Role of type 2 diabetes and hemodialysis in serum adipolin concentrations: A preliminary study

Adipolin protects against renal injury via PPARα-dependent reduction of inflammasome activation

Although chronic kidney disease (CKD) is a major health problem worldwide, its underlining mechanism is incompletely understood. We previously identified adipolin as an adipokine which provides benefits for cardiometabolic diseases. Here, we investigated the role of adipolin in the development of CKD. Adipolin-deficiency exacerbated urinary albumin excretion, tubulointerstitial fibrosis and oxidative stress of remnant kidneys in mice after subtotal nephrectomy through inflammasome activation. Adipolin positively regulated the production of ketone body, β-hydroxybutyrate (BHB) and expression of a catalytic enzyme producing BHB, HMGCS2 in the remnant kidney. Treatment of proximal tubular cells with adipolin attenuated inflammasome activation through the PPARα/HMGCS2-dependent pathway. Furthermore, systemic administration of adipolin to wild-type mice with subtotal nephrectomy ameliorated renal injury, and these protective effects of adipolin were diminished in PPARα-deficient mice. Thus, adipolin protects against renal injury by reducing renal inflammasome activation through its ability to induce HMGCS2-dependent ketone body production via PPARα activation.

Correlation of Serum Adipolin with Epicardial Fat Thickness and Severity of Coronary Artery Diseases in Acute Myocardial Infarction and Stable Angina Pectoris Patients

OBJECTIVE

Adipolin/C1q/TNF-related protein-12 is a family of CTRPs highly expressed in adipose tissue with glucose-lowering and anti-inflammatory effects. Various risk factors have been suggested in the incidence of cardiovascular diseases, such as a decrease in anti-inflammatory or an increase in inflammatory factors. The purpose of the present study was to investigate the correlation of adipolin with anthropometric, angiographic, echocardiographic, and biochemical parameters.

SUBJECT AND METHODS

A total of 90 patients who were candidates for angiography were included in the study and divided into 3 groups: 30 patients with acute myocardial infarction (AMI), 30 patients with stable angina pectoris (SAP), and 30 subjects as a control group with a history of chest pain but normal angiography. Anthropometric, angiographic, echocardiographic, and biochemical parameters were measured in all subjects.

RESULTS

Serum adipolin levels were significantly decreased in patients with AMI compared with the SAP and control groups (p < 0.001 for both). In addition, there was a negative association between serum levels of adipolin and epicardial fat thickness (EFT) and Gensini score in CAD patients. The results of multivariate linear regression analysis revealed that EFT values were independently associated with serum adipolin levels.

CONCLUSION

The current study showed an independent association of adipolin with EFT for the first time in patients with AMI. Decreased adipolin levels in patients with AMI may be involved in the process of atherosclerosis, which requires further study.

The relationship between serum adipokines and glucose homeostasis in normal-weight and obese patients on hemodialysis: a preliminary study

PURPOSE

Insulin resistance (IR) is a prevalent disorder in advanced renal failure irrespective of diabetes. Adipokines might play a role in IR, which has not been well-documented in uremic conditions. This study investigated the relationship of Zinc-α₂-glycoprotein (ZAG), adipose triglyceride lipase (ATGL), and adipolin with glucose-insulin homeostasis in normal weight (NW) and obese (OB) patients with hemodialysis.

METHODS

In this cross-sectional study, 59 patients (29 NW; 18.5 ≤ BMI < 25 kg/m², and 30 OB; BMI ≥ 30 kg/m²) were studied. Anthropometries, circulating ZAG, adipolin, ATGL, free fatty acids (FFAs), fasting blood glucose (FBG), insulin, and homeostasis model assessment of IR (HOMA)-IR were assessed.

RESULTS

There were no significant differences in age, gender, hemodialysis duration, dialysis adequacy and diabetes between the two groups. ZAG (100.9 ± 37.1 vs. 107.5 ± 30.5 ng/mL, P = 0.03) and adipolin (12.4 ± 1.6 vs. 13.2 ± 2.8 ng/mL, P = 0.002) concentrations were significantly lower, and FFAs (228.1 ± 112.6 vs. 185 ± 119 ng/mL, P = 0.014) were significantly higher in the OB than NW group. No significant differences were observed in ATGL, FBG, insulin and HOMA-IR between the two groups. Patients with lower IR had higher ZAG (112.9 ± 31.7 vs. 94.9 ± 34.5 ng/mL; P = 0.046), lower FFAs (167.8 ± 98.4 vs. 249.9 ± 120.8 ng/mL; P = 0.004), and marginally lower ATGL (9.1 ± 5.2 vs. 12.3 ± 9.6 mIU/mL; P = 0.079) concentrations than those with higher IR. ZAG was negatively (r =  - 0.323, P = 0.018 and r =  - 0.266, P = 0.054) and FFAs were positively (r = 0.321, P = 0.019 and r = 0.353, P = 0.009) correlated with insulin and HOMA-IR, respectively. ATGL was directly correlated with FFAs (r = 0.314, P = 0.018).

CONCLUSIONS

Novel adipokines, ZAG and ATGL, might contribute to glucose-insulin homeostasis in hemodialysis. Understanding potential causative, diagnostic or therapeutic roles of adipokines in IR require further studies.