Effect of metabolic control on homocysteine levels in type 2 diabetic patients: a 3-year follow-up

Plasma Homocysteine Level Is Independently Associated With Conventional Atherogenic Lipid Profile and Remnant Cholesterol in Adults

Background

Homocysteine (Hcy) is an independent risk factor for cardiovascular disease, while mechanisms are unclear. Despite inconsistent and limited, epidemiological and experimental studies indicated that hyperhomocysteinemia (HHcy) affected lipid metabolism. This study aims to investigate the association of plasma Hcy with traditional lipid profiles and remnant cholesterol (RC) in Chinese adults.

Methods

In total, 7,898 subjects aged 20–79 years who underwent a physical examination at Beijing Chao-Yang Hospital in Beijing were included in this study. Fasting plasma total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), lipoprotein (a) [Lp(a)], Hcy, and other metabolic risk factors were measured by routine automated laboratory methods. RC was calculated as TC minus HDL-C and LDL-C. The linear regression model and logistic regression model were used to assess the relationship between Hcy and lipids after adjusting potential confounders.

Results

Of the subjects, the median level of plasma Hcy was 13.0 μmol/L and 32.3% had HHcy. Plasma Hcy was negatively associated with HDL-C, ApoA1, and Lp(a) and positively associated with TG levels after adjusting age, sex, body mass index, blood pressure, alanine transaminase, aspartate transaminase, creatinine, uric acid, and glucose. HHcy significantly increased the risk of low HDL-C [odds ratio (OR) 1.26; 95%CI (1.11–1.44); p < 0.001]. The net mediation effects of ApoA1 on the relationship between Hcy and HDL-C before and after adjusting confounders were 46.9 and 30.6%, respectively. More interestingly, the RC level was significantly elevated in subjects with HHcy after adjusting other influencing factors (p = 0.025). Hcy presented a positive correlation with RC levels after adjusting the above confounding factors (β = 0.073, p = 0.004), and the correlation was still significant even after controlling other lipids, including TG, LDL-C, HDL-C, ApoA1, ApoB, and Lp(a).

Conclusion

Our study showed that plasma Hcy was not only significantly associated with conventional atherogenic lipids but also independently correlated with RC levels beyond other lipids after controlling potential confounders. This finding proposes that identifying Hcy-related dyslipidemia risk, both traditional lipids and RC residual risk, is clinically relevant as we usher in a new era of targeting Hcy-lowering therapies to fight against dyslipidemia or even cardiovascular disease.

The Role of Early Revascularization and Biomarkers in the Management of Diabetic Foot Ulcers: A Single Center Experience

Diabetic neuropathy and Peripheral Arterial Disease (PAD) are the main etiological factors in foot ulceration. Herein, we report our experience of diabetic foot ulceration (DFU) management, with an analysis of the relationship between the rate of lower extremity amputation, in persons with infected DFU, after revascularization procedures performed to prevent major amputation. This study highlights the role of different biomarkers, showing their usefulness and potentiality in diabetic foot ulcer management, especially for the early diagnosis and therapy effectiveness monitoring. A retrospective analysis, from September 2016 to January 2021, of diabetic patients presenting diabetic foot with DFU, was performed. All patients were treated with at least one vascular procedure (endovascular, open, hybrid procedures) targeting PAD lesions. Outcomes measured were perioperative mortality and morbidity. Freedom from occlusion, primary and secondary patency, and amputation rate were registered. A total of 267 patients, with a mean age of 72.5 years, were included in the study. The major amputation rate was 6.2%, minor amputation rate was 17%. In our experience, extreme revascularization to obtain direct flow reduced the rate of amputations, with an increase in ulcer healing.

