Hyperhomocysteinemia, as an independent risk factor for retinal venous occlusion in an Indian population

Hyperhomocysteinemia Causing Vascular Occlusion and Complicated by Heparin-Induced Thrombocytopenia and Gastrointestinal Bleed

Homocysteine, an intermediate amino acid, is involved in methionine metabolism, which is crucial for various physiological pathways, including protein synthesis and DNA methylation. Elevated levels of homocysteine have been implicated as both a modifiable and unmodifiable risk factor in cardiovascular disease, influencing atherosclerotic disease formation and hypercoagulability. Mechanisms linking elevated homocysteine levels to vascular occlusion involve endothelial dysfunction, inflammation, and enhanced thrombotic potential. We present the case of a 54-year-old female with hyperhomocysteinemia-induced hypercoagulability causing acute limb ischemia, necessitating below-knee amputation.

Prevention and Treatment of Retinal Vein Occlusion: The Role of Diet-A Review

Retinal vein occlusion (RVO) is the second most common retinal disorder. In comparison to diabetic retinopathy or age-related macular degeneration, RVO is usually an unexpected event that carries a greater psychological impact. There is strong evidence to suggest that cardiovascular diseases are the most common risk factors in this pathology and it has long been known that a higher consumption of fish, nuts, fruits, and vegetables has a protective effect against these types of conditions. In the last several years, interest in plant-based diets has grown in both the general population and in the scientific community, to the point to which it has become one of the main dietary patterns adopted in Western countries. The aim of this review is to investigate the potential impact of macro- and micronutrients on retinal vein occlusion.

Role of hyperhomocysteinemia and Vitamin B12 deficiency in central and hemi-central retinal vein occlusion: A case-control study

BACKGROUND

Retinal venous occlusive diseases have been recognized as a major cause of ocular morbidity. Hyperhomocysteinemia could be a potentially modifiable risk factor.

OBJECTIVE

To determine the association of hyperhomocysteinemia with central and hemi-central retinal vein occlusion (CRVO and HCRVO), the correlation of serum levels of homocysteine with Vitamin B12 and folate levels and the association of Vitamin B12 deficiency with hyperhomocysteinemia.

METHODS

In this case-control study, patients with CRVO and HCRVO, and age- and gender-matched controls without CRVO and HCRVO, who met the eligibility criteria, were enrolled after obtaining informed consent. Data obtained from participants using a questionnaire, complete ophthalmological examination and relevant investigations, including estimation of serum homocysteine, Vitamin B12 and folate levels, were collated and analyzed.

RESULTS

Thirty-nine cases with CRVO and HCRVO and 39 age- and gender-matched controls were studied. We found a significant association of hypertension (P < 0.01), hyperlipidemia (P = 0.01), and abnormal blood profile (P < 0.01) with retinal vein occlusion. There was no statistically significant association of hyperhomocysteinemia with CRVO and HCRVO (P = 0.81). However, we found a high prevalence of both hyperhomocysteinemia (43.58% of cases and 53.84% of controls; P = 0.81) and Vitamin B12 deficiency (23.08% of cases and 38.46% of controls; P = 0.14) in cases and controls, without a statistically significant difference between the two groups with respect to both parameters. Our study also found a negative correlation of serum levels of homocysteine with Vitamin B12 (Pearson correlation co-efficient - 0.3874, P = 0.0005), and folate (Pearson correlation coefficient - 0.3886, P = 0.0004) of the study participants. Among the study participants (n = 78), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 7.0 (2.26-21.72) times those of patients without Vitamin B12 deficiency (P = 0.001). Similarly, among the cases (CRVO, n = 39), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 7.0 (1.22-40.09) times those of patients without Vitamin B12 deficiency (P = 0.029). In the control group also (non-CRVO, n = 39), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 6.67 (1.47-30.21) times those of patients without Vitamin B12 deficiency (P = 0.014).

CONCLUSION

Hyperhomocysteinemia was not found to be an independent risk factor for retinal vein occlusion in our study. However, we found a high prevalence of hyperhomocysteinemia and Vitamin B12 deficiency in both cases and controls, without a statistically significant difference between the two groups with respect to both parameters. We also found a negative correlation of serum homocysteine levels with Vitamin B12 and folate levels. The odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were seven times those of patients without Vitamin B12 deficiency. Hypertension, hyperlipidemia, and abnormal blood profile had a significant association with CRVO and HCRVO. Many of the systemic risk factors for retinal vein occlusions are found to be associated with elevation of serum homocysteine levels, which may be part of a final common pathway in bringing about a state of accelerated atherosclerosis, leading to CRVO or HCRVO. Therefore, lowering serum levels of homocysteine by Vitamin B12 and folate supplementation could have a role in the prevention of these diseases.

Cystoid Macular Edema Associated With Venous Stasis in a Patient With Previously Undiagnosed Hyperhomocysteinemia

A 74-year-old female patient visited our department reporting unilateral painless vision reduction in her left eye noticed a few months ago. Clinical examination revealed decreased visual acuity in the left eye. Fundoscopy showed bilateral retinal venous stasis with cystoid macular edema in the affected eye, also confirmed by optical coherence tomography (OCT) imaging. OCT angiography showed no evidence of ischemia.

