Exercise attenuates the perioperative neurocognitive disorder induced by hyperhomocysteinemia in mice

The perioperative neurocognitive disorder (PND) is a severe complication that affects millions of surgical patients each year. Homocysteine (Hcy) is known to increase the risk of developing PND in both young and elderly mice. However, whether Hcy alone can induce cognitive deficits in middle-aged mice (12-month-old), whether exercise can attenuate Hcy-induced hippocampus-related cognitive deficits after surgery through suppressing neuroinflammation, synaptic elimination, and the level of Hcy remains unknown. The present study aimed to answer these questions through testing the possibility of establishing a PND model using 12-month-old mice which received homocysteine injections before exploratory laparotomy and the therapeutic mechanism of exercise. In the present study, it was found that levels of serum homocysteine were age-dependently increased in mice with a significant difference between that of 18-month-old mice and 6-week, 6-month, and 12-month-old mice. PND occurred in 18-month but not in 12-month-old mice after exploratory laparotomy under isoflurane anesthesia. Intraperitoneal injection of Hcy for 3 consecutive days before surgery rendered 12-month-old mice to develop PND after abdominal laparotomy under isoflurane anesthesia at a minimal dosage of 20 mg/kg. Neuroinflammation and synaptic elimination was present in 12-month-old preoperative Hcy-injected mice. Preoperative voluntary wheel exercise could prevent PND in 12-month-old mice that have received Hcy injection before surgery, which might be related to the decreased level of serum Hcy. Activation of glial cells, proinflammatory phenotype markers and synaptic elimination were attenuated in the hippocampus of 12-month-old preoperative Hcy-injected mice by this exercise. These results provide direct evidence that hyperhomocysteinemia can induce postoperative cognitive deficits in middle-aged mice. Pre-surgery exercise can effectively prevent Hcy-precipitated postoperative cognitive dysfunction.

Hyperhomocysteinemia may aggravate abdominal aortic aneurysm formation by up-regulating RASSF2

Abdominal aortic aneurysm (AAA) is a fatal cardiovascular disorder with high mortality and morbidity rates. To date, no drug has shown to significantly alleviate the risk of AAA. Previous studies have indicated that hyperhomocysteinemia (HHcy) significantly increases the incidence of AAA by disrupting endothelial cell homeostasis; however, the potential molecular mechanisms require clarification. Herein, we aimed to integrate transcriptomics analysis and molecular biology experiments to explore the potential molecular targets by which HHcy may increase the incidence of AAA. We integrated two AAA data profiles (GSE57691 and GSE7084) based on previously published microarray ribonucleic acid sequencing (RNAseq) data from the GEO database. Additionally, 500 μM homocysteine-treated human aorta endothelium cells microarray dataset (GSE175748) was downloaded and processed. Subsequently, single-cell RNA-seq profiles of the aortic aneurysms (GSE155468) were downloaded, scaled, and processed for further analysis. The microarray profiles analysis demonstrated that the Ras association domain family member 2 (RASSF2) and interleukin (IL)-1β are potentially the target genes involved in the HHcy-mediated aggravation of AAA formation. Single-cell RNAseq analysis revealed that RASSF2 might impair endothelial cell function by increasing inflammatory cell infiltration to participate in AAA formation. Finally, we conducted reverse transcription quantitative polymerase chain reaction and immunofluorescence analysis to validate the up-regulated mRNA expression of RASSF2 (p = 0.008) and IL-1β (p = 0.002) in AAA tissue compared to control tissue. Immunofluorescence staining revealed overexpression of RASSF2 protein in AAA tissue sections compared to control tissue (p = 0.037). Co-localization of RASSF2 and the aortic endothelium cell marker, CD31, was observed in tissue sections, indicating the potential involvement of RASSF2 in aortic endothelial cells. To summarise, our preliminary study revealed that HHcy may worsen AAA formation by up-regulating the expression of RASSF2 and IL-1β in aortic endothelium cells.

Prevalence and clinical correlates of hyperhomocysteinemia in Chinese urban population with hypertension

Context

The coexistence of hypertension and elevated homocysteine (Hcy) levels has a mutually reinforcing impact on the susceptibility to cardio-cerebrovascular disease.

Objective

The aim was to assess the prevalence, clinical correlation, and demographic characteristics of hyperhomocysteinemia (HHcy) within the Chinese urban population with hypertension.

Methods

A cohort of 473 individuals with hypertension were selected from four communities in Shenzhen, China. Demographic attributes, clinical profiles, and lifestyle behaviors were gathered and compared between individuals with and without HHcy. A logistic regression model was employed to examine potential factors associated with the prevalence of HHcy. Correlation between Hcy levels and clinical characteristics was assessed through multiple linear regression analysis.

Results

The prevalence of HHcy in the population with hypertension was 31.3%. In comparison to individuals without HHcy, those with HHcy exhibited a higher proportion of males, a higher prevalence of smoking and alcohol consumption, and a higher proportion of cases with the homozygous (TT) genotype at the MTHFR C677T polymorphism. Moreover, individuals with HHcy had lower levels of folic acid (FA), and lower fruit and vitamin B12 intake. Furthermore, the risk factors for HHcy were male (B = 1.430, OR = 4.179) and MTHFR (TT) (B = 1.086, OR = 2.961). In addition, the multiple linear regression analysis revealed a significant association between Hcy levels and gender (B = -2.784, P = 0.004), MTHFR genotypes (B = 1.410, P = 0.005), and FA levels (B = -0.136, P = 0.030).

Conclusion

The high prevalence of HHcy among hypertensive patients in this Chinese urban population underscores the necessity for interventions targeting modifiable risk factors such as dietary choices and lifestyle practices.

Homocysteine and Parkinson's disease

Homocysteine (Hcy) is an important metabolite in methionine metabolism. When the metabolic pathway of homocysteine is abnormal, it will accumulate in the body and eventually lead to hyperhomocysteinemia. In recent years, many studies have found that hyperhomocysteinemia is related to the occurrence and development of Parkinson's disease. This study reviews the roles of homocysteine in the pathogenesis of Parkinson's disease and illustrates the harmful effects of hyperhomocysteinemia on Parkinson's disease.

Adult-onset combined methylmalonic acidemia and hyperhomocysteinemia, cblC type with aortic dissection and acute kidney injury: a case report

BACKGROUND

Combined methylmalonic acidemia (MMA) and hyperhomocysteinemia, cobalamin C (cblC) type, also named cblC deficiency is a rare autosomal recessive genetic metabolic disease. It progressively causes neurological, hematologic, renal and other system dysfunction. The clinical manifestations are relatively different due to the onset time of disease.

CASE PRESENTATION

This report describes a rare case of a 26 year old man with cblC deficiency who developed life-threatening aortic dissection and acute kidney injury (AKI) and showed neuropsychiatric symptoms with elevated serum homocysteine and methylmalonic aciduria. After emergent operation and intramuscular cobalamin supplementation therapy, the male recovered from aortic dissection, neurological disorder and AKI. Finally, two previously published compound heterozygous variants, c.482G > A (p.R161Q) and c.658_660del (p.K220del) in the MMACHC gene were detected in this patient and he was confirmed to have cblC deficiency.

CONCLUSIONS

Poor cognizance of presenting symptoms and biochemical features of adult onset cblC disease may cause delayed diagnosis and management. This case is the first to depict a case of adult-onset cblC deficiency with aortic dissection. This clinical finding may contribute to the diagnosis of cblC deficiency.

Hyperhomocysteinemia in Adult Patients: A Treatable Metabolic Condition

Hyperhomocysteinemia (HHcy) is recognized as an independent risk factor for various significant medical conditions, yet controversy persists around its assessment and management. The diagnosis of disorders afffecting homocysteine (Hcy) metabolism faces delays due to insufficient awareness of its clinical presentation and unique biochemical characteristics. In cases of arterial or venous thrombotic vascular events, particularly with other comorbidities, it is crucial to consider moderate to severe HHcy. A nutritional approach to HHcy management involves implementing dietary strategies and targeted supplementation, emphasizing key nutrients like vitamin B6, B12, and folate that are crucial for Hcy conversion. Adequate intake of these vitamins, along with betaine supplementation, supports Hcy remethylation. Lifestyle modifications, such as smoking cessation and regular physical activity, complement the nutritional approach to enhance Hcy metabolism. For individuals with HHcy, maintaining a plasma Hcy concentration below 50 μmol/L consistently is vital to lowering the risk of vascular events. Collaboration with healthcare professionals and dietitians is essential for developing personalized dietary plans addressing the specific needs and underlying health conditions. This integrated approach aims to optimize metabolic processes and reduce the associated health risks.

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of type 2 diabetes mellitus and dyslipidemia, but not coronary artery disease in a Chinese Han population

Background

Relationships of the polymorphisms in fat mass and obesity-associated gene (FTO) and peroxisome proliferator-activated receptor delta gene (PPARD) with metabolic-related diseases remain to be clarified.

Methods

One thousand three hundred and eighty-one subjects were enrolled. Metabolic-related diseases including obesity, dyslipidemia, hyperhomocysteinemia, hyperuricemia, hypertension, type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) were defined based on diagnostic criteria. FTO rs9939609 and rs17817449, and PPARD rs2016520 and rs2267668 polymorphisms were genotyped by using polymerase chain reaction-restricted fragment length polymorphism method.

