Severe Hyperhomocysteinemia Research Articles

A study of the degree of inflammatory response of atherosclerotic plaque in the coronary artery in patients with impaired metabolism of homocysteine and vitamin D

Increased homocysteine (HC) levels and vitamin D deficiency play an important role in the progression of cardiovascular disease (CVD). However, to date, in medical publications, the issues of the influence of hyperhomocysteinemia (HHC) and vitamin D deficiency on the degree of the inflammatory response of atherosclerotic plaque (AsP) are insufficiently covered, which requires a detailed study of this problem. There is an opinion that inflammation contributes to the pathogenesis of CVD, therefore the identification of inflammation markers can improve the assessment of the risk of cardiovascular diseases.The aim of the study was to assess the morphological picture of inflammatory lesions of the atherosclerotic plaque depending on the degree of hyperhomocysteinemia and levels of vitamin D deficiency in patients with coronary artery disease.Materials and methods. The study analyzed data from 26 patients who, in addition to determining the level of homocysteine and vitamin D, underwent morphological studies of atherosclerotic plaque from the lumen of the coronary arteries. Samples were obtained during coronary artery bypass grafting. Depending on the level of HC and vitamin D, the patients were divided into 3 groups: the first group – patients with normal levels of homocysteine (up to 10 µmol/L) and vitamin D (more than 30 µmol/L); the second group – patients with hyperhomocysteinemia (10.38–40.08 μmol/l) and a sufficient level of vitamin D (more than 30 ng/ml); The third group – patients with hyperhomocysteinemia (more than 10.38 μmol/l) and vitamin D deficiency (less than 30 ng/ml).Results. Evaluating the morphology of AsP, we were interested in the presence of lymphocytes and segmented neutrophils, indicating an inflammatory process in the atherosclerotic plaque. In our work, a positive correlation was established between the concentration of HC (γ = 0.92) and the degree of the inflammatory response of ASB. A negative correlation was also found between the level of vitamin D (γ = -0.81) and the degree of ASP inflammation. The overwhelming number of patients, both 2 and 3 groups of the study, had exacerbations of the inflammatory process of ASB, which was confirmed by the presence of segmented neutrophils (7–10 segments in 2 mm2 plaques), corresponding to the 3rd degree of the inflammatory reaction.Conclusions. Most CHD patients have high homocysteine levels and vitamin D deficiency. Hyperhomocysteinemia and hypovitaminosis D affect the quantitative and qualitative complications of atherosclerotic plaque. Patients with severe hyperhomocysteinemia and vitamin D deficiency had a more pronounced inflammatory response of atherosclerotic plaque.

GluN2 Subunit-Dependent Redox Modulation of NMDA Receptor Activation by Homocysteine.

Homocysteine (HCY) molecule combines distinct pharmacological properties as an agonist of N-methyl-d-aspartate receptors (NMDARs) and a reducing agent. Whereas NMDAR activation by HCY was elucidated, whether the redox modulation contributes to its action is unclear. Here, using patch-clamp recording and imaging of intracellular Ca2+, we study dithiothreitol (DTT) effects on currents and Ca2+ responses activated by HCY through native NMDARs and recombinant diheteromeric GluN1/2A, GluN1/2B, and GluN1/2C receptors. Within a wide range (1–800 μM) of [HCY]s, the concentration–activation relationships for recombinant NMDARs revealed a biphasicness. The high-affinity component obtained between 1 and 100 µM [HCY]s corresponding to the NMDAR activation was not affected by 1 mM DTT. The low-affinity phase observed at [HCY]s above 200 μM probably originated from thiol-dependent redox modulation of NMDARs. The reduction of NMDAR disulfide bonds by either 1 mM DTT or 1 mM HCY decreased GluN1/2A currents activated by HCY. In contrast, HCY-elicited GluN1/2B currents were enhanced due to the remarkable weakening of GluN1/2B desensitization. In fact, cleaving NMDAR disulfide bonds in neurons reversed the HCY-induced Ca2+ accumulation, making it dependent on GluN2B- rather than GluN2A-containing NMDARs. Thus, estimated concentrations for the HCY redox effects exceed those in the plasma during intermediate hyperhomocysteinemia but may occur during severe hyperhomocysteinemia.

