Higher Plasma Homocysteine Levels Research Articles

Case presentation: a severe case of cobalamin c deficiency presenting with nephrotic syndrome, malignant hypertension and hemolytic anemia

BackgroundThe etiology of nephrotic syndrome can vary, with underlying metabolic diseases being a potential factor. Cobalamin C (cblC) defect is an autosomal recessive inborn error of metabolism caused by mutations in the MMACHC gene, resulting in impaired vitamin B12 processing. While cblC defect typically manifests with hematological and neurological symptoms, renal involvement is increasingly recognized but remains rare.Case PresentationWe describe a 7-month-old male patient presenting with fatigue and edema. His initial laboratory findings showed anemia, thrombocytopenia, hypoalbuminemia and proteinuria. Further examinations reveals hemolysis in peripheral blood smear. During his follow up respiratory distress due to pleural effusion in the right hemithorax was noticed. And fluid leakage to the third spaces supported a diagnosis of nephrotic syndrome. The patient’s condition deteriorated, leading to intensive care admission due to, hypertensive crisis, and respiratory distress. High total plasma homocysteine and low methionine levels raised suspicion of cobalamin metabolism disorders. Genetic testing confirmed biallelic MMACHC gene mutations, establishing the diagnosis of cblC defect. Treatment with hydroxycobalamin, folic acid, and betaine led to remarkable clinical improvement.Discussion/ConclusionThis case underscores the significance of recognizing metabolic disorders like cblC defect in atypical presentations of nephrotic syndrome. Early diagnosis and comprehensive management are vital to prevent irreversible renal damage. While cblC defects are more commonly associated with atypical hemolytic uremic syndrome, this case highlights the importance of considering cobalamin defects in the differential diagnosis of nephrotic syndrome, especially when associated with accompanying findings such as hemolysis. Our case, which has one of the highest homocysteine levels reported in the literature, emphasizes this situation again.

High plasma homocysteine levels predict the progression from mild cognitive impairment to dementia

High levels of blood homocysteine (HCy), a well-known cardiovascular risk factor and promoter of oxidative stress, have been associated with the incidence of cognitive impairment and dementia. Nonetheless, contrasting data are still present on its involvement in the progression from Mild Cognitive Impairment (MCI) to overt dementia.In this study we aimed to observe whether blood HCy level are associated with the evolution from MCI, divided into amnestic MCI (aMCI) and non-amnestic MCI (naMCI), to dementia.Blood HCy was measured in 311 MCI subjects (aMCI: 64%, naMCI: 36%) followed-up for a median of 33 months (range 10–155 months). At follow-up, 137 individuals converted to dementia (naMCI, n = 34; aMCI, n = 103). Based on HCy distribution, subjects in the highest tertile had a greater risk to convert to dementia compared to tertile I (Hazard Ratio (95% confidence interval): 2.25 (1.05–4.86); p = 0.04). aMCI subjects did not show increased risk to convert to dementia with increasing HCy concentration, but was significant in naMCI (p = 0.04). We observed a non-significant increase in the risk of progression to dementia from naMCI/low HCy (reference group, HCy cutoff value = 16 μmol/L) to naMCI/high HCy, but it was significant from aMCI/low HCy (HR: 2.73; 95%CI: 1.06–7.0; p:0.03), to aMCI/high HCy (HR: 3.24; 95%CI: 1.17–8.47; p:0.02).Our results suggest that HCy levels are associated with the progression from MCI to dementia. This association seems significant only for the naMCI group, indirectly supporting the notion that hyperhomocysteinemia damages the nervous system through its role as a vascular risk factor.

