Impact of Obesity-Related Inflammation on Cardiac Metabolism and Function

Association of Body Mass Index with Outcomes in Patients with Heart Failure with Reduced Ejection Fraction (HFrEF)

Heart failure (HF) is a major health issue, affecting up to 2% of the adult population worldwide. Given the increasing prevalence of obesity and its association with various cardiovascular diseases, understanding its role in HFrEF outcomes is crucial. This study aimed to investigate the impact of obesity on in-hospital mortality and prolonged hospital stay in patients with heart failure with reduced ejection fraction (HFrEF). We conducted a retrospective analysis of 425 patients admitted to the cardiology unit at the University Clinical Hospital in Wroclaw, Poland, between August 2018 and August 2020. Statistical analyses were performed to evaluate the interactions between BMI, sex, and comorbidities on in-hospital mortality. Significant interactions were found between sex and BMI as well as between BMI and post-stroke status, affecting in-hospital mortality. Specifically, increased BMI was associated with decreased odds of in-hospital mortality in males (OR = 0.72, 95% CI: 0.55-0.94, p < 0.05) but higher odds in females (OR = 1.18, 95% CI: 0.98-1.42, p = 0.08). For patients without a history of stroke, increased BMI reduced mortality odds (HR = 0.78, 95% CI: 0.64-0.95, p < 0.01), whereas the effect was less pronounced in those with a history of stroke (HR = 0.89, 95% CI: 0.76-1.04, p = 0.12). In conclusion, the odds of in-hospital mortality decreased significantly with each 10% increase in BMI for males, whereas for females, a higher BMI was associated with increased odds of death. Additionally, BMI reduced in-hospital mortality odds more in patients without a history of cerebral stroke (CS) compared to those with a history of CS. These findings should be interpreted with caution due to the low number of observed outcomes and potential interactions with BMI and sex.

Adiposity, fat-free mass and incident heart failure in 500 000 individuals

BACKGROUND AND AIMS

The independent role of body fat distribution and fat-free mass in heart failure (HF) risk is unclear. We investigated the role of different body composition compartments in risk of HF.

METHODS

Present analyses include 428 087 participants (mean age 55.9 years, 44% male) from the UK Biobank. Associations of long-term average levels of body composition measures with incident HF were determined using adjusted Cox proportional hazards regression models.

RESULTS

Over a median follow-up of 13.8 years, there were 10 455 first-ever incident HF events. Overall, HF risk was more strongly associated with central adiposity (waist circumference (WC) adjusted for body mass index (BMI); HR 1.38, 95% CI 1.32 to 1.45) than general adiposity (BMI adjusted for WC; HR 1.22, 95% CI 1.16 to 1.27). Although dual X-ray absorptiometry-derived body fat remained positively related to HF after adjustment for fat-free mass (HR 1.37, 95% CI 1.18 to 1.59), the association of fat-free mass with HF was substantially attenuated by fat mass (HR 1.12, 95% CI 1.01 to 1.26) while visceral fat (VAT) remained associated with HF independent of subcutaneous fat (HR 1.20, 95% CI 1.09 to 1.33). In analyses of HF subtypes, HF with preserved ejection fraction was independently associated with all fat measures (eg, VAT: HR 1.23, 95% CI 1.12 to 1.35; body fat: HR 1.36, 95% CI 1.17 to 1.57) while HF with reduced ejection fraction was not independently associated with fat measures (eg, VAT: HR 1.29, 95% CI 0.98 to 1.68; body fat: HR 1.29, 95% CI 0.80 to 2.07).

CONCLUSIONS

This large-scale study shows that excess adiposity and fat mass are associated with higher HF risk while the association of fat-free mass with HF could be explained largely by its correlation with fat mass. The study also describes the independent relevance of body fat distribution to HF subtypes, suggesting different mechanisms may be driving their aetiopathogenesis.

Association Between Insulin Resistance and Myosteatosis Measured by Abdominal Computed Tomography

CONTEXT

Ectopic fat deposition in skeletal muscle, termed myosteatosis, is a key factor in developing insulin resistance.

OBJECTIVE

This work aimed to evaluate the association between insulin resistance and myosteatosis in a large Asian population.

METHODS

A total of 18 251 participants who had abdominal computed tomography were included in this cross-sectional study. Patients were categorized into 4 groups according to quartiles of Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). The total abdominal muscle area (TAMA) at the L3 vertebral level was segmented into normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA), and intermuscular adipose tissue (IMAT). The absolute values of TAMA, NAMA, LAMA, and IMAT and the ratios of NAMA/BMI, LAMA/BMI, and NAMA/TAMA were used as myosteatosis indices.

RESULTS

The absolute values of TAMA, NAMA, LAMA, and IMAT appeared to increase with higher HOMA-IR levels, and LAMA/BMI showed a similar upward trend. Meanwhile, the NAMA/BMI and NAMA/TAMA index showed downward trends. As HOMA-IR levels increased, the odds ratios (ORs) of the highest quartile of NAMA/BMI and NAMA/TAMA index decreased and that of LAMA/BMI increased. Compared with the lowest HOMA-IR group, the adjusted ORs (95% CI) in the highest HOMA-IR group for the lowest NAMA/TAMA quartile were 0.414 (0.364-0.471) in men and 0.464 (0.384-0.562) in women. HOMA-IR showed a negative correlation with NAMA/BMI (r = -0.233 for men and r = -0.265 for women), and NAMA/TAMA index (r = -0.211 for men and r = -0.214 for women), and a positive correlation with LAMA/BMI (r = 0.160 for men and r = 0.119 for women); P was less than .001 for all.

CONCLUSION

In this study, a higher HOMA-IR level was significantly associated with a high risk of myosteatosis.

