Clinical usefulness of plasma homocysteine in vascular disease

Using a 3-hydroxyflavone derivative as a fluorescent probe for the indirect determination of aminothiols separated by ion-pair HPLC

Homocysteine, cysteine, cysteinyl-glycine, and glutathione are significant biological aminothiols (ATs) that are marker-molecules in Down syndrome, Alzheimer's disease, or have been implicated as risk factors in atherosclerosis and other vascular diseases, and therefore rapid determination of these molecules is desirable. After reduction of the disulfides, a widely used method utilizes derivatization with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonate (SBD-F) as a fluorogenic probe prior to reversed-phase HPLC separation followed by fluorescence detection. The traditional HPLC determination of ATs is time consuming and economically expensive. We have developed an ion-pair HPLC method coupled with indirect fluorescence detection after post-column reaction with a 2,4-dinitrobenzenesulfonate derivative of a 3-hydroxyflavone. The accuracy, precision, post-column temperature and residence time, and limit-of-detection were evaluated. Sample throughput and reduced sample preparation time of over an hour for the existing methods to less than 20 minutes for the new method is also demonstrated. No statistical differences in HCy, Cys, or Cys-Gly determinations in plasma samples were observed between our method and the traditional HPLC method.

Recreational Nitrous Oxide Abuse: Prevalence, Neurotoxicity, and Treatment

Nitrous oxide (N₂O), also known as "laughing gas," is a colorless, nonirritating gas. Clinically, it is widely used as an inhaled anesthetic, analgesic, and anxiolytic. In recent years, recreational abuse of N₂O has become increasingly common, especially among young adults and adolescents, but many of them lack awareness of the possible side effects associated with this drug. N₂O abuse can damage multiple systems, especially the nervous system, but the exact mechanism of N₂O toxicity remains controversial. At present, an increasing number of cases of nervous system damage caused by N₂O abuse have been reported both at home and abroad. Discontinuation of N₂O use and timely supplementation with vitamin B12 are essential for a good prognosis. Long-term abuse without timely treatment will eventually lead to irreversible neurological damage. In this article, we discuss the epidemiology of N₂O abuse, neurotoxicity mechanisms, clinical manifestations, relevant auxiliary examinations, treatments, and prognosis to improve social awareness of N₂O exposure risk, especially among users and clinicians.

Role of hyperhomocysteinemia in proliferative diabetic retinopathy: A case-control study

Purpose:

Hyperhomocysteinemia has been postulated as a potential risk factor for the development and progression of diabetic retinopathy. The aim of this study was to determine the association of hyperhomocysteinemia with proliferative diabetic retinopathy (PDR).

Methods:

This was a hospital-based, case–control study, conducted at a tertiary care ophthalmic center in South India. Thirty-nine patients with proliferative diabetic retinopathy were enrolled as cases, and 39 age- and gender-matched patients with no diabetic retinopathy (No DR) were enrolled as controls. Fasting serum homocysteine estimation, as well as baseline investigations, were done in all participants. Data regarding demographic profile and risk factors were documented. Data were analyzed using Chi-square test and independent t-test, as appropriate.

Results:

The prevalence of hyperhomocysteinemia was higher in PDR (59%) compared to “No DR” (48.7%); however, this difference was not statistically significant (P = 0.36). Similarly, the mean serum homocysteine level in cases was higher than in controls, but this was not statistically significant (17.98 + 6.26 μmol/L vs. 17.71 + 8.17 μmol/L; P = 0.87). Longer duration of diabetes, hypertension, anemia, and renal dysfunction were found to be significantly associated with PDR.

Conclusion:

The prevalence of hyperhomocysteinemia as well as the mean serum levels of homocysteine were found to be higher in the cases with PDR, compared to the controls with No DR, although the difference was not statistically significant. Longer duration of diabetes, hypertension, anemia, and renal dysfunction were significantly associated with PDR.

Prevalence and clinical-demographic correlates of hyperhomocysteinemia in inpatients with bipolar disorder in a Han Chinese population

Recent studies have reported that hyperhomocystinemia (HHcy) is highly prevalent in patients with bipolar disorder (BD), placing them at greater risk of cardiovascular disease and possibly serving as a disease biomarker. However, the correlation of HHcy with demographic or clinical parameters is not well known. In this study, we examined the prevalence of HHcy and its association with these parameters in a sample of Chinese BD patients. Fasting plasma homocysteine (Hcy) levels were determined in 198 BD inpatients and 84 healthy controls. HHcy was defined when Hcy concentration exceeded 15.0µmol/L. Affective symptomatology was assessed by the Young Mania Rating Scale, Hamilton Depression Rating Scale and the Clinical Global Impressions severity scale. Compared to healthy controls, BD patients had a significantly higher prevalence (34.85% vs. 19.05%) of HHcy and a higher absolute level of homocysteine. Logistic regression analysis demonstrated that BD patients with HHcy were more likely to be male, have elevated BMI, more frequent treatment on lithium but less on valproate. These results suggest that Chinese inpatients with bipolar disorder have a higher rate of HHcy than the general population, and those at greatest risk are male, have an elevated BMI, and take more lithium but less valproate therapy.

