Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adenosine deaminase (ADA) is suggested to be an important enzyme for modulating the bioactivity of insulin, but its clinical significance in diabetes mellitus (DM) is not yet characterized. We measured the serum levels of ADA isoenzymes (ADA1 and ADA2) in healthy donors (HD, n = 52), insulin-dependent diabetes mellitus (IDDM, n = 53) patients and non-insulin-dependent diabetes mellitus (NIDDM, n = 65) patients. The mean serum level of ADA1 in HD, IDDM or NIDDM patients was, respectively 6.5, 8.1 or 9.5 units/l (P < 0.001 vs. HD) and that of ADA2 in HD, IDDM or NIDDM patients was 7.0, 14.9 (P < 0.001 vs. HD) or 11.2 units/l (P < 0.001 vs. HD), respectively. Normalization of the blood glucose level by the hospitalization was associated with the decrease in ADA2 (but not ADA1) activity in 6 of 8 IDDM or 11 of 12 NIDDM poorly controlled patients. ADA2 (but not ADA1) activity in the poorly controlled NIDDM patients directly correlated with the hemoglobin A1c level (P < 0.002). Measurement of serum ADA2 activity may be important to better understand the clinical aspects of both IDDM and NIDDM. The pathogenic role of elevated ADA activity in the sera of DM patients was addressed.
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PMID:Elevated adenosine deaminase activity in the serum of patients with diabetes mellitus. 782 Nov 97

The early stages of diabetic retinopathy (DR) are characterized by alterations similar to neurodegenerative and inflammatory conditions such as increased neural apoptosis, microglial cell activation and amplified production of pro-inflammatory cytokines. Adenosine regulates several physiological functions by stimulating four subtypes of receptors, A1AR, A2AAR, A2BAR, and A3AR. Although the adenosinergic signaling system is affected by diabetes in several tissues, it is unknown whether diabetic conditions in the retina can also affect it. Adenosine delivers potent suppressive effects on virtually all cells of the immune system, but its potential role in the context of DR has yet to be studied in full. In this study, we used primary mixed cultures of rat retinal cells exposed to high glucose conditions, to mimic hyperglycemia, and a streptozotocin rat model of type 1 diabetes to determine the effect diabetes/hyperglycemia have on the expression and protein levels of adenosine receptors and of the enzymes adenosine deaminase and adenosine kinase. We found elevated mRNA and protein levels of A1AR and A2AAR, in retinal cell cultures under high glucose conditions and a transient increase in the levels of the same receptors in diabetic retinas. Adenosine deaminase and adenosine kinase expression and protein levels showed a significant decrease in diabetic retinas 30 days after diabetes induction. An enzymatic assay performed in retinal cell cultures revealed a marked decrease in the activity of adenosine deaminase under high glucose conditions. We also found an increase in extracellular adenosine levels accompanied by a decrease in intracellular levels when retinal cells were subjected to high glucose conditions. In conclusion, this study shows that several components of the retinal adenosinergic system are affected by diabetes and high glucose conditions, and the modulation observed may uncover a possible mechanism for the alleviation of the inflammatory and excitotoxic conditions observed in diabetic retinas.
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PMID:Effect of diabetes/hyperglycemia on the rat retinal adenosinergic system. 2384 Jul 23