MTHFRC 677T Gene Polymorphism and Homocysteine in North China Patients with Varicocele

To investigate the correlation between methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism, homocysteine, and male infertility with varicocele in North China. One Hundred infertile males with varicocele (VC; grade II-III, VC group) and 100 healthy males with normal semen parameters and no varicocele (NC group) were recruited for PCR microarray, blood and semen testing. Compared with the CC genotype in the NC group, the TT genotype in the NC group and the CC genotype in the VC group showed no significant changes in sperm motility (P=0.191; P=0.130), sperm density (P=0.591, P=0.643), plasma homocysteine level (P=0.511; P=0.677), and seminal plasma MDA (P=0.752; P=0.451). In contrast, VC patients with the TT genotype had higher plasma homocysteine level and seminal plasma MDA levels (P <0.001), lower partial pressure of oxygen in seminal pulse (PO2; P <0.001) and poorer sperm quality (P <0.001), as compared with the CC genotype. This suggests that MTHFR C677C>T may not be a risk factor for male Varicocele in North China. However, this may affect the oxidative stress associated with homocysteine expression, which in turn affects semen parameters in VC patients. Larger studies are needed to validate our findings.

Nitrous oxide induced spinal cord oedema with normal serum B12 level with high plasma homocysteine level

Nitrous oxide induced spinal cord oedema with normal serum B12 level with high plasma homocysteine level

Plasma metabolomic profile in orthostatic intolerance children with high levels of plasma homocysteine

BackgroundOrthostatic intolerance, which includes vasovagal syncope and postural orthostatic tachycardia syndrome, is common in children and adolescents. Elevated plasma homocysteine levels might participate in the pathogenesis of orthostatic intolerance. This study was designed to analyze the plasma metabolomic profile in orthostatic intolerance children with high levels of plasma homocysteine.MethodsPlasma samples from 34 orthostatic intolerance children with a plasma homocysteine concentration > 9 µmol/L and 10 healthy children were subjected to ultra-high-pressure liquid chromatography and quadrupole-time-of-flight mass spectrometry analysis.ResultsA total of 875 metabolites were identified, 105 of which were significantly differential metabolites. Choline, 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine, 1-(1Z-octadecenyl)-2-(4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoyl)-sn-glycero-3-phosphocholine, histidine, isocitric acid, and DL-glutamic acid and its downstream metabolites were upregulated, whereas 1-palmitoyl-sn-glycero-3-phosphocholine, 1-stearoyl-sn-glycerol 3-phosphocholine, sphingomyelin (d18:1/18:0), betaine aldehyde, hydroxyproline, and gamma-aminobutyric acid were downregulated in the orthostatic intolerance group compared with the control group. All these metabolites were related to choline and glutamate. Heatmap analysis demonstrated a common metabolic pattern of higher choline, 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine, and DL-glutamic acid, and lower sphingomyelin (d18:1/18:0), 1-stearoyl-sn-glycerol 3-phosphocholine, and 1-palmitoyl-sn-glycero-3-phosphocholine in patients with certain notable metabolic changes (the special group) than in the other patients (the common group). The maximum upright heart rate, the change in heart rate from the supine to the upright position, and the rate of change in heart rate from the supine to the upright position of vasovagal syncope patients were significantly higher in the special group than in the common group (P < 0.05). Choline, 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine, and DL-glutamic acid were positively correlated with the rate of change in heart rate from the supine to the upright position in vasovagal syncope patients (P < 0.05).ConclusionsThe levels of choline-related metabolites and glutamate–related metabolites changed significantly in orthostatic intolerance children with high levels of plasma homocysteine, and these changes were associated with the severity of illness. These results provided new light on the pathogenesis of orthostatic intolerance.

Vitamin B12 status and hyperhomocysteinemia in patients with Rheumatoid arthritis treated with methotrexate and folic acid

