Peripheral Oxygen Extraction and Exercise Limitation in Asymptomatic Patients with Diabetes Mellitus

Glucagon-Like Peptide-1 Receptor Agonists and Sodium Glucose Cotransporter-2 Inhibitors and Cardiorespiratory Fitness Interaction

INTRODUCTION

Cardiorespiratory fitness (CRF) is a stronger predictor of mortality than traditional risk factors and is a neglected vital sign of health. Enhanced fitness is a cornerstone in diabetes management and is most often delivered concurrently with pharmacological agents, which can have an opposing impact, as has been reported with metformin. Considering the rapid evolution of diabetes medications with improved cardiovascular outcomes, such as glucagon-like peptide-1 receptor agonists and sodium glucose cotransporter-2 inhibitors, it is of importance to consider the influence of these vis-a-vis effects on CRF.

MATERIALS AND METHODS

Combining the words glucagon-like peptide-1 receptor agonists and sodium glucose cotransporter-2 inhibitors with cardiorespiratory fitness, an online search was done using PubMed, Embase, Scopus, Web of Science, Scientific Electronic Library Online, and Cochrane.

RESULTS

There were only a few randomized controlled studies that included CRF, and the results were mostly neutral. A handful of smaller studies detected improved CRF using sodium glucose cotransporter-2 inhibitors in patients with congestive heart failure.

CONCLUSIONS

Since CRF is a superior prognosticator for cardiovascular outcomes and both medications can cause lean muscle mass loss, the current review highlights the paucity of relevant interactive analysis.

Development of a Physiologically Based Pharmacokinetic Population Model for Diabetic Patients and its Application to Understand Disease-drug-drug Interactions

INTRODUCTION

The activity changes of cytochrome P450 (CYP450) enzymes, along with the complicated medication scenarios in diabetes mellitus (DM) patients, result in the unanticipated pharmacokinetics (PK), pharmacodynamics (PD), and drug-drug interactions (DDIs). Physiologically based pharmacokinetic (PBPK) modeling has been a useful tool for assessing the influence of disease status on CYP enzymes and the resulting DDIs. This work aims to develop a novel diabetic PBPK population model to facilitate the prediction of PK and DDI in DM patients.

METHODS

First, mathematical functions were constructed to describe the demographic and non-CYP physiological characteristics specific to DM, which were then incorporated into the PBPK model to quantify the net changes in CYP enzyme activities by comparing the PK of CYP probe drugs in DM versus non-DM subjects.

RESULTS

The results show that the enzyme activity is reduced by 32.3% for CYP3A4/5, 39.1% for CYP2C19, and 27% for CYP2B6, while CYP2C9 activity is enhanced by 38% under DM condition. Finally, the diabetic PBPK model was developed through integrating the DM-specific CYP activities and other parameters and was further used to perform PK simulations under 12 drug combination scenarios, among which 3 combinations were predicted to result in significant PK changes in DM, which may cause DDI risks in DM patients.

CONCLUSIONS

The PBPK modeling applied herein provides a quantitative tool to assess the impact of disease factors on relevant enzyme pathways and potential disease-drug-drug-interactions (DDDIs), which may be useful for dosing regimen optimization and minimizing the DDI risks associated with the treatment of DM.

A narrative review of exercise participation among adults with prediabetes or type 2 diabetes: barriers and solutions

Type 2 diabetes (T2D) has been rising in prevalence over the past few decades in the US and worldwide. T2D contributes to significant morbidity and premature mortality, primarily due to cardiovascular disease (CVD). Exercise is a major cornerstone of therapy for T2D as a result of its positive effects on glycemic control, blood pressure, weight loss and cardiovascular risk as well as other measures of health. However, studies show that a majority of people with T2D do not exercise regularly. The reasons given as to why exercise goals are not met are varied and include physiological, psychological, social, cultural and environmental barriers to exercise. One potential cause of inactivity in people with T2D is impaired cardiorespiratory fitness, even in the absence of clinically evident complications. The exercise impairment, although present in both sexes, is greater in women than men with T2D. Women with T2D also experience greater perceived exertion with exercise than their counterparts without diabetes. These physiological barriers are in addition to constructed societal barriers including cultural expectations of bearing the burden of childrearing for women and in some cultures, having limited access to exercise because of additional cultural expectations. People at risk for and with diabetes more commonly experience unfavorable social determinants of health (SDOH) than people without diabetes, represented by neighborhood deprivation. Neighborhood deprivation measures lack of resources in an area influencing socioeconomic status including many SDOH such as income, housing conditions, living environment, education and employment. Higher indices of neighborhood deprivation have been associated with increased risk of all-cause, cardiovascular and cancer related mortality. Unfavorable SDOH is also associated with obesity and lower levels of physical activity. Ideally regular physical activity should be incorporated into all communities as part of a productive and healthy lifestyle. One potential solution to improve access to physical activity is designing and building environments with increased walkability, greenspace and safe recreational areas. Other potential solutions include the use of continuous glucose monitors as real-time feedback tools aimed to increase motivation for physical activity, counseling aimed at improving self-efficacy towards exercise and even acquiring a dog to increase walking time. In this narrative review, we aim to examine some traditional and novel barriers to exercise, as well as present evidence on novel interventions or solutions to overcome barriers to increase exercise and physical activity in all people with prediabetes and T2D.

