The Relationship Between Plasma Glucagon-Like Peptide-1, C-Reactive Protein and Adiponectin Levels in Obese Patients with Normal and Impaired Glucose Tolerance

ABSTRACT

Objective: One of the most important pathophysiological changes occurring in obese patients is systemic inflammation. This study aims to examine the relationship between C-reactive protein (an inflammatory marker), anti-inflammatory adiponectin, and glucagon-like peptide- 1, which is an important incretin hormone involved in the pathogenesis of Type 2 diabetes mellitus, in obese patients having normal and impaired glucose tolerance.

Material and Methods: This study observed 60 obese patients having body mass index ≥30 kg/m . Out of the 60 obese patients, 30 patients showed normal glucose tolerance, while the remaining 30 had impaired glucose tolerance. Another group (control group) included 20 healthy individuals having normal body mass index. Plasma adiponectin, glucagon-like peptide-1, fasting insulin, lipid profile, hemoglobin a1c and C- reactive protein levels were examined in all the patients, including the control group.

Results: Obese patients with impaired glucose tolerance and normal glucose tolerance were compared to patients in the healthy control group. It was determined that both the categories of obese patients possessed significantly higher C-reactive protein levels and lower glucagon- like peptide-1 levels than those of the healthy control group (respectively p=0.001, p=0.001, p=0.001, p=0.001). Moreover, the adiponectin levels were observed to be lower in the impaired glucose tolerance group than that in the healthy control group (p=0.010). However, there was no significant difference within the impaired glucose tolerance group with regard to C-reactive protein, glucagon-like peptide-1, and adiponectin levels. The correlation analysis revealed a significant positive correlation between C-reactive protein, body mass index, and waist circumference in the normal glucose tolerance group (respectively, r=0.427, p=0.019 and r=0.407, p=0.026). On the other hand, no significant correlation was observed between glucagon-like peptide-1, adiponectin, and the other parameters in these subjects. Furthermore, a significantly negative correlation was observed in the impaired glucose tolerance group in terms of glucagon-like peptide-1 levels and waist circumference (r=- 0.380, p=0.038). Nevertheless, no significant correlation was observed among C-reactive protein levels, adiponectin, and other parameters in this patient group.

Conclusion: The high C-reactive protein level observed among obese patients in this study may indicate the involvement of an inflammatory process in obese patients. The observation of high C-reactive protein and low glucagon-like peptide-1, as well as adiponectin levels among obese patients, can be used as a marker for tracking the progression of diabetes in impaired glucose tolerance patients during the followup examinations. Moreover, the positive correlation among C-reactive protein, body mass index, and waist circumference in normal glucose tolerance patients, as well as the negative correlation between glucagon-like peptide-1 levels and waist circumference in impaired glucose tolerance patients, supports this claim.