BackgroundRheumatoid arthritis (RA) is an inflammatory arthritis in which the immune system targets synovial joints. Methotrexate serves as the mainstay of treatment for RA due to its efficacy. However, patients treated with methotrexate are uniquely at risk for vitamin B12 deficiency and hyperhomocysteinemia due to coincident disease risk factors and the fact that methotrexate use is associated with malabsorption. The objective of this study was to assess for vitamin B12 deficiency among patients with RA treated with methotrexate and folic acid. MethodsThis cross-sectional study included 50 patients with RA treated with methotrexate and folic acid and 49 patients with RA treated with other therapies. Patients were matched by age, sex, race, renal function, and disease activity. We compared plasma vitamin B12, methylmalonic acid, and homocysteine levels between these two groups utilizing quantitative and categorical analyses. ResultsThirty-seven (74%) RA patients on methotrexate and folic acid had elevated plasma homocysteine levels compared with only 27 (55%) RA patients receiving other therapies (P < 0.05). The proportion of patients with low vitamin B12 and high methylmalonic acid levels did not differ between the two groups. ConclusionsOur data show high plasma homocysteine levels among RA patients treated with methotrexate and folic acid. While plasma vitamin B12 levels were similar between the two groups, high plasma homocysteine is also a sensitive marker of vitamin B12 deficiency. Additional studies should evaluate for the presence of clinical features of vitamin B12 deficiency and hyperhomocysteinemia among RA patients treated with methotrexate and folic acid.

Glial changes are associated with cerebrovascular integrity in hyperhomocysteinemia‐induced VCID in mouse and human brain

AbstractBackgroundWith the aged population estimated to double by 2050 and the rate of dementia expected to triple, it is critical to identify treatments for dementia. One of the leading causes of dementia is vascular contributions to cognitive impairment and dementia (VCID), and is frequently found co‐morbidly with Alzheimer’s disease, the other leading cause of dementia. A modifiable risk factor for VCID is hyperhomocysteinemia (HHcy), which is defined as elevated levels of plasma homocysteine (a non‐protein‐forming amino acid), and most late‐life HHcy is caused by impaired B vitamin absorption. Although HHcy is a risk factor for VCID, the mechanism through which it induces cognitive impairment remains unclear.MethodWe used human and mouse brain tissue to determine glial and vascular changes associated with HHcy. Wild‐type (C57Bl6J) mice were placed on a HHcy or control diet for 6, 10, 14, or 18 weeks. Using qPCR, we investigated pro‐ and anti‐inflammatory cytokines. We also determined changes in microglia (IBA‐1) and identified the number of microhemorrhages and cognitive changes. In humans, we identified 31 autopsied research volunteers with antemortem homocysteine levels; 13 cases had normal plasma homocysteine levels (&lt;14µmol/L) and 18 had high plasma homocysteine levels (&gt;14µmol/L). We determined whether the level of plasma homocysteine was associated with microglia (IBA‐1) and astrocytes (GFAP) as well as microhemorrhages and atherosclerosis severity in the frontal and occipital cortices. Both gene expression and protein inflammatory markers were measured to determine associations with plasma homocysteine.ResultIn our mouse model of HHcy, we identified a time course of glial changes that first begins with an increase in pro‐inflammatory cytokines and increases in microglial staining at 6 weeks on diet. This is followed by cognitive changes at 10 weeks on diet. Finally, at 14 weeks on diet, we see significant cognitive deficits due to HHcy. In human tissue, HHcy was associated with more microglia but fewer astrocytes, a significant decrease in inflammation and increased microhemorrhages in the frontal cortex.ConclusionTaken together, this data shows that in both mouse and human tissue, HHcy induces significant glial and vascular pathology that could be driven by inflammatory effects.

The Relationship between Elevated Homocysteine and Metabolic Syndrome in a Community-Dwelling Middle-Aged and Elderly Population in Taiwan.

(1) Background: Metabolic syndrome has become a serious health problem in society. Homocysteine is a biomarker for cardiovascular disease. We investigated the relationship between homocysteine levels and metabolic syndrome. (2) Methods: A total of 398 middle-aged and elderly individuals were included in our study. First, we divided the participants into two groups: the metabolic syndrome group and the nonmetabolic syndrome group. Second, according to tertiles of homocysteine levels from low to high, the participants were divided into first, second, and third groups. Pearson's correlation was then calculated for homocysteine levels and metabolic factors. Scatterplots are presented. Finally, the risk of metabolic syndrome in the second and third groups compared with the first group was assessed by multivariate logistic regression. (3) Results: In our study, the metabolic syndrome group had higher homocysteine levels, and the participants in the third group were more likely to have metabolic syndrome. Multivariate logistic regression revealed that the third group, which had the highest homocysteine level, was associated with metabolic syndrome with an odds ratio of 2.32 compared with the first group after adjusting for risk factors. (4) Conclusions: We concluded that high plasma homocysteine levels were independently associated with MetS in our study population.