Bilateral findings raised suspicion for a systemic underlying cause. Laboratory tests showed elevated homocysteine plasma levels. Brain MRI showed ischemic encephalopathy.

Hyperhomocysteinemia creates a hypercoagulable state and therefore it is a risk factor for vascular thrombosis and retinal vein occlusion. Our patient was considered to suffer from an impending retinal vein occlusion due to venous stasis, causing a persistent macular edema, and, therefore, was treated with anti-vascular endothelial growth factor (VEGF) injections. She was also prescribed oral folic acid for life. Her visual acuity showed improvement and remained stable for a long period of time. When macular edema reoccurred she was treated with another intravitreal injection.

Association of homocysteine with type 1 diabetes mellitus: a meta-analysis

PURPOSE

To figure out the association between plasma Hcy status and type 1 diabetes mellitus (T1DM).

METHODS

We searched the PubMed Web of Science, and The Cochrane Library to identify eligible studies. The Newcastle-Ottawa Quality Assessment Scale was used to assess the quality of selected studies. All analyses were performed using the STATA, version 12 software.

RESULTS

15 studies were included in this investigation. Our meta-analysis indicated that plasma Hcy concentrations in T1DM patients without any complications were normal compared with healthy people [13 studies, SMD: -0.08, 95% confidence interval (CI): -0.44 to 0.28, P=0.67]. However, a significant elevation of plasma Hcy concentrations was observed in T1DM patients with only diabetic retinopathy (DR) (5 studies, SMD: 0.34, 95% CI: 0.13 to 0.55, P=0.002), only diabetic nephropathy (DN) (4 studies, SMD: 0.76, 95% CI: 0.18 to 1.33, P=0.01) and both the two complications (3 studies, SMD: 1.05, 95% CI: 0.03 to 2.07, P=0.043) compared with T1DM patients without any complications.

CONCLUSIONS

Homocysteine levels elevate in T1DM patients with DR and DN, but don't elevate in T1DM without any complications.

Hyperhomocysteinemia, a biochemical tool for differentiating ischemic and nonischemic central retinal vein occlusion during the early acute phase

PURPOSE

The purpose of the study was to differentiate ischemic central retinal vein occlusion (CRVO) from nonischemic CRVO during the early acute phase using plasma homocysteine as a biochemical marker.

METHODS

Fasting plasma homocysteine, serum vitamin B12, and folate levels were measured in 108 consecutive unilateral elderly adult (age >50 years) ischemic CRVO patients in the absence of local and systemic disease and compared with a total of 144 age and sex matched nonischemic CRVO patients and 120 age and sex matched healthy control subjects.

RESULTS

Homocysteine level was significantly increased in the patients with ischemic CRVO in comparison with nonischemic CRVO patients (p = 0.009) and also in comparison with control subjects (p < 0.001). Analysis also showed that hyperhomocysteinemia was associated with increased incidence of ischemic CRVO (odds ratio, 18) than that for nonischemic CRVO (odds ratio, 4.5). Serum vitamin B12 and folate levels were significantly lower (p < 0.001) in CRVO patients compared to the control but were not significantly different between nonischemic and ischemic CRVO patients (p > 0.1).

CONCLUSIONS

Hyperhomocysteinemia can be regarded as useful in differentiating nonischemic and ischemic CRVO during the early acute phase in absence of local and systemic disease in the elderly adult (age >50 years) population.

Retino-choroidal ischemia in central retinal vein occlusion

A 41-year-old gentleman with insulin dependent diabetes had decreased vision in the right eye due to non-ischemic central retinal vein occlusion with macular edema. One month following intravitreal ranibizumab, he developed retino-choroidal ischemia with further loss of vision. Authors show the fluorescein angiographic transition from non-ischemic central retinal vein occlusion to retino-choroidal ischemia.

Homocysteine, methylenetetrahydrofolate reductase C677T polymorphism, and risk of retinal vein occlusion: an updated meta-analysis

Background

To evaluate the role of plasma total homocysteine (tHcy) and homozygosity for the thermolabile variant of the methylenetetrahydrofolate reductase (MTHFR) C677T genotype in the risk of retinal vein occlusion (RVO).

Methods

Relevant studies were selected through an extensive search of PubMed, EMBASE, and the Web of Science databases. Summary weighted mean differences (WMDs) or odds ratios (ORs) and 95% confidence intervals (CI) were calculated with a random-effects model.

Results

Forty-two studies with 6445 participants were included in this updated systematic review and meta-analysis. The mean plasma tHcy level in the RVO patients was significantly higher than in the controls (WMD =2.13 μmol/L; 95% CI: 1.29 to 2.98, P < 0.001), but there was evidence of between-study heterogeneity (P < 0.001). No significant association between MTHFR C677T genotype and RVO was found under all genetic models.

Conclusion

There was some evidence that plasma tHcy is associated with an increased risk of RVO. There was no evidence to suggest an association between homozygosity for the MTHFR C677T genotype and RVO.

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.