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) (p(over 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.