Relationship of Homocysteine With Gender, Blood Pressure, Body Mass Index, Hemoglobin A1c, and the Duration of Diabetes Mellitus Type 2

Introduction Increased levels of homocysteine (Hcy) may lead to endothelial damage and increase the risk of cardiovascular and renal malfunction. The current study aimed to evaluate the association of serum Hcy levels with gender, body mass index (BMI), duration of diabetes mellitus type 2 (DMT2), hemoglobin A1c (HbA1c), and blood pressure (BP).  Methodology  A prospective observational study was conducted at Hayatabad Medical Complex in Peshawar, Pakistan in the department of endocrinology from June 2020 to June 2021. All patients with diagnosed DMT2 above the age of 18 years were included in the study. Individuals with unconfirmed diagnoses with ages over 75 years were excluded from the study. All data including the patient's age, gender, and medical history were recorded. Height and weight were used to calculate the BMI. BP was examined thrice and a mean value was recorded for each patient. For laboratory investigation, a vial of 3 ml blood was extracted keeping sterile and aseptic conditions by a trained nurse. The sample was sent for the determination of HbA1c and serum Hcy levels. Measurement of serum Hcy was done by chemiluminescent microparticle immunoassay. All data were documented by the researchers on a predefined pro forma.  Results A total of 188 patients with DMT2 were included in the study with a mean age ± SD of 54.65 ± 8.42 years. Normal (<15 micromoles per liter [mcmol/l]) serum Hcy levels were reported in 75 (39.89%) individuals, while in 47 (41.59%) individuals, there was severe (>100 mcmol/l) hyperhomocysteinemia. More than half of the patients, i.e. 157 (83.52%), had HbA1c of greater than 7%, which indicated poor glycemic control. The study revealed that the majority of the female patients, i.e. 37 (78.72%), had severe hyperhomocysteinemia (p<0.0001). Similarly, there was a direct correlation between HbA1c levels and serum Hcy. Severe hyperhomocysteinemia was found in over 80% of the patients with poor glycemic control, i.e. HbA1c >7% (p<0.0001). Furthermore, the duration of DMT2 and hypertension were both significantly associated with increased levels of Hcy with p-values of <0.0001 and <0.0001, respectively. However, no association was found between hyperhomocysteinemia and BMI.  Conclusion The study revealed that increased levels of serum Hcy were associated with female gender, poor glycemic control (HbA1c >7%), BP, and duration of DMT2. However, the study failed to find an association between serum Hcy and BMI. It is recommended that patients with poor glycemic control or those with the duration of DMT2 of more than five years must be regularly checked for hyperhomocysteinemia and renal function tests.  Large-scale and multi-center studies are required in order to determine the validity of these findings. The current study suggests that patients with diabetes mellitus and hypertension are likely to have increased levels of Hcy and, therefore, must be regularly screened for hyperhomocysteinemia.

Association of homocysteine with body mass index, blood pressure, HbA1c and duration of diabetes in type 2 diabetics

Objective

To determine the Homocysteine levels in type 2 diabetics and correlate homocysteine with HbA1c levels, BMI, blood pressure and duration of diabetes.

Methods

This cross-sectional study was conducted in Endocrinology Unit of Hayatabad Medical Complex (HMC) Peshawar and Rehman Medical Institute (RMI) Peshawar over a period of six months from July 2015 to December 2015. Data was recorded and analyzed in SPSS v 20. P value of less than 0.05 was taken as significant. Bivariate Pearson's correlation test was used to see the relationship between homocysteine and BMI, systolic BP and duration of diabetes.

Results

One hundred twenty five patients were included in our study in which female were 68% and 32% were male with mean age of 51.45 ±8.37 years. Mean BMI expressed in kg/m² was 28.71±4.76, mean systolic blood pressure was 130±20.98 mmHg, mean diastolic blood pressure was 83.36±11.28 mmHg and mean duration of diabetes was 7.018± 6.18 years. Significant correlation was found between systolic blood pressure (r: 0.239, p: 0.007) and duration of diabetes with homocysteine (r: 0.302, p: 0.001). The correlation of homocysteine with HbA1c and BMI was not significant.

Conclusion

Systolic blood pressure and duration of diabetes showed a significant positive correlation with homocysteine. The correlation of homocysteine with HbA1c was not certain from researcher's point of view and further studies of larger sample size and longer duration must be conducted to ascertain the association between the two variables.

Endothelial nitric oxide synthase gene (T786C and G894T) polymorphisms in Egyptian patients with type 2 diabetes

BACKGROUND

Genetic factors play important role in the development of type 2 diabetes and diabetic nephropathy. Endothelial nitric oxide synthase (eNOS) gene is responsible for the bioavailability of nitric oxide and endothelial function.

