Differential expression of dipeptidyl peptidase-IV (DPP-IV) in Indian type-2 diabetic population

Dipeptidyl peptidase IV (CD26; E.C. 3.4.14.5) is plasma membrane glycoprotein exopeptidase. There are no data on both phenotypic or genotypic expression and polymorphism of DPP-IV in Indian type-2 diabetic patients. Therefore we estimated the dipeptidyl peptidase IV (DPP-IV) levels in Indian type 2 diabetic population.

Selection of study group was as follows: 1. Twenty seven nondiabetic subjects (control group). 2. Twenty five newly detected diabetic patients (without treatment). 3. Fifty four diabetic patients on drug treatment (metformin and glibenclamide) for more than 3 yrs. Again this group was subdivided on the basis of HbAlc level (25 subjects only) into, 3a.moderately controlled (HbAlc 6-8%), 3b.uncontrolled (HbAlc >8%). In all the subjects both fasting and post-prandial blood sugar was estimated and ADA criteria was taken for the diagnosis. In the same subjects fasting and post-lunch dipeptidyl peptidase IV (DPP IV) enzyme levels were estimated. HbAlc levels were studied in 25 subjects of drug combination treated group (3a and b), and the levels were compared with DPP IV enzyme.

Fasting DPP-IV levels in different groups were statistically significant. Similarly post-prandial DPP-IV levels in different groups were statistically significant, except between the non diabetic Vs anti diabetic drug treated group. On comparison the ratio of fasting and post-prandial DPP IV levels is <1 in non-diabetic and newly detected diabetic groups and in anti-diabetic drug treated group (3a and b) the ratio is >1. Based on HbAlc levels moderately controlled group showed significant p value regarding fasting and postprandial DPP-IV levels.

Fasting DPP IV levels were raised in newly detected and drug-treated diabetic subjects in comparison to normal subjects and post-prandial levels are markedly raised in newly detected diabetic group only. Fasting and post-prandial DPP IV levels varied significantly in moderately controlled diabetic group (HbAlc 6-8%) basing on p value fasting 0.001 and post-prandial 0.005. Fasting and post-prandial DPP IV ratio is >1 in antidiabetic drug treated group, whereas it is <1 in normal control group and newly detected diabetic group. This change may be attributed to chronicity of diabetes or uncontrolled diabetic status or due to effect of metformin on post-prandial DPP IV levels.