Gut related inflammation and cardiorespiratory fitness in patients with CAD and type 2 diabetes: a sub-study of a randomized controlled trial on exercise training

AIM: Gut leakage has been shown to associate with low-grade inflammation and lower cardiorespiratory fitness in diabetic subjects. We aimed to investigate whether gut leakage markers related to cardiorespiratory fitness in patients with both coronary artery disease and type 2 diabetes, and whether these were affected by long-term exercise training. METHODS: Patients with angiographically verified coronary artery disease and type 2 diabetes mellitus (n = 137) were randomized to either 12 months exercise intervention or conventional follow-up. A cardiopulmonary exercise test and fasting blood samples were obtained before and after intervention to assess VO(2)peak and the biomarkers soluble CD14, lipopolysaccharide-binding protein and intestinal fatty-acid binding protein as markers of gut leakage. RESULTS: 114 patients completed the intervention satisfactory. VO(2)peak correlated inversely to sCD14 (r = − 0.248, p = 0.004) at baseline. Dividing sCD14 into quartiles (Q), VO(2)peak was significantly higher in Q1 vs. Q2–4 (p = 0.001), and patients in Q2-4 (sCD14 > 1300 ng/mL) had an OR of 2.9 (95% CI 1.2–7.0) of having VO(2)peak below median (< 23.8 ml/kg/min) at baseline. There were no statistically significant differences in changes in gut leakage markers between the two randomized groups (all p > 0.05) after 12 months. CONCLUSIONS: Cardiorespiratory fitness related inversely to sCD14, suggesting physical capacity to be associated with gut leakage in patients with CAD and T2DM. Long-term exercise training did not affect circulating gut leakage markers in our population. Trial registration NCT01232608, Registered 02 November 2010—Retrospectively registered at https://clinicaltrials.gov/ct2/show/NCT01232608?term=NCT01232608&draw=2&rank=1 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13098-021-00655-2.