Glucose-6-phosphate-dehydrogenase deficiency as a risk factor for pterygium

Dynamic thiol disulphide homeostasis in patients with surfer's eye: a case-control study

PURPOSE

The role of oxidative stress in the pathogenesis of pterygium is still unclear. However, abnormal thiol disulfide homeostasis levels are involved in the pathogenesis of various systemic or ocular diseases. We aim to analyze dynamic thiol disulphide homeostasis in patients suffering from conjunctival pterygium using a contemporary technique.

METHODS

Thirty-eight subjects suffering from pterygium and 35 age-gender matched healthy volunteers were recruited for the study. For each case, total thiol, disulfide and native thiol levels in blood were obtained. Additionally, the ratio of disulfide over total thiol, native thiol over total thiol and disulfide over native thiol were computed.

RESULTS

The level of median native thiol was lower in pterygium group (318.2 µmol/L vs. 333.4 µmol/L) and median disulfide was slightly higher in pterygium group (24.3 µmol/L vs. 22.8 µmol/L) compared to control group. Both disulfide over total thiol and disulfide over native thiol ratios were higher in pterygium group, ratio of native thiol over total thiol was found to be higher in control group. Nevertheless, none of those differences were statistically significant at 95% confidence level. Notably, correlation test pointed to a negative correlation both between pterygium grade and native thiol and between total thiol and pterygium grade in pterygium group (P = 0.03 and 0.02, respectively).

CONCLUSION

A negative correlation hinting that slightly weakened dynamic thiol disulphide homeostasis in subjects with pterygium, a local ocular disease. Further studies with larger sample sizes may shed light on this potential relationship and justify systemic antioxidant therapies in these cases.

Immobilization Increases the Stability and Reusability of Pigeon Pea NADP+ Linked Glucose-6-Phosphate Dehydrogenase

Immobilization of enzymes is valuably important as it improves the stability and hence increases the reusability of enzymes. The present investigation is an attempt for immobilization of purified glucose-6-phosphate dehydrogenase from pigeon pea on different matrix. Maximum immobilization was achieved when alginate was used as immobilization matrix. As compared to soluble enzyme the alginate immobilized enzyme exhibited enhanced optimum pH and temperature. The alginate immobilized enzyme displayed more than 80% activity up to 7 continuous reactions and more than 50% activity up to 11 continuous reactions.

Epidemiology and Associated Morbidity of Pterygium: A Large, Community-Based Case-Control Study

BACKGROUND

To evaluate the prevalence and risk factors of various conditions among patients with pterygium.

METHODS

A retrospective observational case control study of 4,037 patients who were diagnosed with pterygium in the Central District of Clalit Health Services in Israel from 2000-2009. A total of 16,054 randomly selected controls from the district HMO members. Personal, medical, and demographic information were extracted from patients' files. We calculated the prevalence of various ocular, systemic, and demographic conditions as risk factors for pterygium.

RESULTS

The average age of pterygium patients was 58.4 ± 14 years; 56.9% were male. A significant tendency to develop pterygium was found among individuals of lower socioeconomic status (p < 0.001) and in populations living in rural areas (p < 0.001). A logistic regression model adjusted to marital status, socio-economic class, and area of living was performed. The following conditions were significantly associated with pterygium: blepharitis (OR = 1.71; 99.9% CI: 1.53-1.93), chalazia (OR = 1.46; 99.9% CI: (1.19-1.78)), anxiety (OR = 1.14, 99.9% CI: 0.98-1.33), and G6PD deficiency (OR = 1.85; 99.9% CI: 1.11-3.07). Schizophrenia (OR 0.31; 99.9% CI: 0.19-0.50) and smoking (OR 0.82; 99.9% CI: 0.76-0.89) were significantly less prevalent among pterygium patients.

CONCLUSIONS

Pterygium etiology is multifactorial. Some demographic, systemic, and periocular conditions are significantly more prevalent and some are less prevalent among pterygium patients. Better understanding of the pathophysiological association between those diseases and pterygium may help in its prevention and treatment.

Glucose-6-phosphate dehydrogenase--beyond the realm of red cell biology

Glucose-6-phosphate dehydrogenase (G6PD) is critical to the maintenance of NADPH pool and redox homeostasis. Conventionally, G6PD deficiency has been associated with hemolytic disorders. Most biochemical variants were identified and characterized at molecular level. Recently, a number of studies have shone light on the roles of G6PD in aspects of physiology other than erythrocytic pathophysiology. G6PD deficiency alters the redox homeostasis, and affects dysfunctional cell growth and signaling, anomalous embryonic development, and altered susceptibility to infection. The present article gives a brief review of basic science and clinical findings about G6PD, and covers the latest development in the field. Moreover, how G6PD status alters the susceptibility of the affected individuals to certain degenerative diseases is also discussed.

