Identification of predictive factors interacting with heart rate reduction for potential beneficial clinical outcomes in chronic heart failure: A systematic literature review and meta-analysis

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We used Bayesian statistics to illustrate factors that affect HR reduction therapy.

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HR-reducing therapy was associated with significant reductions in risk.

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Presence of comorbid T2DM significantly affected mortality risk.

Background

There is an absence of clinical evidence on what factors modify the effect of heart rate (HR)-reducing treatment on mortality and morbidity in symptomatic heart failure patients with reduced ejection fraction (HFrEF). We performed a Bayesian meta-analysis and meta-regression to identify predictive factors that interact with HR-reducing therapy.

Methods

A systematic review was performed to identify randomized placebo-controlled trials that enrolled symptomatic HFrEF patients. The primary objective was to evaluate how different predictive factors modify the efficacy of HR-reducing therapy on clinical outcomes. Secondary objectives included the evaluation of subgroups stratified by a HR reduction threshold of 10 bpm.

Results

Data from 20 studies were synthesized and HR-reducing therapy was responsible for 16.7 %, 16.4 %, and 21.1 % risk reductions in all-cause mortality, cardiovascular (CV)-related mortality, and rehospitalization due to worsening HF (WHF), respectively. Empirical Bayes meta-regression showed that type 2 diabetes mellitus (T2DM) significantly modified the efficacy of HR-reducing therapy on all-cause mortality (slope = 0.012 in log risk ratio (RR) per 1 %-unit [95 % credible interval (CrI) 0.004, 0.021]) and CV-related mortality (0.01 in log RR per 1 %-unit [95 % CrI 0.0003, 0.0200]). There were insufficient studies to perform a meta-regression when stratifying by a HR reduction threshold of 10 bpm; however, when including all studies, we observed a significant effect modification for rehospitalization due to WHF (p = 0.004).

Conclusions

This meta-analysis focused on the central tenet of HR-reducing therapy and revealed that T2DM is a predictor of HR-reducing treatment effect on all-cause mortality and CV-related mortality in HFrEF patients.

Impaired glucose regulation, SARS-CoV-2 infections and adverse COVID-19 outcomes

Impaired glucose regulation (IGR) is common world-wide, and is correlated with Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) the virus that causes Coronavirus disease 2019 (COVID-19). However, no systematic reviews are available on the topic, and little is known about the strength of the evidence underlying published associations. The current systematic review identified consistent, reproducible associations but several limitations were observed including: (1) a consistent lack of robust confounder adjustment for risk factors collected prior to infection; (2) lack of data on insulin resistance or glycemia measures [Hemoglobin A1c (HbA1c) or glucose]; (3) few studies considering insulin resistance, glucose or HbA1c values in the clinically normal range as a predictor of SARS-CoV-2 risk; (4) few studies assessed the role of IGR as a risk factor for infection among initially uninfected samples; (5) a paucity of population-based data considering SARS-CoV-2 as a risk factor for the onset of IGR. While diabetes status is a clear predictor of poor prognosis following a SARS-CoV-2 infection, causal conclusions are limited. It is uncertain whether interventions targeting dysglycemia to improve SARS-CoV-2 outcomes have potential to be effective, or if risk assessment should include biomarkers of diabetes risk (ie, insulin and glucose or HbA1c) among diabetes-free individuals. Future studies with robust risk factor data collection, among population-based samples with pre-pandemic assessments will be important to inform these questions.

A comprehensive guide to the pharmacologic regulation of angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 entry receptor

The recent emergence of coronavirus disease-2019 (COVID-19) as a global pandemic has prompted scientists to address an urgent need for defining mechanisms of disease pathology and treatment. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for COVID-19, employs angiotensin converting enzyme 2 (ACE2) as its primary target for cell surface attachment and likely entry into the host cell. Thus, understanding factors that may regulate the expression and function of ACE2 in the healthy and diseased body is critical for clinical intervention. Over 66% of all adults in the United States are currently using a prescription drug and while earlier findings have focused on possible upregulation of ACE2 expression through the use of renin angiotensin system (RAS) inhibitors, mounting evidence suggests that various other widely administered drugs used in the treatment of hypertension, heart failure, diabetes mellitus, hyperlipidemias, coagulation disorders, and pulmonary disease may also present a varied risk for COVID-19. Specifically, we summarize mechanisms on how heparin, statins, steroids and phytochemicals, besides their established therapeutic effects, may also interfere with SARS-CoV-2 viral entry into cells. We also describe evidence on the effect of several vitamins, phytochemicals, and naturally occurring compounds on ACE2 expression and activity in various tissues and disease models. This comprehensive review aims to provide a timely compendium on the potential impact of commonly prescribed drugs and pharmacologically active compounds on COVID-19 pathology and risk through regulation of ACE2 and RAS signaling.