Stromelysin-1 5A/6A and eNOS T-786C Polymorphisms, MTHFR C677T and A1298C Mutations, and Cigarette-Cannabis Smoking: A Pilot, Hypothesis-Generating Study of Gene-Environment Pathophysiological Associations With Buerger’s Disease

Buerger’s disease (BD) etiologies are poorly understood. Beyond smoking cessation, medical-surgical treatments have limited success. We hypothesized that mutations associated with arterial vasospasm (stromelysin-1 5A/6A, eNOS T-786C) and C677T-A1298C methylene tetrahydrofolate reductase (MTHFR) interacted with cigarette-cannabis smoking, reducing vasodilatory nitric oxide (NO), promoting arterial spasm-thrombosis. Of 21 smoking BD patients (14 men [2 siblings], 7 women; 20 white, 1 African-American), compared to 21 age-gender-race matched healthy controls, 5A/6A stromelysin- 1 homozygosity was present in 7 of 21 (33%) BD cases versus 5 of 21 (24%) controls (risk ratio 1.4; 95% confidence interval [CI] 0.5-3.7), and eNOS T-786C homozygosity was present in 3 of 21 (14%) BD cases versus 1 of 21 (5%) controls (risk ratio 3.0; 95% CI 0.3-26.6). C677T MTHFR homozygosity or compound C677T-A1298C heterozygosity was present in 7 of 21 cases (33%) versus 11 of 21 controls (52%) (risk ratio 0.6; 95% CI 0.3-1.3). In 18 patients who stopped and 3 who continued smoking, all stromelysin-1 5A/6A and/or eNOS heterozygotes-homozygotes, superficial phlebitis, lower limb gangrenous ulcers, and intractable ischemic rest pain with arterial occlusion progressed despite conventional medical therapy, threatening amputation. In 15 patients, to increase vasodilatory NO via endothelial NO synthase, l-arginine (15 g/day) was given, along with folic acid (5 mg), vitamin B6 (100 mg), and B12 (2000 mg/day) to optimize homocysteine metabolism and reduce asymmetric dimethylarginine, a NO synthase inhibitor. Unexpectedly quickly and strikingly, within 8 weeks to 8 months receiving l-arginine-folic acid, 11 of 15 treated patients improved with uniform pain reduction, ulcer healing, and in 5, full recovery of previously absent peripheral pulses. In smokers homo/heterozygous for stromelysin-1 5A/6A and eNOS T-786C mutations, we speculate that the development and severity of BD are related to a gene-environment vasospastic interaction with reduced NO-mediated vasodilatation. Increasing NO production by l-arginine while optimizing homocysteine metabolism by folic acid-B6-B12 may have therapeutic benefit. Further blinded, placebo-controlled studies are needed to determine whether our observations can be generalized to larger BD cohorts.

Homocysteine as a risk factor for hypertension: a 2-year follow-up study

Homocysteine (Hcy) is regarded as a risk factor for hypertension, but research on the causal relationship between Hcy and hypertension is limited. In the present study, we prospectively tracked the blood pressure progression of a normotensive population with different Hcy levels over a 2-year period. The incidence of hypertension with increasing Hcy quartiles produced an approximately U-shaped curve, with significance in males. Compared with the third quartile, the risk of hypertension in the first and second quartiles was increased by 1.55 (95% confidence interval [CI] 1.154–2.081) fold and 1.501 (95% CI 1.119–2.013) fold, respectively, with the increase being more significant in males. In conclusion, Hcy is related to hypertension incidence with the results approximating an U-shaped curve. Low Hcy levels might also increase the risk of hypertension.

The Effect of Vitamin B12 Infusion on Prevention of Nitrous Oxide-induced Homocysteine Increase: A Double-blind Randomized Controlled Trial

OBJECTIVE

Nitrous oxide is a common inhalation anesthetic agent in general anesthesia. While it is widely accepted as a safe anesthetic agent, evidence suggests exposure to this gas, leads to hyperhomocysteinemia. The present study aimed to evaluate the effects of single-dose intravenous infusions of vitamin B12, before and after the induction of nitrous oxide anesthesia on homocysteine levels after the surgery.