Telomere length and mtDNA copy number in human cystathionine β-synthase deficiency

Telomere shortening and mitochondrial DNA (mtDNA) copy number are associated with human disease and a reduced life span. Cystathionine β-synthase (CBS) is a housekeeping enzyme that catalyzes the first step in metabolic conversion of homocysteine (Hcy) to cysteine. Mutations in the CBS gene cause CBS deficiency, a rare recessive metabolic disease, manifested by severe hyperhomocysteinemia (HHcy) and thromboembolism, which ultimately reduces the life span. However, it was not known whether telomere shortening or mtDNA is involved in the pathology of human CBS deficiency. We quantified leukocyte telomere length (TL), mtDNA copy number, and plasma Hcy levels in CBS−/− patients (n = 23) and in sex- and age-matched unaffected CBS+/+ control individuals (n = 28) 0.08–57 years old. We found that TL was significantly increased in severely HHcy CBS−/− female patients but unaffected in severely HHcy CBS−/− male patients, relative to the corresponding CBS+/+ controls who had normal plasma Hcy levels. In multiple regression analysis TL was associated with CBS genotype in women but not in men. MtDNA copy number was not significantly affected by the CBS−/− genotype. Taken together, these findings identify the CBS gene as a new locus in human DNA that affects TL in women and illustrate a concept that a housekeeping metabolic gene can be involved in telomere biology. Our findings suggest that neither telomere shortening nor reduced mtDNA copy number contribute to the reduced life span in CBS−/− patients.

No evidence for an association of plasma homocysteine levels and refractive error - Results from the population-based Gutenberg Health Study (GHS).

There is a strong association between severe hyperhomocysteinemia and myopia. Thus we studied the hypothesis that even moderately increased levels of homocysteine (Hcy) might be a potentially treatable risk factor for myopia. The Gutenberg Health Study (GHS) is a population-based, prospective, observational cohort study in Germany, including 15,010 participants aged between 35 and 74 at recruitment. The baseline examination was conducted from 2007-2012. Refraction was measured using autorefraction (HARK 599, Carl Zeiss AG, Jena, Germany). Hcy was measured by an immunoassay. We included only phakic participants without a history of corneal surgery or corneal laser treatment. We used linear regression models to evaluate the potential association between Hcy and refraction at baseline, and between Hcy and change in refraction between baseline and 5-year-follow-up examination. We used generalized estimating equation models to account for the correlation between fellow eyes. We included 13,749 participants, categorized as having no myopia (spherical equivalent > -0.75 D, 65.2%), low myopia (-0.75 D--2.75 D, 21.5%), moderate myopia (-3.00 D- 5.75 D, 9.8%) and high myopia (≤ -6 D, 3.5%). Median Hcy levels were similar in all groups (μmol/l). We observed no association of Hcy with refraction or 5-year change in refraction in the models adjusted for age, sex and socioeconomic status. We found no evidence for an association of Hcy levels and refractive error.

The Cbs Locus Affects the Expression of Senescence Markers and mtDNA Copy Number, but not Telomere Dynamics in Mice.

Cystathionine β-synthase (CBS) is a housekeeping enzyme that catalyzes the first step of the homocysteine to cysteine transsulfuration pathway. Homozygous deletion of the Cbs gene in mice causes severe hyperhomocysteinemia and reduces life span. Here, we examined a possible involvement of senescence, mitochondrial DNA, and telomeres in the reduced life span of Cbs−/− mice. We found that senescence-related p21, Pai-1, Mcp1, and Il-6 mRNAs were significantly upregulated (2–10-fold) in liver, while p21 was upregulated in the brain of Cbs−/− mice (n = 20) compared with control Cbs+/− siblings (n = 20) in a sex- and age-dependent manner. Telomere length in blood (n = 80), liver (n = 40), and brain (n = 40) was not affected by the Cbs−/− genotype, but varied with sex and/or age. Levels of mitochondrial DNA tended to be reduced in livers, but not brains and blood, of Cbs−/− females (n = 20–40). The Cbs−/− genotype significantly reduced Tert mRNA expression in brain, but not liver, in a sex- and age-dependent manner. Multiple regression analysis showed that the senescence-related liver (but not brain) mRNAs and liver (but not brain or blood) mitochondrial DNA were associated with the Cbs genotype. In contrast, telomere length in blood, brain, and liver was not associated with the Cbs genotype or hyperhomocysteinemia, but was associated with sex (in brain and liver) and age (in brain and blood). Taken together, these findings suggest that the changes in senescence marker expression and mtDNA levels, but not telomere shortening, could account for the reduced life span of Cbs−/− mice.