Obesity and Outcomes in COVID-19: When an Epidemic and Pandemic Collide

Obesity has reached epidemic proportions in the United States and in much of the westernized world, contributing to considerable morbidity. Several of these obesity-related morbidities are associated with greater risk for death with coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 penetrates human cells through direct binding with angiotensin-converting enzyme 2 receptors on the cell surface. Angiotensin-converting enzyme 2 expression in adipose tissue is higher than that in lung tissue, which means that adipose tissue may be vulnerable to COVID-19 infection. Obese patients also have worse outcomes with COVID-19 infection, including respiratory failure, need for mechanical ventilation, and higher mortality. Clinicians need to be more aggressive when treating obese, especially severely obese, patients with COVID-19 infection.

Metabolic Targets in Nonalcoholic Fatty Liver Disease

The prevalence and diagnosis of nonalcoholic fatty liver disease (NAFLD) is on the rise worldwide and currently has no FDA-approved pharmacotherapy. The increase in disease burden of NAFLD and a more severe form of this progressive liver disease, nonalcoholic steatohepatitis (NASH), largely mirrors the increase in obesity and type 2 diabetes (T2D) and reflects the hepatic manifestation of an altered metabolic state. Indeed, metabolic syndrome, defined as a constellation of obesity, insulin resistance, hyperglycemia, dyslipidemia and hypertension, is the major risk factor predisposing the NAFLD and NASH. There are multiple potential pharmacologic strategies to rebalance aspects of disordered metabolism in NAFLD. These include therapies aimed at reducing hepatic steatosis by directly modulating lipid metabolism within the liver, inhibiting fructose metabolism, altering delivery of free fatty acids from the adipose to the liver by targeting insulin resistance and/or adipose metabolism, modulating glycemia, and altering pleiotropic metabolic pathways simultaneously. Emerging data from human genetics also supports a role for metabolic drivers in NAFLD and risk for progression to NASH. In this review, we highlight the prominent metabolic drivers of NAFLD pathogenesis and discuss the major metabolic targets of NASH pharmacotherapy.

Using a Cageside Device for Testing Glycosylated Hemoglobin in Cynomolgus Macaques (Macaca fascicularis)

Nonhuman primates naturally develop type 2 diabetes mellitus and exhibit clinical features that are similar to those observed in humans, including obesity, insulin resistance, dyslipidemia, and pancreatic pathology. The glycosylated hemoglobin (HbA1C) test is the primary test used for diabetes management in humans because it reflects the average blood glucose levels over the previous 3 mo. The HbA1C results are a better predictor of potential risk of complications than are single or episodic measures of glucose levels. HbA1C levels have proven useful for the diagnosis and monitoring of blood glucose levels in NHP, but for testing by a commercial laboratory, the test requires a vial of whole blood, results are not available for several days, and the test is expensive. The cageside device requires a single drop of blood, it displays the HbA1C percentage in 5 min, and the cost per sample is less than for sending it to a commercial lab. We therefore assessed the correlation between a cageside test using a handheld unit and the commercial lab test for measuring HbA1C in cynomolgus macaques. From both normal and confirmed diabetic animals, 4 mL blood was collected from a peripheral vessel and sent to a commercial lab for HbA1C testing. At the same time, a drop of capillary blood was collected and tested immediately in the HbA1C cageside test. A comparison of the results revealed significant correlation between the cageside and commercial lab tests. Therefore, we feel that the HbA1C test using handheld device may help to rule out nondiabetics and indicate which animals require additional testing.

