The role of growth factors on renal tubular cells submitted to hypoxia and deprived of glucose

Background. in acute renal failure (ARF) renal tubular cell death and detachment can be induced by necrotic and apoptotic mechanisms. Several studies have demonstrated some benefits of the use of growth factors in experimental models of ARF. Methods. MDCK cells were cultured in a glucose-free medium for 24 h and were submitted to hypoxia (pO(2) around 35 mmHg) for additional 24 h. To evaluate the possible protective role of growth factors, EGF, IGF-I or HGF were added to the medium (20 ng mL). LDH release, viability (acridine orange and ethidium bromide dyes) and quantification of apoptotic cells (Hoechst 33342 dye fluorescence) were determined. Results. in the injury group, an increase on LDH release (60% vs. 3%) and on number of apoptotic cells (22% vs. 0.2%) which was associated with a reduced cell viability (61% vs. 94%) when compared with controls. Only HGF, not EGF or IGF-I, was able to protect cells from injury. HGF caused a significant reduction on LDH release (30%) and on number of apoptotic cells (5%), with an increase on viability cellular (79%). Conclusions. HGF decreases cell death on MDCK cells after hypoxic-induced injury, probably acting in both necrotic and apoptotic mechanisms.Universidade Federal de São Paulo, Div Nephrol, Escola Paulista Med, São Paulo, BrazilUniversidade Federal de São Paulo, Div Nephrol, Escola Paulista Med, São Paulo, BrazilWeb of Scienc

Utility of circulating tumor DNA in cancer diagnostics with emphasis on early detection

Abstract Various recent studies have focused on analyzing tumor genetic material released into the blood stream, known as circulating tumor DNA (ctDNA). Herein, we describe current research on the application of ctDNA to cancer management, including prognosis determination, monitoring for treatment efficacy/relapse, treatment selection, and quantification of tumor size and disease burden. Specifically, we examine the utility of ctDNA for early cancer diagnostics focusing on the development of a blood test to detect cancer in asymptomatic individuals by sequencing and analyzing mutations in ctDNA. Next, we discuss the prospect of using ctDNA to test for cancer, and present our calculations based on previously published empirical findings in cancer and prenatal diagnostics. We show that very early stage (asymptomatic) tumors are not likely to release enough ctDNA to be detectable in a typical blood draw of 10 mL. Data are also presented showing that mutations in circulating free DNA can be found in healthy individuals and will likely be very difficult to distinguish from those associated with cancer. We conclude that the ctDNA test, in addition to its high cost and complexity, will likely suffer from the same issues of low sensitivity and specificity as traditional biomarkers when applied to population screening and early (asymptomatic) cancer diagnosis