Prevalence of hyperhomocysteinaemia, selected determinants and relation to hypertension severity in Northern-Nigerian hypertensives: the ABU homocysteine survey.

This study aimed at evaluating the prevalence of hyperhomocysteinaemia in Northern-Nigerian hypertensives and its association with hypertension severity and some major determinants as data regarding these are lacking in sub-Saharan Africa. A Community-based cross-sectional study done on 120 randomly-selected hypertensive patients who responded to an ABU radio frequency modulated invitation for free health-screening at the Ahmadu Bello University (ABU) Medical Centre from January 2016 to June 2016. The percentage of participants with high homocysteine levels, their anthropometric parameters and blood pressures were determined. Plasma homocysteine (hcy) was classified as normal (5-15), moderate (>15-30), intermediate (31-100) and severe (>100) µmol/L. Kruskal-Wallis test was applied and log-transformed homocysteine (Ln10Homocysteine) was correlated with systolic and diastolic blood pressures as well as age, body mass index, fasting blood glucose, glomerular filtration rate, hypertension duration and Ln10folate in males and females using the Pearson's Correlation analysis. There were 83(69.2%) females and 37(30.8%) males with Median homocysteine of 20.8 µmol/L and 22.0 µmol/L respectively (p=0.003). Hyperhomocysteinaemia was found in 118(98.3%) hypertensives while 2(1.7%) subjects had normo-homocysteinaemia. Moderate hyperhomocysteinaemia (Median, 20.8 µmol/L) was identified in 105(87.5%) and intermediate (Median, 40 µmol/L) in 13(10.8%) (p<0.001). No subject had severe hyperhomocysteinaemia. Homocysteine was higher (p=0.003) in subjects with Stage 2 systolic hypertension. Ln10Homocysteine was significantly (p<0.001) correlated with blood pressure (SBP: r=0.45; DBP: r=0.40) and age (r=0.33). The prevalence of hyperhomocysteinaemia in North-Western Nigerian hypertensives is high as against normal healthy controls. Plasma homocysteine is higher with severe systolic hypertension and positively associated with age. No specific grants but Micro Nova Pharmaceuticals Limited, Nigeria and Emzor Pharmaceutical Industries, Lagos, Nigeria supported with drugs.

Severe hyperhomocysteinemia and peripheral neuropathy as side effects of nitrous oxide in two patients with sickle cell disease

Nitrous oxide (N2O) is a widely used anesthetic agent. We report two patients with sickle cell disease (SCD) who presented with complications following the use of N2O. Patient 1, a 15-year-old girl, presented severe hyperhomocysteinemia, pancytopenia, vitamin B12 deficiency, and peripheral polyneuropathy after massive use of N2O for pain management. At the 1-year follow-up, hyperhomocysteinemia and B12 deficiency had resolved, but she had persisting mild symptoms of polyneuropathy. Patient 2, a 17-year-old boy, presented only severe hyperhomocysteinemia, only partially corrected by initial B12 supplementation. Careful monitoring of N2O use, especially in patients with SCD, is mandatory to prevent complications.

Author response: Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura.

In “Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura,” Cho et al. described a 37-year-old woman with a history of Henoch-Schonlein purpura with leukocytoclastic vasculitis and immune mesangiopathic glomerulonephritis who presented with recurrent ischemic infarcts and was found to have hyperhomocysteinemia due to homozygous cystathionine β-synthase (CBS), then developed moyamoya vasculopathy requiring a direct bypass on the left and an encephalo-duro-arterio-synangiosis procedure on the right. The authors suggested that the cerebral, skin, and renal changes are all the result of CBS deficiency. In review of this case, Drs. Gaillard and Arquizan postulate that the underlying mechanism was likely a systemic vasculitis with CNS involvement and question whether (1) inflammatory markers, autoantibodies, and serologies were checked in serum or CSF, (2) a brain biopsy was obtained, or (3) a trial of steroids or immunosuppressants was given. Cho et al. respond that (1) serial cerebral angiograms showed progressive intracranial stenosis consistent with moyamoya vasculopathy, not with vasculitis, and (2) CSF showed no pleocytosis, and inflammatory and infectious tests were negative. They note that there was no recurrence of skin or renal events despite the absence of systemic therapy, making the diagnosis of secondary CNS vasculitis unlikely. While both Cho et al. and Drs. Gaillard and Arquizan agree that the high-resolution MRI was suggestive of vasculitis, Cho et al. believe it is consistent with a moyamoya-like vasculopathy and that this case represents a new phenotype of CBS deficiency.

