Hyperhomocysteinemia enhances vascular inflammation and accelerates atherosclerosis in a murine model

Homocysteine contributes to atherogenic transformation of the aorta in rabbits in the absence of hypercholesterolemia

Atherosclerosis, the leading cause of cardiovascular disease, cannot be sufficiently explained by established risk factors, including cholesterol. Elevated plasma homocysteine (Hcy) is an independent risk factor for atherosclerosis and is closely linked to cardiovascular mortality. However, its role in atherosclerosis has not been fully clarified yet. We have previously shown that rabbits fed a diet deficient in B vitamins and choline (VCDD), which are required for Hcy degradation, exhibit an accumulation of macrophages and lipids in the aorta, aortic stiffening and disorganization of aortic collagen in the absence of hypercholesterolemia, and an aggravation of atherosclerosis in its presence. In the current study, plasma Hcy levels were increased by intravenous injections of Hcy into balloon-injured rabbits fed VCDD (VCDD+Hcy) in the absence of hypercholesterolemia. While this treatment did not lead to thickening of aortic wall, intravenous injections of Hcy into rabbits fed VCDD led to massive accumulation of VLDL-triglycerides as well as significant impairment of vascular reactivity of the aorta compared to VCDD alone. In the aorta intravenous Hcy injections into VCDD-fed rabbits led to fragmentation of aortic elastin, accumulation of elastin-specific electron-dense inclusions, collagen disorganization, lipid degradation, and autophagolysosome formation. Furthermore, rabbits from the VCDD+Hcy group exhibited a massive decrease of total protein methylated arginine in blood cells and decreased creatine in blood cells, serum and liver compared to rabbits from the VCDD group. Altogether, we conclude that Hcy contributes to atherogenic transformation of the aorta not only in the presence but also in the absence of hypercholesterolemia.

SAH is a major metabolic sensor mediating worsening metabolic crosstalk in metabolic syndrome

In this study, we observed worsening metabolic crosstalk in mouse models with concomitant metabolic disorders such as hyperhomocysteinemia (HHcy), hyperlipidemia, and hyperglycemia and in human coronary artery disease by analyzing metabolic profiles. We found that HHcy worsening is most sensitive to other metabolic disorders. To identify metabolic genes and metabolites responsible for the worsening metabolic crosstalk, we examined mRNA levels of 324 metabolic genes in Hcy, glucose-related and lipid metabolic systems. We examined Hcy-metabolites (Hcy, SAH and SAM) by LS-ESI-MS/MS in 6 organs (heart, liver, brain, lung, spleen, and kidney) from C57BL/6J mice. Through linear regression analysis of Hcy-metabolites and metabolic gene mRNA levels, we discovered that SAH-responsive genes were responsible for most metabolic changes and all metabolic crosstalk mediated by Serine, Taurine, and G3P. SAH-responsive genes worsen glucose metabolism and cause upper glycolysis activation and lower glycolysis suppression, indicative of the accumulation of glucose/glycogen and G3P, Serine synthesis inhibition, and ATP depletion. Insufficient Serine due to negative correlation of PHGDH with SAH concentration may inhibit the folate cycle and transsulfurarion pathway and consequential reduced antioxidant power, including glutathione, taurine, NADPH, and NAD+. Additionally, we identified SAH-activated pathological TG loop as the consequence of increased fatty acid (FA) uptake, FA β-oxidation and Ac-CoA production along with lysosomal damage. We concluded that HHcy is most responsive to other metabolic changes in concomitant metabolic disorders and mediates worsening metabolic crosstalk mainly via SAH-responsive genes, that organ-specific Hcy metabolism determines organ-specific worsening metabolic reprogramming, and that SAH, acetyl-CoA, Serine and Taurine are critical metabolites mediating worsening metabolic crosstalk, redox disturbance, hypomethylation and hyperacetylation linking worsening metabolic reprogramming in metabolic syndrome.

Nicotinamide N-methyltransferase (NNMT): a novel therapeutic target for metabolic syndrome

Metabolic syndrome (MetS) represents a constellation of metabolic abnormalities, typified by obesity, hypertension, hyperglycemia, and hyperlipidemia. It stems from intricate dysregulations in metabolic pathways governing energy and substrate metabolism. While comprehending the precise etiological mechanisms of MetS remains challenging, evidence underscores the pivotal roles of aberrations in lipid metabolism and insulin resistance (IR) in its pathogenesis. Notably, nicotinamide N-methyltransferase (NNMT) has recently surfaced as a promising therapeutic target for addressing MetS. Single nucleotide variants in the NNMT gene are significantly correlated with disturbances in energy metabolism, obesity, type 2 diabetes (T2D), hyperlipidemia, and hypertension. Elevated NNMT gene expression is notably observed in the liver and white adipose tissue (WAT) of individuals with diabetic mice, obesity, and rats afflicted with MetS. Knockdown of NNMT elicits heightened energy expenditure in adipose and hepatic tissues, mitigates lipid accumulation, and enhances insulin sensitivity. NNMT catalyzes the methylation of nicotinamide (NAM) using S-adenosyl-methionine (SAM) as the donor methyl group, resulting in the formation of S-adenosyl-l-homocysteine (SAH) and methylnicotinamide (MNAM). This enzymatic process results in the depletion of NAM, a precursor of nicotinamide adenine dinucleotide (NAD+), and the generation of SAH, a precursor of homocysteine (Hcy). Consequently, this cascade leads to reduced NAD+ levels and elevated Hcy levels, implicating NNMT in the pathogenesis of MetS. Moreover, experimental studies employing RNA interference (RNAi) strategies and small molecule inhibitors targeting NNMT have underscored its potential as a therapeutic target for preventing or treating MetS-related diseases. Nonetheless, the precise mechanistic underpinnings remain elusive, and as of yet, clinical trials focusing on NNMT have not been documented. Therefore, further investigations are warranted to elucidate the intricate roles of NNMT in MetS and to develop targeted therapeutic interventions.

Does Improving Depression Symptoms in Young Adults With Inflammatory Bowel Disease Alter Their Microbiome?

BACKGROUND

Patients with inflammatory bowel diseases (IBDs) are more likely to have depression and anxiety symptoms compared with healthy individuals and those with other chronic illnesses. Previous studies have shown a link between the microbiome composition and depression symptoms; however, many antidepressant medications have antibacterial activity confounding cross-sectional studies of these populations. Therefore, we aimed to determine whether we could detect longitudinal changes in the microbiome of a subset of patients who participated in a previously published mindfulness-based cognitive therapy (MBCT) study to improve depression symptoms in adolescents and young adults with IBD.

METHODS

Stool samples were collected at baseline and 8 weeks (n = 24 participants, 37 total samples, 13 paired samples). During this time, some participants achieved a 50% reduction in their depression symptoms either through MBCT or treatment as usual with their mental health team (responders). The microbiome composition and function of responders were compared with participants who did not improve their depression scores (nonresponders). Depression scores were determined using the depression, anxiety, and stress score (DASS-21), and metagenomic sequencing of stool samples was performed.

RESULTS

No difference in alpha diversity was found between responders and nonresponders. Beta diversity measures were similarly unchanged. Clinical features including fecal calprotectin, C-reactive protein, and serum IL-6 levels were unchanged.

CONCLUSIONS

In this small longitudinal study, we were not able to detect longitudinal changes in the microbiome associated with improvement in depression scores. Follow-up studies that are sufficiently powered to detect changes in the microbiome are required to confirm our results.

The characteristics of arterial risk factors and ankle-brachial index in patients with lower extremity chronic venous diseases: results from the BEST study

BACKGROUND

The aim of our study was to explore the characteristics of the arterial risk factors and ankle-brachial index (ABI) in patients with lower extremity chronic venous disease (LECVD).

METHODS

A total of 2642 subjects were employed in our study. The lifestyle and clinical data were collected. The history of vascular diseases contained coronary artery disease, stroke, hypertension, and diabetes. ABI low than 0.9 was considered as lower extremity artery disease (LEAD). A series of blood indicators were measured.

RESULTS

Patients with ABI low than 0.9 belonged to the group of LEAD. Age, smoking, drinking, hypertension, diabetes mellitus, lipid-lowering drug, antidiabetic, total protein, total protein, triglyceride, low-density lipoprotein cholesterol, glycosylated hemoglobin and homocysteine were the common risk factors shared by LEAD and LECVD (P<0.05). The prevalence of LEAD in patients with LECVD was higher than those without LECVD (P<0.05). In Pearson correlation analysis, LECVD was related to LEAD (P<0.05). Before and after adjusted shared factors, as the performance of the logistic regression models, LEAD was an independent risk factor for the prevalence of LECVD (OR=2.937, 95% CI: [1.956, 4.411], P<0.001).

CONCLUSIONS

Our study demonstrated that an ABI lower than 0.9 is an independent risk factor for LECVD.