AIM

To assess the association of the endothelial nitric oxide synthase (eNOS) (T786C and G894T) single nucleotide polymorphisms with Egyptian type 2 diabetes mellitus and diabetic nephropathy.

PATIENTS AND METHODS

A total of 200 type 2 diabetic patients and 100 apparently healthy volunteers as controls were included in the study. They were subjected to clinical examination and laboratory tests: fasting blood glucose, HBA1C, lipid profile, serum creatinine, blood urea and albumin creatinine ratio (ACR). Assessment of the T786C and G894T polymorphisms in the eNOS gene was done using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

There was no significant difference in distribution of eNOS T-786C polymorphism between patients and controls; TT genotype of eNOS G894T was more frequent in diabetic patients with and without albuminuria compared to controls. Patients were divided into 3 groups according to ACR. Normoalbuminuria: 37 patients with ACR ≤ 30 mg/g, microalbuminuria: 96 patients with ACR > 30 mg/g and ≤ 300 mg/g, and macroalbuminuria: 67 patients with ACR > 300 mg/g. There was no significant difference in genotype distribution of eNOS T-786C between the 3 groups of diabetic patients. The prevalence of TT genotype of eNOS G894T was higher in microalbuminuria patients compared to other groups.

CONCLUSION

eNOS G894T variant may increase risk of type 2 diabetes with lack of association between eNOS T786C, eNOS G894T and DN in Egyptians.

Plasma homocysteine levels are associated with macular thickness in type 2 diabetes without diabetic macular edema

PURPOSE

To explore the relationships between macular thickness and the plasma concentrations of homocysteine, vitamin B12, folate, and other known risk factors for patients with diabetes without diabetic macular edema (DME).

METHODS

Fasting venous blood samples were collected from 252 subjects (126 relatively healthy subjects with type 2 diabetes without diabetic macular edema and 126 age- and gender-matched controls). Measurement of macular thickness and volume was performed for those subjects using SD-OCT. The plasma concentrations of homocysteine, vitamin B12, folate, and other known risk factors were analyzed in all the patients and controls using multiple linear regression models.

RESULTS

An increase in the serum levels of homocysteine was present within patients with type 2 diabetes compared to healthy individuals. The mean total plasma homocysteine levels were associated with a greater central subfield macular thickness (CSMT), average macular thickness (AMT), and average macular volume (AMV) in patients with type 2 diabetes without DME, after adjusting for age, sex, duration of diabetes, and HbA1c. Each 1 mmol/L increase in tHcy level was associated with a 6.57 µm greater CSMT (95% confidence interval [CI] 1.78, 11.36), a 4.51 µm greater AMT (95% CI 1.05, 7.98), and a 4.72 mm³ greater AMV (95% CI 1.23, 8.21).

CONCLUSIONS

Higher homocysteine levels were associated with an increased CSMT, AMT, and AMV in diabetic patients without DME. This link may indicate that patients with type 2 diabetes with increased levels of plasma tHcy are more prone to develop a clinical manifestation of DME.

Influence of the angiotensin converting enzyme insertion or deletion genetic variant and coronary restenosis risk: evidence based on 11,193 subjects

The insertion/deletion (I/D) polymorphism of the gene encoding angiotensin converting enzyme is a controversial risk factor for restenosis after percutaneous transluminal coronary angioplasties (PTCA) in patients. Genetic association studies can be problematic to reproduce due to insufficient power, phenotypic heterogeneity, population stratification, small effect of the variant and even publication biases. To derive a more precise estimation of the relationship as well as to quantify the between-study heterogeneity and potential bias, a meta-analysis including 11,193 patients from 33 published cohort studies was performed. In a combined analysis, the summary per-allele odds ratio for restenosis was 1.31 (95% CI: 1.08-1.58, P = 0.006), and 1.22 (95% CI: 0.95-1.56, P = 0.12), for PTCA-stent and PTCA-balloon, respectively. In the subgroup analysis by ethnicity, significantly increased restenosis risks after PTCA-stent were found in Asians for the polymorphism; whereas no significant associations were found among Caucasians. As for restenosis risks after PTCA-balloon, no evidence of any gene-disease association was obtained in the stratified analyses according to ethnicity and study size. In conclusion, this meta-analysis demonstrated that the DD homozygous of ACE I/D polymorphism was significantly associated with elevated restenosis susceptibility after PTCA-stent among Asian populations.

