Evaluation of markers of renal proximal tubular injury and glomerular filtration rate reduction incidence in patients with hepatitis B infection using Tenofovir

• Grant number: 12/04617-0
• Support Opportunities: Regular Research Grants
• Start date: June 01, 2012
• End date: May 31, 2014
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Elen Almeida Romão
• Grantee: Elen Almeida Romão
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Ana de Lourdes Candolo Martinelli ; Fernanda Fernandes Souza ; Márcio Dantas

Abstract

The hepatitis B virus infection is a public health problem. Treatment-naïve individuals with HBeAg reagents and not cirrhotic are indicated to use Tenovovir (TDF) as the first choice. Acute kidney injury and insipidus diabetes have already been reported as consequence of Tenofovir use. In addition, there are descriptions of renal proximal tubular (RPT) injury with characteristics similar to Fanconi Syndrome. The renal tubular injury is characterized by glycosuria, loss of filtered bicarbonate, phosphaturia, uricosuria and loss of low molecular weight protein. Slow glomerular filtration rate reduction due to TDF use has already been reported. The period of drug use for the damage to occur is not well known. The most studies to investigate TDF nephrotoxicity were performed with HIV infected patients. It is speculated that nephrotoxicity may be exacerbated by the use of other medications, currently used by HIV infected patients, which compete with the tubular transport or TDF metabolism increasing its serum level. The aim of this study is to evaluate the RPT injury and glomerular filtration rate reduction incidence due to TDF use. 25 Hepatitis B infected patients that are going to initiate TDF use and 10 patients that will not use the drug will be monitored. Blood and urine samples will be taken before patients begin the TDF use and, after that, biannually during 2 years. At the end of follow-up the RPT injury and glomerular filtration rate reduction incidence due to TDF will be evaluated through the following dosages: glucose, phosphorus, blood gases, chloride, creatinine and serum cystatin C, microalbuminuria, proteinuria, low molecular weight proteinuria (NGAL), creatinine clearance, phosphaturia, uricosuria, glycosuria and urine routine. (AU)