Results

Patients with T2DM or dyslipidemia had a higher frequency of AA, AT or AA + AT genotypes as well as A allele of FTO rs9939609 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.04 for all). Patients with T2DM or dyslipidemia had a higher frequency of GG, GT or GG + GT genotypes as well as G allele of FTO rs17817449 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.03 for all). Multivariate logistic regression analyses showed that FTO rs9939609 and rs17817449 polymorphisms were independently associated with T2DM as well as dyslipidemia after adjustment for age, sex, smoking and other metabolic diseases. FTO rs9939609 and rs17817449 polymorphisms were not associated with obesity, hyperhomocysteinemia, hyperuricemia, hypertension and CAD. Obese or T2DM carriers of the AA or AT genotype of the FTO rs9939609 polymorphism had a higher prevalence of dyslipidemia compared to non-obese or non-T2DM carriers of the AA or AT genotype (P = 0.03 for both). Among the carriers of GG or GT genotype of the FTO rs17817449 polymorphism, the prevalence of dyslipidemia in obese patients was higher than that in non-obese subjects (P < 0.01). PPARD rs2016520 and rs2267668 polymorphisms were not correlated with any of the metabolic-related diseases in the study population.

Conclusion

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of T2DM and dyslipidemia, and the risk is further increased among obese individuals. PPARD rs2016520 and rs2267668 polymorphisms are not associated with metabolic-related diseases.

Histone deacetylase 9 exacerbates podocyte injury in hyperhomocysteinemia through epigenetic repression of Klotho

Although hyperhomocysteinemia (hHcys) has been recognized as an important independent risk factor in the progression of end-stage renal disease and the development of cardiovascular complications related to end-stage renal disease, the mechanisms triggering pathogenic actions of hHcys are not fully understood. The present study was mainly designed to investigate the role of HDACs in renal injury induced by hHcys. Firstly, we identified the expression patterns of HDACs and found that, among zinc-dependent HDACs, HDAC9 was preferentially upregulated in the kidney from mice with hHcys. Deficiency or pharmacological inhibition of HDAC9 ameliorated renal injury in mice with hHcys. Moreover, podocyte-specific deletion of HDAC9 significantly attenuated podocyte injury and proteinuria. In vitro, gene silencing of HDAC9 attenuated podocyte injury by inhibiting apoptosis, reducing oxidative stress and maintaining the expressions of podocyte slit diaphragm proteins. Mechanically, we proved for the first time that HDAC9 reduced the acetylation level of H3K9 in the promoter of Klotho, then inhibited gene transcription of Klotho, finally aggravating podocyte injury in hHcys. In conclusion, our results indicated that targeting of HDAC9 might be an attractive therapeutic strategy for the treatment of renal injury induced by hHcys.

Diminished ovarian reserve is associated with metabolic disturbances and hyperhomocysteinemia in women with infertility

BACKGROUND

To distinguish the metabolic profile between women with diminished ovarian reserve (DOR) and those with normal ovarian reserve (NOR).

METHODS

In this retrospective study, we enrolled 524 women under the age of 40 who were experiencing infertility: 261 in the DOR group and 263 in the NOR group. Physical characteristics and metabolic parameters were compared between these two groups.

RESULTS

Women with DOR exhibited a higher propensity for elevated parameters including body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), as well as heightened serum levels of homocysteine (Hcy), triglycerides (TG), low-density lipoprotein (LDL), and triglyceride-glucose (TyG) index, while concurrently experiencing reduced serum levels of high-density lipoprotein (HDL) (P < 0.05). Furthermore, the incidence rates of TG ≥ 1.7 mmol/L, hyperhomocysteinemia (HHcy), BMI ≥ 25 kg/m2, SBP/DBP ≥ 130/85 mmHg, and metabolic syndrome (MS) were significantly elevated within the DOR group as compared to the NOR group (P < 0.05).

CONCLUSION

The prevalence of metabolic disturbances and HHcy were notably elevated in women with infertility and DOR compared to those with NOR.

Development and Validation of a Novel Model for Predicting Coronary Heart Disease in Snoring Hypertensive Patients with Hyperhomocysteinemia

Hypertensive patients with snoring and elevated plasma homocysteine levels are common. When these factors are combined, the risk of coronary heart disease (CHD) is high. Herein, we developed and validated an easy-to-use nomogram to predict high-risk CHD in snoring hypertensive patients with elevated plasma homocysteine.Snoring patients (n = 1,962) with hyperhomocysteinemia and hypertension were divided into training (n = 1,373, 70%) and validation (n = 589, 30%) sets. We extracted CHD predictors using multivariate Cox regression analysis, then constructed a nomogram model. Internal validation using 1,000 bootstrap resampling was performed to assess the consistency and discrimination of the predictive model using the area under the receiver operating characteristic curve (AUC) and calibration plots.We constructed a nomogram model with the extracted predictors, including age, waist-height ratio, smoking, and low-density lipoprotein cholesterol levels. The AUCs of the training and validation cohorts at 80 months were 0.735 (95% CI: 0.678-0.792) and 0.646 (95% CI: 0.547-0.746), respectively. The consistency between the observed CHD survival and the probability of CHD survival in the training and validation sets was acceptable based on the calibration plots. A total of more than 151 points in the nomogram can be used in the identification of high-risk patients for CHD among snoring hypertensive patients with elevated plasma homocysteine.We developed a CHD risk prediction model for snoring hypertension patients with hyperhomocysteinemia. Our findings provide a useful clinical tool for the rapid identification of high-risk CHD at an early stage.

The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment

As aging societies in the western world face a growing prevalence of vascular cognitive impairment and Alzheimer's disease (AD), understanding their underlying causes and associated risk factors becomes increasingly critical. A salient concern in the western dietary context is the high consumption of methionine-rich foods such as red meat. The present review delves into the impact of this methionine-heavy diet and the resultant hyperhomocysteinemia on accelerated cerebrovascular and brain aging, emphasizing their potential roles in cognitive impairment. Through a comprehensive exploration of existing evidence, a link between high methionine intake and hyperhomocysteinemia and oxidative stress, mitochondrial dysfunction, inflammation, and accelerated epigenetic aging is drawn. Moreover, the microvascular determinants of cognitive deterioration, including endothelial dysfunction, reduced cerebral blood flow, microvascular rarefaction, impaired neurovascular coupling, and blood-brain barrier (BBB) disruption, are explored. The mechanisms by which excessive methionine consumption and hyperhomocysteinemia might drive cerebromicrovascular and brain aging processes are elucidated. By presenting an intricate understanding of the relationships among methionine-rich diets, hyperhomocysteinemia, cerebrovascular and brain aging, and cognitive impairment, avenues for future research and potential therapeutic interventions are suggested.

[Research progress on the role and mechanism of endothelial dysfunction in hyperhomocysteine-induced atherosclerosis]

Hyperhomocysteinemia (HHcy) is considered to be an independent risk factor for cardiovascular diseases, but the molecular mechanisms underlying its pathogenesis are not fully understood. Endothelial dysfunction is a key initiating factor in the pathogenesis of atherosclerosis, which is commonly observed in almost all HHcy-induced vascular diseases. HHcy promotes oxidative stress, inhibits nitric oxide production, suppresses hydrogen sulfide signaling pathway, promotes endothelial mesenchymal transition, activates coagulation pathways, and promotes protein N-homocysteination and cellular hypomethylation, all of which can cause endothelial dysfunction. This article reviews the specific links between HHcy and endothelial dysfunction, and highlights recent evidence that endothelial mesenchymal transition contributes to HHcy-induced vascular damage, with a hope to provide new ideas for the clinical treatment of HHcy-related vascular diseases.

Folate and retinal vascular diseases

Folate, a pteroylglutamic acid derivative, participates in fundamental cellular metabolism. Homocysteine, an amino acid, serves as an intermediate of the methionine cycle and can be converted back to methionine. Hyperhomocysteinemia is a recognized risk factor for atherosclerotic and cardiovascular diseases. In recent decades, elevated plasma homocysteine levels and low folate status have been observed in many patients with retinal vascular diseases, such as retinal vascular occlusions, diabetic retinopathy, and age-related degeneration. Homocysteine-induced toxicity toward vascular endothelial cells might participate in the formation of retinal vascular diseases. Folate is an important dietary determinant of homocysteine. Folate deficiency is the most common cause of hyperhomocysteinemia. Folate supplementation can eliminate excess homocysteine in plasma. In in vitro experiments, folic acid had a protective effect on vascular endothelial cells against high glucose. Many studies have explored the relationship between folate and various retinal vascular diseases. This review summarizes the most important findings that lead to the conclusion that folic acid supplementation might be a protective treatment in patients with retinal vascular diseases with high homocysteine or glucose status. More research is still needed to validate the effect of folate and its supplementation in retinal vascular diseases.

Identification of methylation-regulated genes modulating microglial phagocytosis in hyperhomocysteinemia-exacerbated Alzheimer's disease

BACKGROUND

Hyperhomocysteinemia (HHcy) has been linked to development of Alzheimer's disease (AD) neuropathologically characterized by the accumulation of amyloid β (Aβ). Microglia (MG) play a crucial role in uptake of Aβ fibrils, and its dysfunction worsens AD. However, the effect of HHcy on MG Aβ phagocytosis remains unstudied.