Relationship between homocysteine and non-dipper pattern in patients with type 2 diabetes mellitus

OBJECTIVE

The rate of reduction of nocturnal blood pressure (NBP) is lesser than normal in patients with type 2 diabetes mellitus (type 2 DM). Hyperhomocysteinemia (HHC) disrupts vascular structure and function, no matter the underlying causes. The risk of development of vascular disease is greater in diabetic patients with hyperhomocysteinemia than in patients with normal homocystein levels. The aim of the study was to investigate whether there are differences of homocystein levels in dipper and non-dippers patients with type 2 DM.

SUBJECTS AND METHODS

We compared 50 patien-ts (33 females, 17 males) with type 2 DM and 35 healthy individuals (18 females, 17 males ) in a control group. Ambulatory blood pressure monitoring (ABPM) was performed and homocysteine levels were measured in all patients.

RESULTS

We found that the percentage of non-dipper pattern was 72% in patients with type 2 DM and 57% in control group. In diabetic and control individuals, homocystein levels were higher in non-dipper (respectively 13.4 ± 8.1 µmol/L and 11.8 ± 5 µmol/L) than in dipper subjects (respectively, 11.8 ± 5.8 µmol/L and 10.1 ± 4.2 µmol/L), but there was no significant difference between the two groups (respectively, p = 0.545, p = 0.294).

CONCLUSION

In both groups, homocystein levels were higher in non-dipper than in dipper participants, but there was no significant difference between the groups. High homocystein levels and the non-dipper pattern increases cardiovascular risk. Therefore, the relationship between nocturnal blood pressure changes and homocystein levels should be investigated in a larger study.

Association between genetic polymorphism of the angiotensin-converting enzyme and diabetic nephropathy: a meta-analysis comprising 26,580 subjects

Introduction: The effect of angiotensin-converting enzyme ( ACE) insertion/deletion (I/D) polymorphism on risk of diabetic nephropathy (DN) is still conflicting. The present meta-analysis was performed to evaluate the overall risk of this polymorphism associated with DN in different groups.

Materials and methods: A predefined search was performed on 14,108 DN cases and 12,472 controls from 63 published studies by searching electronic databases and reference lists of relevant articles.

Results: In this meta-analysis, we found a significant association between the ACE I/D polymorphism and the risk of DN for all genetic models (ID versus II: odds ratio [OR] = 1.12, 95% confidence interval [CI] 1.02–1.24; DD versus II: OR = 1.27, 95% CI 1.13–1.44; allele contrast: OR = 1.15, 95% CI 1.08–1.23; dominant model: OR = 1.18, 95% CI 1.07–1.31; and recessive model: OR = 1.18, 95% CI 1.08–1.30, respectively). In stratified analysis by ethnicity and DM type, we further found that the Asian group with type 2 diabetes mellitus (T2DM) showed a significant association for all genetic models (ID versus II: OR = 1.25, 95% CI 1.07–1.47; DD versus II: OR = 1.57, 95% CI 1.24–1.98; allele contrast: OR = 1.30, 95% CI 1.15–1.46; dominant model: OR = 1.37, 95% CI 1.10–1.69; and recessive model: OR = 1.34, 95% CI 1.15–1.56, respectively).

Conclusions: Our study suggested that the ACE I/D polymorphism may contribute to DN development, especially in the Asian group with T2DM.

Mild hyperhomocysteinemia, C677T polymorphism on methylenetetrahydrofolate reductase gene and the risk of macroangiopathy in type 2 diabetes: a prospective study