Editors' note: Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura

In “Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura,” Cho et al. described a 37-year-old woman with a history of Henoch-Schonlein purpura with leukocytoclastic vasculitis and immune mesangiopathic glomerulonephritis who presented with recurrent ischemic infarcts and was found to have hyperhomocysteinemia due to homozygous cystathionine β-synthase (CBS), then developed moyamoya vasculopathy requiring a direct bypass on the left and an encephalo-duro-arterio-synangiosis procedure on the right. The authors suggested that the cerebral, skin, and renal changes are all the result of CBS deficiency. In review of this case, Drs. Gaillard and Arquizan postulate that the underlying mechanism was likely a systemic vasculitis with CNS involvement and question whether (1) inflammatory markers, autoantibodies, and serologies were checked in serum or CSF, (2) a brain biopsy was obtained, or (3) a trial of steroids or immunosuppressants was given. Cho et al. respond that (1) serial cerebral angiograms showed progressive intracranial stenosis consistent with moyamoya vasculopathy, not with vasculitis, and (2) CSF showed no pleocytosis, and inflammatory and infectious tests were negative. They note that there was no recurrence of skin or renal events despite the absence of systemic therapy, making the diagnosis of secondary CNS vasculitis unlikely. While both Cho et al. and Drs. Gaillard and Arquizan agree that the high-resolution MRI was suggestive of vasculitis, Cho et al. believe it is consistent with a moyamoya-like vasculopathy and that this case represents a new phenotype of CBS deficiency. In “Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura,” Cho et al. described a 37-year-old woman with a history of Henoch-Schonlein purpura with leukocytoclastic vasculitis and immune mesangiopathic glomerulonephritis who presented with recurrent ischemic infarcts and was found to have hyperhomocysteinemia due to homozygous cystathionine β-synthase (CBS), then developed moyamoya vasculopathy requiring a direct bypass on the left and an encephalo-duro-arterio-synangiosis procedure on the right. The authors suggested that the cerebral, skin, and renal changes are all the result of CBS deficiency. In review of this case, Drs. Gaillard and Arquizan postulate that the underlying mechanism was likely a systemic vasculitis with CNS involvement and question whether (1) inflammatory markers, autoantibodies, and serologies were checked in serum or CSF, (2) a brain biopsy was obtained, or (3) a trial of steroids or immunosuppressants was given. Cho et al. respond that (1) serial cerebral angiograms showed progressive intracranial stenosis consistent with moyamoya vasculopathy, not with vasculitis, and (2) CSF showed no pleocytosis, and inflammatory and infectious tests were negative. They note that there was no recurrence of skin or renal events despite the absence of systemic therapy, making the diagnosis of secondary CNS vasculitis unlikely. While both Cho et al. and Drs. Gaillard and Arquizan agree that the high-resolution MRI was suggestive of vasculitis, Cho et al. believe it is consistent with a moyamoya-like vasculopathy and that this case represents a new phenotype of CBS deficiency.

Author response: Cerebello-spinal tDCS in ataxia: A randomized, double-blind, sham-controlled, crossover trial

In “Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura,” Cho et al. described a 37-year-old woman with a history of Henoch-Schonlein purpura with leukocytoclastic vasculitis and immune mesangiopathic glomerulonephritis who presented with recurrent ischemic infarcts and was found to have hyperhomocysteinemia due to homozygous cystathionine β-synthase (CBS), then developed moyamoya vasculopathy requiring a direct bypass on the left and an encephalo-duro-arterio-synangiosis procedure on the right. The authors suggested that the cerebral, skin, and renal changes are all the result of CBS deficiency. In review of this case, Drs. Gaillard and Arquizan postulate that the underlying mechanism was likely a systemic vasculitis with CNS involvement and question whether (1) inflammatory markers, autoantibodies, and serologies were checked in serum or CSF, (2) a brain biopsy was obtained, or (3) a trial of steroids or immunosuppressants was given. Cho et al. respond that (1) serial cerebral angiograms showed progressive intracranial stenosis consistent with moyamoya vasculopathy, not with vasculitis, and (2) CSF showed no pleocytosis, and inflammatory and infectious tests were negative. They note that there was no recurrence of skin or renal events despite the absence of systemic therapy, making the diagnosis of secondary CNS vasculitis unlikely. While both Cho et al. and Drs. Gaillard and Arquizan agree that the high-resolution MRI was suggestive of vasculitis, Cho et al. believe it is consistent with a moyamoya-like vasculopathy and that this case represents a new phenotype of CBS deficiency.