A Potential Role for the Receptor for Advanced Glycation End-Products (RAGE) in the Development of Secondhand Smoke-Induced Chronic Sinusitis

Chronic sinusitis (CS) is characterized by sinonasal inflammation, mucus overproduction, and edematous mucosal tissue. CS impacts one in seven adults and estimates suggest up to 15% of the general U.S. population may be affected. This research sought to assess a potential role for receptors for advanced glycation end-products (RAGE), an inflammatory receptor expressed in tissues exposed to secondhand smoke (SHS). Human sinus tissue sections were stained for RAGE and S100s, common RAGE ligands. Wild-type mice and mice that over-express RAGE in sinonasal epithelium (RAGE TG) were maintained in room air (RA) or exposed to secondhand smoke (SHS) via a nose-only delivery system five days a week for 6 weeks. Mouse sections were stained for RAGE and tissue lysates were assayed for cleaved caspase 3, cytokines, or matrix metalloproteases. We discovered increased RAGE expression in sinus tissue following SHS exposure and in sinuses from RAGE TG mice in the absence of SHS. Cleaved caspase-3, cytokines (IL-1β, IL-3, and TNF-α), and MMPs (-9 and -13) were induced by SHS and in tissues from RAGE TG mice. These results expand the inflammatory role of RAGE signaling, a key axis in disease progression observed in smokers. In this relatively unexplored area, enhanced understanding of RAGE signaling during voluntary and involuntary smoking may help to elucidate potential therapeutic targets that may attenuate the progression of smoke-related CS.

KPNA2 Silencing, Regulated by E3 Ubiquitin Ligase FBXW7, Alleviates Endothelial Dysfunction and Inflammation Through Inhibiting the Nuclear Translocation of p65 and IRF3: A Possible Therapeutic Approach for Atherosclerosis

Atherosclerosis (AS), characterized by a maladaptive inflammatory response, is one of the most common causes of death among the elderly. Karyopherin subunit alpha 2 (KPNA2), a member of the nuclear transport protein family, has been reported to play a pro-inflammatory role in various pathological processes by regulating the nuclear translocation of pro-inflammatory transcription factors. However, the function of KPNA2 in AS remains unknown. ApoE-/- mice were fed high-fat diets for 12 weeks to establish an AS mice model. Human umbilical vein endothelial cells (HUVECs) were treated with lipopolysaccharide (LPS) to establish an AS cell model. We found that KPNA2 was upregulated in the aortic roots of atherosclerotic mice and LPS-stimulated cells. KPNA2 knockdown inhibited LPS-induced secretion of pro-inflammatory factors and monocyte-endothelial adhesion in HUVECs, whereas KPNA2 overexpression exerted the opposite effects. p65 and interferon regulatory factor 3 (IRF3), the transcription factors known to regulate the transcription of pro-inflammatory genes, interacted with KPNA2, and their nuclear translocations were blocked following KPNA2 silencing. Furthermore, we found that KPNA2 protein level was decreased by E3 ubiquitin ligase F-box and WD repeat domain containing 7 (FBXW7), which was downregulated in the atherosclerotic mice. FBXW7 overexpression induced ubiquitination with subsequent proteasomal degradation of KPNA2. Meanwhile, the effects of KPNA2 deficiency on atherosclerotic lesions were further confirmed by in vivo experiments. Taken together, our study indicates that KPNA2 downregulation, regulated by FBXW7, may alleviate endothelial dysfunction and related inflammation in the progression of AS by suppressing the nuclear translocation of p65 and IRF3.

Folate Deficiency Increased Microglial Amyloid-β Phagocytosis via the RAGE Receptor in Chronic Unpredictable Mild-Stress Rat and BV2 Cells

Depression is often considered one of the prevalent neuropsychiatric symptoms of Alzheimer's disease (AD). β-amyloid (Aβ) metabolism disorders and impaired microglia phagocytosis are potential pathological mechanisms between depression and AD. Folate deficiency (FD) is a risk factor for depression and AD. In this study, we used a chronic unpredictable mild stress (CUMS) rat model and a model of Aβ phagocytosis by BV2 cells to explore the potential mechanisms by which FD affects depression and AD. The results revealed that FD exacerbated depressive behavior and activated microglia in CUMS rats, leading to an increase in intracellular Aβ and phagocytosis-related receptors for advanced glycation end products (RAGE). Then, in vitro results showed that the expression of the RAGE receptor and M2 phenotype marker (CD206) were upregulated by FD treatment in BV2 cells, leading to an increase in Aβ phagocytosis. However, there was no significant difference in the expression of toll-like receptor 4 (TLR4) and clathrin heavy chain (CHC). Furthermore, when using the RAGE-specific inhibitor FPS-ZM1, there was no significant difference in Aβ uptake between folate-normal (FN) and FD BV2 cell groups. In conclusion, these findings suggest FD may promote microglia phagocytosis Aβ via regulating the expression of RAGE or microglia phenotype under Aβ treatment.

Additive effect between homocysteine and low-density-lipoprotein cholesterol upon incidence of novel carotid plaque formation: data from a Chinese community-based cohort

OBJECTIVE

Homocysteine (HCY) has been associated with carotid plaque in cross-sectional studies, but the prospective relationship between HCY and incident carotid plaque has not been well established. The purpose of this study was to investigate the association between HCY and incidence of novel carotid plaque in a Chinese community-based population without pre-existing carotid atherosclerosis and to assess the additive effect of HCY and low-density lipoprotein cholesterol (LDL-C) on the incidence of novel plaque.

METHODS

At baseline, we measured HCY and other risk factors in subjects aged ≥ 40 years. All participants underwent carotid ultrasound examinations at baseline and after an average of 6.8 years of follow-up. Incidence of plaque was identified if plaque was absent at baseline, but plaque was detected at the end of follow-up. A total of 474 subjects were included in the analysis.

RESULTS

The incidence of novel carotid plaque was 24.47%. Multivariate regression analyses showed that HCY was independently associated with a 1.05-fold-higher likelihood for incident novel plaque (adjusted odds ratio [OR] = 1.05, 95% confidence interval [CI]: 1.01-1.09, P = 0.008). Using tertile 1 and tertile 2 for reference, the top HCY tertile (T3) showed a 2.28-fold-higher likelihood for incident plaque (adjusted OR = 2.28, 95%CI: 1.33-3.93, P = 0.002). The combination of HCY T3 and LDL-C ≥ 3.4 mmol/L had the highest risk for novel plaque formation (adjusted OR = 3.63, 95%CI: 1.67-7.85, P = 0.001) compared to those without either condition. In the LDL-C ≥ 3.4 mmol/L subgroup, HCY was significantly associated with incidence of plaque (adjusted OR = 1.16, 95%CI: 1.04-1.28, P = 0.005, P-interaction = 0.023).

CONCLUSION

In the Chinese community-based population, HCY was independently associated with the incidence of novel carotid plaque. There were additive effect between HCY and LDL-C on the incidence of plaque, the highest risk was observed in individuals with both high HCY levels and LDL-C ≥ 3.4 mmol/L. Our findings suggest that HCY may be a potential target for preventing the incidence of carotid plaque, particularly in individuals with elevated LDL-C levels.

Dissecting the impact of dietary fiber type on atherosclerosis in mice colonized with different gut microbial communities

Dietary fiber consumption has been linked with improved cardiometabolic health, however, human studies have reported large interindividual variations in the observed benefits. We tested whether the effects of dietary fiber on atherosclerosis are influenced by the gut microbiome. We colonized germ-free ApoE-/- mice with fecal samples from three human donors (DonA, DonB, and DonC) and fed them diets supplemented with either a mix of 5 fermentable fibers (FF) or non-fermentable cellulose control (CC) diet. We found that DonA-colonized mice had reduced atherosclerosis burden with FF feeding compared to their CC-fed counterparts, whereas the type of fiber did not affect atherosclerosis in mice colonized with microbiota from the other donors. Microbial shifts associated with FF feeding in DonA mice were characterized by higher relative abundances of butyrate-producing taxa, higher butyrate levels, and enrichment of genes involved in synthesis of B vitamins. Our results suggest that atheroprotection in response to FF is not universal and is influenced by the gut microbiome.

The gastrointestinal-brain-microbiota axis: a promising therapeutic target for ischemic stroke

Ischemic stroke is a highly complex systemic disease characterized by intricate interactions between the brain and gastrointestinal tract. While our current understanding of these interactions primarily stems from experimental models, their relevance to human stroke outcomes is of considerable interest. After stroke, bidirectional communication between the brain and gastrointestinal tract initiates changes in the gastrointestinal microenvironment. These changes involve the activation of gastrointestinal immunity, disruption of the gastrointestinal barrier, and alterations in gastrointestinal microbiota. Importantly, experimental evidence suggests that these alterations facilitate the migration of gastrointestinal immune cells and cytokines across the damaged blood-brain barrier, ultimately infiltrating the ischemic brain. Although the characterization of these phenomena in humans is still limited, recognizing the significance of the brain-gastrointestinal crosstalk after stroke offers potential avenues for therapeutic intervention. By targeting the mutually reinforcing processes between the brain and gastrointestinal tract, it may be possible to improve the prognosis of ischemic stroke. Further investigation is warranted to elucidate the clinical relevance and translational potential of these findings.