METHODS

We isolated MG from the cerebrum of HHcy mice with genetic cystathionine-β-synthase deficiency (Cbs-/-) and performed bulk RNA-seq. We performed meta-analysis over transcriptomes of Cbs-/- mouse MG, human and mouse AD MG, MG Aβ phagocytosis model, human AD methylome, and GWAS AD genes.

RESULTS

HHcy and hypomethylation conditions were identified in Cbs-/- mice. Through Cbs-/- MG transcriptome analysis, 353 MG DEGs were identified. Phagosome formation and integrin signaling pathways were found suppressed in Cbs-/- MG. By analyzing MG transcriptomes from 4 AD patient and 7 mouse AD datasets, 409 human and 777 mouse AD MG DEGs were identified, of which 37 were found common in both species. Through further combinatory analysis with transcriptome from MG Aβ phagocytosis model, we identified 130 functional-validated Aβ phagocytic AD MG DEGs (20 in human AD, 110 in mouse AD), which reflected a compensatory activation of Aβ phagocytosis. Interestingly, we identified 14 human Aβ phagocytic AD MG DEGs which represented impaired MG Aβ phagocytosis in human AD. Finally, through a cascade of meta-analysis of transcriptome of AD MG, functional phagocytosis, HHcy MG, and human AD brain methylome dataset, we identified 5 HHcy-suppressed phagocytic AD MG DEGs (Flt1, Calponin 3, Igf1, Cacna2d4, and Celsr) which were reported to regulate MG/MΦ migration and Aβ phagocytosis.

CONCLUSIONS

We established molecular signatures for a compensatory response of Aβ phagocytosis activation in human and mouse AD MG and impaired Aβ phagocytosis in human AD MG. Our discoveries suggested that hypomethylation may modulate HHcy-suppressed MG Aβ phagocytosis in AD.

Maternal hyperhomocysteinemia increases seizures susceptibility of neonatal rats

AIMS

Neonatal seizures are severe pathologies which may result in long-term neurological consequences. High plasma concentrations of homocysteine - hyperhomocysteinemia (hHCy) - are associated with epilepsy. In the present study, we evaluated susceptibility to seizure of neonatal rats with prenatal hHCy.

MAIN METHODS

Prenatal hHCy was induced by feeding females with a high-methionine diet. Experiments were performed on pups during the first three postnatal weeks. Flurothyl-induced epileptic behavior was assessed according to Racine's scale. Epileptiform activity in the hippocampus was recorded using electrophysiological methods. The balance of excitation/inhibition, functional GABAergic inhibition and GABA reversal potential in hippocampal neurons were analyzed.

KEY FINDINGS

Rats with hHCy developed more severe stages of behavioral patterns during flurothyl-induced epilepsy with shorter latency. Electrophysiological recordings demonstrated higher background neuronal activity in rats with hHCy. Seizure-like events triggered by flurothyl (in vivo) or 4-aminopyridine (in vitro) showed shorter latency, higher power and amplitude. An increased glutamate/GABA synaptic ratio was shown in the pyramidal neurons of rats with hHCy and more slices demonstrated excitation by isoguvacine, a selective GABA(A) receptor agonist, during the first and second postnatal weeks. The GABA driving force and the reversal potential of GABA(A) currents were more positive during the second postnatal week for hHCy rats.

SIGNIFICANCE

The higher susceptibility to seizures in rats with prenatal hHCy due to a shift in the balance of excitation/inhibition toward excitation may underlie the clinical evidence about the association of hHCy with an increased risk of epilepsy.

Hyperhomocysteinemia, High Altitude, and Varied Retinal Manifestations: Unravelling the Enigma

Rana, Vipin, Meenu Dangi, Sandepan Bandopadhayay, Vijay K. Sharma, Satyabrat Srikumar, Jitesh Goyal, and B.V. Rao. Hyperhomocysteinemia, High Altitude, and Varied Retinal Manifestations: Unravelling the Enigma. High Alt Med Biol. 24:234-237, 2023.-We present five cases of young defense personnel, who were posted at high altitude (HA) for >6 months and presented with reduction of vision between June 2022 and February 2023. The diagnosis made were ocular ischemic syndrome, central retinal artery occlusion, central retinal vein occlusion, branch retinal vein occlusion, and branch retinal artery occlusion. There were no associated comorbidities. Hematological workup revealed increased serum homocysteine and hemoglobin in all patients. Computed tomography angiography was done in cases of ocular ischemic syndrome, and central retinal artery occlusion, which revealed occlusion of carotid artery. All patients were given tab folic acid in view of hyperhomocysteinemia (HHcy). This case series highlights that prolonged exposure to HA may lead to HHcy, which can directly or indirectly lead to various sight-threatening retinal diseases. Thus, effective preventive strategies, such as dietary or pharmacological interventions aimed at lowering serum homocysteine levels, are crucial for individuals posted at HA for longer duration.

Atorvastatin rescues hyperhomocysteinemia-induced cognitive deficits and neuroinflammatory gene changes

BACKGROUND

Epidemiological data suggests statins could reduce the risk of dementia, and more specifically, Alzheimer's disease (AD). Pre-clinical data suggests statins reduce the risk of dementia through their pleiotropic effects rather than their cholesterol lowering effects. While AD is a leading cause of dementia, it is frequently found co-morbidly with cerebral small vessel disease and other vascular contributions to cognitive impairment and dementia (VCID), which are another leading cause of dementia. In this study, we determined if atorvastatin ameliorated hyperhomocysteinemia (HHcy)-induced VCID.

METHODS

Wild-type (C57Bl6/J) mice were placed on a diet to induce HHcy or a control diet each with or without atorvastatin for 14 weeks. Mice underwent novel object recognition testing before tissue collection. Plasma total cholesterol and total homocysteine as well as related metabolites were measured. Using qPCR and NanoString technology, we profiled glial cell-associated gene expression changes. Finally, microglial morphology, astrocyte end feet, and microhemorrhages were analyzed using histological methods.

RESULTS

Atorvastatin treatment of HHcy in mice led to no changes in total cholesterol but decreases in total homocysteine in plasma. While HHcy decreased expression of many glial genes, atorvastatin rescued these gene changes, which mostly occurred in oligodendrocytes and microglia. Microglia in HHcy mice with atorvastatin were trending towards fewer processes compared to control with atorvastatin, but there were no atorvastatin effects on astrocyte end feet. While atorvastatin treatment was trending towards increasing the area of microhemorrhages in HHcy mice in the frontal cortex, it only slightly (non-significantly) reduced the number of microhemorrhages. Finally, atorvastatin treatment in HHcy mice led to improved cognition on the novel object recognition task.

CONCLUSIONS

These data suggest that atorvastatin rescued cognitive changes induced by HHcy most likely through lowering plasma total homocysteine and rescuing gene expression changes rather than impacts on vascular integrity or microglial changes.

Hyperhomocysteinemia Increases Vascular Risk in Stroke Patients with Chronic Kidney Disease

AIMS

We aimed to assess the prognostic impact of hyperhomocysteinemia (HHcy) on the recurrent vascular event risk in stroke patients with or without chronic kidney disease (CKD).

METHODS

In this prospective observational study, 621 patients (mean age, 69.5 years; male, 62.2%) with ischemic stroke or transient ischemic attack were consecutively enrolled within 1 week of onset and followed-up for 1 year. HHcy was defined as elevated levels of fasting total homocysteine ＞15 µmol/L. CKD was defined as an estimated glomerular filtration rate of ＜60 mL/min/1.73 m2 or a history of renal replacement therapy. The primary outcome was a composite of major adverse cardiovascular events (MACEs), including nonfatal stroke, nonfatal acute coronary syndrome, major peripheral artery disease, and vascular death.

RESULTS

The prevalence of HHcy was 18.5%. Patients with HHcy were more likely to have intracranial (37.4% versus 24.8%; p=0.008) and extracranial (20.9% versus 13.0%; p=0.037) artery stenosis than were those without HHcy. At 1 year, patients with HHcy were at a greater risk of MACE than were those without HHcy (annual rate, 17.8% versus 10.4%; log-rank p=0.033). In the Cox proportional hazard regression models, HHcy was independently associated with an increased risk of MACE in patients with CKD (adjusted hazard ratio [HR], 2.06; 95% confidence interval [CI], 1.02-4.20), whereas HHcy was not predictive of MACE in those without CKD (adjusted HR, 1.00; 95% CI, 0.30-3.32).

CONCLUSIONS

Elevated levels of serum homocysteine can be an important modifiable risk factor in stroke patients with CKD, but not in those without CKD.

Homocysteine as a predictor and prognostic marker of atherosclerotic cardiovascular disease: a systematic review and meta-analysis

OBJECTIVE

Hyperhomocysteinemia is a well-known marker that is associated with an increased risk of atherosclerosis due to its toxic effect on endothelial cells. This, in turn, leads to cardiovascular injury and increases morbidity. Different studies have shown alterations in the levels of homocysteine with respect to multiple disease states. Whether this non-traditional marker is associated with cardiovascular injury or not is subject to conflicting results. The purpose of this systematic review is to evaluate the role of homocysteine in the formation of atherosclerotic cardiovascular disease in young adults and children.

MATERIALS AND METHODS

This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (PRISMA). A search was done using specific keywords, including "homocysteine", "coronary artery disease", and "atherosclerosis", amongst several others, from the databases of PubMed, COCHRANE, and EBSCO. The data items included the diseased sample population along with the intervention used, or investigations carried out and the findings of the studies. Finally, 35 eligible studies were included.

