Hydroxyproline in Urine Microvesicles as a Biomarker of Fibrosis in the Renal Transplant Patient
María José Torres Sánchez,
María Carmen Ruiz Fuentes,
Elena Clavero García,
Noelia Rísquez Chica,
Karla Espinoza Muñoz,
María José Espigares Huete,
Mercedes Caba Molina,
Antonio Osuna,
Rosemary Wangensteen
Affiliations
María José Torres Sánchez
Nephrology Department, Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria, Ibs Granada, University of Granada, 18071 Granada, Spain
María Carmen Ruiz Fuentes
Nephrology Department, Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria, Ibs Granada, University of Granada, 18071 Granada, Spain
Elena Clavero García
Nephrology Department, Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria, Ibs Granada, University of Granada, 18071 Granada, Spain
Noelia Rísquez Chica
Nephrology Department, Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria, Ibs Granada, University of Granada, 18071 Granada, Spain
Karla Espinoza Muñoz
Nephrology Department, Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria, Ibs Granada, University of Granada, 18071 Granada, Spain
María José Espigares Huete
Nephrology Department, Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria, Ibs Granada, University of Granada, 18071 Granada, Spain
Mercedes Caba Molina
Department of Pathological Anatomy, Provincial Unit of Pathological Anatomy of Granada (UPIGAP), Instituto de Investigación Biosanitaria, Ibs Granada, University of Granada, 18071 Granada, Spain
Antonio Osuna
Department of Medicine, University of Granada, 18071 Granada, Spain
Rosemary Wangensteen
Area of Physiology, Department of Health Sciencies, University of Jaen, 23071 Jaen, Spain
Background/Objectives: Interstitial fibrosis/tubular atrophy in kidney transplantation is an unspecific lesion induced by immune and non-immune factors, which determines the progression of chronic kidney disease. Hydroxyproline is an imino acid that is part of the molecule of collagen. The aim of this study was to assess hydroxyproline in urine microvesicles as a marker of fibrosis in the renal transplant patient. Patients and Methods: An observational cross-sectional study was conducted on 46 renal transplant patients who had undergone renal biopsy with diagnostic intention, as well as 19 healthy controls. Clinical, histological, and laboratory variables were collected at the time of marker determination and renal function was analyzed 2 years later. Hydroxyproline was measured in urine microvesicles. Results: Renal transplant patients showed a higher microvesicular concentration of hydroxyproline compared to the control group, with the following medians (interquartile range (IQR)): 28.024 (5.53) ng/mL vs. 2.51 (1.16) ng/mL, p p = 0.034). No significant correlation was observed between urinary markers and serum creatinine, calcium, and parathyroid hormone (PTH). Conclusions: The concentration of hydroxyproline in urinary microvesicles increased in renal transplant patients relative to healthy controls. Hydroxyproline in urinary microvesicles is a marker of chronic renal inflammation in transplanted patients, and further studies are required to confirm this finding in other pathologies, as well as the association with fibrosis and the evolution of renal function.