Targeting Astrocyte Signaling Alleviates Cerebrovascular and Synaptic Function Deficits in a Diet-Based Mouse Model of Small Cerebral Vessel Disease

Despite the indispensable role that astrocytes play in the neurovascular unit, few studies have investigated the functional impact of astrocyte signaling in cognitive decline and dementia related to vascular pathology. Diet-mediated induction of hyperhomocysteinemia (HHcy) recapitulates numerous features of vascular contributions to cognitive impairment and dementia (VCID). Here, we used astrocyte targeting approaches to evaluate astrocyte Ca2+ dysregulation and the impact of aberrant astrocyte signaling on cerebrovascular dysfunction and synapse impairment in male and female HHcy diet mice. Two-photon imaging conducted in fully awake mice revealed activity-dependent Ca2+ dysregulation in barrel cortex astrocytes under HHcy. Stimulation of contralateral whiskers elicited larger Ca2+ transients in individual astrocytes of HHcy diet mice compared with control diet mice. However, evoked Ca2+ signaling across astrocyte networks was impaired in HHcy mice. HHcy also was associated with increased activation of the Ca2+/calcineurin-dependent transcription factor NFAT4, which has been linked previously to the reactive astrocyte phenotype and synapse dysfunction in amyloid and brain injury models. Targeting the NFAT inhibitor VIVIT to astrocytes, using adeno-associated virus vectors, led to reduced GFAP promoter activity in HHcy diet mice and improved functional hyperemia in arterioles and capillaries. VIVIT expression in astrocytes also preserved CA1 synaptic function and improved spontaneous alternation performance on the Y maze. Together, the results demonstrate that aberrant astrocyte signaling can impair the major functional properties of the neurovascular unit (i.e., cerebral vessel regulation and synaptic regulation) and may therefore represent a promising drug target for treating VCID and possibly Alzheimer's disease and other related dementias.SIGNIFICANCE STATEMENT The impact of reactive astrocytes in Alzheimer's disease and related dementias is poorly understood. Here, we evaluated Ca2+ responses and signaling in barrel cortex astrocytes of mice fed with a B-vitamin deficient diet that induces hyperhomocysteinemia (HHcy), cerebral vessel disease, and cognitive decline. Multiphoton imaging in awake mice with HHcy revealed augmented Ca2+ responses in individual astrocytes, but impaired signaling across astrocyte networks. Stimulation-evoked arteriole dilation and elevated red blood cell velocity in capillaries were also impaired in cortex of awake HHcy mice. Astrocyte-specific inhibition of the Ca2+-dependent transcription factor, NFAT, normalized cerebrovascular function in HHcy mice, improved synaptic properties in brain slices, and stabilized cognition. Results suggest that astrocytes are a mechanism and possible therapeutic target for vascular-related dementia.

Hyperhomocysteinemia in Cardiovascular Diseases: Revisiting Observational Studies and Clinical Trials

Thromboembolic manifestations are relatively frequent in patients with intermediate/severe hyperhomocysteinemia (>30 µmol/L) related to inherited disorders and deficiencies in vitamin B12 and folate. In contrast, moderate hyperhomocysteinemia (15-30 µmol/L) is a modest predictor of cardiovascular risk. The recognition of homocysteine as a cardiovascular risk factor has been challenged by some but not all randomized clinical trials. We reviewed the main data of this controversy and formulated conclusions to be translated in clinical practice.Homocysteine-lowering trials have been performed in cardiovascular subjects with moderate but not intermediate/severe hyperhomocysteinemia despite the dose-effect risk association. The first meta-analyses found no benefit and led cardiology societies not recommending homocysteine in the assessment of cardiovascular risk. This guideline challenged the need to diagnose and treat the nutritional and genetic causes of intermediate/major hyperhomocysteinemia and was not revised when larger meta-analyses concluded to a reduced risk of stroke. In a recent observational study, 84% of consecutive cardiovascular patients assessed for homocysteine had intermediate or major hyperhomocysteinemia, which was properly assessed in only half of the cases and related to B12 and/or folate deficiency and Addison/Biermer disease in 55% of these cases.In conclusion, revisiting observational studies and clinical trials suggests that cardiovascular patients should be screened for hyperhomocysteinemia, when no other risk factor is found. Patients with intermediate/major hyperhomocysteinemia should be properly assessed and treated for B vitamin deficiencies and inherited disorders according to current guidelines. Further trials are needed to assess the effect of lowering homocysteine according to hyperhomocysteinemia categories at baseline.

Epigenetic Regulation of Macrophage Polarization in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of hospitalization and death worldwide, especially in developing countries. The increased prevalence rate and mortality due to CVDs, despite the development of several approaches for prevention and treatment, are alarming trends in global health. Chronic inflammation and macrophage infiltration are key regulators of the initiation and progression of CVDs. Recent data suggest that epigenetic modifications, such as DNA methylation, posttranslational histone modifications, and RNA modifications, regulate cell development, DNA damage repair, apoptosis, immunity, calcium signaling, and aging in cardiomyocytes; and are involved in macrophage polarization and contribute significantly to cardiac disease development. Cardiac macrophages not only trigger damaging inflammatory responses during atherosclerotic plaque formation, myocardial injury, and heart failure but are also involved in tissue repair, remodeling, and regeneration. In this review, we summarize the key epigenetic modifications that influence macrophage polarization and contribute to the pathophysiology of CVDs, and highlight their potential for the development of advanced epigenetic therapies.

Assessment of Atherosclerosis in Ischemic Stroke by means of Ultrasound of Extracranial/Intracranial Circulation and Serum, Urine, and Tissue Biomarkers

It is a common practice to take into consideration age, diabetes, smoking, treated and untreated systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol for the prediction of atherosclerosis and stroke. There are, however, ultrasound markers in use for the assessment of atherosclerosis and the evaluation of stroke risk. Two areas of investigation are of interest: the carotid artery and the intracranial arterial circulation. Again, within the domain of the carotid artery, two ultrasonic markers have attracted our attention: intima media thickness of the carotid artery and the presence of carotid plaque with its various focal characteristics. In the domain of intracranial circulation, the presence of arterial stenosis and the recruitment of collaterals are considered significant ultrasonic markers for the above-mentioned purpose. On the other hand, a series of serum, urine, and tissue biomarkers are found to be related to atherosclerotic disease. Future studies might address the issue of whether the addition of proven ultrasonic carotid indices to the aforementioned serum, urine, and tissue biomarkers could provide the vascular specialist with a better assessment of the atherosclerotic load and solidify their position as surrogate markers for the evaluation of atherosclerosis and stroke risk.

Genetic expression changes and pathologic findings associated with hyperhomocysteinemia in human autopsy brain tissue

Introduction

Vascular contributions to cognitive impairment and dementia (VCID) are a leading cause of dementia. An underappreciated, modifiable risk factor for VCID is hyperhomocysteinemia (HHcy), defined by elevated levels of plasma homocysteine, most often due to impaired B vitamin absorption in aged persons. Studies aimed at identifying neuropathologic features and gene expression profiles associated with HHcy have been lacking.

Methods

A subset of research volunteers from the University of Kentucky Alzheimer's Disease Research Center longitudinal cohort came to autopsy and had ante mortem plasma homocysteine levels available. Brain tissue and blood plasma drawn closest to death were used to measure homocysteine and related metabolites in the current pilot study. Genetic expression profiles of inflammatory markers were evaluated using the Human Neuroinflammation NanoString panel. Further analyses included an evaluation of plasma homocysteine effects on amyloid beta, tau, ionized calcium-binding adaptor molecule 1, and glial fibrillary acidic protein immunohistochemistry in the frontal and occipital cortices. Analytes and other study outcomes were evaluated in relation to ante mortem HHcy status: We identified 13 persons with normal ante mortem plasma homocysteine levels (<14 µmol/L) and 18 who had high plasma homocysteine levels (≥14 µmol/L).

Results

Participants with HHcy demonstrated increased levels of several plasma homocysteine cycle metabolites such as total cysteine, S-adenosyl-homocysteine, cystathionine, and choline. Inflammatory gene expression profiles showed a general downregulation in the setting of elevated plasma homocysteine. HHcy was associated with more and longer microglial processes, but smaller and fewer astrocytes, especially in participants of older age at death. HHcy in older participants was also associated with occipital cortex microhemorrhages and increased severity of atherosclerosis throughout the cerebral vasculature.

Conclusions

Increased plasma homocysteine and older age were associated with the downregulation of inflammatory gene expression markers in association with significant glial and vascular pathology changes. Impaired immune function is a plausible mechanism by which HHcy increases cerebrovascular damage leading to impaired cognitive function.