RESULTS

Young patients with atherosclerotic cardiovascular disease were more likely to have elevated levels of homocysteine compared to elderly patients. Elevated levels of homocysteine have been observed with several genetic, nutritional deficiencies, and autoimmune states such as rheumatoid arthritis. On the other hand, decreased levels of homocysteine have been observed after certain intervention treatments, such as oral contraceptive pills, L-thyroxine, and even the adoption of certain diets. In the majority of studies, whenever homocysteine levels were higher than normal, this was reflected by an increased carotid intima-media thickness.

CONCLUSIONS

Homocysteine has a high correlation with atherosclerotic cardiovascular disease in young and overweight patients. In addition, the relationship of homocysteine with smoking, genetic polymorphism, specific hormonal and renal disorders, nutritional deficiencies (vitamin B12 and folic acid), and the use of specific medicines are among the other recurring findings. Given that many of these studies focus only on women, the relationship between homocysteine and atherosclerotic cardiovascular diseases in males is still unclear. Whether males are more prone to hyperhomocysteinemia needs to be assessed. Still, precise processes underlying variations in homocysteine in relation to all influencing factors are unclear and need further studies.

Comprehensive transcriptomics and metabolomics analyses reveal that hyperhomocysteinemia is a high risk factor for coronary artery disease in a chinese obese population aged 40-65: a prospective cross-sectional study

BACKGROUND

Clinical observations suggest a complex relationship between obesity and coronary artery disease (CAD). This study aimed to characterize the intermediate metabolism phenotypes among obese patients with CAD and without CAD.

METHODS

Sixty-two participants who consecutively underwent coronary angiography were enrolled in the discovery cohort. Transcriptional and untargeted metabolomics analyses were carried out to screen for key molecular changes between obese patients with CAD (CAD obese), without CAD (Non-CAD obese), and Non-CAD leans. A targeted GC-MS metabolomics approach was used to further identify differentially expressed metabolites in the validation cohorts. Regression and receiver operator curve analysis were performed to validate the risk model.

RESULTS

We found common aberrantly expressed pathways both at the transcriptional and metabolomics levels. These pathways included cysteine and methionine metabolism and arginine and proline metabolism. Untargeted metabolomics revealed that S-adenosylhomocysteine (SAH), 3-hydroxybenzoic acid, 2-hydroxyhippuric acid, nicotinuric acid, and 2-arachidonoyl glycerol were significantly elevated in the CAD obese group compared to the other two groups. In the validation study, targeted cysteine and methionine metabolomics analyses showed that homocysteine (Hcy), SAH, and choline were significantly increased in the CAD obese group compared with the Non-CAD obese group, while betaine, 5-methylpropanedioic acid, S-adenosylmethionine, 4-PA, and vitamin B2 (VB2) showed no significant differences. Multivariate analyses showed that Hcy was an independent predictor of obesity with CAD (hazard ratio 1.7; 95%CI 1.2-2.6). The area under the curve based on the Hcy metabolomic (HCY-Mtb) index was 0.819, and up to 0.877 for the HCY-Mtb.index plus clinical variables.

CONCLUSION

This is the first study to propose that obesity with hyperhomocysteinemia is a useful intermediate metabolism phenotype that could be used to identify obese patients at high risk for developing CAD.

Hypertension and cystatin C account for sex differences in serum homocysteine levels in acute coronary syndrome subjects with normal serum creatinine

BACKGROUND

Hyperhomocysteinemia is one of cardiovascular disease risk factors and fasting homocysteine levels are significantly elevated in male compared to female acute coronary syndrome (ACS) patients with normal renal function. However, it is not known the sex related determinants of plasma homocysteine levels in ACS subjects without renal dysfunction.

METHODS

A total of 165 ACS participants with normal plasma creatinine who underwent coronary angiography were included in the present study. Clinical parameters, homocysteine, fasting glucose and lipid profile, hemoglobin, white blood cell, platelets, creatinine, cystatin C, blood urea nitrogen, uric acid (UA), and albumin were measured. Multivariate linear regression analyses were used to recognize the predictive factors for homocysteine.

RESULTS

The levels of plasma homocysteine were significantly higher in men than in women (P < 0.0001). In males, homocysteine (log10) was positively associated with hypertension (r = 0.569, P < 0.001), creatinine (r = 0.367, P < 0.001) and cystatin C (log10) (r = 0.333, P = 0.001). In females, homocysteine (log10) was positively correlated with age (r = 0.307, P = 0.107), hypertension (r = 0.456, P < 0.001), creatinine (r = 0.341, P = 0.008), cystatin C (log10) (r = 0.429, P = 0.001) and UA (r = 0.569, P < 0.001) whereas was negatively associated with LDL-C (r =  - 0.298, P = 0.021) and ApoB (r =  - 0.273, P = 0.033). Parameters up to statistical significance in males or females were incorporated into the stepwise linear regression models. In men, hypertension (P < 0.001) and creatinine (P = 0.031) were independently related to homocysteine. Most of the variability of homocysteine levels in males were only determined by hypertension. In women, cystatin C (log10) (P = 0.004) and hypertension (P = 0.005) were independently related to homocysteine (log10). Plasma cystatin C had a higher explanatory value than hypertension in females.

CONCLUSIONS

Hypertension and cystatin C could explain most of the sex differences in serum homocysteine levels in ACS subjects with normal serum creatinine. This finding suggested the importance of making different strategies in males and females to manage hyperhomocysteinemia effectively in ACS subjects without renal dysfunction.

Cerebral venous thrombosis associated with hyperhomocysteinemia and iron-deficiency anemia induced by autoimmune gastritis: A case report and literature review

Cerebral venous thrombosis (CVT) is a rare disease, occurring in 0.5%-1% of all patients with strokes. Systemic and hereditary diseases and traumas are potential causes of CVT. We report a case of CVT and systemic thromboembolism complicated with hyperhomocysteinemia and iron-deficiency anemia caused by autoimmune gastritis. A 47-year-old female patient was admitted to the emergency department due to difficulty in movement, impaired consciousness, and urinary incontinence. Brain computed tomography (CT) and magnetic resonance imaging (MRI) showed bilateral thalamic edema associated with venous sinus thrombosis and embolic cerebral infarction in the deep white matter of the bilateral cerebral hemispheres. In addition, contrast enhanced whole-trunk CT scan showed deep femoral thrombosis and pulmonary artery embolism. She had no medical history of diseases or drug use that may cause thrombosis. Blood test results revealed iron-deficiency anemia and hyperhomocysteinemia, which were determined to be the cause of systemic thromboembolism. The patient tested positive for intrinsic factor antibodies. Moreover, the patient was diagnosed with autoimmune gastritis by gastrointestinal endoscopy. Therapies including anticoagulant and replacement with iron and vitamin B12 were administered. The patient was discharged from the hospital without neurological deficits. A favorable clinical course was achieved with anticoagulant administration and replacement therapy with iron and vitamin B12 for cerebral arteriovenous embolism that developed due to autoimmune gastritis.

Surgical outcomes following encephaloduroarteriosynangiosis in moyamoya disease associated with hyperhomocysteinemia

INTRODUCTION

This study investigated the effect of indirect revascularization surgery in adult patients with moyamoya disease (MMD) complicated with hyperhomocysteinemia (HHcy), and the effect of HHcy on the progression of adult MMD.

METHODS

A retrospective case-control study was conducted in patients with MMD, with or without HHcy (n = 123). Postoperative collateral angiogenesis was evaluated using the Matsushima grading system and disease progression using the Suzuki staging system. Cerebral blood flow was evaluated before and after surgery using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) and neurological function prognosis using the improved Rankin score (mRS). Univariate and multivariate logistic regression analyses were performed to determine risk factors for the clinical outcomes.

RESULTS

There was no significant difference in the Suzuki stage composition ratios between the HHcy group and the non-HHcy group before and after surgery. Non-HHcy patients were more likely to grow new collateral circulating vessels after encephaloduroarteriosynangiosis (EDAS). Moreover, postoperative DSC-MRI indicated that the time to peak significantly improved.

CONCLUSIONS

HHcy level may be a specific predictor of adverse clinical outcomes after EDAS in patients with MMD and a risk factor for poor collateral circulation and poor prognosis. Patients with MMD complicated with HHcy need to strictly control homocysteine levels before EDAS surgery.

Combined use of amlodipine and folic acid are significantly more efficacious than amlodipine alone in lowering plasma homocysteine and blood pressure among hypertensive patients with hyperhomocysteinemia and intolerance to ACEI: A multicenter, randomized, double-blind, parallel-controlled clinical trial

Hyperhomocysteinemia with hypertension can synergistically increase the risk of stroke. The China stroke primary prevention trial showed that combining 0.8 mg folic acid (FA) with angiotensin-converting enzyme inhibitor (ACEI) can effectively lower plasma total homocysteine (tHcy) and blood pressure (BP); and reduce first stroke risk by additional 21% compared to ACEI alone. However, intolerance to ACEI is common in Asians and amlodipine can be alternative. This is a multicenter, randomized, double-blind, parallel-controlled clinical trial (RCT) which evaluated whether amlodipine combined with FA is more efficacious than amlodipine alone in lowering tHcy and BP among Chinese hypertensive with hyperhomocysteinemia and intolerance to ACEI. 351 Eligible patients were randomly assigned by 1:1:1 ratio to receive amlodipine-FA tablet daily (amlodipine 5 mg/FA 0.4 mg, A group); amlodipine 5 mg/FA 0.8 mg tablet daily (B group); amlodipine 5 mg daily (C group, control group). Follow-up was conducted at 2, 4, 6, and 8 weeks. The primary outcome was efficacy of lowering both tHcy and BP at the end of 8-week treatment. Compared with C group, A group had a significantly higher rate of lowering both tHcy and BP (23.3% vs. 6.0%; Odds Ratio [OR], 8.68; 95% CI, 3.04-24.78, P < .001); B group also had a higher rate of lowering both tHcy and BP (20.3% vs. 6.0%; OR: 5.90; 95% CI, 2.11-16.47, P < .001). This RCT showed amlodipine combined with FA compared with amlodipine alone, each had significantly higher efficacy of lowering both tHcy and BP. No difference was found in BP-lowering and occurrence of adverse events between the three groups.