Progressive right ventricular dysfunction and exercise impairment in patients with heart failure and diabetes mellitus: insights from the T.O.S.CA. Registry

Background

Findings from the T.O.S.CA. Registry recently reported that patients with concomitant chronic heart failure (CHF) and impairment of insulin axis (either insulin resistance—IR or diabetes mellitus—T2D) display increased morbidity and mortality. However, little information is available on the relative impact of IR and T2D on cardiac structure and function, cardiopulmonary performance, and their longitudinal changes in CHF.

Methods

Patients enrolled in the T.O.S.CA. Registry performed echocardiography and cardiopulmonary exercise test at baseline and at a patient-average follow-up of 36 months. Patients were divided into three groups based on the degree of insulin impairment: euglycemic without IR (EU), euglycemic with IR (IR), and T2D.

Results

Compared with EU and IR, T2D was associated with increased filling pressures (E/e′ratio: 15.9 ± 8.9, 12.0 ± 6.5, and 14.5 ± 8.1 respectively, p < 0.01) and worse right ventricular(RV)-arterial uncoupling (RVAUC) (TAPSE/PASP ratio 0.52 ± 0.2, 0.6 ± 0.3, and 0.6 ± 0.3 in T2D, EU and IR, respectively, p < 0.05). Likewise, impairment in peak oxygen consumption (peak VO₂) in TD2 vs EU and IR patients was recorded (respectively, 15.8 ± 3.8 ml/Kg/min, 18.4 ± 4.3 ml/Kg/min and 16.5 ± 4.3 ml/Kg/min, p < 0.003). Longitudinal data demonstrated higher deterioration of RVAUC, RV dimension, and peak VO₂ in the T2D group (+ 13% increase in RV dimension, − 21% decline in TAPSE/PAPS ratio and − 20% decrease in peak VO₂).

Conclusion

The higher risk of death and CV hospitalizations exhibited by HF-T2D patients in the T.O.S.CA. Registry is associated with progressive RV ventricular dysfunction and exercise impairment when compared to euglycemic CHF patients, supporting the pivotal importance of hyperglycaemia and right chambers in HF prognosis.

Trial registration ClinicalTrials.gov identifier: NCT023358017

Impact of diabetes on cardiopulmonary function: the added value of a combined cardiopulmonary and echocardiography stress test

Type 2 diabetes mellitus (T2DM) represents a major health issue worldwide, as patients with T2DM show an excess risk of death for cardiovascular causes, twice as high as the general population. Among the many complications of T2DM, heart failure (HF) deserves special consideration as one of the leading causes of morbidity and reduced life expectancy. T2DM has been associated with different phenotypes of HF, including HF with reduced and preserved ejection fraction. Cardiopulmonary exercise testing (CPET) can evaluate the metabolic and ventilatory alterations related to myocardial dysfunction and/or peripheral impairment, representing a unique tool for the clinician to study the whole HF spectrum. While CPET allows for a thorough evaluation of functional capacity, it cannot directly differentiate central and peripheral determinants of effort intolerance. Combining CPET with imaging techniques could provide even higher accuracy and further insights into the progression of the disease since signs of left ventricular systolic and diastolic dysfunction can be detected during exercise, even in asymptomatic diabetic individuals. This review aims to dissect the alterations in cardiopulmonary function characterising patients with T2DM and HF to improve patient risk stratification.

Mechanisms of reduced peak oxygen consumption in subjects with uncomplicated type 2 diabetes

Background

Type 2 diabetes mellitus (T2D) increases the risk of incident heart failure (HF), whose earliest fingerprint is effort intolerance (i.e. impaired peak oxygen consumption, or VO_2peak). In the uncomplicated T2D population, however, the prevalence of effort intolerance and the underpinning mechanistic bases are uncertain. Leveraging the multiparametric characterization allowed by imaging-cardiopulmonary exercise testing (iCPET), the aim of this study is to quantify effort intolerance in T2D and to dissect the associated cardiopulmonary alterations.

Methods

Eighty-eight adults with well-controlled and uncomplicated T2D and no criteria for HF underwent a maximal iCPET with speckle tracking echocardiography, vascular and endothelial function assessment, as well as a comprehensive biohumoral characterization. Effort intolerance was defined by a VO_2peak below 80% of maximal predicted oxygen uptake.

Results

Forty-eight patients (55%) had effort intolerance reaching a lower VO_2peak than T2D controls (16.5 ± 3.2 mL/min/kg, vs 21.7 ± 5.4 mL/min/kg, p < 0.0001). Despite a comparable cardiac output, patients with effort intolerance showed reduced peak peripheral oxygen extraction (11.3 ± 3.1 vs 12.7 ± 3.3 mL/dL, p = 0.002), lower VO₂/work slope (9.9 ± 1.2 vs 11.2 ± 1.4, p < 0.0001), impaired left ventricle systolic reserve (peak S’ 13.5 ± 2.8 vs 15.2 ± 3.0, p = 0.009) and global longitudinal strain (peak-rest ΔGLS 1.7 ± 1.5 vs 2.5 ± 1.8, p = 0.03) than subjects with VO_2peak above 80%. Diastolic function, vascular resistance, endothelial function, biohumoral exams, right heart and pulmonary function indices did not differ between the two groups.

Conclusions

Effort intolerance and reduced VO_2peak is a severe and highly prevalent condition in uncomplicated, otherwise asymptomatic T2D. It results from a major defect in skeletal muscle oxygen extraction coupled with a subtle myocardial systolic dysfunction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01314-6.