The role of hyperhomocysteinemia as a risk factor for diabetic long-term complications has not been sufficiently evaluated in prospective studies, considering specific correlates of homocysteine (tHcy) concentration and traditional cardiovascular disease (CVD) risk factors. Fasting tHcy, vitamin B12 and folate plasma levels, the common methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism, as well as clinical and lifestyle information were assessed in 216 type 2 diabetic patients attending two outpatient clinics, who had a follow-up evaluation at 65 ± 9 months for the incidence of macroangiopathy. At basal evaluation, mild hyperhomocysteinemia (tHcy ≥ 15 μmol/l) was diagnosed in 21.3% of participants. At follow-up, hyperhomocysteinemia and the distribution of MTHFR C677T genotype did not significantly differ according to the incidence of macroangiopathy. Multiple variables adjusted ORs (95% CI) for CVD associated with mild hyperhomocysteinemia were 1.01 (0.37-2.82); P > 0.05; those associated with MTHFR TT genotype were 0.46 (0.15-1.38); P > 0.05. Although the prevalence of hyperhomocysteinemia was higher in diabetic men (26.9%) than in women (16.1%; P > 0.05), similar results were also observed in a separate sex-analysis. At the multivariate analysis, including in the model other potential CVD risk factors, only creatinine clearance was a significant risk factor for the development of macroangiopathy. In this cohort of diabetic subjects, mild hyperhomocysteinemia and the MTHFR TT genotype are not significant risk factors for the development of macroangiopathy; impaired renal function was confirmed as a significant predictor of this complication.

Endothelial nitric oxide synthase gene polymorphisms and diabetic nephropathy: a HuGE review and meta-analysis

Candidate-gene association studies that examined the association between polymorphisms of endothelial nitric oxide synthase (NOS3) gene (G894T, 4b/a, and T786C) and diabetic nephropathy or diabetes leading to severe nephropathy produced inconclusive results. Thus, a meta-analysis of all candidate-gene association studies with endothelial nitric oxide synthase genotyping (7401 cases and 8046 controls) was conducted. Other study designs, such as family-based association studies and genome-wide linkage and association studies were also reviewed for supportive evidence of implication of endothelial nitric oxide synthase gene in diabetic nephropathy. The meta-analysis showed that G894T is significantly associated with diabetic nephropathy and diabetes leading to severe nephropathy in type 2 diabetics and in East Asians, respectively. Concerning the 4b/a polymorphism and its relationship to diabetes leading to severe nephropathy, a significant association was shown for East Asians. Heterogeneity between studies was in general high. There was no differential magnitude of effect in large versus small studies. One genome-wide linkage scan provided evidence of linkage nearby the endothelial nitric oxide synthase locus. Studies exploring gene and environment interactions with endothelial nitric oxide synthase polymorphisms may help understand better the genetics of diabetic nephropathy.

Methylenetetrahydrofolate reductase gene polymorphism as a risk factor for diabetic nephropathy: a meta-analysis

Investigations into the association between diabetic nephropathy (DN) and MTHFR C677T gene polymorphism in several case-control studies has yielded contradictory results. To shed light on these inconclusive findings, a meta-analysis of all available studies relating the C677T polymorphism to the risk of developing DN was conducted. The PubMed database was searched, and case-control studies investigating the association between MTHFR C677T gene polymorphism and DN were included in the meta-analysis. The meta-analysis included 15 studies, of which 8 involved Caucasians and 5 East Asians; 11 studies involved subjects with type 2 diabetes and 4 with type 1 diabetes. The main analysis (all studies) revealed significant heterogeneity between the studies (P(Q)<0.01) and a marginal association between the 677T allele and the risk of developing DN; the random effects (RE) pooled odds ratio (OR) was 1.30 (1.03-1.64). However, the sensitivity analysis (exclusion of studies not in Hardy-Weinberg equilibrium) produced non-significant results. The recessive model derived significant results in main analysis [fixed effects (FE) OR=1.32 (1.10-1.58), P(Q)=0.27], and in type 2 diabetes [FE OR=1.30 (1.06-1.60), P(Q)=0.38]. The additive model produced significant association in main analysis [RE OR=1.65 (1.13-2.42), P(Q)<0.01] in Caucasians [FE OR=1.48 (1.11-1.98), P(Q)=0.17] and in type 2 diabetes [RE OR=1.65 (1.03-2.67), P(Q)<0.01]. However, sensitivity analysis diminished the significant results in type 2 diabetes. There is no differential magnitude of effect in large versus small studies. In conclusion, although there is some evidence of association between MTHFR C677T gene polymorphism and DN, the above findings reinforce the need for further and more rigorous association studies.