Dietary Methionine via Dose-Dependent Inhibition of Short-Chain Fatty Acid Production Capacity Contributed to a Potential Risk of Cognitive Dysfunction in Mice

High-methionine diets induce impaired learning and memory function, dementia-like neurodegeneration, and Alzheimer's disease, while low-methionine diets improve learning and memory function. We speculated that variations in intestinal microbiota may mediate these diametrically opposed effects; thus, this study aimed to verify this hypothesis. The ICR mice were fed either a low-methionine diet (LM, 0.17% methionine), normal methionine diet (NM, 0.86% methionine), or high-methionine diet (HM, 2.58% methionine) for 11 weeks. We found that HM diets damaged nonspatial recognition memory, working memory, and hippocampus-dependent spatial memory and induced anxiety-like behaviors in mice. LM diets improved nonspatial recognition memory and hippocampus-dependent spatial memory and ameliorated anxiety-like behavior, but the differences did not reach a significant level. Moreover, HM diets significantly decreased the abundance of putative short-chain fatty acid (SCFA)-producing bacteria (Roseburia, Blautia, Faecalibaculum, and Bifidobacterium) and serotonin-producing bacteria (Turicibacter) and significantly increased the abundance of proinflammatory bacteria Escherichia-Shigella. Of note, LM diets reversed the results. Consequently, the SCFA and serotonin levels were significantly decreased with HM diets and significantly increased with LM diets. Furthermore, HM diets induced hippocampal oxidative stress and inflammation and selectively downregulated the hippocampus-dependent memory-related gene expression, whereas LM diets selectively upregulated the hippocampus-dependent memory-related gene expression. In conclusion, dietary methionine via dose-dependent inhibition of SCFA production capacity contributed to a potential risk of cognitive dysfunction in mice.

Distribution and Determinants of Plasma Homocysteine Levels in a Preconception Population: A Retrospective Single-Center Study

BACKGROUND Raised plasma homocysteine (Hcy) levels have been associated with various diseases and pregnancy complications. Preconception is the primary prevention period to prevent birth defects. This retrospective study aimed to investigate the distribution of plasma Hcy levels among men and women at preconception and further evaluate the factors influencing plasma Hcy levels in a Southern China population. MATERIAL AND METHODS Sex, age, serum folate levels, plasma Hcy levels, and the time of Hcy and folate detection were obtained by medical records. Univariate analysis and multi-factor mixed virtual linear regression were used to explore the distribution and determinants of plasma Hcy levels. RESULTS A total of 3031 participants (1091 men [35.99%] and 1940 women [64.01%]) were included. The average levels of Hcy and the rates of hyperhomocysteinemia (HHcy) in men were higher than those in women (P<0.05). Hcy levels were observed to be lowest during autumn and highest during winter (P<0.05). In the normal Hcy (NHcy) group, serum folate levels were higher than in the HHcy group (P<0.05). Regression analysis suggested that sex, season, and serum folate levels had an effect on Hcy levels, but age was not an influencing factor of Hcy level in the preconception population. CONCLUSIONS This retrospective study showed that Hcy levels are higher in men and in the winter season. Sex, season, and serum folate levels were the influencing factors of Hcy in the preconception population.

Deficiency of B vitamins leads to cholesterol-independent atherogenic transformation of the aorta

Atherosclerosis, the leading cause of cardiovascular disease responsible for the majority of deaths worldwide, cannot be sufficiently explained by established risk factors, including hypercholesterolemia. Elevated plasma homocysteine is an independent risk factor for atherosclerosis and is strongly linked to cardiovascular mortality. However, the role of homocysteine in atherosclerosis is still insufficiently understood. Previous research in this area has been also hampered by the lack of reproducible in vivo models of atherosclerosis that resemble the human situation. Here, we have developed and applied an automated system for vessel wall injury that leads to more homogenous damage and more pronounced atherosclerotic plaque development, even at low balloon pressure. Our automated system helped to glean vital details of cholesterol-independent changes in the aortic wall of balloon-injured rabbits. We show that deficiency of B vitamins, which are required for homocysteine degradation, leads to atherogenic transformation of the aorta resulting in accumulation of macrophages and lipids, impairment of its biomechanical properties and disorganization of aortic collagen/elastin in the absence of hypercholesterolemia. A combination of B vitamin deficiency and hypercholesterolemia leads to thickening of the aorta, decreased aortic water diffusion, increased LDL-cholesterol and impaired vascular reactivity compared to any single condition. Our findings suggest that deficiency of B vitamins leads to atherogenic transformation of the aorta even in the absence of hypercholesterolemia and aggravates atherosclerosis development in its presence.

Serum Homocysteine and Vascular Calcification: Advances in Mechanisms, Related Diseases, and Nutrition

Identifying and preventing modifiable risk factors for cardiovascular disease is very important. Vascular calcification has been studied clinically as an asymptomatic preclinical marker of atherosclerosis and a risk factor for cardio-cerebrovascular disease. It is known that higher homocysteine levels are associated with calcified plaques and the higher the homocysteine level, the higher the prevalence and progression of vascular calcification. Homocysteine is a byproduct of methionine metabolism and is generally maintained at a physiological level. Moreover, it may increase if the patient has a genetic deficiency of metabolic enzymes, nutritional deficiencies of related cofactors (vitamins), chronic diseases, or a poor lifestyle. Homocysteine is an oxidative stress factor that can lead to calcified plaques and trigger vascular inflammation. Hyperhomocysteinemia causes endothelial dysfunction, transdifferentiation of vascular smooth muscle cells, and the induction of apoptosis. As a result of transdifferentiation and cell apoptosis, hydroxyapatite accumulates in the walls of blood vessels. Several studies have reported on the mechanisms of multiple cellular signaling pathways that cause inflammation and calcification in blood vessels. Therefore, in this review, we take a closer look at understanding the clinical consequences of hyperhomocysteinemia and apply clinical approaches to reduce its prevalence.

Association between homocysteinemia and mortality in CKD: A propensity-score matched analysis using NHANES-National Death Index

Hyperhomocysteinemia (HHcy) is considered a risk factor for cardiovascular disease (CVD), including chronic kidney disease (CKD). In this study, we investigated the association between levels of serum homocysteine (Hcy) and mortality, inferred from the presence of CKD. Our study included data of 9895 participants from the 1999 to 2016 National Health and Nutrition Examination Surveys (NHANES). Multivariable-adjusted Cox proportional hazard models using propensity-score, were used to examine dose-response associations between Hcy level and mortality. A total of 9895 participants, 1025 (10.3%) participants were diagnosed with CKD. In a multivariate Cox regression analysis including all participants, Hcy level was significantly associated with all-cause mortality in the nonCKD group, compared to the 1st quartile in the fully adjusted model (2nd quartile: hazard ratio (HR) 1.75, 95% confidence interval (CI) 1.348-2.274, P < .001; 3rd quartile: HR 2.22, 95% CI 1.726-2.855, P < .001; 4th quartile: HR 3.77, 95% CI 2.952-4.830, P < .001). However, this finding was not observed in the CKD group. The observed pattern was similar after propensity score matching. In the nonCKD group, overall mortality increased in proportion to Hcy concentration (2nd quartile: HR 2.19, 95% CI 1.299-3.709, P = .003; 3rd quartile: HR 2.60, 95% CI 1.570-4.332, P < .001; 4th quartile: HR 3.72, 95% CI 2.254-6.139, P < .001). However, the risk of all-cause mortality according to the quartile of Hcy level, did not increase in the CKD group. This study found a correlation between the Hcy level and mortality rate only in the nonCKD group. These altered risk factor patterns may be attributed to protein-energy wasting or chronic inflammation status, that is accompanied by CKD.

A systematic review and meta-analysis expounding the relationship between methylene tetrahydrofolate reductase gene polymorphism and the risk of intracerebral hemorrhage among populations

Background: The relationship between methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphism with the risk of intracerebral hemorrhage (ICH) has remained to be controversial in recent years. This meta-analysis is aimed to confirm the association of these.

Methods: Systematically searching the related studies from the PubMed, Embase, Cochrane Library, China national knowledge internet database from 1 January 1990 to 1 June 2022. The odd ratio (ORs) and 95% confidence interval (CIs) of gene-disease correlation in various gene models were calculated by fixed or random effect model of meta-analysis. We included 20 case-control studies in this meta-analysis with a total of 1,989 ICH patients and 4,032 health controls originated from Asian, Caucasian, and African populations.

Results: The statistical analysis demonstrated the association of MTHFR C677T gene polymorphism with ICH in allele model [OR_{T VS. C} = 1.20 (95%CI: 1.06–1.36)]; homozygote model [OR _{TT VS. CC} = 1.50 (95%CI: 1.20–1.88)]; dominant model [OR _{CT+ TT VS. CC} = 1.23 (95%CI: 1.03–1.48)] and recessive model [OR_{TT VS. CT+CC} = 1.37 (95%CI: 1.17–1.60)]. Besides, we also found the relationship of MTHFR C677T gene polymorphism with Asian in four comparison model (OR_{T VS. C} = 1.19.95%CI:1.09–1.37, OR_{TT VS. CC} = 1.46.95%CI: 1.15–1.85, OR _{CT+ TT VS. CC} = 1.25.95%CI: 1.01–1.54, OR_{TT VS. CT+CC} = 1.34.95%CI: 1.54–1.17) and Caucasian in four comparison model (OR_{T VS. C} = 1.90.95%CI: 1.22–2.97, OR_{TT VS. CC} = 2.67.95%CI: 1.42–5.00, OR _{CT+ TT VS. CC} = 1.56.95%CI: 1.05–2.32, OR_{TT VS. CT+CC} = 2.25.95%CI: 1.46–4.00). But no statistically significant correlation between A1298C polymorphism and the occurrence of ICH was detected in four studies.