Features of the Course of Various types of Stroke in Patients Exposed to Low-dose Radiation

BACKGROUND: There is limited number of studies about peculiarities of cardiovascular diseases in population of different region by the zone of radiation exposure risk. AIM: The aim of the study was to study the effect of radiation factor on the pathogenesis of stroke. MATERIALS AND METHODS: To study the in influence of radiation factor on pathogenesis of stroke, 358 stroke patients were distributed based on the place of their residence into corresponding zones of radiation risk: 53 patients lived in zone of extremely high radiation level (488–100 cSV, zone I): 75 - from the zone of maximal radiation exposure (35–100 cSV, zone II), 158 - from zone with high radiation exposure (35–7 cSV, zone III), and 72 patients were the residents of minimal radiation risk (1–7 cSV, zone IV). RESULTS: The study of coagulation hemostasis had revealed the significant increase of fibrinogen level in patients from zone I: 4.7 ± 0.14% versus 3.2 ± 0.11%, in patients living in minimal radiation risk zone (p &lt; 0.01). The patients from extremely high radiation risk had significant decrease in fibrinolysis time in comparison to patients from zone IV (p &lt; 0.05). The primary APS was diagnosed in 24 (6.7%) patients in total group of stroke patients (11 males and 13 females), from which 21 patients with ischemic stroke and 3 with hemorrhagic stroke. Leiden Va defect was found significantly more often in patients lived in high radiation risk zone (9.4%), in 13.5% stroke patients from zone II, in 13.2% patients lived in zone I, in comparison to 6.9% patients lived in zone IV. The patients from zone I had significantly higher level of plasma homocysteine in comparison to patients from other zones, (p &lt; 0.01). Furthermore, the significantly higher levels of plasma homocysteine were found in the group with maximal and high radiation exposure, in comparison to the group of patients from minimal risk zone (p &lt; 0.05). CONCLUSIONS: We can see the presence of indirect evidences of modifying influence of radiation factor on pathogenic mechanisms of stroke.

Contribution of astrocytic MMP9 toward progression of VCID pathology

AbstractBackgroundVascular contributions to cognitive impairment and dementia (VCID) is one of the leading causes of dementia. High levels of plasma homocysteine or hyperhomocysteinemia has been characterized as a risk factor for VCID however, the mechanism underlying the connection between hyperhomocysteinemia and development of VCID pathology remains elusive. I hypothesize that hyperhomocysteinemia initiates a pro‐inflammatory cascade that increases the activity of MMP9 causing both perivascular astrocytes to dissociate from their vessels and initiating the degradation of endothelial cell tight junction proteins, leading to blood brain barrier dysfunction and the progression toward VCID pathology.MethodFor in vivo studies, C57BL6 WT and MMP9KO mice were placed on a control diet or a diet deficient in folate, vitamins B6 and B12 and enriched in methionine to induce hyperhomocysteinemia for 4, 8, 12, and 16 weeks. For in vitro, experiments, primary astrocytes from WT and MMP9KO mice were treated with a 50μM homocysteine stimulus or an inflammatory stimulus (TNF‐a, IL‐1b and C1q) for 48 hours and the conditioned media was collected. This homocysteine or inflammatory astrocyte conditioned media was then used to treat WT endothelial cells. Immunohistochemistry and gene expression analysis were used to determine neuroinflammatory changes while histology was used to identify changes in astrocytic end‐feet proteins, tight junction proteins, vascular density and microhaemorrhages. Both gel and in situ zymography were used to assess proteinase activity of MMP9 and related gelatinases. Western blots were used to investigate substrates of MMP9 including claudin, occludin and β‐dystroglycan. Behaviour was assessed using rotarod, novel object recognition and spontaneous alternation testing. Transendothelial electrical resistance and sodium fluorescein assays were used to measure the integrity of endothelial cell tight junctions in vitro.ResultStudies are underway to examine changes in cognition, microhaemorrhages, neuroinflammation, astrocyte end‐foot integrity, tight junction protein integrity and activity of MMP9.ConclusionCollectively, our findings suggest that astrocytic MMP9 may play an integral role in the mechanism associating homocysteine induced neuroinflammation with vascular pathogenesis leading to VCID, highlighting this pathway as an important subject for future study.

