A dose-response study of aerobic training for oxygen uptake, oxidative stress and cardiac autonomic function in type 2 diabetes mellitus: study protocol for a randomized controlled trial

Correlation between impaired hemodynamic response and cardiopulmonary fitness in middle-aged type 2 diabetes mellitus patients: a case-control study

PURPOSE

Impaired cardiorespiratory fitness (CRF) is a predictor of mortality in patients with type 2 diabetes mellitus (T2DM). It is still not known how the exercise hemodynamic response correlates with CRF. The purpose was to assess the correlation between hemodynamic changes and CRF in middle-aged patients with T2DM.

METHODS

After 1:1 matching by age and sex, 139 T2DM patients and 139 non-T2DM controls who completed the exercise treadmill test were included. Maximal aerobic capacity (VO_2max), exercise-induced changes in heart rate (ΔHR), systolic blood pressure (ΔSBP), diastolic blood pressure (ΔDBP), and rate-pressure product (ΔRPP) were measured. HRR₁ was calculated as the maximum heart rate minus the heart rate after 1 min of rest.

RESULTS

Compared to the control population, T2DM patients had decreased ΔHR (87 (77, 97) v 93 (84, 104) bpm, p < 0.05), ΔRPP (3833.64 ± 1670.34 v 4381.16 ± 1587.78 bpm∙mmHg, p < 0.05), HRR₁ (21 (14, 27) v 21 (17, 27) bpm, p < 0.05), and VO_2max (32.76 ± 5.63 v 34.68 ± 5.70 ml/kg/min, p < 0.05). Multiple linear regression analysis showed that ΔHR and HRR₁, yielded a positive correlation with VO_2max in T2DM patients (β = 0.325, P < 0.001; β = 0.173, P = 0.01).

CONCLUSION

The presence of impaired hemodynamic response and VO_2max in middle-aged T2DM patients and the association of impaired ΔHR, HRR₁, and VO_2max may indicate a physiological pathway of impaired CRF, and our results support the need for cardiorespiratory screening and individualized treatment of middle-aged T2DM patients.

Identification of Antidiabetic Metabolites from Paederia foetida L. Twigs by Gas Chromatography-Mass Spectrometry-Based Metabolomics and Molecular Docking Study

Paederia foetida L. (Rubiaceae) is a climber which is widely distributed in Asian countries including Malaysia. The plant is traditionally used to treat various diseases including diabetes. This study is to evaluate the enzymatic inhibition activity of Paederia foetida twigs extracts and to identify the metabolites responsible for the bioactivity by gas chromatography-mass spectrometry (GC-MS) metabolomics profiling. Three different twig extracts, namely, hexane (PFH), chloroform (PFC), and methanol (PFM), were submerged for their α-amylase and α-glucosidase inhibition potential in 5 replicates for each. Results obtained from the loading column scatter plot of orthogonal partial least square (OPLS) model revealed the presence of 12 bioactive compounds, namely, dl-α-tocopherol, n-hexadecanoic acid, 2-hexyl-1-decanol, stigmastanol, 2-nonadecanone, cholest-8(14)-en-3-ol, 4,4-dimethyl-, (3β,5α)-, stigmast-4-en-3-one, stigmasterol, 1-ethyl-1-tetradecyloxy-1-silacyclohexane, ɣ-sitosterol, stigmast-7-en-3-ol, (3β,5α,24S)-, and α-monostearin. In silico molecular docking was carried out using the crystal structure α-amylase (PDB ID: 4W93) and α-glucosidase (PDB ID: 3WY1). α-Amylase-n-hexadecanoic acid exhibited the lowest binding energy of -2.28 kcal/mol with two hydrogen bonds residue, namely, LYS178 and TYR174, along with hydrophobic interactions involving PRO140, TRP134, SER132, ASP135, and LYS172. The binding interactions of α-glucosidase-n-hexadecanoic acid complex ligand also showed the lowest binding energy among 5 major compounds with the energy value of -4.04 kcal/mol. The complex consists of one hydrogen bond interacting residue, ARG437, and hydrophobic interactions with ALA444, ASP141, GLN438, GLU432, GLY374, LEU373, LEU433, LYS352, PRO347, THR445, HIS348, and PRO351. The study provides informative data on the potential antidiabetic inhibitors identified in Paederia foetida twigs, indicating the plant has the therapeutic effect properties to manage diabetes.

Effect of glycemic control and disease duration on cardiac autonomic function and oxidative stress in type 2 diabetes mellitus

Purpose

Cardiac autonomic neuropathy (CAN) is a commonly overlooked complication of type 2 diabetes mellitus (T2DM), with a complex pathogenesis involving hyperglycemia-induced oxidative stress which results in neuronal ischemia and cellular death. The level of hyperglycemia as well as disease duration might be significant determinants of the prognosis of T2DM, but limited studies have explored their relationship with these diabetic complications. Therefore, the purpose of this study was to examine the effect of glycemic control and disease duration on cardiac autonomic function and oxidative stress in patients with T2DM.

Methods

60 T2DM patients along with 63 healthy controls were recruited for the study. Diabetic patients were further classified based on glycemic control (HbA1c levels <8% vs. ≥8%) and disease duration (<5 vs. 5-10 vs. >10 years). All participants were assessed for cardiac autonomic function (HRR: heart rate recovery; HRV: heart rate variability), levels of antioxidant enzymes (CAT: catalase; SOD: superoxide dismutase), serum nitric oxide (NO) and other cardiometabolic risk factors (resting blood pressure, glycemic and lipid profile).

Results

T2DM patients showed a significant reduction in HRR, HRV, CAT, SOD and an increase in LFnu, LF: HF ratio and NO. These impairments were significantly greater for the group with poor glycemic control (p < 0.05). However, no difference for these parameters was observed with respect to different disease durations.

Conclusion

Cardiac autonomic regulation and endogenous antioxidant defense were compromised and levels of nitric oxide found to be raised in patients with Type 2 diabetes. These findings were more pronounced in subjects with poor glycemic control.