METHODS

This double-blind randomized controlled trial was conducted on 60 patients who were scheduled for elective surgery under general anesthesia, presumably lasting for more than two hours. The subjects were randomly allocated to three groups of 20. For the first group, vitamin B12 solution (1 mg/100 ml normal saline) and 100 ml of normal saline (placebo), were infused before and after the induction of anesthesia, respectively. The second group received placebo and vitamin B12 infusion before and after the induction of anesthesia, respectively. The third group received placebo infusions at both times. Homocysteine levels were measured before and 24 hours after the surgery.

RESULTS

The mean homocysteine and vitamin B12 levels were significantly different within the three groups (p<0.001). In patients who had been infused with vitamin B12 before the surgery, homocysteine levels were significantly lower than the other two groups. In the placebo group, homocysteine levels significantly increased after the surgery.

CONCLUSION

Nitrous oxide causes hyperhomocysteinemia after general anesthesia. Since vitamin B12 infusion is a safe and inexpensive method to decrease homocysteine levels in these patients, it may be recommended for patients undergoing nitrous oxide anesthesia to be used before induction of anesthesia.

Plasma Homocysteine is Associated with Retinopathy in Type 1 Diabetic Patients in the Absence of Nephropathy

INTRODUCTION

Previous cross-sectional studies suggested that plasma total homocysteine (tHcy) is associated with retinopathy in patients with type 1 diabetes (T1DM) only in cases of impaired renal function. The objective of this study was to examine whether there is an independent relationship between tHcy and retinopathy in normoalbuminuric T1DM patients with normal estimated glomerular filtration rate (eGFR).

METHODS

The study included 163 normoalbuminuric patients with T1DM and normal renal function (eGFR >60 ≤ 125 ml min(-1) 1.73 m(-2)). Urinary albumin excretion rate (UAE) was measured from at least two 24 h urine samples. Photodocumented retinopathy status was made according to the EURODIAB protocol. tHcy level was measured with the chemiluminescent immunoassay.

RESULTS

Retinopathy was present in 48% of normoalbuminuric patients. Patients with retinopathy were older (49 vs 42 years, p = 0.001), had higher systolic blood pressure (130 vs 120 mmHg, p = 0.001), triglycerides (0.89 vs 0.77 mmol/L, p = 0.01), tHcy (9.8 vs 9.1 µmol/L, p = 0.04), and lower eGFR (100 vs 106 ml min(-1) 1.73 m(-2), p = 0.03). In multivariate logistic regression analysis, after adjustment for variables that reached statistical significance in the univariate analysis, only tHcy was significantly associated with a risk of retinopathy in our subjects (p = 0.02), with odds ratios of 1.02 to 1.43.

CONCLUSION

These data suggest that tHcy is independently associated with retinopathy in normoalbuminuric T1DM with normal eGFR. The mechanisms relating tHcy and retinopathy in T1DM are not clear. Prospectives studies are needed to confirm whether higher tHcy in normoalbuminuric T1DM patients has predictive value for development of retinopathy.

Homocysteine, depression and cognitive function in older adults

BACKGROUND

Depression and high total plasma homocysteine (tHcy) are independently associated with cognitive impairment in older adults. We designed this study to determine if high tHcy is a mediator of cognitive performance in older adults with major depression.

METHODS

We recruited 358 community-dwelling older adults experiencing depressive symptoms, 236 (65.9%) of who met DSM-IV-TR criteria for major depression. Assessment included the Montgomery Asberg Depression Rating Scale (MADRS), fasting tHcy and the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery.

RESULTS

Individuals with major depression and high tHcy had significantly worse immediate verbal and delayed visual recall. Non-depressed participants with high tHcy had lower MMSE, immediate and delayed recall scores than those with normal tHcy. The odds of cognitive inefficiency for those with high tHcy was nearly doubled for the MMSE (OR 1.9, 95%CI 1.1-3.3), immediate (OR 1.9, 95%CI 1.1-3.5) and delayed (OR 1.9, 95%CI 1.1-3.4) word recall after adjusting for age, gender, IHD and MADRS score.

LIMITATIONS

The presence of sub-syndromal depressive symptoms in our non-depressed group and exclusion of participants with established cognitive impairment may limit the generalizability of this study.

CONCLUSIONS

Elevated tHcy was associated with weaker performance in tests of immediate and delayed memory and global cognitive performance when compared to those with normal tHcy independent of the presence of major depression or the severity of depressive symptoms. Homocysteine lowering B-vitamin supplementation may offer a potential therapeutic target to try and mitigate the often-disabling impact of cognitive deficits found in this population.