Evaluation of pathologies associated with hyperhomocysteinemia in human autopsy brain tissue

AbstractBackgroundVascular contributions to cognitive impairment and dementia (VCID) are one of the leading causes of dementia; VCID affects roughly 10‐40% of all dementia patients. A major, yet underrecognized, modifiable risk factor for VCID is hyperhomocysteinemia (HHcy). Defined as elevated levels of plasma homocysteine (a non‐protein‐forming amino acid), most late‐life HHcy is caused by impaired B vitamin absorption. Although HHcy has been recognized as a risk factor for VCID, studies aimed at identifying pathologies associated with HHcy have been lacking.MethodTo determine pathologies associated with HHcy, we identified 31 autopsied research volunteers with antemortem homocysteine levels; 13 cases had normal plasma homocysteine levels (&gt;14μmol/L) and 18 had high plasma homocysteine levels (&lt;14μmol/L). We then measured levels of homocysteine and related metabolites in both plasma samples taken closest to autopsy and frontal cortex. Next, we determined whether the level of plasma homocysteine was associated with several markers identified via immunohistochemistry, including Aβ, PHF‐1, IBA‐1 and GFAP. Plasma and brain protein markers for inflammation and angiogenesis were also measured to determine associations with plasma homocysteine. Finally, we used the Human Neuroinflammation NanoString panel to determine gene expression changes of inflammatory markers associated with high homocysteine levels in the frontal cortex and occipital lobe.ResultPlasma metabolite analysis showed patients who had elevated levels of homocysteine also had increased levels of several homocysteine cycle metabolites such as cysteine, S‐adenosyl‐homocysteine, cystathionine and choline. Flt1, an angiogenic marker, and IL5, an inflammatory marker, had a positive correlation with increased plasma homocysteine. No correlation between IBA‐1 or GFAP immunohistochemistry with plasma homocysteine was found. Gene expression showed that most genes were downregulated in the presence of high plasma homocysteine, including many significant genes involved in apoptosis, growth factor and cytokine signaling, and the innate and adaptive immune response.ConclusionThese preliminary data show that increased plasma homocysteine correlates with protein inflammatory and angiogenic markers and with a significant downregulation of inflammation‐related gene expression markers in the brain. Overall, this could reflect impaired normal immune function, providing possible mechanisms by which hyperhomocysteinemia induces cognitive deficits and cerebrovascular damage.

O-phthalaldehyde assisted surface enhanced Raman spectroscopy selective determination of trace homocysteine in serum

High plasma homocysteine (Hcy) levels may indicate cardiovascular disease. However, sensitive and selective determination of Hcy remains a major challenge. Herein, we present a sensing strategy for Hcy by surface enhanced Raman scattering (SERS) method along with a specific reaction of o-phthalaldehyde (OPA) and Hcy. The obtained adduct 2-(1-carboxyl-3-thiopropyl)-1-isoindolinone (Hcy-OPA) can be directly detected by SERS using gold nanoparticles (Au NPs) as the substrate. The developed SERS method displays superior sensitivity (low detection limit of 2.50 × 10−12 mol L−1) with a broad linear range (5.00 × 10−10 −5.00 × 10−6 mol L−1). As a proof of real application, it can be used to detect Hcy in bovine serum samples with a concentration as low as 5.00 × 10−9 mol L−1, which is free from the interference of the other amino acids and glutathione.

