Plasma adiponectin concentration and insulin resistance: role of successful kidney transplantation

Effects of a Structured Physical Activity Program on Serum Adipokines and Markers of Inflammation and Volume Overload in Kidney Transplant Recipients

BACKGROUND Kidney transplantation (KTx) reverses most abnormalities related to chronic kidney disease (CKD), but sedentary lifestyle persists in most kidney graft recipients. Physical inactivity has been associated with altered adipokine profile and inflammation in CKD. We postulated that increased physical activity achieved through an individually-tailored program can reverse these changes. MATERIAL AND METHODS We included 25 clinically stable KTx recipients at least 12 months after transplantation and with eGFR >30 mL/min and 15 age-matched non-dialysis patients with CKD stage 3. Body composition, pattern of daily physical activity, and serum concentrations of leptin, adiponectin, NT-proBNP, and hsCRP were assessed at baseline. All patients in both groups participated in a 12-week supervised exercise program with short cell phone text reminders. All measurements were repeated after 3 months. RESULTS Active energy expenditure increased significantly during the 3 months in both the KTx and CKD patients, compared with baseline by 47% (p<0.001) and 20% (p=0.01), respectively. Time spent daily on physical activity was also increased (129±83 vs. 194±142 and 81±56 vs. 124±57 min, respectively, p<0.001). Adipose tissue mass decreased significantly in the KTx group (from 40.8±11 to 38.5±10.3 kg, p=0.01). Serum leptin decreased significantly in both KTx and CKD patients (from 11.5±7.0 to 10.0±5.6, p=0.03 and from 14.1±8.3 to 12.2±6.1 ng/mL, p=0.01, respectively). Serum adiponectin increased only in the KTx group (from 1900±953 to 2015±1133 ng/L, p=0.004). Serum CRP decreased in both groups (from 15.1±5.2 to 14.0±5.6 mg/L, p=0.01 in the KTx group and from 16.5±3.9 to 15.4±4.3 mg/L in the CKD group p=0.05). NTpro-BNP was unchanged during the study. CONCLUSIONS Increased physical activity induces beneficial effects on adipokine profile and inflammation but does not seem to affect volume overload in kidney transplant recipients and CKD patients.

Adiponectin is valuable in the diagnosis of acute heart failure with renal insufficiency

Acute heart failure (AHF) is a major public health issue due to its high incidence and poor prognosis; thus, efficient and timely diagnosis is critical for improving the prognosis and lowering the mortality rate. Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is widely used in the diagnosis of AHF; however, its efficacy is controversial in diagnosing AHF with renal insufficiency. There were numerous studies reporting the association of adiponectin (ADPN) and heart diseases. Therefore, the present study aimed to investigate whether ADPN is helpful in identifying AHF with renal insufficiency. A total of 407 participants (218 AHF patients and 189 controls) were enrolled into the current study. The plasma levels of ADPN and NT-proBNP were measured using a sandwich enzyme-linked immunosorbent assay and an electrochemiluminescence immunoassay, respectively. In addition, these levels were compared among the various New York Health Association classes, as well as the ischemic and non-ischemic AHF cases. The correlation between the two biomarkers and the renal function was analyzed by Spearman's correlation, while the diagnostic efficiency of ADPN and NT-proBNP was evaluated in AHF patients with and without renal insufficiency. The results revealed that NT-proBNP exhibited a higher diagnostic efficiency as compared with ADPN in patients without renal insufficiency [area under the receiver operating characteristic curve (AUC), 0.905 vs. 0.775]. By contrast, the ADPN presented a better diagnostic value in comparison with NT-proBNP in AHF with renal insufficiency (AUC, 0.872 vs. 0.828). Therefore, a combination of these two biomarkers may provide an excellent efficacy in the diagnosis of AHF with renal insufficiency (AUC, 0.904; sensitivity, 71.2%; specificity, 98.3%). In conclusion, ADPN is a valuable biomarker for diagnosing AHF, particularly in patients with impaired renal function.

Progranulin serum levels in human kidney transplant recipients: A longitudinal study

BACKGROUND

The adipokine progranulin has metabolic proprieties, playing a role in obesity and insulin resistance. Its levels seems to be dependent of renal function, since higher progranulin concentration is observed in patients with end-stage kidney disease. However, the effect of kidney transplantation on progranulin remains unknown.

OBJECTIVE

To assess the serum progranulin levels in kidney transplant recipients before and after kidney transplantation.

METHODS

Forty-six prospective kidney transplant recipients were included in this longitudinal study. They were evaluated before transplantation and at three and twelve months after transplantation. Clinical, anthropometric and laboratorial measurements were assessed. Progranulin was determined with enzyme-linked immunosorbent assays.