Aspirin decreases the risk of depression in older men with high plasma homocysteine

High total plasma homocysteine (tHcy) is associated with increased risk of cardiovascular events and depression. Consumption of B-vitamins (B6, B9 and B12) reduces tHcy by about 15%, but has equivocal effects on these health outcomes, suggesting that this relationship is either not causal or is confounded by other factors. The results of recent randomized trials suggest that antiplatelet therapy may confound these associations. This cross-sectional study assessed 3687 men aged 69-87 years for history of clinically significant depression (Geriatric Depression Scale 15 items 7) or a recorded diagnosis of depression in the Western Australian Data Linkage System, and collected information on the use of aspirin, B-vitamins and antidepressant medication, along with age, education, living arrangements, smoking history and medical comorbidity as assessed by the Charlson index. Participants donated a blood sample for the measurement of tHcy, and concentrations15 μmol l(-1) were considered high. Five hundred and thirteen (13.9%) men showed evidence of depression, and of those 31.4% had high tHcy, 41.5% were using aspirin, 6.8% were consuming B-vitamins. Multivariate logistic regression showed that high tHcy was associated with increased odds of depression (odds ratio (OR)=1.60, 95% confidence interval (CI)=1.20-2.14), as was the use of B-vitamins (OR=1.95, 95% CI=1.21-3.13). There was a significant interaction between high tHcy and aspirin use (OR=0.57, 95% CI=0.36-0.91), but not between high tHcy and B-vitamin use (OR=0.80, 95% CI=0.26-2.46). The analyses were adjusted for smoking status, Charlson index and use of antidepressants. The results of this study indicate that older men with high tHcy who use aspirin have lower risk of depression, and suggest that antiplatelet therapy may be an effective preventive or management strategy for these cases. Randomized trials are required to confirm the antidepressant effect of aspirin in people with high tHcy.

Homocysteine, methylenetetrahydrofolate reductase C677T polymorphism and cognitive impairment: the health in men study

High total plasma homocysteine (tHcy) has been associated with cognitive impairment in later life, but it is unclear if this association is causal or is due to confounding. The C677T polymorphism of the 5,10 methylenetetrahydrofolate reductase gene (MTHFR) increases basal tHcy, but its contribution to cognitive impairment has not been established. We designed this study to determine if tHcy is causally related to cognitive impairment in later life by investigating its association with high tHcy and the MTHFR-C677T polymorphism. We recruited 1778 older men from the Health in Men Study cohort and established caseness on the basis of the participants' scores on a Telephone Interview for Cognitive Status score 27 in 2008. Exposure to tHcy, gene status and other variables of interest were obtained from assessments 4-7 years earlier. Multivariate logistic regression showed that the odds of cognitive impairment increased with a doubling of tHcy (adjusted odds ratio, OR 1.36; 95% confidence interval, 95% CI 1.02-1.82). Compared with the wild CC genotype, participants with the MTHFR-TT genotype had 46% greater odds of cognitive impairment (OR 1.46, 95% CI 1.01-2.11, P=0.043). The results of this study are consistent with, but do not prove the hypothesis that high tHcy causes cognitive impairment in later life.

Complaints of difficulty to fall asleep increase the risk of depression in later life: the health in men study

OBJECTIVES

To determine if complaints of poor sleep are associated with incident depression in older men.

METHODS

Cohort study with an average follow up period of 6 years (range 3 months to 8.5 years). Participants were 5127 community-dwelling Western Australian older men aged 70-90 years who provided information about sleep problems. The primary outcome of interest of the study was a recorded diagnosis of depressive episode, recurrent depressive disorder or dysthymia in the Western Australian Data Linkage System. Participants completed a health questionnaire that included questions assessing difficulty falling asleep, remaining awake, as well as early morning awakening. Other measured factors included age, education, country of birth, living arrangements, social support, smoking, body mass index, and prevalent diabetes, hypertension, arthritis, chronic respiratory diseases, coronary artery disease, stroke, and cancer. Biochemical measurement of C-reactive protein, testosterone and plasma homocysteine were available for 3800 men.

RESULTS

We found that 60% of men reported at least one sleep problem and that the unadjusted hazard ratio (HR) of depression was higher in men who complained of difficulties to initiate sleep (HR = 2.19, 95% confidence interval--95% CI = 1.47-3.27) or who remained awake most of the night (HR = 1.94, 95% CI = 1.15-3.27). There was no association between early morning awakening and incident depression. The association between incident depression and subjective difficulty falling asleep remained after the analyses were adjusted for other measured factors (HR = 1.83, 95% CI = 1.20-2.79). The association between depression and remaining awake was no longer significant once the analyses were adjusted for confounding (HR = 1.43, 95% CI = 0.81-2.53). A sensitivity analysis confirmed these results.

