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Jander, V.
Effects of maximal cardiopulmonary exercise (CPX) testing on micro- and macrovasculature in people with type 1 diabetes
Humanmedizin; [ Diplomarbeit ] Medizinische Universität Graz; 2022. pp. 66
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- Authors Med Uni Graz:
- Advisor:
- Eckstein Max Lennart
- Moser Othmar
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- Abstract:
- Abstract Introduction For this thesis, we investigated the reaction of the micro- and macrovasculature in Type 1 Diabetes (T1D) to maximum cardiopulmonary exercise (mCPX) testing by representatively measuring asymmetric dimethylarginine (ADMA), pulse wave velocity (PWV), interleukin-6 (IL-6), N-terminal pro-B-type natriuretic peptide (NT-proBNP), central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE) and arteriolar-to-venular diameter ratio (AVR). Additionally, we aimed to analyse the effect of cardiorespiratory fitness (CRF) on microvascular and macrovascular alterations. This was achieved by analysing the correlation between the vasculature-markers and CRF of the study participants. Furthermore, diabetic disease characteristics (diabetes duration, C-peptide, total daily dose of insulin, HbA1C), mCPX-results (mean glucose and lactate concentrations during mCPX, duration of mCPX (tCPX) and VO2max) and subject characteristics (BMI, sex, age) were respectively grouped and subsequently compared to the vasculature-markers. Thereby we were able to gain a better understanding on how, and to what extent, these characteristics, that are all important in the clinical disease evaluation of people with T1D, influence vascular exercise responsiveness and health. Material and Methods Five female and five male physically active participants with T1D underwent a maximal incremental exercise test using a cycle ergometer. The individual fitness was depicted as VO2max [mL*kg-1*min-1], which was acquired from spirometric gas-exchange measurements. IL-6, NT-proBNP, ADMA, PWV, and retinal imaging were measured immediately before (T0), immediately after (T1) and 30 min (T2), 60 min (T3), and, if applicable, 24 h (T4) after the CPX testing. Before and during mCPX, the participants personal and diabetic disease characteristics were determined, and glucose and lactate concentrations were periodically measured. Results NT-proBNP (p = 0.010) and IL-6 (p = 0.023) both showed a significant increase while ADMA (p = 0.011) was significantly decreased following mCPX. There was no significant difference in PWV, AVR, CRAE and CRVE between T0 and the other timepoints. The linear regression analysis did not show a significant (p > 0.05) correlation between VO2max and any of the investigated vasculature parameters at the timepoints. However, there was a significant (p(two tailed) = 0.0092; r2=0.59) inverse correlation betweenVO2max and change of ADMA concentrations from T0 to T1. The grouped analysis of the parameters showed a significant difference (adjusted p-value = 0.020) between PWV of the group with detectable C-peptide and the group that had no detectable C-peptide secretion at T0 and a significant difference (adjusted p value = 0.030) between the NT-proBNP values of the C-peptide groups at T1 was found. The grouping by sex revealed a significantly (adjusted p-value = 0.00006) elevated IL-6 concentration in females at T0. The grouping by diabetes duration, TDD/kg, HbA1C, BMI and age did not show significant (p > 0.05) differences. AVR showed a significant correlation with tCPX (p = 0.032; r2 = 0.82) and with mean glucose concentrations at T3 (p = 0.047; r2 = 0.78). The other parameters did not correlate significantly (p > 0.05) with the duration of mCPX, mean glucose concentrations or mean lactate concentrations at any of the time points. Conclusion The results show a clear beneficial effect of mCPX on IL-6, NT-proBNP and ADMA, while underlining the ambiguous effects of CPX in T1D. PWV and retinal vessel calibres were, differently than results in healthy subjects, not significantly influenced by mCPX. The change of most of the parameters was not associated with CRF, implying that people with T1D benefit from CPX independently of their exercise capacity. We found a positive correlation between VO2max and change in ADMA concentration between pre- to post mCPX showing that individuals with T1D can exercise induced