High plasma homocysteine level is associated with increased prevalence of the non-remission state in rheumatoid arthritis: Findings from the KURAMA cohort.

We aimed to determine the clinical impact of plasma homocysteine levels on disease activity and clinical remission in patients with rheumatoid arthritis (RA). A cross-sectional study was conducted using KURAMA (Kyoto University Rheumatoid Arthritis Management Alliance) database. We enrolled 291 female patients, who were treated in a treat-to-target manner. We measured plasma total homocysteine using a liquid chromatography-tandem mass spectrometry system and collected clinical data including a 28-joint RA disease activity score-erythrocyte sedimentation rate (DAS28-ESR). Clinical remission of disease activity was defined as a DAS28-ESR < 2.6. In a univariable analysis, the plasma homocysteine concentration was significantly and positively associated with DAS-28-ESR and was higher in the non-remission group than in the remission group. The cutoff value of the plasma homocysteine level was calculated to be 7.9 nmol/mL by the test of the receiver operating characteristic curve analysis. In a multivariable analysis, after adjusting for clinically relevant variables, the high homocysteine level remained a significant positive association for DAS28-ESR (estimate 0.27, P = .0019) and a positive factor for the presence of RA non-remission (odds ratio 2.39, P = .0071). Increased plasma homocysteine levels showed a significant positive association with current disease activity and the non-remission state in female patients with RA under treat-to-target treatment. The findings suggest the potential utility of plasma homocysteine as a disease state marker reflecting conditions that are treatment failure and difficult to remission and may provide clinical evidence on the interplay between homocysteine and inflammatory activation in RA.

Hyperhomocysteinemia Increases Cortical Excitability and Aggravates Mechanical Hyperalgesia and Anxiety in a Nitroglycerine-Induced Migraine Model in Rats.

Homocysteine is a sulfur-containing endogenous amino acid leading to neurotoxic effects at high concentrations. Population studies suggest an association between plasma homocysteine levels and the risk of migraine headaches. The aim of this study was to analyze the sensitivity of rats with prenatal hyperhomocysteinemia (hHCY) in respect of the development of behavioral correlates of headache and spreading cortical depolarization (CSD) in a migraine model induced by the administration of the nitric oxide (NO) donor nitroglycerin. Animals with hHCY were characterized by migraine-related symptoms such as mechanical hyperalgesia, high-level anxiety, photophobia, as well as an enhanced level of neuronal activity in the somatosensory cortex along with a lower threshold of CSD generation. Likewise, acute or chronic intermittent administration of nitroglycerin also induced the development of mechanical allodynia, photophobia and anxiety in control groups. However, these symptoms were more pronounced in rats with hHCY. Unlike hHCY, nitroglycerin administration did not affect the threshold of CSD generation, but like hHCY, increased the background neuronal activity in layers 2/3 and 4 of the cerebral cortex. The latter was more pronounced in animals with hHCY. Thus, the migraine profile associated with hHCY can be further exaggerated in conditions with enhanced levels of migraine triggering the gaseous transmitter NO. Our data are consistent with the view that high levels of plasma homocysteine can act as a risk factor for the development of migraine.

Endothelial Nitric Oxide Synthase Gene Polymorphisms Increase Risk of Deep Vein Thrombosis by Altering Homocysteine Levels.