Editors' note: Cerebello-spinal tDCS in ataxia: A randomized, double-blind, sham-controlled, crossover trial

In “Cerebello-spinal tDCS in ataxia: A randomized, double-blind, sham-controlled, crossover trial,” Benussi et al. exposed 20 patients with neurodegenerative ataxia to cerebello-spinal transcranial direct current stimulation (tDCS) and sham stimulation and found that tDCS resulted in significant improvement in performance, motor cortex excitability, and cerebellar brain inhibition. Matsugi speculated that Benussi et al.'s findings demonstrate that spinal-cerebellar functional connectivity is retained in spinocerebellar ataxia and improved with tDCS. He noted that further study into cerebellar brain facilitation and inhibition and spinal direct current stimulation in this patient population are needed. Benussi et al. replied that they believe simultaneous spinal and cerebellar tDCS synergistically improves cerebellar function and spasticity, and agreed that further studies on the distinct and combined effects of cerebellar and spinal tDCS are needed, as stimulation may benefit this patient population for whom no drugs are available. In “Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura,” Cho et al. described a 37-year-old woman with a history of Henoch-Schonlein purpura with leukocytoclastic vasculitis and immune mesangiopathic glomerulonephritis who presented with recurrent ischemic infarcts and was found to have hyperhomocysteinemia due to homozygous cystathionine β-synthase (CBS), then developed moyamoya vasculopathy requiring a direct bypass on the left and an encephalo-duro-arterio-synangiosis procedure on the right. The authors suggested that the cerebral, skin, and renal changes are all the result of CBS deficiency. In review of this case, Drs. Gaillard and Arquizan postulate that the underlying mechanism was likely a systemic vasculitis with CNS involvement and question whether (1) inflammatory markers, autoantibodies, and serologies were checked in serum or CSF, (2) a brain biopsy was obtained, or (3) a trial of steroids or immunosuppressants was given. Cho et al. respond that (1) serial cerebral angiograms showed progressive intracranial stenosis consistent with moyamoya vasculopathy, not with vasculitis, and (2) CSF showed no pleocytosis, and inflammatory and infectious tests were negative. They note that there was no recurrence of skin or renal events despite the absence of systemic therapy, making the diagnosis of secondary CNS vasculitis unlikely. While both Cho et al. and Drs. Gaillard and Arquizan agree that the high-resolution MRI was suggestive of vasculitis, Cho et al. believe it is consistent with a moyamoya-like vasculopathy and that this case represents a new phenotype of CBS deficiency.

Reader response: Cerebello-spinal tDCS in ataxia: A randomized, double-blind, sham-controlled, crossover trial.

In “Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura,” Cho et al. described a 37-year-old woman with a history of Henoch-Schonlein purpura with leukocytoclastic vasculitis and immune mesangiopathic glomerulonephritis who presented with recurrent ischemic infarcts and was found to have hyperhomocysteinemia due to homozygous cystathionine β-synthase (CBS), then developed moyamoya vasculopathy requiring a direct bypass on the left and an encephalo-duro-arterio-synangiosis procedure on the right. The authors suggested that the cerebral, skin, and renal changes are all the result of CBS deficiency. In review of this case, Drs. Gaillard and Arquizan postulate that the underlying mechanism was likely a systemic vasculitis with CNS involvement and question whether (1) inflammatory markers, autoantibodies, and serologies were checked in serum or CSF, (2) a brain biopsy was obtained, or (3) a trial of steroids or immunosuppressants was given. Cho et al. respond that (1) serial cerebral angiograms showed progressive intracranial stenosis consistent with moyamoya vasculopathy, not with vasculitis, and (2) CSF showed no pleocytosis, and inflammatory and infectious tests were negative. They note that there was no recurrence of skin or renal events despite the absence of systemic therapy, making the diagnosis of secondary CNS vasculitis unlikely. While both Cho et al. and Drs. Gaillard and Arquizan agree that the high-resolution MRI was suggestive of vasculitis, Cho et al. believe it is consistent with a moyamoya-like vasculopathy and that this case represents a new phenotype of CBS deficiency.