Conclusion: MTHFR C677T gene polymorphism increases the risk of ICH in Asian and Caucasian populations but has no impact on the incidence in African communities. More importantly, the risk of ICH increases in TT genotype individuals in comparison to CT and CC genotype individuals in Asian and Caucasian populations.

Homocysteine and atrial fibrillation: novel evidences and insights

Atrial fibrillation (AF) is one of the most prevalent rhythm disorders worldwide, with around 37.574 million cases around the globe (0.51 % global population).  Different studies showed a high informative value of different biomarkers, including such related to the systemic inflammation, biomechanical stress and fibrosis. In this review article we aimed to study only the relation of homocysteine to the AF development. Homocysteine is a sulfur-containing amino acid, that is produced in the process of methionine metabolism. Which is a non-canonical amino acid, that is derived from the food proteins. From the scientific point of view there is a relation between hyperhomocysteinemia and myocardial fibrosis, but these mechanisms are complicated and not sufficiently studied. Homocysteine regulates activity of the ion channels through their redox state. Elevated homocysteine level can condition electrical remodeling of the cardiomyocytes through the increase of sodium current and change in the function of rapid sodium channels, increase of inwards potassium current and decrease in amount of rapid potassium channels. High homocysteine concentration also leads to the shortening of the action potential, loss of the rate adaptation of the action potential and persistent circulation of the re-entry waves. In a series of experimental studies on mice there was an association found between the homocysteine level and activity of vascular inflammation. Elevation of homocysteine level is an independent factor of the thromboembolic events and AF relapses. Population studies showed, that homocysteine is an independent risk factor for AF. So, homocysteine is an interesting target for up-stream therapy.

Association of Homocysteine Levels With Medial Temporal Lobe Atrophy Among Carriers and Non-carriers of APOE ε4 in MCI Subjects

Background

Different clinical subtypes of mild cognitive impairment (MCI) involve heterogeneous underlying etiologies. This study investigated the association between demographics, neuropsychological performance, apolipoprotein E (APOE) genotype and magnetic resonance imaging (MRI) measures in patients with MCI (amnestic [aMCI] and non-amnestic [naMCI]).

Methods

This case-control study included 130 aMCI patients, 58 naMCI patients, and 1,106 healthy controls (HCs). APOE genotypes, medial temporal lobe atrophy (MTA), neurological evaluation results, and white matter hyperintensities (WMH) were investigated. Serum folate and vitamin B12 concentrations were analyzed by radioimmunoassay, and plasma hyperhomocysteinemia (Hcy) was assessed by a high-performance liquid chromatography-fluorescence method.

Results

Serum folate levels were significantly lower, but plasma Hcy levels were higher, in patients with aMCI and naMCI than in healthy controls. There were significantly higher MTA scores in the aMCI group than the healthy control group. Multiple linear regression showed that serum Hcy and folate concentrations were positively associated with MTA (p < 0.05), while APOE4 showed a significant negative association with MTA in the aMCI group (p < 0.01). In addition, moderate/severe WMH showed a significant negative association with MTA in the naMCI and HC groups (p < 0.01).

Conclusion

The combined presence of APOE4 and Hcy is associated with aMCI in elderly individuals, while moderate/severe WMH is related to naMCI, which suggests etiological differences across MCI subtypes.

Homocysteine, Vitamins B6 and Folic Acid in Experimental Models of Myocardial Infarction and Heart Failure—How Strong Is That Link?

Cardiovascular diseases are the leading cause of death and the main cause of disability. In the last decade, homocysteine has been found to be a risk factor or a marker for cardiovascular diseases, including myocardial infarction (MI) and heart failure (HF). There are indications that vitamin B6 plays a significant role in the process of transsulfuration in homocysteine metabolism, specifically, in a part of the reaction in which homocysteine transfers a sulfhydryl group to serine to form α-ketobutyrate and cysteine. Therefore, an elevated homocysteine concentration (hyperhomocysteinemia) could be a consequence of vitamin B6 and/or folate deficiency. Hyperhomocysteinemia in turn could damage the endothelium and the blood vessel wall and induce worsening of atherosclerotic process, having a negative impact on the mechanisms underlying MI and HF, such as oxidative stress, inflammation, and altered function of gasotransmitters. Given the importance of the vitamin B6 in homocysteine metabolism, in this paper, we review its role in reducing oxidative stress and inflammation, influencing the functions of gasotransmitters, and improving vasodilatation and coronary flow in animal models of MI and HF.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection is Associated with Homocysteine Level and Clinical Outcomes in Ischemic Stroke Patients

BACKGROUND: Since its emergence in December 2019 and declared as pandemic in March 2020, the drastic increase in cases of coronavirus disease 2019 (COVID-19) is alarming the importance of disease monitoring in order to prevent further complication, like ischemic stroke. One of the efforts is utilizing biomarker. For instance, elevated homocysteine level, already known risk factor of ischemic stroke, is currently identified in COVID-19 patients. AIM: To assess factor associated with homocysteine level and clinical outcomes of ischemic stroke patients. Methods: A cross-sectional study was conducted at Dr. Zainoel Abidin Hospital di Indonesia between March and August 2021. Ischemic stroke patients who had physical and neurology examinations, SARS-CoV-2 RT-PCR swab, chest x-ray, electrocardiography, head CT-scan and the total homocysteine level were included. To assess the factors associated with homocysteine level and the outcomes of ischemic stroke patients, the independent Student t-test or Anova and chi-squared were used, respectively. RESULTS: We included 62 ischemic stroke patients of which 32 (51.6%) were male and the age ranged between 30 and 80 years. Out of total, 60 patients (96.8%) were survived after the hospital admission. There was a significant association between gender and having COVID-19 with homocysteine level (p=0.012 and p=0.020, respectively). Having COVID-19 was the only variable significantly associated with the outcome of the ischemic stroke patient (p=0.035). CONCLUSION: COVID-19 is associated with homocysteine level and the clinical outcome in ischemic stroke patients. Therefore, SARS-CoV-2 infection in ischemic stroke or vice versa need to be monitored closely in hospital settings.

Status of hyperhomocysteinemia in China: results from the China Stroke High-risk Population Screening Program, 2018

A nationwide survey was conducted from October 2018 to September 2019 to assess the prevalence of hyperhomocysteinemia (Hhcy) and its influencing factors in China. A standardized questionnaire was used to collect information. Hhcy was defined as the level of serum homocysteine (HCY) ⩾ 15.0µmol/L. The H-type hypertension (HHYP) was defined as hypertension with an elevated serum HCY 15.0µmol/L). Finally, 110 551 residents ⩾ 40 years of age from 31 provinces in the mainland of China were included. Overall, the median serum HCY level was 10.9µmol/L (interquartile range 7.9-15.1). A total of 28 633 participants (25.9%) were defined as Hhcy. The Hhcy prevalence ranged from 7.9% in Shanghai to 56.8% in Tianjin. The data showed that serum HCY levels were associated with age, male gender, cigarette smoking, hypertension, diabetes, ethnicity, endurance in exercise (inverse), and fruit and vegetable intake (inverse). In addition, 15 486 participants were defined as HHYP, and the rate was 14.0%. HHYP was an independent predictor of stroke with an adjusted odds ratio of 1.752 (95% CI 1.338-2.105). The geographical distribution pattern of the Hhcy epidemic reflects dynamic differences, and national strategies should be carried out to further improve the care of patients with Hhcy across China.

Vitamin B12 and gut-brain homeostasis in the pathophysiology of ischemic stroke

Stroke is a leading cause of morbidity and mortality worldwide. It inflicts immeasurable suffering on patients and their loved ones and carries an immense social cost. Efforts to mitigate the impact of stroke have focused on identifying therapeutic targets for the prevention and treatment. The gut microbiome represents one such potential target given its multifaceted effects on conditions known to cause and worsen the severity of stroke. Vitamin B12 (VB12) serves as a cofactor for two enzymes, methylmalonyl-CoA synthase and methionine synthase, vital for methionine and nucleotide biosynthesis. VB12 deficiency results in a buildup of metabolic substrates, such as homocysteine, that alter immune homeostasis and contribute to atherosclerotic disorders, including ischemic stroke. In addition to its support of cellular function, VB12 serves as a metabolic cofactor for gut microbes. By shaping microbial communities, VB12 further impacts local and peripheral immunity. Growing evidence suggests that gut dysbiosis-related immune dysfunction induced by VB12 deficiency may potentially contributes to stroke pathogenesis, its severity, and patient outcomes. In this review, we discuss the complex interactions of VB12, gut microbes and the associated metabolites, and immune homeostasis throughout the natural history of ischemic stroke.

The regulation of Ero1-alpha in homocysteine-induced macrophage apoptosis and vulnerable plaque formation in atherosclerosis

BACKGROUND AND AIMS

Hyperhomocysteinemia (HHcy) is an independent risk factor for atherosclerosis and plaque vulnerability. Macrophage apoptosis mediated by endoplasmic reticulum (ER) stress plays an important role in the pathogenesis of HHcy-aggravated atherosclerosis. Endoplasmic reticulum oxidoreductase 1α (Ero1α) is critical for ER stress-induced apoptosis. We hypothesized that Ero1α may contribute to ER-stress induced macrophage apoptosis and plaque stability in advanced atherosclerotic lesions by HHcy.