Platelet counts affect the association between hyperhomocysteinemia and pregnancy complications

BACKGROUND

The joint effect of platelet and other modifiers on the risk of pregnancy complications is unknown. This study investigated whether platelet count (PC) and total homocysteine (tHcy) level have a synergistic effect on the incidence of pregnancy complications in a Chinese population.

METHODS

Total 11,553 consecutive pregnant women who received whole blood cell and biochemical tests at the time of admission for labor in Changzhou Maternal and Child Health Care Hospital were analyzed. The primary outcome was the prevalence of pregnancy complications: gestational diabetes mellitus (GDM), intrahepatic cholestasis of pregnancy (ICP), pre-eclampsia (PE), and pregnancy induced hypertension (PIH).

RESULTS

The prevalence of GDM, ICP, PE, and PIH was 8.4%, 6.2%, 3.4%, and 2.1%, respectively. The highest rate of ICP (28.6%) was observed in women with high tHcy (> 15 μmol/L) and low PC (quartile 1); and the lowest rate of GDM (0.6%) was found in women with high tHcy and high PC (quartiles 2 to 4). In low PC group, the prevalence of ICP in women with high tHcy was significantly higher than that in women with low tHcy (≤ 15 μmol/L) (28.6% vs. 8.4%), representing an absolute risk increment of 20.2% and a relative risk increment of 3.3-fold (OR: 3.34; 95% CI: 1.55, 7.17; P = 0.002), whereas no joint effect was observed among high PC group.

CONCLUSIONS

Among Chinese pregnant women, one subgroup (high tHcy and low PC) has the highest risk of ICP and another (high tHcy and high PC) has the lowest risk of GDM; tHcy and platelet could be used as indicators to identify the women with high risk of ICP or low risk of GDM.

Hyperhomocysteinemia activates NLRP3 inflammasome to cause hepatic steatosis and insulin resistance via MDM2-mediated ubiquitination of HSF1

Hyperhomocysteinemia (HHcy) is associated with nonalcoholic fatty liver disease (NAFLD) and insulin resistance (IR). However, the underlying mechanism is still unknown. Recent studies have demonstrated that NLRP3 inflammasome activation plays a vital role in NAFLD and IR. Our study aimed to explore whether NLRP3 inflammasome contributed to HHcy-induced NAFLD and IR as well as dissected the underlying mechanism. C57BL/6 mice were fed a high-methionine diet (HMD) for 8 weeks to establish the HHcy mouse model. Compared with a chow diet, HMD induced hepatic steatosis (HS) and IR as well as activation of hepatic NLRP3 inflammasome. Moreover, HHcy-induced NAFLD and IR characterization disclosed that NLRP3 inflammasome activation occurred in liver tissue of HMD-fed mice, but was very marginal in either NLRP3^-/- or Caspase-1^-/- mice. Mechanistically, high levels of homocysteine (Hcy) up-regulated the expression of mouse double minute 2 homolog (MDM2), which directly ubiquitinates heat shock transcription factor 1 (HSF1) and consequently activated hepatic NLRP3 inflammasome in vivo and in vitro. In addition, in vitro experiments showed P300-mediated HSF1 acetylation at K298 hindered MDM2-mediated ubiquitination of HSF1 at K372, which plays important role in determining the HSF1 level. Importantly, either inhibition of MDM2 by JNJ-165 or activation of HSF1 by HSF1A reversed HMD-induced hepatic NLRP3 inflammasome, and consequently alleviated HS and IR in mice. This study demonstrates that NLRP3 inflammasome activation contributes to HHcy-induced NAFLD and IR, and further identified that HSF1 as a new substrate of MDM2 and its decrease on MDM2-mediated ubiquitination at K372 modulates NLRP3 inflammasome activation. These findings may provide novel therapeutic strategies aimed at halting HS or IR.

Homocysteine Levels in Severe OSA Patients Before and After TORS-OSA Surgery

OBJECTIVE

The increased risk of cardiovascular diseases owing to a high level of serum homocysteine has been widely reported. Literature has demonstrated that patients with obstructive sleep apnea/hypopnea syndrome (OSA) had a higher homocysteine level than control group. This study aimed to investigate the alteration of serum homocysteine levels in severe OSA patients receiving transoral robotic surgery (TORS).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary academic medical center.

METHODS

Data of polysomnography (PSG) and serum homocysteine levels before and at least 3 months after the surgery were collected and analyzed via paired t tests. A subgroup analysis based on the preoperative homocysteine level (≥15 mcmol/L, as hyperhomocysteinemia group) was conducted to compare the intergroup differences of homocysteine decrease. Pearson's correlation was used to survey the relationships between the changes of major PSG parameters and the levels of homocysteine decrease at baseline and after TORS-OSA surgery.

RESULTS

Two hundred sixty-one patients with severe OSA were enrolled. There were significant improvements in major PSG parameters after TORS-OSA surgery. Homocysteine levels significantly decreased from 12.1 ± 3.9 to 11.4 ± 3.7 mcmol/L (difference = -0.7 ± 2.8 mcmol/L, p = .001) postoperatively, which was shown in the hyperhomocysteinemia group (difference = -2.9 ± 4.7 mcmol/L, p = .007) to a greater extent. Pearson's correlation revealed that ΔODI (oxygen desaturation index/h) was the predominant estimate with a positive association with Δhomocysteine (r = 0.525, p = .012).

CONCLUSION

TORS-OSA surgery could decrease homocysteine levels in OSA patients. The effects were more relevant in severe OSA patients with abnormal preoperative homocysteine levels.

Significance of Hyperhomocysteinemia in Immediate As Well As Long-Term Health Risk/s in Women with Polycystic Ovary Syndrome: a Probabilistic Model Using Dynamic Bayesian Network Analysis

Polycystic ovary syndrome (PCOS) is a heterogeneous entity comprising broad spectra of ovarian disorders with trademark features of metabolic syndrome like insulin resistance, obesity, and dyslipidaemia to name a few. Hyperhomocysteinemia, an independent risk factor of metabolic syndrome, has been suggested as a causative factor in spontaneous miscarriage in PCOS. However, it is yet to be resolved whether hyperhomocysteinemia has a contributory role in the pathogenesis or could direct long-term sequences of the syndrome. A total of 2355 women with history of one or more first trimester abortions were screened and 1539 were selected for the study. Selected patients were initially divided by the presence or absence of PCOS, while subsequent stratification was based on hyperhomocysteinemia, insulin resistance, and/or obesity. The miscarriage population/s was mostly represented by hyperhomocysteinemia in both the cohorts (PCOS: 69.08% vs. non-PCOS: 56.68%). ROC-AUC values suggest increased predisposition of hyperhomocysteinemia-mediated miscarriage (hyperhomocysteinemia: 0.778; insulin resistance: 0.601; BMI: 0.548). A probabilistic causal model was designed using dynamic Bayesian network to evaluate the time-series data points before, during, and after pregnancy which revealed a possibility of 32.24% (n = 79) of PCOS cohort developing hypertension, 26.94% (n = 66) of onset of diabetes and 4.49% cardiovascular disease 3 years following pregnancy. We conclude hyperhomocysteinemia may possibly contribute to spontaneous miscarriage and related to metabolic derailments later in life.

Mechanism of arterial injury exacerbated by hyperhomocysteinemia in spontaneously hypertensive rats

Hypertension associated with hyperhomocysteinemia (HHcy) accounts for 75% of hypertension in China. HHcy plays a synergistic role with hypertension in vascular injury and significantly increases the incidence of cardiovascular and cerebrovascular diseases. The present study aimed to explore the molecular mechanism of HHcy-induced arterial injury in hypertension. Spontaneously hypertensive rats (SHR) were injected intraperitoneally with DL-homocysteine (Hcy) to construct the model of hypertension associated with HHcy (HHcy + SHR). Biological network was employed to identify the material basis of arterial injury in hypertension associated with HHcy. The prediction molecules in oxidative stress and inflammation pathways were experimentally verified by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot (WB) analysis. The HHcy + SHR group significantly increased oxidative stress pathway molecules: nicotinamide adenine dinucleotide phosphate oxidase (Nox); inflammatory pathway molecules: vascular adhesion protein-1 (VAP-1), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-a); as well as inflammatory pathway regulatory factors: nuclear factor-κ-gene binding (NF-κB) p65 and protein kinase B (Akt1). Among them, IL-6 was also significantly increased in the HHcy group. Both oxidative stress and inflammation contributed to the arterial injury of hypertension associated with HHcy, and inflammation mechanism might play a leading role in HHcy aggravating arterial injury, at least partially through the Akt1/NF-κB p65/IL-6 signaling pathway.