LIMITATIONS

The evaluation of the exposure (sleep disturbance) was limited to self-rating questions that were not externally validated. The diagnosis of depression was based on administrative record linkage rather than structure clinical interviews. The observational nature of the study limits our ability to ascribe a causal relationship between complaints of poor sleep and incident depression.

CONCLUSIONS

Complaints of difficulty falling asleep increase the risk of incident depression in older men. Clarifying the mechanisms that underlie this association should become an international research priority, as they may contribute to guide interventions designed to decrease the burden of depression in later life.

Hyperhomocysteinemia Prevalence Among Patients With Venous Thromboembolism

The aim of this study is to evaluate the plasma total homocysteine level in patients with venous thromboembolism (VTE) and to investigate the effect of different risk factors on plasma levels. Ninety-three-patients with VTE and 37-control participants diagnosed with other than VTE were included in the study. Plasma homocysteine levels and the factors affecting plasma homocysteine levels were evaluated. Plasma homocysteine level was higher among patients with VTE compared to the controls independent from vitamin B12 and folate levels. The prevalence of hyperhomocysteinemia in VTE was 63%. Plasma homocysteine level was higher in patients with PE than deep venous thrombosis (DVT; 23 ± 13.7 vs 16 ± 5.8 μmol/L, P = .018). With regression analysis hyperhomocysteinemia was found to be associated with a 4.8-fold increased risk of VTE. Hyperhomocysteinemia is a common and possibly modifiable risk factor that should be considered when screening patients with VTE. Secondary causes of hyperhomocysteinemia especially vitamin B12 deficiency should be monitored in patients with VTE to prevent recurrences.

Homocysteine, estrogen and cognitive decline

BACKGROUND

Factors that contribute to cognitive decline in women from midlife remain poorly understood. There are circumstantial data indicating a positive association between homocysteine and cognitive decline and that endogenous and exogenous estrogen may influence homocysteine levels. The aim of this review was to establish what is known of the relationships between cognitive change and homocysteine levels, and the impact of the menopause transition and exogenous estrogen on homocysteine levels.

METHODS

We reviewed the recent published literature from 1993 to 2005 pertaining to the current understanding of the relationship(s) between plasma homocysteine levels and cognitive functioning and endogenous hormone levels and exogenous estrogen use in women.

RESULTS

Hyperhomocysteinemia is consistently associated with cognitive decline. Dietary supplementation with vitamins may assist in normalizing homocysteine levels; however, there is no evidence that this results in favorable effects on cognition. Changes in endogenous estrogen levels are inversely associated with changes in serum homocysteine. Consistent with this, estrogen therapy is associated with reductions in plasma homocysteine, with the greatest effects reported in women with higher levels of homocysteine at baseline. Limited data indicate that tibolone is associated with little change in homocysteine. The use of raloxifene, the most studied selective estrogen receptor modulator, is associated with a modest reduction in homocysteine.

CONCLUSIONS

There are data to suggest an underlying link between homocysteine levels and cognitive decline. There is also evidence for a link between both the menopause transition and use of exogenous estrogen therapy and homocysteine levels. Clinical data do not support a role for exogenous estrogen in the prevention of dementia in older women; however, the 'window of opportunity' theory suggests that there is a need for randomized controlled trials to evaluate the role of estrogen in the early postmenopausal years to protect against cognitive decline in later life.

Preditores sócio-demográficos, de estilo de vida e gineco-obstétricos das concentrações séricas ou plasmáticas de homocisteína, ácido fólico e vitaminas B12 e B6 em mulheres de baixa renda de São Paulo, Brasil

O presente estudo investigou fatores sócio-demográficos, de estilo de vida e gineco-obstétricos associados às concentrações séricas ou plasmáticas de homocisteína, ácido fólico, vitaminas B12 e B6 em mulheres de baixa renda de São Paulo, Brasil. Concentrações séricas de ácido fólico e vitamina B12 foram analisadas por fluoroimunoensaio; concentrações plasmáticas de homocisteína e vitamina B6, por cromatografia líquida de alta performance em fase reversa. Variáveis independentes foram inicialmente selecionadas segundo pressupostos teóricos, correlação de Pearson ou teste Kruskal-Wallis (p < 0,20). Concentrações alteradas segundo pontos de corte para homocisteína, ácido fólico, vitaminas B12 e B6 foram observadas em 20%, 6%, 11% e 67% das participantes, respectivamente. Idade foi positivamente correlacionada à vitamina B6 e homocisteína plasmáticas (p < 0,001). Índice de massa corporal foi positivamente correlacionado à vitamina B6 plasmática (p < 0,001). Modelos de regressão linear múltiplos explicaram 10,2%, 5,8%, 14,4% e 9,4% das concentrações de ácido fólico, vitamina B12, vitamina B6 e homocisteína, respectivamente. No presente estudo, variáveis sócio-demográficas, de estilo de vida e gineco-obstétricas apresentaram contribuição importante na variação das concentrações dos indicadores bioquímicos avaliados.