Reader response: Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura.

In “Severe hyperhomocysteinemia manifesting as moyamoya vasculopathy and Henoch-Schonlein purpura,” Cho et al. described a 37-year-old woman with a history of Henoch-Schonlein purpura with leukocytoclastic vasculitis and immune mesangiopathic glomerulonephritis who presented with recurrent ischemic infarcts and was found to have hyperhomocysteinemia due to homozygous cystathionine β-synthase (CBS), then developed moyamoya vasculopathy requiring a direct bypass on the left and an encephalo-duro-arterio-synangiosis procedure on the right. The authors suggested that the cerebral, skin, and renal changes are all the result of CBS deficiency. In review of this case, Drs. Gaillard and Arquizan postulate that the underlying mechanism was likely a systemic vasculitis with CNS involvement and question whether (1) inflammatory markers, autoantibodies, and serologies were checked in serum or CSF, (2) a brain biopsy was obtained, or (3) a trial of steroids or immunosuppressants was given. Cho et al. respond that (1) serial cerebral angiograms showed progressive intracranial stenosis consistent with moyamoya vasculopathy, not with vasculitis, and (2) CSF showed no pleocytosis, and inflammatory and infectious tests were negative. They note that there was no recurrence of skin or renal events despite the absence of systemic therapy, making the diagnosis of secondary CNS vasculitis unlikely. While both Cho et al. and Drs. Gaillard and Arquizan agree that the high-resolution MRI was suggestive of vasculitis, Cho et al. believe it is consistent with a moyamoya-like vasculopathy and that this case represents a new phenotype of CBS deficiency.

Homocysteine Modification in Protein Structure/Function and Human Disease

Epidemiological studies established that elevated homocysteine, an important intermediate in folate, vitamin B12, and one carbon metabolism, is associated with poor health, including heart and brain diseases. Earlier studies show that patients with severe hyperhomocysteinemia, first identified in the 1960s, exhibit neurological and cardiovascular abnormalities and premature death due to vascular complications. Although homocysteine is considered to be a nonprotein amino acid, studies over the past 2 decades have led to discoveries of protein-related homocysteine metabolism and mechanisms by which homocysteine can become a component of proteins. Homocysteine-containing proteins lose their biological function and acquire cytotoxic, proinflammatory, proatherothrombotic, and proneuropathic properties, which can account for the various disease phenotypes associated with hyperhomocysteinemia. This review describes mechanisms by which hyperhomocysteinemia affects cellular proteostasis, provides a comprehensive account of the biological chemistry of homocysteine-containing proteins, and discusses pathophysiological consequences and clinical implications of their formation.

Relationship Among Serum Homocysteine, Serum Folate And Left Ventricular Ejection Fraction In Chronic Kidney Disease

Background: Homocysteine (Hcy) a sulfurcontaining, non-protein a-amino is now considered an independent non-traditional risk factor for vascular disease. In Chronic Kidney Disease (CKD) highly prevalent hyperhomocysteinemia which is often associated with decreased folate concentrations is thought to contribute to increased cardiovascular morbidity. So, the aim of this cross-sectional study was to investigate the relations among serum homocysteine, serum folate and Left Ventricular Ejection Fraction (LVEF) in the context of native CKD patients. Materials and methods: A total of one-thirty (130) participants were recruited between June and July 2016. Among them ninety (90) were CKD patients of stage III, IV &amp; V and forty (40) were healthy controls.eGFR was calculated by MDRD formula. Different groups were created based on serum homocysteine level and eGFR. Results: In this study, hyperhomocysteinemia was seen in 97% CKD patients compared to 52.50% in controls. The CKD patients with elevated homocysteine levels had higher serum creatinine, LDL and systolic BP but they had lower eGFR, serum folateand LVEF than those with normal homocysteine concentrations. As the severity of homocysteinemia increased, eGFR and serum folate decreased. LVEFalso reduced significantly with increasing severity of hyperhomocysteinemia i.e. from 68% in those withouthyperhomocysteinemia to 41.33% in those with severe hyperhomocysteinemia. Chi-squared tests and odds ratios proved significant associations of hyperhomocysteinemia and folate deficiency with CKD. Higher homocysteine concentrations were also associated with low folate and low LVEF. Here, serum homocysteine correlated negatively with eGFR, serum folate and LVEF and positively with LDL and systolic BP. Conclusion: Inconclusion, this study revealed significant associationsamong hyperhomocysteinemia, low serum folate and low LVEF in the native CKD patients. The consistency of homocysteine- eGFR and homocysteine-LVEF correlations suggests that serum homocysteine may provide useful additional information about CKD and associated high cardiovascular morbidity.&#x0D; JCMCTA 2018 ; 29 (1) : 35-41