Hypertension and hyperhomocysteinemia as modifiable risk factors for Alzheimer's disease and dementia: New evidence, potential therapeutic strategies, and biomarkers

This review summarizes recent evidence on how mid-life hypertension, hyperhomocysteinemia (HHcy) and blood pressure variability, as well as late-life hypotension, exacerbate Alzheimer's disease (AD) and dementia risk. Intriguingly, HHcy also increases the risk for hypertension, revealing the importance of understanding the relationship between comorbid cardiovascular risk factors. Hypertension-induced dementia presents more evidently in women, highlighting the relevance of sex differences in the impact of cardiovascular risk. We summarize each major antihypertensive drug class's effects on cognitive impairment and AD pathology, revealing how carbonic anhydrase inhibitors, diuretics modulating cerebral blood flow, have recently gained preclinical evidence as promising treatment against AD. We also report novel vascular biomarkers for AD and dementia risk, highlighting those associated with hypertension and HHcy. Importantly, we propose that future studies should consider hypertension and HHcy as potential contributors to cognitive impairment, and that uncovering the underlying molecular mechanisms and biomarkers would aid in the identification of preventive strategies.

Using hyperhomocysteinemia and body composition to predict the risk of non-alcoholic fatty liver disease in healthcare workers

Purpose

This study investigated associations between serum homocysteine levels, body composition, and the probability of having nonalcoholic fatty liver disease (NAFLD) in Chinese healthcare workers.

Patients and Methods

A total of 4028 healthcare workers were enrolled in this study, and all underwent a physical examination. Body composition was measured using multifrequency bioelectrical impedance analysis.

Results

There were 1507 NAFLD patients (72.26% male, 27.74% female) and 2521 controls (39.83% male, 60.17% female). Body mass index (BMI), waistline, neck-circumference (NC), abdominal visceral fat area (AVFA), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), glucose (Glu), homocysteinemia (hcy) were higher in the NAFLD group than controls. Additionally, the skeletal-muscle was associated with a lower risk of NAFLD, whereas BMI, waistline, NC, hyperhomocysteinemia (HHcy) were associated with a higher risk of NAFLD. The best NC cut-off point for NAFLD was 34.45 cm (sensitivity 83.3% and specificity 83.9%) in women with HHcy, and the best skeletal-muscle content cut-off point for NAFLD was 41.335% (sensitivity 74.2% and specificity 65.6%) in men with HHcy.

Conclusion

Interactions between skeletal-muscle content, NC, and HHcy may affect the incidence of NAFLD in healthcare workers. This may provide a novel approach for diagnosing NAFLD.

Idiopathic intracranial hypertension in patients with cerebral small vessel disease: A case report

INTRODUCTION

Idiopathic intracranial hypertension (IIH) is a clinical syndrome characterized by increased intracranial pressure (ICP) without any identifiable cause. However, restrictions of cerebrospinal fluid absorption from the cerebral venous system, the glymphatic system overflow, and the cerebrospinal fluid's lymphatic pathways may be involved in the pathophysiology of IIH. Furthermore, an impaired glymphatic system is also implicated in the initiation and progression of cerebral small vessel disease (CSVD). Here, we reported a case of CSVD with concomitant IIH, possibly associated with the brain's glymphatic and lymphatic system dysfunction.

CASE CONCERN

A 39-year-old male presented with worsening headaches over the bilateral parietal areas during the past year and nausea for 2 days. Fundus examination revealed bilateral papilledema and lumbar puncture suggestive of elevated ICP, laboratory results showed hyperhomocysteinemia and mutation of methylenetetrahydrofolate reductase C677T. On magnetic resonance imaging, subcortical small infarct, white matter lesions, lacunes, enlarged perivascular spaces and dilatation of the optic nerve sheaths was detected, and right transverse sinus stenosis and a hypoplastic left sinus were showed on contrast-enhanced magnetic resonance venography.

DIAGNOSIS

The diagnoses of IIH, CSVD, transverse sinus stenosis, and hyperhomocysteinemia were performed.

INTERVISION AND OUTCOMES

The patient received antihypertensive, antiplatelet, anti-atherosclerotic, and homocysteine-lowering therapies. Finally, the patient's symptoms remised, and the increased ICP returned to normal; however, the bilateral TSS persisted after 3 months of follow-up.

CONCLUSIONS

In this case, we speculate that the normal glymphatic outflow pathway may serve as a compensatory mechanism for regulating increased ICP in patients with bilateral venous sinus obstruction, indicating impaired venous outflow pathway, possibly associated with dysfunction of the glymphatic and lymphatic systems in patients with CSVD.

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.

The protective mechanism of folic acid on hyperhomocysteinemia-related arterial injury in spontaneously hypertensive rats: Folic acid against arterial inflammation

BACKGROUND

Hypertension associated with hyperhomocysteinemia (HHcy) is correlated with a high risk of vascular diseases. Studies found that folic acid (FA) supplementation can reduce the risk of cardiovascular and cerebrovascular events. The aim of the present study was to explore the potential mechanisms of FA attenuating HHcy-related arterial injury in spontaneously hypertensive rats (SHRs).

METHODS

24 SHRs were randomized into the control group, the HHcy group, and the HHcy + FA group (8 per group). The SHRs in the HHcy group and the HHcy + FA group were given DL-Hcy intraperitoneally to mimic hypertension associated with HHcy. The SHRs in the HHcy + FA group were given FA by gavage to mimic an FA-fortified diet. The histopathology and immunohistochemistry of rat aorta and carotid artery were analyzed, and the relative expression levels of immune/inflammation and oxidative stress molecules in arterial tissue were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot.

RESULTS

FA significantly reduced the expression levels of nuclear factor-κ-gene binding (NF-κB) p65/Rela and interleukin-6 (IL-6) in rat arterial tissues, as well as the levels of plasma HHcy and serum malondialdehyde (MDA) in hypertension associated with HHcy rats (p < 0.05). At the same time, FA significantly increased the serum superoxide dismutase (SOD) level in hypertension associated with HHcy rats, and even the SOD level of the HHcy + FA group was higher than that of the control group (p < 0.05). However, HHcy induced the opposite results of the above indicators in SHRs compared with the control group (p < 0.05).

CONCLUSIONS

The arterial protection mechanisms of FA are related to reducing the concentration of HHcy to eliminate the tissue toxicity of HHcy, inhibiting NF-κBp65/Rela/IL-6 pathway molecules to regulate inflammatory response, and promoting the potential anti-oxidative stress pathway molecules to reduce oxidative stress level.

HOMOCYSTEINE LEVEL IN PATIENTS WITH POLYCYSTIC OVARY SYNDROME WITH AND WITHOUT INSULIN RESISTANCE

Until recent period, hyperinsulinemia and hyperandrogenism were thought to be involved in the pathogenesis of polycystic ovary syndrome (PCOS), however, in recent years several studies reported that hyperhomocysteinemia, which may be associated with insulin resistance, plays important role in the pathogenesis of PCOS. Therefore, hyperhomocysteinemia (HHcy) can be considered as one of the newly identified characteristics of PCOS. The aim of the study was to evaluate homocysteine (Hcy) levels in patients with PCOS with and without insulin resistance. The study was conducted in 59 patients with PCOS aged 13-35 (mean age 24.5±3.5). Patients were divided into 2 groups: Group I - 38 patients with PCOS and insulin resistance, Group II - 21 patients with PCOS without insulin resistance. PCOS patients as well were divided into 3 subgroups according to homocysteine values: low - ≤ 6.09 μmol/l, moderate - 6.10-9.33 μmol/l, high >9.34 μmol/l). In patients with PCOS and insulin resistance were established a significant increase in homocysteine levels, HOMA-IR and BMI indicators compared to those patients with PCOS without insulin resistance. In the group of patients with PCOS with insulin resistance homocysteine level with increased and high normal level of homocysteine (high Hcy subgroup, >9.34 μmol/l) were significantly more common (84.2%) compared to patients without insulin resistance (52%). Homocysteine level is significantly elevated in patients with PCOS, and insulin resistance compared to patients without insulin resistance. In the management of patients with PCOS, along with correction of insulin resistance, control and correction of homocysteine level should be considered, which will improve their reproductive outcome.

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.

The roles of homocysteinemia and methylmalonic acidemia in kidney injury in atypical hemolytic uremic syndrome caused by cobalamin C deficiency

BACKGROUND

Cobalamin C (cblC), a vitamin B12 processing protein, plays a crucial role in metabolism for the conversion of homocysteine to methionine and methylmalonyl-CoA to succinyl-CoA. CblC deficiency, an inborn error of cobalamin processing, is a rare cause of atypical hemolytic-uremic syndrome (aHUS) and results in hyperhomocysteinemia and methylmalonic aciduria. Both substances are thought to contribute to thrombotic microangiopathy (TMA) in cblC deficiency patients. However, the roles of homocysteine and methylmalonic acid (MMA) in these patients remain unclear. We want to shed more light on the contributions of homocysteine and MMA levels as contributing factors for thrombotic microangiopathy (TMA)/aHUS by a follow-up of a cblC deficiency patient over 6 years.