The effects of raloxifene and tibolone on homocysteine and vascular histopathological changes

The aim of the present study was to examine the effects of raloxifene (RLX) and tibolone (TBN) on plasma homocysteine (Hcy) levels and their relationship with atherosclerotic changes in the walls of the carotid artery in ovariectomised rats. Thirty surgically ovariectomised Wistar albino rats after a menopausal period of 6 cycles were randomly assigned to receive RLX 0.01 mg/kg/day (n=10), TBN 0.04 mg/kg/day (n=10) and the same dose of placebo (n=10) for 6 cycles. Serum levels of vitamin B12, folate and Hcy were measured and carotid arteries were examined histopathologically following the termination of treatment. Hcy levels were 3.27+/-0.97, 2.57+/-0.32 and 2.28+/-0.12 micromol/l, Vitamin B12 levels were 901.90+/-239.76, 694.70+/-112.20 and 631+/-309.44 pg/ml and folate levels were 73.80+/-12.71, 72.51+/-7.05 and 84.79+/-20.82 ng/ml in receiving RLX, TBN and placebo respectively. Hcy levels were increased by RLX vs. placebo (P=0.006) but not by TBN vs. placebo (P=0.070). Vitamin B12 levels were found to be elevated by TBN vs. the control group (P=0.041) but not by RLX vs. placebo (P=0.059). Histopathological examination of carotid arteries from rats receiving both RLX and TBN revealed no difference vs. placebo. Data obtained from the study support the view that neither RLX nor TBN appears to have a primary protective effect on vascular disease by effecting the metabolism of Hcy at menopause.

Homocysteine and diabetic retinopathy

OBJECTIVE

Homocysteine is an emerging risk factor for cardiovascular and nondiabetic ocular vaso-occlusive diseases. However, studies of the relationship between homocysteine and diabetic retinopathy have reported inconsistent results. The purpose of this study was to evaluate the relationship between plasma total homocysteine concentration and diabetic retinopathy.

RESEARCH DESIGN AND METHODS

We assessed the homocysteine-retinopathy relationship in 168 men and women with type 2 diabetes in a community-based, cross-sectional study. We photodocumented diabetic retinopathy status and measured plasma total homocysteine concentration using a commercial fluorescence polarization immunoassay enzymatic kit. Data for selected clinical/demographic variables and established risk factors for diabetic retinopathy were obtained from fasting blood samples and an interviewer-assisted lifestyle questionnaire.

RESULTS

A higher mean plasma total homocysteine concentration was observed in diabetic individuals with retinopathy than in those without retinopathy (11.5 mumol/l [95% CI 10.4-12.5] vs. 9.6 mumol/l [9.1-10.2], P = 0.001). Furthermore, the relationship between homocysteine and diabetic retinopathy was not explained by renal dysfunction and was independent of the other major risk factors for diabetic retinopathy (duration of diabetes, A1C, and systolic blood pressure) and determinants of higher homocysteine concentrations (age, sex, and red cell folate) (odds ratio 1.20 [95% CI 1.023-1.41], P = 0.024).

CONCLUSIONS

Plasma total homocysteine concentration may be a useful biomarker and/or a novel risk factor for increased risk of diabetic retinopathy in people with type 2 diabetes.

Effects of dydrogesterone on the vascular system

Estrogens exert beneficial effects on the vascular system, while progestogens generally have a negative impact (e.g. vasoconstrictor effects on the arterial system). In contrast, dydrogesterone appears to be largely neutral in terms of biochemical markers and indirect clinical endpoints, such as blood pressure, that act as surrogate markers for vascular function. Studies on lipid and carbohydrate metabolism, which can also influence vascular function, demonstrate that the addition of dydrogesterone intensifies rather than attenuates beneficial estrogenic effects. Dydrogesterone also has largely neutral effects on hemostasis. Since there are relatively few data available on clinical parameters such as blood flow measurements, especially in women with pre-existing cardiovascular diseases, increased risks cannot be excluded for a combination of estrogen replacement with dydrogesterone. Further studies should focus on this open question since dydrogesterone, with its largely neutral properties, might be a suitable option, including for older women already at increased cardiovascular risk.

Association of cardiovascular risk factors and disease with depression in later life

OBJECTIVE

The objective of this study is to determine the association between established cardiovascular risk factors and depression among older men.

