Association of diabetic autonomic neuropathy with red blood cell aldose reductase activity

Erythrocyte metabolism

Our aim is to present an updated overview of the erythrocyte metabolism highlighting its richness and complexity. We have manually collected and connected the available biochemical pathways and integrated them into a functional metabolic map. The focus of this map is on the main biochemical pathways consisting of glycolysis, the pentose phosphate pathway, redox metabolism, oxygen metabolism, purine/nucleoside metabolism, and membrane transport. Other recently emerging pathways are also curated, like the methionine salvage pathway, the glyoxalase system, carnitine metabolism, and the lands cycle, as well as remnants of the carboxylic acid metabolism. An additional goal of this review is to present the dynamics of erythrocyte metabolism, providing key numbers used to perform basic quantitative analyses. By synthesizing experimental and computational data, we conclude that glycolysis, pentose phosphate pathway, and redox metabolism are the foundations of erythrocyte metabolism. Additionally, the erythrocyte can sense oxygen levels and oxidative stress adjusting its mechanics, metabolism, and function. In conclusion, fine-tuning of erythrocyte metabolism controls one of the most important biological processes, that is, oxygen loading, transport, and delivery.

The Relationship between Erythrocytes and Diabetes Mellitus

High blood glucose level (hyperglycemia) is a leading indicator of diabetes mellitus (DM). Erythrocytes are the most abundant cells in the circulation and the first to perceive changes in plasma composition. Long-lasting hyperglycemia affects the structure and function of erythrocytes. The detection of erythrocyte-related indicators can provide a valuable reference for the prevention, diagnosis, and treatment of DM and its complications. This paper reviews the normal structure and function of erythrocytes, the changes in erythrocytes in patients with diabetes, and the role of erythrocytes in the development of diabetic complications to provide more indicators for the early prevention of DM complications and to monitor the therapeutic effect of DM.

Static and Dynamic Pupillary Responses in Patients with Different Stages of Diabetic Retinopathy

This study aimed to investigate pupillary involvement in patients with type 2 diabetes mellitus (DM) and to evaluate whether there is a relationship between severity of diabetic retinopathy (DR) and pupillary responses. The study included 133 individuals in four groups: proliferative DR, non-proliferative DR, DM group without retinal involvement and a control group. Static pupillometry measurements including scotopic pupil diameter (PD), mesopic PD, low photopic PD, high photopic PD, and dynamic pupillometry measurements, including resting diameter, amplitude, latency, velocity, duration of pupil contraction and latency, duration, and velocity of pupil dilatation were taken using an automated quantitative pupillometry system. The correlations between glycosylated haemoglobin values and duration of DM with these parameters were also investigated. The study showed that patients with DR may also have diabetic autonomic neuropathy and pupillometry can be a useful screening tool for detecting diabetic autonomic neuropathy.

Additive Effect of Topical Nepafenac on Mydriasis in Patients With Diabetes Mellitus

OBJECTIVES

To evaluate the additive effect of topical nepafenac on pupil diameter (PD) in patients with diabetes mellitus (DM) and cataract.

METHODS

This prospective comparative study included the patients having cataract surgery with and without DM. Two consecutive PD measurements were taken using an automatic quantitative pupillometry system (MonPack One, Metrovision). A baseline measurement was taken, then one drop of nepafenac % 0.1 (Nevanac; Alcon, Fort Worth, TX) was instilled only to the eye that will be operated on (study eye). Cyclopentolate 1.0% (Sikloplejin; Abdi İbrahim, İstanbul, Turkey) was instilled to both eyes (study eye/fellow eye) 5 minutes later. The second measurement was taken at 1 hour after this application.

RESULTS

The DM group consisted of 43 patients, and the control group consisted of 39 participants. The baseline PDs of both eyes were similar in the DM group (P=0.070) and the control group (P=0.345). The change in pupil size from baseline to mydriasis was statistically significantly greater in the study eyes (2.69±0.53) than fellow eyes (2.54±0.61) in the DM group (P=0.009), but there was no statistically significant difference in the control group (2.94±0.63 vs. 2.86±0.58). When the groups were compared, the PD changes were similar in the study eyes between groups (P=0.065), while the PD changes in the fellow eyes were lower in the DM group (P=0.017).

CONCLUSIONS

Nepafenac has been shown additive effect on pupil dilation in diabetic patients before cataract surgery.