The Effect Tenofovir Disoproxil Fumarate (TDF) and Tenofovir Alafenamide (TAF) on Small Intestine Gut Wall

Several studies among people living with HIV (PLWH) have shown more weight gain with tenofovir alafenamide (TAF) than with tenofovir disoproxil fumarate (TDF). This difference could be due to weight increasing effect of TAF and / or weight decreasing effect of TDF. When TDF is ingested, it gets absorbed in the beginning of the small intestine. TDF is processed into free tenofovir (TFV) within the enterocytes, whereas TAF is not. The effect of TFV on enterocytes is not known, but in kidney tubular cells TFV seems to damage mitochondria and that seems lead to TDF-associated kidney toxicity. In the present cross sectional study the investigators hypothesize that TDF but not TAF causes damage in the small intestine gut wall and that may lead to poorer absorption of nutrients and opposing effects on body weigh. Twelve stable PLWH who have been treated with TDF for at least past 6 months and 12 PLWH who have similarly been treated with TAF for at least past 6 months will be recruited. The participants will have a gastroscopy done with biopsies taken from the small intestine. These biopsies will be examined for mitochondrial damage and other potential pathological findings. In addition, blood concentrations of several nutrients absorbed from the same part of the small intestine as TDF and blood concentrations of some markers of intestinal damage will be measured.