Prophylactic effects of the glucagon-like Peptide-1 analog liraglutide on hyperglycemia in a rat model of type 2 diabetes mellitus associated with chronic pancreatitis and obesity

The objective of this study was to investigate the effects of liraglutide, an analog of human glucagon-like peptide 1 (GLP1), on WBN/Kob-Lepr(fa) (fa/fa) rats, which spontaneously develop type 2 diabetes mellitus with pancreatic disorder and obesity. Male fa/fa rats (age, 7 wk) were allocated into 4 groups and received liraglutide (37.5, 75, 150 μg/kg SC) or saline (control group) once daily for 4 wk. All rats in the control group became overweight and developed hyperglycemia as they aged. Although the rats given liraglutide showed a dose-dependent reduction in food intake, no significant effects on body weight or fat content occurred. In the liraglutide groups, the development of hyperglycemia was suppressed, even as plasma insulin concentrations increased in a dose-dependent manner. Intravenous glucose tolerance testing of the liraglutide-treated rats confirmed improvement of glucose tolerance and enhanced insulin secretion. Histologic examination revealed increased numbers of pancreatic β-cell type islet cells and increased proliferation of epithelial cells of the small ducts in the liraglutide-treated groups. Although our study did not reveal a significant decrease in obesity after liraglutide administration, the results suggest a marked antidiabetic effect characterized by increased insulin secretion in fa/fa rats with pancreatic disorders.

Obesity in rhesus and cynomolgus macaques: a comparative review of the condition and its implications for research

Obesity is an increasingly important health issue in both humans and animals and has been highly correlated as a risk factor for hyperglycemic conditions in humans. Naturally occurring obesity has been extensively studied in nonhuman primates with a focus on the development of biomarkers for characterizing overweight individuals and tracking the progression of obesity to conditions such as type 2 diabetes mellitus. Animal models have provided a basic understanding of metabolism and carbohydrate physiology, and continue to contribute to ongoing research of obesity and its adverse health effects. This review focuses on spontaneous obesity in rhesus and cynomolgus macaques as a model for human obesity and type 2 diabetes mellitus, including associated risk factors for the development of obesity and obesity-related health conditions. Little is known about preventive measures to minimize obesity while maintaining a healthy colony of macaques, and numerous complexities such as social status, feeding behaviors, timing of feeding, food distribution, and stress have been identified as contributing factors to overweight body condition in both single and group housed nonhuman primates. As in humans, increased body weight and obesity in macaques affect their overall health status. These conditions may interfere with the suitability of some animals in various studies unrelated to obesity.

Determination of hemoglobin A1c and fasting blood glucose reference intervals in captive chimpanzees (Pan troglodytes)

Type 2 diabetes mellitus (T2DM), reaching epidemic proportions in humans, has emerged as a disease in aging captive populations of adult chimpanzees; however, little information is available regarding T2DM in chimpanzees. Our goals were to: (1) distinguish between normal, healthy chimpanzees and those with early (prediabetes) or advanced diabetes; (2) establish and compare the fasting (16 h) blood glucose reference range for chimpanzees at our facility with published reference ranges; and (3) establish hemoglobin A1c (HbA1c) reference intervals for healthy, nondiabetic chimpanzees and define threshold values for prediabetes and diabetes. If reliable, our reference ranges for FBG and HbA1c could become clinical tools for screening animals at risk and for monitoring therapeutic progress. The overall incidence of T2DM in our colony of 260 chimpanzees is 0.8% but is increased to 3.7% in animals older than 30 y (geriatric). For our defined reference intervals, chimpanzees with FBG or HbA1c levels up to the 85th percentile (glucose, less than or equal to 105 mg/dL; HbA1c, less than or equal to 5.0%) were considered healthy; those whose values lay between the 86th and 95th percentiles (glucose, 106 to 119 mg/dL; HbA1c, 5.1% to 5.2%) were possibly prediabetic, and animals whose values exceeded the 95th percentile (glucose, greater than or equal to 120 mg/dL; HbA1c, greater than 5.3%) were identified as potentially having diabetes. We found that our FBG range was comparable to other published results, with a positive correlation between HbA1c and glucose. Furthermore, the negligible HbA1c response to acute stress or recent food consumption suggests that HbA1c is highly useful for evaluating glycemic control during treatment of diabetic chimpanzees and is more informative concerning overall glucose control than are FBG levels alone.