METHODS

The authors conducted a cross-sectional study of a community-representative sample of 5,439 men aged 71-89 years. Cardiovascular disease and risk factors assessed included history of diabetes, hypertension, angina, myocardial infarction, and stroke; current smoking; total cholesterol and fractions; triglycerides; total plasma homocysteine; and MTHFR677 genotype. Depression was defined by a Geriatric Depression Scale 15 items score of 7 or greater.

RESULTS

A complete data set was available for 4,204 men, of whom 212 were depressed (5%). Men who were depressed reported higher frequency of diabetes (23.1% versus 13.2%), angina (30.2% versus 20.4%), myocardial infarction (26.2% versus 16.0%), and stroke (23.6% versus 9.1%) than nondepressed men. Participants with depression were also more likely to have plasma homocysteine above 15 mumol/L (39.1% versus 25.5%) and high triglycerides (32.1% versus 20.9%) than nondepressed subjects. Depressed older men were also more likely to be active smokers (9.9% versus 4.8%). The other factors measured in the study were not significantly associated with depression. Estimation of the population-attributable fraction (PAF) after logistic regression showed that high plasma homocysteine had the highest PAF for depression (PAF:15%, 95% confidence interval [95% CI]: 5%-23%) followed by high triglycerides (PAF: 11%, 95% CI: 2%-18%), angina (PAF: 9%, 95% CI: 2%-15%), stroke (PAF: 8%, 95% CI: 3%-13%), diabetes (PAF: 7%, 95% CI: 1%-13%), myocardial infarction (PAF: 5%, 95% CI: 0%-11%), and smoking (PAF: 5%, 95% CI: 1%-9%).

CONCLUSIONS

High plasma homocysteine and triglycerides appear to account for a considerable proportion of cases of depression in older men. The successful management of these risk factors may contribute to decrease the prevalence of depression in later life.

Modelling of increased homocysteine in ischaemic stroke: post-hoc cross-sectional matched case-control analysis in young patients

BACKGROUND & PURPOSE: Hyperhomocysteinaemia has been postulated to participate in pathogenesis of ischaemic stroke (IS). However, especially in young adults, there is possibility of significantly increased IS risk due to increased ‘normal’ homocysteinaemia, i.e., ‘hidden’ (‘pathologically dormant’) prevalence within a healthy, normally-defined range. We performed a post-hoc modelling investigation on plasma total homocysteinaemia (THCY) in gender- and age-matched young patients in the acute IS phase. We evaluated relationships between THCY and prevalence of other potential risk factors in 41 patients vs. 41 healthy controls. METHOD: We used clinical methods, instrumental and neuroimmaging procedures, risk factors examination, total plasma homocysteine measurements and other laboratory and statistical modelling techniques. RESULTS: IS patients and healthy controls were similar not only for matching variables, but also for smoking, main vitamin status, serum creatinine and lipid profile. Patients with IS, however, had lower vitamin B6 levels and higher THCY, fibrinogen and triglycerides (TGL). At multivariate stepwise logistic regression only increased THCY and TGL were significantly and independently associated with the risk for stroke (72% model accuracy, p model=0.001). An increase of THCY with 1.0 µmol/L was associated with 22% higher risk of ischaemic stroke [adjusted OR=1.22 (95%CI 1.03?1.44)]. In this way, novel lower cut-off value for HCY of 11.58 µmol/L in younger patients has been revealed (ROC AUC= 0.67, 95CI% 0.55-0.78, p=0.009). CONCLUSION: The new THCY cut-off clearly discriminated between absence and presence of IS (sensitivity>63%, specificity>68%) irrespectively of age and gender and may be applied to better evaluate and more precisely define, as earlier as possible, the young patients at increased IS risk.

Is plasma homocysteine a modifiable risk factor for stroke?

Increased levels of plasma total homocysteine (tHcy) can be caused by genetic mutations, vitamin deficiencies, renal and other diseases, and numerous drugs. Raised tHcy also correlate with increasing age, and are associated with laboratory evidence of atherogenesis (e.g. endothelial dysfunction) and thrombosis, and with epidemiological evidence of an increased risk of atherothrombotic vascular disease, including ischemic stroke. The association between raised tHcy and increased risk of ischemic stroke is independent of other known vascular risk factors and is biologically plausible; however, randomized controlled trials have not revealed a causal relationship. The recently published Vitamins In Stroke Prevention (VISP) trial identified no significant reduction in the relative risk of stroke by lowering tHcy with B-vitamin therapy among 3,680 patients with recent ischemic stroke. It did not, however, reliably exclude a modest but important reduction of up to 20% in relative risk of stroke. Currently, there is insufficient evidence to confirm that homocysteine is a modifiable causal risk factor for stroke, or to recommend routine screening for, or treatment of, raised tHcy concentrations with folic acid and other vitamins, to prevent ischemic stroke.

