertension and H-type hypertension groups. The diameter of retinal vessels and retinopathy were evaluated by retinal fundus photography. The differences of retinal vessel abnormalities between H-type hypertension and isolated hypertension were investigated by univariate and multivariate regression.

Results

A total of 191 hypertensive patients were included, of which 86 were with isolated hypertension and 105 with H-type hypertension. The H-type hypertension group had a higher ratio of retinopathy(P = 0.004) and higher degree of retinal arteriosclerosis (P = 0.005) than the isolated hypertension group. CRAE (107.47 ± 13.99µ m vs. 113.49 ± 11.72µ m, P = 0.002) and AVR (0.55 ± 0.06 vs. 0.58 ± 0.06, P = 0.001) were smaller in H-type hypertension group than those in isolated hypertension group. Multivariate analysis showed that after adjusting for age, sex, course of hypertension and diabetes, H-type hypertension was an independent risk factor of retinopathy (OR, 2.259; 95%CI, 1.165—4.378; P = 0.016), CRAE (β=-5.669; 95%CI, -9.452—-1.886; P = 0.004), and AVR (β=-0.023; 95%CI, -0.039—-0.007; P = 0.005).

Conclusions

H-type hypertension is closely related to more retinal vessel abnormalities than isolated hypertension. Controlling H-type hypertension may reduce the risk of small vascular damage.

A rare infective cause of stroke in an immunocompetent child

BACKGROUND

Infections are a common cause of childhood stroke with variable presentation. The current case describes a rare infective cause of venous and arterial stroke in an immunocompetent girl with management implications.

CASE DESCRIPTION

A 12 year old girl, presented with history of fever for 10 days, painful swelling of right eye for 7 days and altered sensorium for 2 days. On examination, she had right eye orbital cellulitis and fullness of right paranasal area. On nervous system examination, she was delirious, had right eye ophthalmoparesis, left upper motor neuron facial palsy and signs of meningeal inflammation. Her contrast enhanced CT head and subsequent MRI brain with arteriography and venography revealed right cavernous sinus and distal internal carotid artery thrombosis. She was started on intravenous ceftriaxone and vancomycin and subcutaneous heparin. In view of persistent symptoms, endoscopic debridement of right nasal cavity was done, which showed growth of aspergillus flavus. Subsequently, she was started on intravenous voriconazole. Within a week, she was afebrile, her inflammatory and neurological signs started improving. She was discharged after 3 weeks of intravenous voriconazole which was continued for 3 more weeks orally. Her procoagulant and immunodeficiency work up were normal. At 4 months follow up, she showed both clinical and radiological resolution.

CONCLUSIONS

Despite high mortality described in sino-orbital aspergillosis, early and appropriate treatment led to optimal outcome. In deep seated infections, isolation of etiological organism should be attempted, particularly when patient doesn't respond to conventional antimicrobial therapy.

Gas Chromatography-Mass Spectrometry Based Approach for the Determination of Methionine-Related Sulfur-Containing Compounds in Human Saliva

Gas chromatography-mass spectrometry technique (GC-MS) is mainly recognized as a tool of first choice when volatile compounds are determined. Here, we provide the credible evidence that its application in analysis can be extended to non-volatile sulfur-containing compounds, to which methionine (Met), homocysteine (Hcy), homocysteine thiolactone (HTL), and cysteine (Cys) belong. To prove this point, the first method, based on GC-MS, for the identification and quantification of Met-related compounds in human saliva, has been elaborated. The assay involves simultaneous disulfides reduction with tris(2-carboxyethyl)phosphine (TCEP) and acetonitrile (MeCN) deproteinization, followed by preconcentration by drying under vacuum and treatment of the residue with a derivatizing mixture containing anhydrous pyridine, N-trimethylsilyl-N-methyl trifluoroacetamide (MSTFA), and trimethylchlorosilane (TMCS). The validity of the method was demonstrated based upon US FDA recommendations. The assay linearity was observed over the range of 0.5-20 µmol L^-1 for Met, Hcy, Cys, and 1-20 µmol L^-1 for HTL in saliva. The limit of quantification (LOQ) equals 0.1 µmol L^-1 for Met, Hcy, Cys, while its value for HTL was 0.05 µmol L^-1. The method was successfully applied to saliva samples donated by apparently healthy volunteers (n = 10).