RESULTS

Serum progranulin significantly decreased in the early period after transplantation (from 72.78 ± 2.86 ng/mL before transplantation to 40.65 ± 1.49 ng/mL at three months; p<0.01) and increased at one year (53.15 ± 2.55 ng/mL; p<0.01 vs. three months), remaining significantly lower than before transplantation (p<0.01) (pover time<0.01). At one year after transplantation, there was a significant increase in body mass index, trunk fat and waist circumference compared to immediate period after transplantation. Progranulin was associated with waist circumference and fasting plasma glucose after adjusted for age, gender, study period, glomerular filtration rate, interleukin-6, high sensitivity C reactive protein and adiponectin.

CONCLUSION

Progranulin serum levels are increased before transplantation and a reduction is observed in the early period after transplantation, possibly attributed to an improvement in renal function. At one year after transplantation, an increment in progranulin is observed, seems to be independent of glomerular filtration, and remained significantly lower than before transplantation.

Effect of Transplant on Platelet Function Markers (P-Selectin and Platelet Aggregation) and Adiponectin in Renal Transplant Patients

OBJECTIVES

In chronic kidney disease, both bleeding and thrombotic complications are observed, although with expected recovery after a successful transplant. Adiponectin has protective properties with respect to atherogenesis and inflammation. Plasma adiponectin levels are markedly elevated among patients with end-stage renal disease and are lower after kidney transplant. However, this topic is still debated in the literature. Here, we evaluated the effect of transplant on platelet function markers (P-selectin and platelet aggregation) and adiponectin in renal transplant patients.

MATERIALS AND METHODS

Our study included 14 renal transplant patients. Preoperative and week 1, month 1, month 6, year 1, and year 2 samples after transplant were studied. In addition to plasma adiponectin, P-selectin levels, and platelet aggregation tests, biochemical tests and coagulation parameters were also studied.

RESULTS

We observed a significant decrease in adiponectin levels 2 years after transplant. Platelet function tests with ADP and collagen were significantly improved, and no changes in P-selectin, ristocetin, and epinephrine levels were observed.

CONCLUSIONS

According to our findings, glomerular filtration rate has an important effect on platelet function, but adiponectin levels became normal only in the second year after transplant. Late improvement of low-density lipoprotein cholesterol and adiponectin after transplant suggested to us that patients with kidney transplant may still have risk of cardiovascular events, especially in the first years.

Adipocytokines in renal transplant recipients

In the last two decades, perceptions about the role of body fat have changed. Adipocytes modulate endocrine and immune homeostasis by synthesizing hundreds of hormones, known as adipocytokines. Many studies have been investigating the influences and effects of these adipocytokines and suggest that they are modulated by the nutritional and immunologic milieu. Kidney transplant recipients (KTRs) are a unique and relevant population in which the function of adipocytokines can be examined, given their altered nutritional and immune status and subsequent dysregulation of adipocytokine metabolism. In this review, we summarize the recent findings about four specific adipocytokines and their respective roles in KTRs. We decided to evaluate the most widely described adipocytokines, including leptin, adiponectin, visfatin and resistin. Increasing evidence suggests that these adipocytokines may lead to cardiovascular events and metabolic changes in the general population and may also increase mortality and graft loss rate in KTRs. In addition, we present findings on the interrelationship between serum adipocytokine levels and nutritional and immunologic status, and mechanisms by which adipocytokines modulate morbidity and outcomes in KTRs.

Plasma adiponectin before and after kidney transplantation

The role of plasma adiponectin (ADPN) in patients with impaired kidney function and following kidney transplantation (Tx) is debated. We aimed to: (i) determine whether pretransplant ADPN level is an independent risk factor for deterioration of glucose tolerance including development of new-onset diabetes mellitus after Tx, (ii) describe which parameters that influence the ADPN concentration before and after Tx. Fifty-seven nondiabetic kidney allograft recipients and 40 nondiabetic uraemic patients were included. The Tx group was examined at baseline and 3 and 12 months after Tx. The uraemic control group was examined twice, separated by 12 months. ADPN levels declined significantly following Tx (P < 0.0001), while estimated glomerular filtration rate (eGFR) increased (P < 0.0005). eGFR, BMI and insulin sensitivity index were independently associated with ADPN in a multivariate regression analysis, whereas an ordinal logistic regression analysis revealed no predictive characteristic of ADPN for aggravation of the glucose tolerance after Tx. In conclusion, kidney transplantation is accompanied by a significant reduction in ADPN concentration. Several factors determine the ADPN concentration before and after Tx including kidney function, insulin resistance, use of immunosuppressive agents and BMI. Pretransplant ADPN level did not predict development of new-onset diabetes mellitus or even deterioration of the glucose tolerance following Tx.