METHODS

Apoe^-/- mice were maintained on drinking water containing homocysteine (Hcy, 1.8 g/L) to establish HHcy atherosclerotic models. The role of Ero1α in atherosclerotic plaque stability, macrophage apoptosis and ER stress were monitored in the plaque of aortic roots in HHcy Apoe^-/- mice with or without silence or overexpression of Ero1α through lentivirus. Mouse peritoneal macrophages were used to confirm the regulation of Ero1α on ER stress dependent apoptosis in the presence of HHcy.

RESULTS

Atherosclerotic plaque vulnerability and macrophage apoptosis were promoted in Apoe^-/- mice by high Hcy diet, accompanied by the upregulation of Ero1α expression and ER stress. Inhibition of Ero1α prevented macrophage apoptosis and atherosclerotic plaque vulnerability, and vice versa. Consistently, in mouse peritoneal macrophages, ER stress and apoptosis were attenuated by Ero1α deficiency, but enhanced by Ero1α overexpression.

CONCLUSIONS

Hcy, via upregulation of Ero1α expression, activates ER stress-dependent macrophage apoptosis to promote vulnerable plaque formation in atherosclerosis. Ero1α may be a potential therapeutic target for atherosclerosis induced by Hcy.

Cross-Sectional Examination of Homocysteine Levels with Sarcopenia and Its Components in Memory Clinic Outpatients

BACKGROUND

Homocysteine is a common risk factor for cognitive impairment and sarcopenia. However, very few studies have shown an association between sarcopenia and serum homocysteine levels after adjustment for cognitive function.

OBJECTIVE

The purpose of this study was to investigate the relationship between homocysteine and sarcopenia in memory clinic patients.

METHODS

This cross-sectional study investigated outpatients in a memory clinic. We enrolled 1,774 participants (≥65 years old) with measured skeletal muscle mass index (SMI), hand grip strength (HGS), and homocysteine. All participants had undergone cognitive assessments and were diagnosed with dementia, mild cognitive impairment, or normal cognition. Patient characteristics were compared according to sarcopenia presence, SMI level, or HGS. Multivariate logistic regression analysis was performed to determine the association of homocysteine with sarcopenia, low SMI, or low HGS. Next, linear regression analysis was performed using HGS as a continuous variable.

RESULTS

Logistic regression analysis showed that low HGS was significantly associated with homocysteine levels (p = 0.002), but sarcopenia and low SMI were not. In linear regression analysis, HGS was negatively associated with homocysteine levels after adjustment for Mini-Mental State Examination score (β= -2.790, p < 0.001) or clinical diagnosis of dementia (β= -3.145, p < 0.001). These results were similar for men and women.

CONCLUSION

Our results showed a negative association between homocysteine and HGS after adjustment for cognitive function. Our findings strengthen the assumed association between homocysteine and HGS. Further research is needed to determine whether lower homocysteine levels lead to prevent muscle weakness.

Fetal Programming by Methyl Donor Deficiency Produces Pathological Remodeling of the Ascending Aorta

[Figure: see text].

A narrative review on the role of folate-mediated one-carbon metabolism and its associated gene polymorphisms in posing risk to preeclampsia

Preeclampsia (PE) presents a major obstetrical problem for mother and fetus which is characterized by the onset of hypertension and proteinuria in formerly normotensive women. Altered folate-mediated one-carbon metabolism is one of the factors for PE development either due to nutritional insufficiencies such as folate deficiency or polymorphisms in genes that code for the key enzymes of the cycle. Commonly, there are four genes in the cycle whose polymorphisms have been described in relation to PE. These factors could cause elevation of homocysteine; the toxic metabolite, which subsequently leads to the development of PE. Sufficient levels of folate have been considered important during pregnancy and may reduce the risk of development of PE. This review aims at discussing genetic polymorphisms and nutritional deficiencies as probable predisposing factors and suggests considering fetal genotypes, varied ethnicities, and interaction of various other factors involved to render better conclusiveness to the present studies.

Hyperhomocysteinemia and low vitamin B12 are associated with the risk of early pregnancy loss: A clinical study and meta-analyses

One-carbon metabolism is crucial for the maintenance of healthy pregnancy and alterations in this pathway have been associated with various pregnancy-related complications. Therefore, the present study was conducted to test the hypothesis that the altered folic acid, vitamin B12 and homocysteine levels are associated with the risk of early pregnancy loss (EPL). Plasma folic acid, vitamin B12 and homocysteine levels were analyzed in 83 females with EPL and 70 healthy pregnant females in their first trimester. Further, meta-analyses of folic acid, vitamin B12 and homocysteine were also performed involving various eligible studies. Results from our case-control study and meta-analysis showed that folic acid deficiency is not associated with the risk of EPL. On the other hand, low vitamin B12 and hyperhomocysteinemia were individually found to be significant risk factors for EPL in the present study (P < .01, P < .05, respectively) and meta-analysis as well (P < .001, P < .05, respectively). Vitamin B12 deficiency in combination with hyperhomocysteinemia was a more serious risk factor for EPL (Odds Ratio = 4.98, P = 0.002). Therefore, we conclude that vitamin B12 deficiency and elevated homocysteine levels are independent risk factors for EPL, and of higher risk when combined. The assessment of vitamin B12 and homocysteine levels may serve as a good screening marker for EPL risk.

The Effects of Medicinal Plants and Bioactive Natural Compounds on Homocysteine

BACKGROUND

Among non-communicable diseases, cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity in global communities. By 2030, CVD-related deaths are projected to reach a global rise of 25 million. Obesity, smoking, alcohol, hyperlipidemia, hypertension, and hyperhomocysteinemia are several known risk factors for CVDs. Elevated homocysteine is tightly related to CVDs through multiple mechanisms, including inflammation of the vascular endothelium. The strategies for appropriate management of CVDs are constantly evolving; medicinal plants have received remarkable attention in recent researches, since these natural products have promising effects on the prevention and treatment of various chronic diseases. The effects of nutraceuticals and herbal products on CVD/dyslipidemia have been previously studied. However, to our knowledge, the association between herbal bioactive compounds and homocysteine has not been reviewed in details. Thus, the main objective of this study is to review the efficacy of bioactive natural compounds on homocysteine levels according to clinical trials and animal studies.

RESULTS

Based on animal studies, black and green tea, cinnamon, resveratrol, curcumin, garlic extract, ginger, and soy significantly reduced the homocysteine levels. According to the clinical trials, curcumin and resveratrol showed favorable effects on serum homocysteine. In conclusion, this review highlighted the beneficial effects of medicinal plants as natural, inexpensive, and accessible agents on homocysteine levels based on animal studies. Nevertheless, the results of the clinical trials were not uniform, suggesting that more well-designed trials are warranted.

Vitamin B12 and Folate as Risk Factors for Retinal Vein Occlusion: A Meta-Analysis

PURPOSE

To evaluate the association between serum vitamin B12/folate and retinal vein occlusion (RVO).

METHODS

A comprehensive search of the PubMed database was performed, which identified 271 abstracts to be screened. Ten studies met our inclusion criteria and a meta-analysis of these comparative case-control studies was performed on the mean ± standard deviation serum vitamin B12 and folate levels, without language restrictions. Nine studies with 720 patients with RVO and 613 controls were included in the meta-analysis for vitamin B12, and 10 studies with 784 patients with RVO and 677 controls in the meta-analysis for folate.

RESULTS

There was no statistically significant difference between patients with RVO and controls in serum vitamin B12 levels (mean difference: - 40.25 pg/mL, p = 0.28), either central RVO (mean difference: - 18.24 pg/mL, p = 0.71) or branch RVO (mean difference: - 23.56 pg/mL, p = 0.48). On the contrary, the plasma folate level was significantly lower in RVO patients than in controls (mean difference: - 1.34 ng/mL, p = 0.001), as well as in patients with CRVO compared to controls (mean difference: - 1.48 ng/mL, p = 0.006), but not in BRVO patients (mean difference: - 0.72 ng/mL, p = 0.11).

CONCLUSIONS

RVO is associated with low serum folate levels, but not with serum vitamin B12 levels.