Therapeutic potential of nutraceuticals to protect brain after stroke

Stroke leads to significant neuronal death and long-term neurological disability due to synergistic pathogenic mechanisms. Stroke induces a change in eating habits and in many cases, leads to undernutrition that aggravates the post-stroke pathology. Proper nutritional regimen remains a major strategy to control the modifiable risk factors for cardiovascular and cerebrovascular diseases including stroke. Studies indicate that nutraceuticals (isolated and concentrated form of high-potency natural bioactive substances present in dietary nutritional components) can act as prophylactic as well as adjuvant therapeutic agents to prevent stroke risk, to promote ischemic tolerance and to reduce post-stroke consequences. Nutraceuticals are also thought to regulate blood pressure, delay neurodegeneration and improve overall vascular health. Nutraceuticals potentially mediate these effects by their powerful antioxidant and anti-inflammatory properties. This review discusses the studies that have highlighted the translational potential of nutraceuticals as stroke therapies.

Dietary supplements in the management of varicocele-induced infertility: A review of potential mechanisms

Varicocele is a main cause of lower production of spermatozoon and infertility with multiple pathophysiological mechanisms. In the past decades, the use of dietary supplements has significantly increased due to both the modern lifestyle and the food shortages of the industrialised countries. The purpose of this review paper is to collect scientific evidences from basic and clinical studies which support the use of dietary supplements to define the clinical framework for patients with varicocele. In the present review, we used keywords such as dietary supplements, varicocele, male infertility, oxidative stress, DNA fragmentation, sperm parameters to find the proper articles. The standard search biomedical engines were used for seeking the papers. The use of dietary supplements such as minerals, vitamins and antioxidants has an essential role in the prevention and treatment of varicocele by increasing the levels of antioxidant enzymes (e.g. peroxidase, superoxide dismutase and catalase) and decreasing the levels of inflammatory markers (e.g. tumour necrosis factor-α, interleukin-6 and interleukin-1) in testis. According to the results, the dietary supplements may alleviate the spermatogenesis in varicocele patients through different mechanisms such as suppression of stress oxidative and inflammation in testicular tissue.

Regulation of the parental gene GRM4 by circGrm4 RNA transcript and glutamate-mediated neurovascular toxicity in eyes

Epigenetic memory plays crucial roles in gene regulation. It not only modulates the expression of specific genes but also has ripple effects on transcription as well as translation of other genes. Very often an alteration in expression occurs either via methylation or demethylation. In this context, "1-carbon metabolism" assumes a special significance since its dysregulation by higher levels of homocysteine; Hcy (known as hyperhomocysteinemia; HHcy), a byproduct of "1-Carbon Metabolism" during methionine biosynthesis leads to serious implications in cardiovascular, renal, cerebrovascular systems, and a host of other conditions. Currently, the circular RNAs (circRNAs) generated via non-canonical back-splicing events from the pre-mRNA molecules are at the center stage for their essential roles in diseases via their epigenetic manifestations. We recently identified a circular RNA transcript (circGRM4) that is significantly upregulated in the eye of cystathionine β-synthase-deficient mice. We also discovered a concurrent over-expression of the mGLUR4 receptor in the eyes of these mice. In brief, circGRM4 is selectively transcribed from its parental mGLUR4 receptor gene (GRM4) functions as a "molecular-sponge" for the miRNAs and results into excessive turnover of the mGLUR4 receptor in the eye in response to extremely high circulating glutamate concentration. We opine that this epigenetic manifestation potentially predisposes HHcy people to retinovascular malfunctioning.