Subclinical reduced G6PD activity in rheumatoid arthritis and Sjögren's Syndrome patients: relation to clinical characteristics, disease activity and metabolic syndrome

OBJECTIVE

Glucose-6-phosphate dehydrogenase (G6PD) is an important site of metabolic control in the pentose phosphate pathway. The purpose of this study was to investigate the enzyme activity of G6PD in Rheumatoid Arthritis (RA) and Sjögren's Syndrome (SS) patients not known to be deficient in this enzyme. It was also within the scope of the aim to find the relation of G6PD to the presence of metabolic syndrome (MetS) in these patients.

METHODS

Erythrocyte G6PD activity was evaluated in 40 RA patients, 30 SS patients and in 30 age- and sex-matched control. The clinical characteristics, disease activity score (DAS28), SS disease activity (SSDAI) and damage (SSDDI) indices and presence of MetS of the included patients were analyzed in relation to the enzyme level.

RESULTS

The G6PD activity in RA patients (7.72 ± 3.57 U/g Hb) was significantly reduced compared to that in the SS patients (11.55 ± 3.14 U/g Hb) and control (13.23 ± 3.34 U/g Hb) especially those with MetS (4.61 ± 1.84 U/g Hb) (p < 0.001). There was a significant negative correlation of the G6PD activity with the disease duration and DAS28 (p < 0.001).

CONCLUSION

The results of this study, suggest that G6PD not only does not protect against MetS in RA, but may even be considered a risk factor for the development of this disorder. The identification of regulatory tools for G6PD activity may prove promising for treating the associated metabolic disorders and chronic inflammation in RA.

Immobilization and applications of glucose-6-phosphate dehydrogenase: a review

Immobilized enzymes have been used extensively in the fields of food industry, materials processing, textiles, detergents, biochemical and chemical industries, biotechnology, and pharmaceuticals. Studies on immobilization of glucose-6-phosphate dehydrogenase have been less extensive than those for other industrially applicable enzymes. Immobilization of glucose-6-phosphate dehydrogenase has been carried out for the formation of biosensors for the estimation of glucose, ATP, phosphate, and so on. The present review deals with the attempts made for immobilization of glucose-6-phosphate dehydrogenase and its applications for various purposes.

Increased prevalence of proliferative retinopathy in patients with type 1 diabetes who are deficient in glucose-6-phosphate dehydrogenase

AIMS/HYPOTHESIS

Impaired activity of the pentose phosphate pathway of glucose metabolism caused by hereditary deficiency of its key regulatory enzyme glucose-6-phosphate dehydrogenase (G6PD) has consequences that may worsen or attenuate the course of diabetic complications. Decreased availability of NADPH can predispose to oxidative stress and endothelial dysfunction, but can also limit the activity of the polyol pathway and cholesterol synthesis. Reduced availability of pentose phosphates for nucleic acid synthesis could impair cell proliferation. We sought to learn in which direction G6PD deficiency affects diabetic retinopathy.

METHODS

We enrolled patients who were G6PD-deficient or -sufficient with type 1 diabetes of duration 15 years or longer for whom HbA(1c) records were available for at least the previous 3 years. Renal failure and smoking were exclusion criteria. For each participant seven standard field colour photographs were obtained of each eye, and retinopathy was graded in a masked fashion.

RESULTS

The clinical characteristics of the 19 G6PD-deficient patients studied (age 42 ± 9 years, diabetes duration 24 ± 6 years, average HbA(1c) over 3 years 6.7 ± 0.8%) were similar to those of the 35 G6PD-sufficient patients. Almost 90% of patients in both groups had retinopathy; however, proliferative retinopathy was noted solely among G6PD-deficient patients (28%, p = 0.0036 vs G6PD-sufficient). The G6PD-deficient patients also showed a trend for increased frequency of microalbuminuria.

CONCLUSIONS/INTERPRETATION

The data suggest that G6PD deficiency accelerates the microvascular complications of diabetes, and that among the consequences of G6PD deficiency those that can enhance the damage caused by diabetes outweigh those that could be protective.