Erythrocyte aldose reductase activity and sorbitol levels in diabetic retinopathy.
OBJECTIVE
Activation of polyol pathway due to increased aldose reductase (ALR2) activity has been implicated in the development of diabetic complications including diabetic retinopathy (DR), a leading cause of blindness. However, the relationship between hyperglycemia-induced activation of polyol pathway in retina and DR is still uncertain. We investigated the relationship between ALR2 levels and human DR by measuring ALR2 activity and its product, sorbitol, in erythrocytes.


METHODS
We enrolled 362 type 2 diabetic subjects (T2D) with and without DR and 66 normal subjects in this clinical case-control study. Clinical evaluation of DR in T2D patients was done by fundus examination. ALR2 activity and sorbitol levels along with glucose and glycosylated hemoglobin (HbA1C) levels in erythrocytes were determined.


RESULTS
T2D patients with DR showed significantly higher specific activity of ALR2 as compared to T2D patients without DR. Elevated levels of sorbitol in T2D patients with DR, as compared to T2D patients without DR, corroborated the increased ALR2 activity in erythrocytes of DR patients. However, the increased ALR2 activity was not significantly associated with diabetes duration, age, and HbA1C in both the DR group and total T2D subjects.


CONCLUSIONS
Levels of ALR2 activity as well as sorbitol in erythrocytes may have value as a quantitative trait to be included among other markers to establish a risk profile for development of DR.
Reddy
G Bhanuprakash
GB
National Institute of Nutrition, Indian Council of Medical Research, Hyderabad, India. geereddy@yahoo.com
Satyanarayana
A
A
Balakrishna
N
N
Ayyagari
Radha
R
Padma
M
M
Viswanath
K
K
Petrash
J Mark
JM
D000449:Aldehyde Reductase / Q000097:blood*; D001786:Blood Glucose / Q000032:analysis; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2; D003930:Diabetic Retinopathy / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D004912:Erythrocytes / Q000201:enzymology* / Q000378:metabolism; D005260:Female; D005654:Fundus Oculi; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013012:Sorbitol / Q000097:blood
D000449:Aldehyde Reductase; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D013012:Sorbitol; C484670:AKR1B1 protein, human