Case Report: Two Novel Frameshift Mutations in SLC20A2 and One Novel Splice Donor Mutation in PDGFB Associated With Primary Familial Brain Calcification

Primary familial brain calcification (PFBC, OMIM#213600), also known as Fahr's disease, is characterized by bilateral and symmetric brain calcification in the basal ganglia (globus pallidus, caudate nucleus, and putamen), thalamus, subcortical white matter, and cerebellum. PFBC can be caused by loss-of-function mutations in any of the six known causative genes. The most common clinical manifestations include movement disorders, cognitive impairment, and neuropsychiatric signs that gradually emerge in middle-aged patients. To broaden the PFBC mutation spectrum, we examined nine members of a family with PFBC and two sporadic cases from clinical departments, and sequenced all PFBC-causative genes in the index case. Two novel frameshift mutations in SLC20A2 [NM_001257180.2; c.806delC, p.(Pro269Glnfs^*49) and c.1154delG, p.(Ser385Ilefs^*70)] and one novel splice donor site mutation (NM_002608.4, c.456+1G>C, r.436_456del) in PDGFB were identified in the patient cohort. c.806delC co-segregated with brain calcification and led to SLC20A2 haploinsufficiency among the affected family members. The c.456+1G>C mutation in PDGFB resulted in aberrant mRNA splicing, thereby forming mature transcripts containing an in-frame 21 base pair (bp) deletion, which might create a stably truncated protein [p.(Val146_Gln152del)] and exert a dominant negative effect on wild-type PDGFB. All three mutations were located in highly conserved regions among multiple species and predicted to be pathogenic, as evaluated by at least eight common genetic variation scoring systems. This study identified three novel mutations in SLC20A2 and PDGFB, which broadened and enriched the PFBC mutation spectrum.

Suppression of apoptosis in vascular endothelial cell, the promising way for natural medicines to treat atherosclerosis

Atherosclerosis, a chronic multifactorial disease, is closely related to the development of cardiovascular diseases and is one of the predominant causes of death worldwide. Normal vascular endothelial cells play an important role in maintaining vascular homeostasis and inhibiting atherosclerosis by regulating vascular tension, preventing thrombosis and regulating inflammation. Currently, accumulating evidence has revealed that endothelial cell apoptosis is the first step of atherosclerosis. Excess apoptosis of endothelial cells induced by risk factors for atherosclerosis is a preliminary event in atherosclerosis development and might be a target for preventing and treating atherosclerosis. Interestingly, accumulating evidence shows that natural medicines have great potential to treat atherosclerosis by inhibiting endothelial cell apoptosis. Therefore, this paper reviewed current studies on the inhibitory effect of natural medicines on endothelial cell apoptosis and summarized the risk factors that may induce endothelial cell apoptosis, including oxidized low-density lipoprotein (ox-LDL), reactive oxygen species (ROS), angiotensin II (Ang II), tumor necrosis factor-α (TNF-α), homocysteine (Hcy) and lipopolysaccharide (LPS). We expect this review to highlight the importance of natural medicines, including extracts and monomers, in the treatment of atherosclerosis by inhibiting endothelial cell apoptosis and provide a foundation for the development of potential antiatherosclerotic drugs from natural medicines.

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.

Role of hydrogen sulfide in endothelial dysfunction: Pathophysiology and therapeutic approaches

BACKGROUND

The vascular endothelium represents a fundamental mechanical and biological barrier for the maintenance of vascular homeostasis along the entire vascular tree. Changes in its integrity are associated to several cardiovascular diseases, including hypertension, atherosclerosis, hyperhomocysteinemia, diabetes, all linked to the peculiar condition named endothelial dysfunction, which is referred to the loss of endothelial physiological functions, comprehending the regulation of vascular relaxation and/or cell redox balance, the inhibition of leukocyte infiltration and the production of NO. Among the endothelium-released vasoactive factors, in the last years hydrogen sulfide has been viewed as one of the main characters involved in the regulation of endothelium functionality, and many studies demonstrated that H2S behaves as a vasoprotective gasotransmitter in those cardiovascular diseases where endothelial dysfunction seems to be the central issue.

AIM

The role of hydrogen sulfide in endothelial dysfunction-related cardiovascular diseases is discussed in this review.

KEY SCIENTIFIC CONCEPTS

Possible therapeutic approaches using molecules able to release H2S.

Characterization of Early-Stage Alcoholic Liver Disease with Hyperhomocysteinemia and Gut Dysfunction and Associated Immune Response in Alcohol Use Disorder Patients

Heavy alcohol consumption can cause hyperhomocysteinemia, which could be consequential in the proinflammatory response and worsening of the neurobehavioral domains of alcohol use disorder (AUD), such as alcohol withdrawal. We examined the role of heavy drinking, hyperhomocysteinemia, gut dysfunction and inflammation in early-stage alcoholic liver disease (ALD) in AUD patients. A total of 110 AUD patients without clinical manifestations of liver injury were grouped by the serum homocysteine levels (SHL): normal ≤ 13 µmol/L (Group 1 (Gr.1); n = 80), and elevated > 13 µmol/L (Group 2 (Gr.2), n = 30). A comprehensive metabolic panel, SHL, a nutritional assessment, and drinking history assessed by the timeline followback questionnaire were evaluated. A subset analysis was performed on 47 subjects (Gr.1 n = 27; Gr.2 n = 20) for additional measures: Clinical Institute Withdrawal Assessment for Alcohol (CIWA) score, plasma cytokines (interleukin-1β (IL-1β)), gut dysfunction markers (lipopolysaccharide (LPS), and LPS-binding protein (LBP)); 27% of the AUD patients exhibited hyperhomocysteinemia. SHL was significantly associated (p = 0.034) with heavy drinking days (HDD90). Subset analyses showed that the withdrawal ratings were both clinically and statistically (p = 0.033) elevated and significantly associated with hyperhomocysteinemia (p = 0.016) in Gr.2. LBP, IL1-β, SHL, and HDD90 showed significant cumulative effects (adjusted R² = 0.627) on withdrawal ratings in Gr.2 subset. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly higher in all Gr.2 patients; AUROC showed a fair level of true positivity for ALT (0.676), and AST (0.686). Il1-β, LBP, SHL, and HDD90 showed significant cumulative effects (adjusted R² = 0.554) on the elevated ALT in Gr.2 subset as well. The gut-brain derived proinflammatory response, patterns of heavy drinking, and hyperhomocysteinemia were closely associated with clinically elevated alcohol withdrawal and elevated liver injury. Hyperhomocysteinemia could have a potential phenotypic marker response indicative of early-stage ALD along with AUD.

Incremental Accuracy of Blood Biomarkers for Predicting Clinical Outcomes After Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is associated with high mortality, morbidity, and recurrence. Studies have reported the accuracy of several blood biomarkers in predicting clinical outcomes; however, their independent contribution in prediction remains to be established.

AIM

To investigate the incremental accuracy in predicting clinical outcomes in patients with ICH in a north Indian population using blood-based biomarkers.

METHODS

In this study, a total of 250 ICH cases were recruited within 72 hours of onset. Baseline clinical and CT scan measurement were recorded. Homocysteine (HCY), C-reactive protein (CRP), matrix metalloproteinase-9 (MMP9), E-selectin (SELE), and P-selectin (SELP) levels were measured through ELISA. Telephonic follow-up was done by using mRS scale at three months.

RESULTS

The mean age of cohort was 54.9 (SD±12.8) years with 64.8% patients being male. A total of 109 (43.6%) deaths were observed over three months follow-up. Area under the receiver operating characteristics curve-(AUROC) for 90-day mortality were 0.55 (HCY), 0.62 (CRP), 0.57 (MMP9), 0.60 (SELE) and 0.53 (SELP) and for poor outcome at 90-day (mRS: 3-6) were 0.60 (HCY), 0.62 (CRP), 0.54 (MMP9), 0.67 (SELE) and 0.54 (SELP). In multivariable model including age, ICH volume, IVH and GCS at admission, serum SELE (p=0.004) significant for poor outcome with improved AUROC (0.86) and HCY (p=0.04), CRP (p=0.003) & MMP9 (p=0.02) for mortality with least Akaike's Information Criterion-(AIC) (1060.5).

CONCLUSIONS

Our findings suggest that the serum SELE is a significant predictor of poor outcome and HCY, CRP & MMP9 for Mortality in patients with ICH in the north Indian population.

Association of Severity and Prognosis With Elevated Homocysteine Levels in Patients With Intracerebral Hemorrhage

Background: Intracerebral hemorrhage (ICH) has high mortality and morbidity rates in the world. Homocysteine (Hcy) has been demonstrated to be an independent risk factor and could predict the prognosis and recurrence of ischemic stroke. In our study, we aimed to find out the relationship between Hcy levels and the severity and prognosis of patients with ICH.

Methods: Patients' basic characteristics and laboratory examination results, including the concentration of homocysteine, were taken at baseline from January 2014 to September 2016, and a 1 year follow-up, including the modified Rankin Scale and living status, was taken for all the patients. Logistic regression and Kaplan–Meier survival method were used to analyze the relationship between different Hcy levels and clinical outcome.

Results: A total of 551 patients with acute ICH from 13 hospitals in Beijing were enrolled in our study. High Hcy was detected in 284 patients (51.5%). Percentage of male, smoking, drinking, and concentration of hemoglobin A1c and triglyceride levels showed a significant difference between different Hcy level groups (all P-values <0.05). In the logistic regression analysis, high Hcy level is an independent risk factor for the prevalence of 3 month poor prognosis [odd ratio (95% confidence interval) = 1.601 (1.063–2.412), P = 0.0242], especially in female subgroup. In the 1 year follow-up period, high Hcy level patients had a significantly higher rate of fatal incidence compared to normal Hcy level patients (P = 0.0023).

Conclusions: High Hcy level was independently associated with poorer 3 month prognosis and a lower survival rate within 1 year in patients with ICH.

