Adiponectin Fractions Influence the Development of Posttransplant Diabetes Mellitus and Cardiovascular Disease in Japanese Renal Transplant Recipients

Role of leptin and adiponectin in the pathogenesis of post-transplant diabetes mellitus

Solid organ transplantation is a life-saving treatment for patients with end-stage organ failure, but it poses unique challenges due to metabolic and immunological changes in recipients. One significant complication is post-transplant diabetes mellitus (PTDM), which affects a variety of solid organ recipients. Leptin, a hormone produced by adipose tissue, regulates appetite and affects glucose metabolism. High leptin levels are associated with the development of PTDM, especially in kidney transplant recipients. Adiponectin, another adipokine, increases insulin sensitivity and has anti-diabetic properties. Low adiponectin levels are associated with insulin resistance and increase the risk of PTDM. As the incidence of PTDM increases due to the increased life expectancy among transplant patients, understanding the role of adipokines such as leptin and adiponectin becomes crucial for early detection and treatment. Additional studies on other adipokines may also provide valuable information on the pathogenesis of PTDM.

Long-term retrospective observation study to evaluate effects of adiponectin on skeletal muscle in renal transplant recipients

Although it has been reported that chronic kidney disease exacerbates sarcopenia progression, the mechanisms of the process remain unclear. Fifty-one patients who underwent renal transplantation at our hospital since 1998 (31 males and 20 females; aged 29–52 years at the time of transplantation) were retrospectively examined for the relationships among the psoas muscle index (PMI), intramuscular adipose tissue content (IMAC), serum adiponectin fractions (high-/low-molecular-weight) and new-onset diabetes after transplantation (NODAT). Before transplantation, age at kidney transplantation negatively correlated with PMI and positively correlated with IMAC (rS = − 0.427, p < 0.01; rS = 0.464, p < 0.01, respectively). Both at 1 and 5 years after transplantation, PMI was higher than before transplantation (p < 0.01). IMAC transiently decreased to − 0.39 at 1 year after kidney transplantation but subsequently increased to − 0.36 at 5 years after kidney transplantation. Multivariate analyses revealed that the mean increase in high-molecular weight adiponectin concentrations was an exacerbating factor for the mean change in PMI (p = 0.003). Moreover, the mean increases in IMAC were exacerbating factors for NODAT. In conclusion, the increase in the PMI is associated with high–molecular weight adiponectin levels after renal transplantation.

Circulating CTRP9 correlates with the prevention of aortic calcification in renal allograft recipients

Background

Cardiovascular disease (CVD) due to atherosclerosis is a major cause of death in renal allograft recipients. Recently, C1q/TNF-α related protein-9 (CTRP9), which is a paralog of adiponectin (ADPN), has been suggested to be related to the prevention of atherosclerosis and the occurrence of CVD, but this relationship has not been confirmed in renal allograft recipients.

Subjects and methods

The relationships among the serum CTRP9 concentration, serum ADPN concentration, and vascular calcification were investigated in 50 kidney transplantation recipients at our hospital. Calcification of the abdominal aorta was evaluated according to the aortic calcification area index (ACAI) calculated from CT images. Changes in the serum CTRP9 and ADPN fractions and ACAI were examined for 8 years. In addition, the expression of CTRP9 and ADPN and their respective receptors AdipoR1 and R2 in muscular arteries of the kidney was examined by immunofluorescence.

Results

In renal allograft recipients, the serum CTRP9 concentration at the start of the observation was not significant correlated with eGFR or serum high-molecular-weight (HMW)-ADPN concentration (rS = -0.009, p = 0.950; rS = -0.226, p = 0.114, respectively). However, the change in the serum CTRP9 concentration was positively correlated with the change in the serum HMW-ADPN concentration (rS = 0.315, p = 0.026) and negatively correlated with the change in ACAI (rS = -0.367, p = 0.009). Multiple regression analysis revealed that the serum HMW-ADPN concentration was a significant positive factor for the change in the serum CTRP9 concentration. Moreover, for ACAI, an increase in the serum CTRP9 concentration was an improving factor, but aging was an exacerbating factor. Furthermore, colocalization of CTRP9 and AdipoR1 was noted in the luminal side of intra-renal arterial intima.

Conclusion

In renal allograft recipients, both CTRP9 and HMW-ADPN were suggested to prevent the progression of aortic calcification through AdipoR1.

Body Fat Area as a Predictive Marker of New-Onset Diabetes Mellitus After Kidney Transplantation

BACKGROUND

New-onset diabetes after kidney transplantation (NODAT) adversely affects patient survival. Excessive fat accumulation is generally considered a risk factor of NODAT. Body mass index (BMI) and abdominal circumference (AC) are frequently used to assess fat accumulation but cannot directly measure it. This study measured body fat area (BFA) via computed tomography and aimed to clarify whether preoperative BFA can predict the development of NODAT more accurately than BMI and AC.

METHODS

This retrospective study included 62 patients without diabetes mellitus who received living-donor kidney transplantation at our institute between July 2005 and April 2016. We investigated the association between preoperative BMI, AC, and BFA and the development of NODAT.

RESULTS

Eight patients (12.9%) developed NODAT during a mean follow-up period of 78.1 months. The preoperative BMI, AC, and BFA were markedly higher in NODAT patients than in patients without NODAT (P = .05, P = .02, P < .01, respectively). Correlation analyses revealed that BFA had a strong relationship with BMI (r = 0.68, P < .01) and AC (r = 0.77, P < .01). Receiver operating characteristic curve analyses demonstrated that BFA, compared to BMI and AC, had considerable predictive accuracy for the development of NODAT, with an area under the curve of 0.803 (sensitivity 75%, specificity 87%).

CONCLUSIONS

Preoperative BFA could be a predictive marker of NODAT in renal graft recipients. Our findings underline the importance of routine preoperative BFA measurements in clinical practice.

High molecular weight adiponectin inhibits vascular calcification in renal allograft recipients

BACKGROUND

Adiponectin (ADPN) prevents the development/recurrence of cardiovascular events via its anti-atherogenic effects. However, few long-term studies have examined the changes in serum ADPN levels and arterial calcification seen in renal allograft recipients.

SUBJECTS AND METHODS

The effects of the serum ADPN level on arterial calcification were examined in 51 Japanese renal allograft recipients. Abdominal aorta calcification was evaluated on computed tomography using the aortic calcification area index (ACAI). The change in the ACAI and serum high-molecular-weight (HMW)-ADPN fractions were studied over an 8-year period. The arterial expression of ADPN, ADPN receptors (AdipoR)1 and 2, and T-cadherin (cadherin-13) were also examined by immunohistochemistry.

RESULTS

The change in the ACAI were grouped into quartiles and compared with the alterations in the serum levels of each ADPN fraction over an 8-year period. The change in the ACAI was much lower in the patients with highly elevated HMW-ADPN levels.Multiple regression analysis demonstrated that an advanced age at transplant and a history of cardiovascular complications were associated with an increased change in the ACAI, while higher HMW-ADPN concentrations were associated with improvements in the ACAI. Serum HDL-C level was also identified as a positive factor to increase serum HMW-ADPN level.In immunohistochemical examinations, ADPN was detected on CD31-positive arterial endothelial cells from renal allograft biopsy samples. ADPN co-localized with T-cadherin and AdipoR1, but only partially co-localized with AdipoR2.

CONCLUSION

Both HMW-ADPN and HDL-C might inhibit the progression of vascular calcification by promoting ADPN binding to vascular endothelial cells via T-cadherin and AdipoR in Japanese renal allograft recipients.