Severe Hyperhomocysteinemia Decreases Creatine Kinase Activity and Causes Memory Impairment: Neuroprotective Role of Creatine.

In the present study, we investigate the effect of severe hyperhomocysteinemia on biochemical (creatine kinase activity), behavioral (memory tests), and histological assessments (hippocampal volume). A possible neuroprotective role of creatine on hyperhomocysteinemia effects was also evaluated. Severe hyperhomocysteinemia was induced in neonate rats (starting at 6days of age) by treatment with homocysteine (0.3-0.6μmol/g body weight) for 23days. Creatine (50mg/kg body weight) was administered concomitantly with homocysteine. Controls received saline in the same volumes. Twelve hours after the last injection, the rats were submitted to behavioral tests [(recognition task (NOR)] and inhibitory avoidance (IA)]. Following behavioral assessment, the animals were perfused and decapitated, the brain removed for subsequent morphological analysis of the hippocampus. Another group of animals was used to test creatine kinase activity in hippocampus. The results showed that rats treated with homocysteine decreased (44%) the exploration of the novel object in NOR. In the IA task, homocysteine-treated animals presented decreased latencies to step down the platform in short- (32%) and long-term (18%) testings (3h and 7days, respectively), evidencing aversive memory impairment. Hippocampal volume was not altered by homocysteine administration. Hyperhomocysteinemia decreased (45%) creatine kinase activity, and creatine was able to prevent such effect probably by creatine kinase/phosphocreatine/creatine homeostasis, which serves as energy circuit within of the cell. This finding may be associated, at least in part, with memory improvement, suggesting that creatine might represent an effective adjuvant to protect against the effects of high homocysteine plasma levels.

Metabolic changes in pulmonary mitochondria of rats with experimental hyperhomocysteinemia

Hyperhomocysteinemia is a risk factor for many human diseases, including pulmonary pathologies. In this context much interest attracts secondary mitochondrial dysfunction, which is an important link in pathogenesis of diseases associated with hyperhomocysteinemia. The study was conducted using male Wistar rats. It was found that under conditions of severe hyperhomocysteinemia caused by administration of methionine, homocysteine was accumulated in lung mitochondria thus suggesting a direct toxic effect on these organelles. However, we have not observed any significant changes in the activity of mitochondrial enzymes involved in tissue respiration (succinate dehydrogenase) and oxidative phosphorylation (H+-ATPase) and of cytoplasmic lactate dehydrogenase. Also there was no accumulation of lactic acid in the cytoplasm. Animals with severe hyperhomocysteinemia had higher levels of lung mitochondrial protein carbonylation, decreased reserve-adaptive capacity, and increased superoxide dismutase activity. These results indicate that severe hyperhomocysteinemia causes development of oxidative stress in lung mitochondria, which is compensated by activation of antioxidant protection. These changes were accompanied by a decrease in the concentration of mitochondrial nitric oxide metabolites. Introduction to animals a nonselective NO-synthase inhibitor L-NAME caused similar enhancement of mitochondrial protein carbonylation. It demonstrates importance of reducing bioavailability of nitric oxide, which is an antioxidant in physiological concentrations, in the development of oxidative stress in lung mitochondria during hyperhomocysteinemia. Key words: hyperhomocysteinemia, nitric oxide, lung, oxidative stress, mitochondria.