Deep Vein Thrombosis (DVT) is a multicausal disease involving both acquired as well as genetic factors. Nitric oxide is an influential endogenous factor having its role in the development of deep vein thrombosis. It maintains the vascular integrity and any alterations in its levels may lead to a thrombotic event. It may also modulate homocysteine metabolism to cause hyperhomocysteinemia, which is a prominent risk factor for thrombosis. The objective of the study was to study if endothelial nitric oxide gene polymorphisms, 894G/T, and 2479G/A alter the plasma nitric oxide and homocysteine levels which may eventually increase the risk of deep vein thrombosis. One hundred Doppler ultrasonography and computerized tomography confirmed (for cerebral venous thrombosis), non-related DVT patients (M:F = 58:42; age range = 18 to 61 years) served as the study population. Two hundred hospital staff and their relatives or unrelated attendants of the patients served as the controls. Nitric oxide levels were determined by measuring its metabolites (NOx), and EIA was used to measure homocysteine levels. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for detecting the eNOS polymorphisms 894G/T and 2479G/A. In total, DVT subjects have 25% higher plasma levels of homocysteine and 37% lower levels of NOx in their circulation when compared to controls. In tertile analysis of nitric oxide and homocysteine levels, 894G/T and 2479G/A polymorphisms were associated with plasma nitric oxide and homocysteine levels. The increased risk of deep vein thrombosis was associated with endothelial nitric oxide gene polymorphisms and nitric oxide levels, but homocysteine levels were not a risk for deep vein thrombosis. The present study demonstrates that 894G/T and 2479G/A polymorphisms interact with lower levels of nitric oxide and higher levels of homocysteine that may possess the risk of deep vein thrombosis.

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

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. 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 (<14µmol/L) and 18 who had high plasma homocysteine levels (≥14µmol/L). 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. 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.

Homocysteine - Red signal to cardiovascular diseases: A Systematic Review

Over the past few decades, increased plasma homocysteine has proven itself to be named as an independent marker for developing cardiovascular diseases. Its increase can be due to genetic changes in MTHFR, deficiency in CBS, folic acid and vitamin B6 and B12, etc. It also causes apoptotic endothelial cell death and ceases the growth of damaged endothelial cardiac cells. May cause an increase in inflammasome and activate caspases leading to apoptosis.Increased oxidative stress and mast cell degranulation have been shown to cause cardiac hypertrophy; higher plasma homocysteine levels have lengthened the QTc interval, which causes ventricular arrhythmia. It has also been correlated to juvenile thrombosis and deep venous thrombosis. Higher homocysteine levels have also proven to deprive the endothelial NO, which leads to enhanced platelet activation. Also, how malondialdehyde modified LDL acts as an oxidative stress factor. Folate supplementation and Mast cell stabilizers prove to be useful in lowering the mortality induced by Hyperhomocysteinemia. Also, a diet rich in vitamin B6 and B12 should be considered to control homocysteine levels.

Identification of three novel pathogenic mutations in cystathionine beta-synthase gene of Pakistani intellectually disabled patients.

Classical homocystinuria (HCU) is an autosomal recessive inborn error of metabolism, which is caused by the cystathionine-β-synthase (CBS: encoded by CBS) deficiency. Symptoms of untreated classical HCU patients include intellectual disability (ID), ectopia lentis and long limbs, along with elevated plasma methionine, and homocysteine. A total of 429 ID patients (age range: 1.6-23 years) were sampled from Northern areas of Punjab, Pakistan. Biochemical and genetic analyses were performed to find classical HCU disease in ID patients. Biochemically, nine patients from seven unrelated families were identified with high levels of plasma methionine and homocysteine. Targeted exonic analysis of CBS confirmed seven causative homozygous mutations; of which three were novel missense mutations (c.451G>T; p.Gly151Trp, c.975G>C; p.Lys325Asn and c.1039+1G>T splicing), and four were recurrent variants (c.451+1G>A; IVS4+1 splicing, c.770C>T; p.Thr257Met, c.808_810del GAG; p.Glu270del and c.752T>C; p.Leu251Pro). Treatment of patients was initiated without further delay with pyridoxine, folic acid, cobalamin, and betaine as well as dietary protein restriction. The immediate impact was noticed in behavioral improvement, decreased irritability, improved black hair color, and socialization. Overall, health outcomes in this disorder depend on the age and symptomatology at the time of treatment initiation. With personalized treatment and care, such patients can reach their full potential of living as healthy a life as possible. This screening study is one of the pioneering initiatives in Pakistan which would help to minimize the burden of such treatable inborn errors of metabolism in the intellectually disabled patients.