CASE DIAGNOSIS

A 27-day-old Hispanic female presented with abnormal C3-carnitine on her newborn screen, poor feeding, decreased activity, and oligouria. She was diagnosed with cblC deficiency after laboratory results revealed elevated serum homocysteine, and serum MMA along with genetic testing showing a homozygous pathogenic frameshift variant in MMACHC. The patient developed aHUS and acute kidney injury (AKI), which resolved after appropriate therapy. Over 6 years, she continued to have normal kidney function with no thrombocytopenia despite persistently elevated homocysteine and MMA levels.

CONCLUSION

We question the roles of homocysteine and MMA as causative of aHUS/TMA in cblC deficiency as they remained elevated during follow-up but did not result in aHUS/TMA or AKI. Hyperhomocysteinemia and/or MMA caused by other metabolic diseases do not result in aHUS/TMA or AKI. This suggests that other nephrotoxic factors may trigger aHUS/TMA in cblC patients.

Serum uric acid concentration is associated with hyperhomocysteinemia in hypertensive Chinese adults

PURPOSE

This study is to investigate the correlation between serum uric acid levels and hyperhomocysteinemia Chinese adult patients with hypertension.

METHODS

We enrolled 981 hypertensive patients, including unmedicated hypertensives, in our study. There were 453 patients with hyperhomocysteinemia (hyperhomocysteinemia hypertension group) and 528 without it (ordinary hypertension group). We collected histories of coronary heart disease, diabetes, and smoking and tested patients' BMI, blood pressure, fasting serum uric acid, serum total cholesterol, triglycerides, low-density lipoprotein cholesterol, serum creatinine, and homocysteine. Subjects were stratified into four groups according to their serum uric acid quartiles: Q1 group, 249 cases (≤268 μmol/L); Q2 group, 245 cases (269-322 μmol/L); Q3 group, 244 cases (323-378 μmol/L); and Q4 group, 243 cases (≥379 μmol/L). We employ logistic regression analysis to investigate the relationship between serum uric acid levels and the risk of hyperhomocysteinemia in patients with hypertension.

RESULTS

We find that there were significant differences in gender distribution, serum uric acid, BMI, serum creatinine, total cholesterol, and diastolic blood pressure between the two groups (P < 0.05). The prevalence of hyperhomocysteinemia in groups Q1 through Q4 was 26.91% (67/249), 45.31% (111/245), 47.01% (117/244), and 65.02% (158/243), respectively, after adjusting for relevant factors, we find that the risk of hyperhomocysteinemia in the Q4 group was significantly higher than that in the Q1 group (odds ratio = 3.00, 95% confidence interval: 1.83-4.93).

CONCLUSION

We find evidence that an elevated serum uric acid level is an independent indicator for hyperhomocysteinemia in patients with hypertension.

A Study of Srum Homocysteine Level in Ischaemic Stoke

Stroke remains the second leading cause of death world wide after ischaemic heart disease. Stroke occurs mainly due to infarction which accpounts for 85% of etiological factors and 15% due to hemorrhage. Hyperhomocysteinemia is associated with premature atherosclerosis and vascular events and it is an important risk factor for cerebrovascular accidents.

MATERIAL

Case will be selected from patients admitted to medical wards in Navodaya Medical College, Raichur. Duration based study with a minimum of 50 cases for a period of 18 months from august 2019. In all patients admitted with symptoms suggestive of stroke careful methodical examination of central nervous system carried out recording all physical signs in order. In all cases with the help of close relatives the preceding symptoms and risk factors were enquired all patients were subjected to CT scan brain, CBC, FBS, PPBS, lipid profile and serum homocysteine levels were done.

OBSERVATION

In our study we observed that the serum homocysteine levels were elevated in ischemic stroke significantly. The mean serum homocysteine levels were higher in non diabetics(29.57 micromole/ litre) than diabetics (20.75 micromole/litre) and difference was statistically significant (P&lt;0.001). Mean serum Homocysteine levels were higher in age group &lt;65 years(28.73 micromole/litre) than patient age &gt;65 years (20.50 micromole/litre) and the difference was statistically significant (p&lt;0.001). Mean serum heomocysteine levels were higher in hypertensives (26.73 micromole/litre) than normotensive (23.28 micromole/litre) however the difference was statistically not significant (p&gt;0.001).The mean serum homocysteine levels were higher in patients with normal lipid profile(30.97 micromole/litre) than patients with dyslipidemia (21.92 micromole/litre) and the difference was statistically significant (p&lt;0.001).

CONCLUSION

The present study revealed that hyperhomocysteinemia appears to be an important risk factor for ischemic stroke. It is therefore important to use serum homocysteine as an important tool to investigate all cases of ischemic stroke and if serum homocysteine is elevated patient should be put on multivitamins containing vitamin B12, folic acid and pyridoxine to reduce serum homocysteine levels.

Vitamin B12 and chronic kidney disease

Chronic Kidney Disease (CKD) is an emerging public health issue with a fast-growing global prevalence. Impairment in vitamin B12 metabolism is considered a nontraditional risk factor of poor outcomes associated with CKD, and there is greater interest from the scientific community than ever before to explore the role and influence of vitamin B12 in CKD. Homocysteine metabolism forms an important component of the vitamin B12 metabolic pathway. Hyperhomocysteinemia is frequently observed in CKD and End-Stage Kidney Disease (ESKD), but its representation as a prognostic marker for CKD outcomes is still not fully clear. This chapter reviews the vitamin B12 and homocysteine metabolic pathways and their dysfunction in CKD states. Biochemical factors and the MTHFR genetic polymorphisms which disrupt vitamin B12 and homocysteine metabolism are explored. The mechanisms of homocysteine-mediated and vitamin B12-mediated tissue damage in CKD are discussed. This chapter reviews current perspective on definition and measurement of plasma vitamin B12 levels in the CKD population. Updated evidence investigating the prognostic role of vitamin B12 for CKD outcomes is presented. Findings from major clinical trials conducted relating to outcomes from multivitamin (including folic acid and vitamin B12) supplementation in nondialysis and dialysis-dependent CKD are highlighted. The prognostic value of vitamin B12 and effects of vitamin B12 supplementation in the context of kidney transplantation and acute kidney injury is also reviewed. Future research considerations are summarized based on evidence gaps in our knowledge base of this topic. Greater abundance of high-level evidence to guide an approach toward vitamin B12 measurement, monitoring and supplementation in CKD may contribute to improved clinical outcomes.

[Metabolic disorders in hereditary optic neuropathies]

Folate metabolism disorders are known to have a potential involvement in the pathophysiology of mitochondrial diseases. Many researchers suggest that profound systemic folate deficiency may contribute to mitochondrial folate deficiency. Folic acid metabolism is closely related to vitamin B₁₂ and homocysteine. Considering that hereditary optic neuropathies (HON) are mitochondrial diseases, it is important to study the folate status, the content of vitamin B₁₂ and homocysteine in patients with this pathology.

OBJECTIVE

To compare the content of folic acid, vitamin B₁₂ and homocysteine in the blood serum of patients with Leber's hereditary optic neuropathy (LHON) and autosomal recessive optic neuropathy (ARON), optic neuropathy of other genesis, and the comparison group.

MATERIAL AND METHODS

The study involved 58 patients with LHON and ARON, the control group of 49 patients with ischemic, inflammatory, traumatic and compressive optic neuropathies, and the comparison group of 20 healthy volunteers.

RESULTS

A decrease in blood folic acid levels was revealed (4.0±1.6 ng/mL) in patients with HON compared to the control group (p=1.3·10^-8) and the comparison group (p=1·10^-17). The content of vitamin B₁₂ in patients with HON was 380.8±168.1 pg/mL, which was significantly lower than in the comparison group (p=0.0001). The homocysteine content was 14.1±5.6 μmol/L in patients with HON, which was significantly higher than in the control group (p=0.0007) and the comparison group (p=0.000003). At the same time, an increase in homocysteine level of more than 10 µmol/L was revealed in 75% of patients with HON. Similar metabolic disorders were found in groups with various mutations in mitochondrial and nuclear DNA.

CONCLUSION

Patients with HON showed marked decrease in the levels of folic acid and vitamin B₁₂, as well as hyperhomocysteinemia. It is very important to identify the causes of metabolic disorders in order to determine the role of folate deficiency in the development of HON, as well as the possibility of its pharmacological treatment.

Estradiol and Hyperhomocysteinemia Are Linked Predominantly Through Part Renal Function Indicators

BACKGROUND

Previous studies have shown that estrogen, kidney function, and homocysteine (Hcy) or hyperhomocysteinemia (HHcy) are related to each other. However, the underlying biological mechanisms still remain unclear. We aimed to explore the association between estradiol (E2) and HHcy in the female population, and to further evaluate the mediating role of renal function indicators.

METHODS

This unmatched case-control study consisted of 1,044 female participants who were 60.60 ± 12.46 years old. Data on general demographic characteristics, such as age, smoking and drinking status, menopause and so on were collected in a personal interview, and laboratory examinations were performed by well-trained personnel. The mediating effect model was applied to analyze the direct and indirect effects of E2 on Hcy.

RESULTS

The average levels of Hcy and E2 of the participants were 12.6 μmol/L and 14.95 pg/ml. There were statistical differences in renal indexes blood urea nitrogen (BUN), serum creatinine (Scr), uric acid (UA), glomerular filtration rate (GFR) and E2 between HHcy group and non-HHcy group. The logistic regression models showed that UA was risk factor for HHcy (P <0.001), GFR and E2 were protective factors for HHcy after adjusting for confounding factors (P <0.001). The indirect effects of E2 on Hcy through UA and GFR accounted for 14.63 and 18.29% of the total impacts of E2 on Hcy.