The metabolic response to a high-protein, low-carbohydrate diet in men with type 2 diabetes mellitus

We recently reported that in subjects with untreated type 2 diabetes mellitus, a 5-week diet of 20:30:50 carbohydrate-protein-fat ratio resulted in a dramatic decrease in 24-hour integrated glucose and total glycohemoglobin compared with a control diet of 55:15:30. Body weight, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and serum ketones were unchanged; insulin and nonesterified fatty acids were decreased. We now present data on other hormones and metabolites considered to be affected by dietary macronutrient changes. The test diet resulted in an elevated fasting plasma total insulin-like growth factor 1, but not growth hormone. Urinary aldosterone was unchanged; free cortisol was increased, although not statistically. Urinary pH and calcium were unchanged. Blood pressure, creatinine clearance, serum vitamin B12, folate, homocysteine, thyroid hormones, and uric acid were unchanged. Serum creatinine was modestly increased. Plasma alpha-amino nitrogen and urea nitrogen were increased. Urea production rate was increased such that a new steady state was present. The calculated urea production rate accounted for 87% of protein ingested on the control diet, but only 67% on the test diet, suggesting net nitrogen retention on the latter. The lack of negative effects, improved glucose control, and a positive nitrogen balance suggest beneficial effects for subjects with type 2 diabetes mellitus at risk for loss of lean body mass.

Inverse association between plasma homocysteine, sulphonylurea exposure and physical activity: a community-based sample of type 2 diabetes patients in the Skaraborg hypertension and diabetes project

AIM

This study aimed to investigate levels of Homocysteine (tHcy) and folate in a population-based sample of patients with type 2 diabetes. In particular, the study explored modifiable determinants such as treatment for diabetes, life style, glucose control and kidney function.

PATIENTS AND METHODS

In a community-based surveillance of patients with type 2 diabetes, 196 men and 191 women were consecutively identified in primary care and characterized by cardiovascular disease (CVD) risk factors focusing on components in the metabolic syndrome. For categorical associations plasma tHcy was dichotomized using the upper 10 percentiles of the distribution.

RESULTS

Treatment with sulphonylurea was associated with lower serum levels of tHcy compared to those on diet alone. The association was confined to women [odds ratio 0.14; confidence interval 0.03-0.8] and remained significant when differences in factors related to the metabolic syndrome, life style and previous CVD were accounted for, but was lost when adjusted for HbA1c. There was an inverse dose-related association between physical activity and plasma levels of tHcy (men p = 0.006, women p = 0.034), and a positive association with serum levels of creatinine (men p = 0.004, women p < 0.001).

CONCLUSIONS

The association with physical activity might be one contributing explanation for its well-known protective effect on cardiovascular disease. The over risk for vascular complications in diabetic patients with kidney disease may be partially explained by high levels of tHcy and should be further explored. Prospective studies are particularly needed on various treatment for type 2 diabetes and tHcy to explore possible implications for clinical procedures and for public health.

Age and kidney function are the primary correlates of fasting plasma total homocysteine levels in non-diabetic and diabetic adults. Results from the 1999-2002 National Health and Nutrition Examination Survey

Background

Plasma total homocysteine (tHcy) is commonly elevated in persons with diabetes. This may be due to effects of insulin and/or glucose and/or metabolic control on the metabolism or plasma levels of tHcy. This study examined the effects of fasting plasma glucose status on fasting tHcy levels among adults without diabetes, and diabetes per se among adults with a self-report history of diabetes.

Methods

Analysis of data on adults (≥ 20y) who had fasted at least 8 hours, from the National Health and Nutrition Examination Survey (1999–2000 and 2001–2002). Subjects with no self-report history of diabetes were grouped according to fasting plasma glucose status as normal (< 100 mg/dL = NFG, n = 2,244), impaired (≥ 100 < 126 mg/dL = IFG, n = 1,108), or a provisional diagnosis of diabetes (≥ 126 mg/dL = DFG, n = 133). Subjects with a self-report history of diabetes (n = 275) were examined separately.