Elucidating the neurodegnerative sequelae leading to VCID pathology.

Vascular contributions to cognitive impairment and dementia (VCID) are one of the leading causes of dementia. High levels of plasma homocysteine or hyperhomocysteinemia has been characterized as a risk factor for VCID however, the mechanism underlying this connection remains elusive. I hypothesize that hyperhomocysteinemia initiates a pro-inflammatory cascade that increases the activity of matrix metalloproteinase 9 (MMP9) causing perivascular astrocytes to dissociate from their vessels, leading to blood brain barrier dysfunction and the progression toward VCID pathology. For in vivo studies, C57BL6 WT mice were placed on a control diet or a diet deficient in folate, vitamins B6 and B12 and enriched in methionine to induce hyperhomocysteinemia for 6, 10, 14, or 18 weeks. Immunohistochemistry and gene expression analysis were used to determine neuroinflammatory changes while histology was used to identify changes in astrocytic end-feet proteins and microhemorrhages. Gel zymography was used to assess proteinase activity of MMP9. Behavior was assessed using the 2-day radial arm water maze. For in vitro, experiments, primary astrocytes obtained from both WT and MMP9 null mice were placed in a co-culture model with WT primary endothelial cells. Trans-endothelial electrical resistance measurements were used to assess blood brain barrier integrity in response to homocysteine in vitro. After 6 weeks of diet administration, we saw a significant increase in gene expression of TNFα, IL-1β, IL-6 and IL-12α. This was followed by increases in MMP transcription and proteinase activity seen at 10 weeks on diet. Also, beginning at the 10-week time point, cognitive deficits became detectable, which coincided with significant disruptions between astrocytic end-feet and the cerebrovasculature. Finally, there was a significant increase in the number of microhemorrhages after 14 weeks on diet. In vitro, astrocytes showed an increase in MMP9 after 48 hours of homocysteine treatment. Collectively, our findings suggest that astrocytic MMP9 may play an integral role in the mechanism associating homocysteine induced neuroinflammation with vascular pathogenesis leading to VCID. Continued study of the cell specificity and mechanism of MMP9 mediated vascular pathology will allow us to systematically target the various stages of disease and ultimately prevent the progression of VCID.

Gender differences in risk factors for high plasma homocysteine levels based on a retrospective checkup cohort using a generalized estimating equation analysis

BackgroundHyperhomocysteinemia (HHcy) is associated with various health problems, but less is known about the gender differences in risk factors for high plasma homocysteine (Hcy) levels.MethodsIn this study, a retrospective study was carried out on 14,911 participants (7838 males and 7073 females) aged 16–102 years who underwent routine checkups between January 2012 and December 2017 in the Health Management Department of Xuanwu Hospital, China. Anthropometric measurements, including body mass index (BMI) and waist-to-hip ratio, were collected. Fasting blood samples were collected to measure the biochemical indexes. The outcome variable was Hcy level, and a generalized estimating equation (GEE) analysis was used to identify the associations of interest based on gender.ResultsMales exhibited increased Hcy levels (16.37 ± 9.66 vs 11.22 ± 4.76 μmol/L) and prevalence of HHcy (37.0% vs 11.3%) compared with females. Hcy levels and HHcy prevalence increased with age in both genders, except for the 16- to 29-year-old group. GEE analysis indicated that irrespective of gender, aspartate aminotransferase, creatinine, uric acid, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels were positively correlated with Hcy levels, and alanine aminotransferase, total cholesterol and glucose were negatively correlated with Hcy levels. However, age, BMI and triglycerides (TGs) were positively correlated with Hcy levels exclusively in females.ConclusionsGender differences in risk factors for high plasma Hcy levels were noted. Although common correlational factors existed in both genders, age, BMI and TGs were independent risk factors for Hcy levels specifically in females.