BackgroundProlonged exposure to HIV and anti-retroviral therapy (ART) has been linked with endothelial cell activation which subsequently predisposes people living with HIV (PLWH) to cardiovascular diseases. Serum biomarkers of endothelial cell activation such as E-Selectin and endothelial cell-specific molecule-1 (ESM-1) could aid in early detection of PLWH at a risk of cardiovascular diseases. However, there is a paucity of data on these biomarkers like E-selectin and endothelial cell-specific molecule-1 (ESM-1) among PLWH on long term ART (≥ 10 years) in Uganda. The aim of this study is to determine the serum levels of these biomarkers in this population.MethodsThis was a cross-sectional study where we randomly sampled 73 stored serum samples of PLWH who were enrolled in the Infectious Diseases Institute (IDI) ART long term (ALT cohort). We measured serum levels of E-selectin and ESM-1 by ELISA. Data was summarized using median and interquartile range. Inferential statistics were performed to determine predictors of elevated levels of E-selectin.ResultsOf the 73 samples analyzed, 38 (52.1%) were from female participants. The mean age was 54 ± 9.0 years. Twenty participants (27.4%) had a history of smoking while 52 (71.2%) had a history of alcohol intake. Twenty-five (34.3%) of the participants were overweight whereas 4 (5.6%) were obese. Fifty-four (74%) had an undetectable viral load (≤ 0 copies/ml) and the mean duration of ART at the time of sampling (2014/2015) was 10.4 ± 0.4 years. While serum levels of ESM-1 were not detectable in any of our samples, the median E-selectin levels was 147.6 μm/L ranging from 8.44 μm/L and 1,979.36 μm/L. Sixty-seven participants (91.8%) had elevated levels of E-selectin (> 39 μm/L). CD4 count > 500 cells/µl compared to lower counts was a predictor of elevated levels of E-Selectin (adjusted Odd Ratio 12.5, 95% CI (1.03 — 149.95, p < 0.05).ConclusionsThe majority (91.8%) of PLWH on long term ART had elevated levels of E-selectin. Having high CD4 count (> 500 cells/µl) was predictive of elevated levels of E-Selectin. Future work should longitudinally assess the trend of levels of E-selectin and ESM-1 while assessing for cardiovascular diseases endpoint.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12981-023-00519-x.