Results

Fasting tHcy was higher (Ps < 0.01) among non-diabetic subjects with DFG and IFG, compared to NFG (median [95% confidence interval] = 8.6 [8.0–9.2], 8.3 [8.1–8.5], and 7.4 [7.3–7.5] μmol/L, respectively). Diabetic subjects had levels similar to non-diabetic subjects with DFG and IFG (8.3 [7.9–8.6] μmol/L). Age and estimated creatinine clearance were strong correlates of fasting tHcy among non-diabetic subjects (r = 0.38 to 0.44 and r = -0.35 to -0.46, respectively) and diabetic subjects (r = 0.41 and r = -0.46, respectively) (Ps < 0.001), while fasting glucose and glycohemoglobin (HbA_1c) were weaker (but still significant) correlates of tHcy in non-diabetic and diabetic subjects. Fasting glucose status was not a significant independent predictor of fasting tHcy levels in non-diabetic subjects, and HbA_1c was not a significant independent predictor of tHcy in diabetic subjects (Ps > 0.05).

Conclusion

Fasting tHcy levels are elevated among non-diabetic adults with elevated fasting glucose levels, compared to persons with normal fasting glucose levels, and among diabetic adults. However, elevations in fasting tHcy appear to be mediated primarily by age and kidney function, and not by measures of glucose metabolism.

Prevalence of myocardial infarction is related to hyperhomocysteinemia but not influenced by C677T methylenetetrahydrofolate reductase and A2756G methionine synthase polymorphisms in diabetic and non-diabetic subjects

BACKGROUND

Hyperhomocysteinemia has emerged as a novel risk factor for myocardial infarction (MI). Some mechanisms proposed to explain its relationship with coronary events are also shared by major coronary risk factors. We examined whether C677T methylenetetrahydrofolate reductase and A2756G methionine synthase polymorphisms could affect the relative risk for MI.

METHODS

A sample of 196 individuals was divided into four groups (diabetics with MI, n=43; diabetics without MI, n=50; non-diabetics with MI, n=47; non-diabetics without MI, n=56) and compared regarding the prevalence of the polymorphisms, risk factors, and biochemical parameters.

RESULTS

Higher prevalence of hyperhomocysteinemia was found in MI patients (p<0.05 vs. non-MI subjects), in males (p<0.001 vs. female) and in those > or = 65 years (p=0.01 vs. <65 years). Homocysteine was negatively associated with HDL-C (p<0.05) and glucose, although results did not reach significance (p=0.06). Similar distribution of studied polymorphisms was seen in all groups, which presented normal folate and vitamin B12 serum levels.

CONCLUSIONS

Higher homocysteinemia was predominantly observed in men, presenting low HDL-C, and at advancing age. Methylenetetrahydrofolate reductase and methionine synthase polymorphisms did not contribute to risk assessment in diabetic and non-diabetic subjects presenting normal folate levels.

Homocysteine and reactive oxygen species in metabolic syndrome, type 2 diabetes mellitus, and atheroscleropathy: the pleiotropic effects of folate supplementation

Homocysteine has emerged as a novel independent marker of risk for the development of cardiovascular disease over the past three decades. Additionally, there is a graded mortality risk associated with an elevated fasting plasma total homocysteine (tHcy). Metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) are now considered to be a strong coronary heart disease (CHD) risk enhancer and a CHD risk equivalent respectively. Hyperhomocysteinemia (HHcy) in patients with MS and T2DM would be expected to share a similar prevalence to the general population of five to seven percent and of even greater importance is: Declining glomerular filtration and overt diabetic nephropathy is a major determinant of tHcy elevation in MS and T2DM.

There are multiple metabolic toxicities resulting in an excess of reactive oxygen species associated with MS, T2DM, and the accelerated atherosclerosis (atheroscleropathy). HHcy is associated with an increased risk of cardiovascular disease, and its individual role and how it interacts with the other multiple toxicities are presented.

The water-soluble B vitamins (especially folate and cobalamin-vitamin B₁₂) have been shown to lower HHcy. The absence of the cystathionine beta synthase enzyme in human vascular cells contributes to the importance of a dual role of folic acid in lowering tHcy through remethylation, as well as, its action of being an electron and hydrogen donor to the essential cofactor tetrahydrobiopterin. This folate shuttle facilitates the important recoupling of the uncoupled endothelial nitric oxide synthase enzyme reaction and may restore the synthesis of the omnipotent endothelial nitric oxide to the vasculature.