The slow releasing hydrogen sulfide donor GYY4137 reduces neointima formation upon FeCl3 injury of the carotid artery in mice

INTRODUCTION

Neointima formation is closely linked to vascular stenosis and occurs after endothelial damage. Hydrogen sulfide is an endogenous pleiotropic mediator with numerous positive effects on the cardio vascular system.

OBJECTIVE

This study evaluates the effect of the slow releasing hydrogen sulfide donor GYY4137 (GYY) on neointimal formation in vivo.

METHODS

The effect of GYY on neointimal formation in the carotid artery was studied in the FeCl3 injury model in GYY- or vehicle-treated mice. The carotid arteries were studied at days 7 and 21 after treatment by means of histology and immunohistochemistry for proliferating cell nuclear antigen (PCNA) and alpha smooth muscle actin (α-SMA).

RESULTS

GYY treatment significantly reduced the maximal diameter and the area of the newly formed neointima on both days 7 and 21 when compared to vehicle treatment. GYY additionally reduced the number of PCNA- and α-SMA-positive cells within the neointima on day 21 after FeCl3 injury of the carotid artery.

CONCLUSIONS

Summarizing, single treatment with the slow releasing hydrogen sulfide donor GYY reduced the extent of the newly formed neointima by affecting the cellular proliferation at the site of vascular injury.

B Vitamins and Their Role in Immune Regulation and Cancer

B group vitamins represent essential micronutrients for myriad metabolic and regulatory processes required for human health, serving as cofactors used by hundreds of enzymes that carry out essential functions such as energy metabolism, DNA and protein synthesis and other critical functions. B vitamins and their corresponding vitamers are universally essential for all cellular life forms, from bacteria to humans. Humans are unable to synthesize most B vitamins and are therefore dependent on their diet for these essential micronutrients. More recently, another source of B vitamins has been identified which is derived from portions of the 10¹³ bacterial cells inhabiting the gastrointestinal tract. Here we review the expanding literature examining the relationship between B vitamins and the immune system and diverse cancers. Evidence of B vitamin’s role in immune cell regulation has accumulated in recent years and may help to clarify the disparate findings of numerous studies attempting to link B vitamins to cancer development. Much work remains to be carried out to fully clarify these relationships as the complexity of B vitamins’ essential functions complicates an unequivocal assessment of their beneficial or detrimental effects in inflammation and cancers.

Plasma homocysteine levels are positively associated with interstitial lung disease in dermatomyositis patients with anti-aminoacyl-tRNA synthetase antibody

Homocysteine is a sulfhydryl-containing amino acid that is derived from dietary methionine, and there has been increasing evidence that elevated plasma homocysteine levels are associated with increased risk of central and peripheral vascular disorders, including carotid, coronary and peripheral arterial diseases, and Raynaud's phenomenon. Recently, associations of plasma homocysteine levels with autoimmune diseases such as systemic lupus erythematodes and systemic sclerosis have been reported. However, no study analyzed the association between plasma homocysteine levels and dermatomyositis (DM). The objective of this study was to examine plasma homocysteine levels and their clinical associations in patients with DM. Plasma homocysteine levels in 28 Japanese patients with DM and 22 healthy controls were examined. We found that the plasma homocysteine levels in DM patients were significantly higher than those in healthy individuals (15.8 ± 1.1 vs 8.5 ± 0.5 µmol/L, P < 0.01). Presence of mechanic's hand, complication of interstitial lung disease (ILD), high serum Krebs von den Lungen-6 (KL-6), surfactant protein-D and creatine kinase levels, and anti-aminoacyl-tRNA synthetase (ARS) antibody (Ab) positivity were significantly more prevalent among DM patients with elevated plasma homocysteine levels. The plasma homocysteine levels in DM patients with mechanic's hand, ILD and anti-ARS Ab were significantly higher than those in DM without those features. Furthermore, the plasma homocysteine levels were positively correlated with serum KL-6 levels. These results suggest that the pathogenesis of elevated plasma homocysteine levels may be associated with ILD in DM patients, especially with anti-ARS Ab, and further examination is required.

Implication of Hyperhomocysteinemia in Blood Retinal Barrier (BRB) Dysfunction

Elevated plasma homocysteine (Hcy) level, known as hyperhomocysteinemia (HHcy) has been linked to different systemic and neurological diseases, well-known as a risk factor for systemic atherosclerosis and cardiovascular disease (CVD) and has been identified as a risk factor for several ocular disorders, such as diabetic retinopathy (DR) and age-related macular degeneration (AMD). Different mechanisms have been proposed to explain HHcy-induced visual dysfunction, including oxidative stress, upregulation of inflammatory mediators, retinal ganglion cell apoptosis, and extracellular matrix remodeling. Our previous studies using in vivo and in vitro models of HHcy have demonstrated that Hcy impairs the function of both inner and outer blood retinal barrier (BRB). Dysfunction of BRB is a hallmark of vision loss in DR and AMD. Our findings highlighted oxidative stress, ER stress, inflammation, and epigenetic modifications as possible mechanisms of HHcy-induced BRB dysfunction. In addition, we recently reported HHcy-induced brain inflammation as a mechanism of blood–brain barrier (BBB) dysfunction and pathogenesis of Alzheimer’s disease (AD). Moreover, we are currently investigating the activation of glutamate receptor N-methyl-d-aspartate receptor (NMDAR) as the molecular mechanism for HHcy-induced BRB dysfunction. This review focuses on the studied effects of HHcy on BRB and the controversial role of HHcy in the pathogenesis of aging neurological diseases such as DR, AMD, and AD. We also highlight the possible mechanisms for such deleterious effects of HHcy.

Folate deficiency promotes differentiation of vascular smooth muscle cells without affecting the methylation status of regulated genes

Elevated serum homocysteine, an intermediate of cellular one-carbon metabolism, is an independent risk factor for cardiovascular disease (CVD). Folate deficiency increases serum homocysteine and may contribute to CVD progression. Vascular smooth muscle cells (VSMCs) regulate vascular contractility, but also contribute to repair processes in response to vascular injury. Nutritional deficiencies, like folate deficiency, are thought to impact on this phenotypic plasticity, possibly by epigenetic mechanisms. We have investigated the effect of folate deficiency on VSMCs in two cell culture systems representing early and late stages of smooth muscle cells differentiation. We find that folate deficiency promotes differentiation towards a more contractile phenotype as indicated by increased expression of respective marker genes. However, microarray analysis identified markers of striated muscle as the predominant gene expression change elicited by folate deficiency. These changes are not merely a reflection of cell cycle arrest, as foetal calf serum restriction or iron deficiency do not replicate the gene expression changes observed in response to folate deficiency. Folate deficiency only has a marginal effect on global DNA methylation. DNA methylation of CpG islands associated with genes regulated by folate deficiency remains unaffected. This supports our earlier findings in a mouse model system which also did not show any changes in global DNA methylation in response to folate and vitamin B6/B12 deficiency. These data suggest that folate deficiency enhances the expression of smooth muscle marker gene expression, promotes a shift towards a skeletal muscle phenotype, and does not regulate gene expression via DNA methylation.

Elevated plasma homocysteine levels are associated with impaired peripheral microvascular vasomotor response

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Homocysteine > 10 μmol/L is associated with peripheral microvascular endothelial dysfunction (PMED).

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Homocysteine > 10 μmol/L was associated with PMED in older, obese, or hypertensive patients.

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The association of homocysteine and PMED was prominent in patients with B-vitamins.

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Homocysteine > 10 μmol/L was associated with higher major cardiovascular events in univariate analysis.

Background

Hyperhomocysteinemia (HHcy) has been proposed as an important cardiovascular risk factor (cRF). However, little is known about the association between plasma homocysteine levels and peripheral microvascular endothelial dysfunction (PMED), which is an integrated index of vascular health.

Methods

This cross-sectional and retrospective cohort study included patients who underwent non-invasive PMED assessment using reactive hyperemia peripheral arterial tonometry (RH-PAT). The association between HHcy and PMED, and its impact on MACE (all-cause mortality and atherosclerotic cardiovascular events) was investigated.

Results

A total of 257 patients were enrolled (HHcy > 10.0 µmol/L, N = 51; lower levels of homocysteine [LHcy] ≤ 10 µmol/L, N = 206). Patients with HHcy were older, predominantly males, and with more comorbidities than patients with LHcy (p < 0.05 for all). RH-PAT index was lower in patients with HHcy versus LHcy (p = 0.01). A significant association between HHcy and PMED was observed in older (≥60 years), obese (≥30 kg/m²), present/past smokers and hypertensive patients. HHcy was significantly associated with PMED even after adjusting for other cRF and B-vitamins supplementation. HHcy was associated with an increased risk of MACE with a hazard ratio of 3.65 (95% CI 1.41–9.48, p = 0.01) and an adjusted hazard ratio of 2.44 (95% CI 0.91–6.51, p = 0.08) after adjustment for age (≥60 years).

Conclusion

HHcy was independently associated with PMED after adjusting for cRF and B-vitamins supplementation. Thus, the link between homocysteine and MACE could be mediated by endothelial dysfunction, and will require further clarification with future studies.