EFFECT OF FOLIC ACID, PYRIDOXINE AND CYANOCOBALAMIN IN REDUCING THE ELEVATED LEVEL OF HOMOCYSTEINE IN ADVANCE CHRONIC KIDNEY DISEASE AND END-STAGE RENAL DISEASE

Homocysteine is an amino acid that is produced by the body and it can be converted into methionine or cysteine with the aid of B-vitamins and tetrahydrofolate. Renal function is a major determinant of plasma homocysteine concentration, and patients with chronic renal failure have severe hyperhomocysteinemia. The aim of study was to determine the effect of high doses of folic acid, vitamin B6 and B12 to reduce the homocysteine levels in chronic kidney disease patients. In present study, 60 renal failure patients fulfilled study criteria. These 60 patients, were divided into two groups of which 30 were selected into control and 30 were recruited in sample. The average of Hcy levels before starting treatment was obtained 31.14 umol/L. After treating patient with folic acid, vitamin B6 and B12 for a period of 3 months the average serum homocysteine level was measured and resulted 27.43 umol/L. Our study showed decrease and/or improve in average level of serum homocysteine among end stage renal failure and chronic kidney disease patients who have been received folic acid and vitamin B6 and B12 supplements, compared with controls. Risks due to increased homocysteine causes heart disease, stroke, peripheral vascular disease, diabetes. Our study concludes that high doses of folic acid, vitamin B6 and B12 treatment has improved or decreased the levels of Hcy in patients with renal failure, which in turn has reduce the risk of cardiovascular complications. This will improve quality of life of patients and decreases the mortality rate due to cardiovascular disorders.

ASSESSMENT OF CORRECTING ARGININE AND CARNITINE EFFECTS ON ACTIVITY AND DISTRIBUTION OF SKELETAL AND SMOOTH MUSCLE L, H CATHEPSINS IN MARKED HYPERHOMOCYSTEINEMIA

Aim. The aim of the study was to investigate the activity of L, H cathepsins with assessment of changes in permeability of lysosomal membranes of the rat tibial muscle and thoracic aorta wall in conditions of experimental marked hyperhomocysteinemia when introducing L-arginine and carnitine. Materials and methods. Ninety six homogenized samples of muscular tissues (48 tibial muscle samples and 48 thoracic aorta wall samples) from white convectional Wistar male rats served as a material to be studied. Modelling of severe hyperhomocysteinemia was realized by means of a daily intragastric introduction of methionine suspension twice a day. In experimental and control groups, arginine and carnitine were introduced with a six-hour interval from introduction of the corresponding suspension. Results. Blood serum homocystein content in animals receiving methionine (hyperhomocysteinemia modeling) statistically significantly increased versus the corresponding control group (293,10 [273,10; 318,20] and 5,90 [5,50; 6,70] mcmol/l). In the samples of animals receiving L-arginine and carnitine against the background of methionine, homocysteine concentration significantly decreased versus the animals with hyperhomocysteinemia, but did not reach the control group values. Marked hyperhomocysteinemia is accompanied by growth of activity of skeletal and smooth muscle L, H cathepsins, development of lysosomal membrane permeability. Conclusions. Arginine reduces cathepsin H and acid phosphatase activity, has a stabilizing effect on lysosomal membrane in the skeletal muscle and decreases cathepsin L activity with no stabilizing effect on lysosomal membranes in the smooth musculature. Carnitine reduces cathepsin L activity and has a stabilizing effect on lysosomal membrane of the muscular tissues studied.

Homocysteine upregulates hepcidin expression through BMP6/SMAD signaling pathway in hepatocytes

Subjects with severe hyperhomocysteinemia have hypoferric anemia and excessive iron deposition in the liver. Hepcidin, the central regulator of iron homeostasis, plays a key role in iron metabolism. However, the regulation of homocysteine (Hcy) on hepcidin is largely unclear. We conducted experiments in HepG2 cells to identify the mechanisms with which Hcy modulates hepcidin expression. We found that treatment with Hcy dose-dependently increased both hepcidin transcript levels and protein levels, as assessed by quantitative real-time reverse-transcriptase polymerase chain reaction and western blotting, respectively. Hcy also activated BMP6 signaling and increased the phosphorylation of SMAD1/5/8 in HepG2 cells. We found that Hcy's effect on hepcidin expression was impaired by the knockdown of BMP6 and its receptors ALK2/3/6 with siRNAs. These results demonstrated that Hcy up-regulated hepcidin expression through the BMP6/SMAD pathway, suggesting a novel mechanism underlying the hyperhomocysteinemia-associated perturbation of iron homeostasis.