CONCLUSIONS

These data indicated that E2 was a protective factor of HHcy, and the effects of E2 on HHcy may be mediated by renal function indicators UA and GFR.

Prevalence and risk factors for hyperhomocysteinemia: a population-based cross-sectional study from Hunan, China

OBJECTIVES

Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases. We aimed to investigate the prevalence and risk factors for hyperhomocysteinemia, especially modifiable lifestyle factors, such as smoking behaviour and dietary factors.

DESIGN

Population-based cross-sectional study.

SETTING

Hunan Province, China PARTICIPANTS: A total of 4012 participants completed the study, between July 2013 and March 2014. The median age is 55 (interquartile range: 45-63) years, with 1644 males (41%) and 2368 females (59%).

MAIN OUTCOME MEASURES

Homocysteine level were measured by the microplate enzyme immunoassay method. Hyperthomocysteinemia was defined as ≥15 µmol/L. Questionnaire was used to investigate potential risk factors of hyperhomocysteinemia. Crude odd ratio (OR) or adjusted OR with 95% CI were determined by using univariable or multivariable logistic regression models.

RESULTS

The prevalence of hyperhomocysteinemia is 35.4% (45.4% vs 28.5% for men, women, respectively). One-year increase in age is significantly associated with 2% higher risk of hyperhomocysteinemia (OR=1.02, 95% CI: 1.01 to 1.03). One unit increase of BMI is associated with 5% higher risk of hyperhomocysteinemia (OR=1.05, 95% CI: 1.03 to 1.07). Compared with the non-smoker, smoking participants have a 24% higher risk of hyperhomocysteinemia (OR=1.24, 95% CI: 1.006 to 1.53), while the risk for those quitting smoking are not significantly different (OR=1.14, 95% CI: 0.85 to 1.54). compared with those consuming fruit and vegetable at least once every day, those consuming less than once every day had a significantly higher risk of hyperhomocysteinemia (OR=1.29, 95% CI:1.11 to 1.50). In addition, we found there were significant sex interaction with education level or alcohol drinking on the risk of hyperhomocysteinemia (p_interaction <0.05).

CONCLUSIONS

Higher BMI and older age are potential risk factors for hyperhomocysteinemia. Current smoking but not quitting smoking is associated with higher risk of hyperhomocysteinemia. Fruit and vegetable consumption may have protective effect against hyperhomocysteinemia. Alcohol consumption or education level might interact to influence the risk of hyperhomocysteinemia.

Opicapone Protects Against Hyperhomocysteinemia-Induced Increase in Blood-Brain Barrier Permeability

Hyperhomocysteinemia (HHcy)-related brain vascular disorders and brain endothelial dysfunction are important characteristics of the pathogeneses of subarachnoid hemorrhage and stroke. Upregulated homocysteine (Hcy) can impair the integrity of the blood-brain barrier (BBB). Opicapone has been recently licensed for the management of Parkinson's disease (PD); however, it is unknown whether it possesses a protective effect in brain vessels against HHcy. To investigate the beneficial effects of Opicapone on BBB permeability against HHcy, we carried out both in vivo and in vitro experiments. Mice were allocated into four groups: the Control, Opicapone, HHcy, and HHcy + Opicapone. Interestingly, we found that the administration of Opicapone attenuated the increased BBB permeability in Hcy-treated mice, as determined by sodium fluorescein staining. The immunofluorescence staining showed that Opicapone prevented homocysteine-induced reduction of claudin-2 in the mice cortices. The in situ zymography assay revealed that Opicapone suppressed homocysteine-increased matrix metalloproteinases (MMPs) activity in the cortices. In bEnd.3 brain endothelial cells, Opicapone treatment ameliorated homocysteine-induced lactate dehydrogenase (LDH) release and expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Furthermore, Opicapone alleviated homocysteine-induced decrease in claudin-2 level in bEnd.3 cells. In summary, our results show that Opicapone protects against HHcy-induced BBB permeability by reducing the expression and gelatinase activity of MMPs, and increasing the expression of claudin-2.

THE INFLUENCE OF CHRONIC HYPERHOMOCYSTEINEMIA ON PHAGOCYTIC AND METABOLIC ACTIVITY OF PERIPHERAL BLOOD NEUTROPHILS IN CASE OF LIPOPOLYSACCHARIDE-INDUCED PERIODONTITIS

The aim of the study was to investigate the phagocytic and metabolic activity of peripheral blood neutrophils in rats with lipopolysaccharide (LPS)-induced periodontitis combined with chronic thiolactone hyperhomocysteinemia (HHcy).The experiment included non-linear mature male rats (n=48), which were divided into 4 groups: control; animals with a periodontitis model; animals with a model of chronic thiolactone HHcy; animals with a model of periodontitis in combination with chronic thiolactone HHcy. Phagocytic activity, phagocytic index and phagocytic number were determined as indicators of phagocytosis of peripheral blood neutrophils. The oxygen-dependent bactericidal activity of peripheral blood neutrophils was studied using nitroblue tetrazolium test (NBT-test).Our research has found that LPS-induced periodontitis in rats is accompanied by dysfunction of phagocytosis process (increased phagocytic activity with a simultaneous decrease of absorption capacity) and activation of oxygen-dependent microbicidal mechanisms of peripheral blood neutrophils, as indicated by an increase of indices of spontaneous and activated NBT-test. Chronic thiolactone HHcy adversely affects the functional and metabolic activity of peripheral blood neutrophils in case of periodontitis, which is confirmed by a violation of the process of phagocytosis, a more pronounced decrease in absorption capacity and depletion of metabolic reserves of these cells in rats with comorbid course of LPS-induced periodontitis vs. animals with only LPS-induced periodontitis. The observed disorders in the process of phagocytosis in rats with comorbid course of periodontitis are an important factor in reducing the non-specific organism resistance which contributes to the progression of periodontitis. The obtained results reveal new aspects of the high Hcys plasma level influence on the course of inflammatory process in periodontal tissues, which opens opportunities for improving pathogenetic therapy in patients with periodontal disease combined with chronic HHcy.

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.

The link between homocysteine, folic acid and vitamin B12 in chronic kidney disease

Patients with chronic kidney disease or end-stage renal disease experience tremendous cardiovascular risk. Cardiovascular events are the leading causes of death in these patient populations, thus the interest in non-traditional risk factors such as hyperhomocysteinemia, folic acid and vitamin B12 metabolism is growing. Hyperhomocysteinemia is commonly found in CKD patients because of impaired renal metabolism and reduced renal excretion. Folic acid, the synthetic form of vitamin B9, is critical in the conversion of homocysteine to methionine like vitamin B12. Folic acid has also been shown to improve endothelial function without lowering homocysteine, suggesting an alternative explanation for the effect of folic acid on endothelial function. Whether hyperhomocysteinemia represents a reliable marker of cardiovascular risk and cardiovascular mortality or a therapeutic target in this population remains unclear. However, it is reasonable to consider folic acid with or without methylcobalamin supplementation as appropriate adjunctive therapy in patients with CKD. The purpose of this review is to summarize the characteristics of homocysteine, folic acid, and vitamin B12 metabolism, the mechanism of vascular damage, and the outcome of vitamin supplementation on hyperhomocysteinemia in patients with CKD, ESRD, dialysis treatment, and in kidney transplant recipients.

[n-3 Polyunsaturated fatty acid attenuates hyperhomocysteinemia-induced hepatic steatosis by increasing hepatic LXA5 content]

Nonalcoholic fatty liver disease (NAFLD) and hyperhomocysteinemia (HHcy) both are major health problems worldwide, whose incidence are closely related with each other. We previously reported the mechanism of HHcy-caused hepatic steatosis, but the role of n-3 polyunsaturated fatty acid (n-3 PUFA) in HHcy-induced hepatic steatosis remains unclear. In this study, 6-week-old C57BL/6 male mice were given a high methionine diet (HMD, 2% methionine diet), and plasma homocysteine levels were measured by ELISA to confirm the establishment of an HHcy model. Meantime, mice were fed HMD with or without n-3 PUFA supplement for 8 weeks to determine the role and mechanism of n-3 PUFA in hepatic steatosis induced by HHcy. Results showed that n-3 PUFA significantly improved hepatic lipid deposition induced by HHcy. qRT-PCR analysis demonstrated that n-3 PUFA inhibited the upregulation of Cd36, a key enzyme of fatty acid uptake, caused by HHcy. Further, the inhibition of hepatic Cd36 expression was associated with the inactivation of aryl hydrocarbon receptor (Ahr) induced by n-3 PUFA. Of note, mass spectrometry revealed that hepatic content of lipoxin A₅ (LXA₅) was significantly increased in HMD+n-3 PUFA-fed mice compared with that in HMD-fed mice. In primary cultured hepatocytes, LXA₅ treatment markedly reversed homocysteine-evoked Cd36 upregulation and Ahr activation, which resulted in reduced lipid accumulation. In conclusion, we demonstrate that n-3 PUFA inactivates HHcy-induced Ahr-Cd36 pathway by increasing hepatic LXA₅ content, which alleviates hepatic steatosis. Thus, our results may provide a potential strategy for treatment of NAFLD.