Biochemical markers surrogating on vascular effects of sex steroid hormones

The main mechanism of possible cardioprotection by estrogens appears to be a direct effect on the vasculature, resulting in an improvement of endothelial function and inhibition of atherogenesis. Numerous observational and experimental studies have demonstrated a positive correlation between estrogens and various biochemical markers surrogating direct vascular effects. In general, most markers are influenced in a similar way by oral and transdermal hormone therapy, although oral therapy may have a faster and more pronounced effect. The main difference between oral and transdermal administration may be confined to markers that are mainly or exclusively produced in the liver. Clinical studies demonstrate that progestogen addition can have an impact on the beneficial estrogen-induced changes of biochemical markers. Concerning the effects of tibolone, inconsistent data have been found. Overall, tibolone-induced beneficial changes on the various biochemical markers appear to be less marked compared with those of hormone therapy. The few data available on the direct effects of androgens on the vascular wall indicate a less favorable action of androgens on biochemical markers than of estrogens. The practical relevance of marker measurements is currently under discussion. Although evidence strongly supports some of these markers as predictors of acute events, it remains to be established whether modifying circulating levels of these markers will influence outcomes.

[Erectile dysfunction: the role of laboratory in the diagnostic and pronostic evaluation]

OBJECTIVE

To review and to update the different laboratory tests recommended for etiologic diagnostic of erectile dysfunction and to evaluate the effect these tests could have on the pronostic and therapeutic strategy of this pathology.

MATERIAL AND METHODS

We review the last articles related with etiopathogenics and pathophysiologics mechanisms of erectile dysfunction, including our studies on endothelial dysfunction and erectile dysfunction.

RESULTS

The depth and extension of the laboratory protocol in erectile dysfunction is not necessaryly the same in all situations. The age, coincidence of comorbilities, set a different limit between patients demanding complementaries investigations that go beyond the basic request.

CONCLUSIONS

The etiopathogenic laboratory work up in erectile dysfunction is currently changing incorporating news tests. The traditional search of commorbilities like diabetes, hepatic dysfunction, hypogonadism, hyperglucemia is getting broad with recents analitics evaluations related with potential markers of endothelial disease.

Association of Low Red Blood Cell Folate Concentrations with Coronary Artery Disease in Iranians: A Matched Case-Control Study

BACKGROUND

It is not fully established whether the increasing risk of coronary artery disease (CAD) is associated with high plasma homocysteine levels or components of the homocysteine remethylation pathway, e.g. vitamin B(12) or 5-methyltetrahydrofolate (5-MTHF) in plasma and red blood cells (RBC). In this study, we tested the hypothesis that 5-MTHF in RBC, which represents the long-term folate status of individuals, may be a more reliable marker of homocysteine remethylation pathway disturbances, and its deficiency may be associated with CAD in Iranians.

METHODS

Plasma total homocysteine (tHcy), vitamin B(12), and plasma and RBC 5-MTHF were measured in 200 angiographically documented patients and 200 controls matched for sex and age.

RESULTS

In the plasma, tHcy levels were significantly higher in cases compared to controls (geometric mean 12.9 +/- 6.5 vs. 10.6 +/- 5.6 micromol/l, p = 0.04). However, RBC 5-MTHF (527.2 +/- 185.9 vs. 461.3 +/- 117.9 nmol/l, p = 0.007) and vitamin B(12) (254.2 +/- 132.8 vs. 182.2 +/- 110.4 pmol/l, p = 0.04) were significantly higher in controls than patients. RBC 5-MTHF was a strong and independent predictor of plasma tHcy (beta = -0.01, p = 0.003, r(2) = 0.19). Subjects in the lowest quartile of red-cell 5-MTHF had a 2.5-fold increased prevalence of CAD compared to subjects in the highest quartile. The association of CAD in the first quartile with red-cell 5-MTHF remained significant when adjusted for plasma tHcy, vitamin B(12), hypertension and hypercholesterolemia (odds ratio, OR 2.3, confidence interval: 1.1-3.9, p = 0.01). However, the association between CAD in the highest quartile and plasma tHcy decreased and became insignificant when adjusted for red-cell 5-MTHF, vitamin B(12), hypertension and hypercholesterolemia (OR 1.27, confidence interval: 0.96-1.69, p = 0.11).

CONCLUSION

In this study, the association between CAD and low RBC 5-MTHF was stronger than with plasma 5-MTHF and plasma tHcy levels, indicating that RBC 5-MTHF may be a more stable parameter to study disturbances in the homocysteine remethylation pathway in Iranians.