Effect of a Wearable Device-Based Physical Activity Intervention in North Korean Refugees: Pilot Randomized Controlled Trial

BACKGROUND

Effective health interventions for North Korean refugees vulnerable to metabolic disorders are currently unelucidated.

OBJECTIVE

This study aimed to evaluate the effects of digital health interventions in North Korean refugees using a wearable activity tracker (Fitbit device).

METHODS

We conducted a prospective, randomized, open-label study on North Korean refugees aged 19-59 years between June 2020 and October 2021 with a 12-week follow-up period. The participants were randomly assigned to either an intervention group or a control group in a 1:1 ratio. The intervention group received individualized health counseling based on Fitbit data every 4 weeks, whereas the control group wore the Fitbit device but did not receive individualized counseling. The primary and secondary outcomes were the change in the mean daily step count and changes in the metabolic parameters, respectively.

RESULTS

The trial was completed by 52 North Korean refugees, of whom 27 and 25 were in the intervention and control groups, respectively. The mean age was 43 (SD 10) years, and 41 (78.8%) participants were women. Most participants (44/52, 95.7%) had a low socioeconomic status. After the intervention, the daily step count in the intervention group increased, whereas that in the control group decreased. However, there were no significant differences between the 2 groups (+83 and -521 steps in the intervention and control groups, respectively; P=.500). The effects of the intervention were more prominent in the participants with a lower-than-average daily step count at baseline (<11,667 steps/day). After the 12-week study period, 85.7% (12/14) and 46.7% (7/15) of the participants in the intervention and control groups, respectively, had an increased daily step count (P=.05). The intervention prevented the worsening of the metabolic parameters, including BMI, waist circumference, fasting blood glucose level, and glycated hemoglobin level, during the study period.

CONCLUSIONS

The wearable device-based physical activity intervention did not significantly increase the average daily step count in the North Korean refugees in this study. However, the intervention was effective among the North Korean refugees with a lower-than-average daily step count; therefore, a large-scale, long-term study of this intervention type in an underserved population is warranted.

TRIAL REGISTRATION

Clinical Research Information Service KCT0007999; https://cris.nih.go.kr/cris/search/detailSearch.do/23622.

Metabolic Approaches for the Treatment of Dilated Cardiomyopathy

In dilated cardiomyopathy (DCM), where the heart muscle becomes stretched and thin, heart failure (HF) occurs, and the cardiomyocytes suffer from an energetic inefficiency caused by an abnormal cardiac metabolism. Although underappreciated as a potential therapeutic target, the optimal metabolic milieu of a failing heart is still largely unknown and subject to debate. Because glucose naturally has a lower P/O ratio (the ATP yield per oxygen atom), the previous studies using this strategy to increase glucose oxidation have produced some intriguing findings. In reality, the vast majority of small-scale pilot trials using trimetazidine, ranolazine, perhexiline, and etomoxir have demonstrated enhanced left ventricular (LV) function and, in some circumstances, myocardial energetics in chronic ischemic and non-ischemic HF with a reduced ejection fraction (EF). However, for unidentified reasons, none of these drugs has ever been tested in a clinical trial of sufficient size. Other pilot studies came to the conclusion that because the heart in severe dilated cardiomyopathy appears to be metabolically flexible and not limited by oxygen, the current rationale for increasing glucose oxidation as a therapeutic target is contradicted and increasing fatty acid oxidation is supported. As a result, treating metabolic dysfunction in HF may benefit from raising ketone body levels. Interestingly, treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2i) improves cardiac function and outcomes in HF patients with or without type 2 diabetes mellitus (T2DM) through a variety of pleiotropic effects, such as elevated ketone body levels. The improvement in overall cardiac function seen in patients receiving SGLT2i could be explained by this increase, which appears to be a reflection of an adaptive process that optimizes cardiac energy metabolism. This review aims to identify the best metabolic therapeutic approach for DCM patients, to examine the drugs that directly affect cardiac metabolism, and to outline all the potential ancillary metabolic effects of the guideline-directed medical therapy. In addition, a special focus is placed on SGLT2i, which were first studied and prescribed to diabetic patients before being successfully incorporated into the pharmacological arsenal for HF patients.

Bariatric surgery improves outcomes of hospitalizations for acute heart failure: a contemporary, nationwide analysis

BACKGROUND

The link between obesity and poor outcomes in heart failure (HF) has been well-established.

OBJECTIVES

This retrospective study sought to examine national rates and outcomes of acute HF hospitalizations in obese individuals with a prior history of bariatric surgery.

SETTING

Academic, university-affiliated; the United States.

METHODS

Adult admissions (≥18 years) including a diagnosis of severe obesity were identified in the 2016-2019 Nationwide Readmissions Database. Patients who previously underwent bariatric operations were categorized into the Bariatric cohort. Multivariable linear and logistic models were used to assess the association of prior bariatric surgery with outcomes of interest.

RESULTS

Of an estimated 10,343,828 admissions for a diagnosis of severe obesity, 925,716 (8.9%) comprised the bariatric cohort. After risk adjustment, bariatric surgery was associated with significantly decreased odds of acute HF hospitalization (adjusted odds ratio [AOR]: .40, 95% confidence interval [CI]: .38-.41). Among acute HF hospitalizations, prior bariatric surgery was linked to lower odds of mortality (AOR: .68, 95% CI: .52-.89), prolonged mechanical ventilation (AOR .44, 95% CI: .32-.61), acute renal failure (AOR: .76, 95% CI: .70-.82), and prolonged hospitalization (AOR: .77, 95% CI: .68-.87). Bariatric surgery was linked to a decrement of 1 day (95% CI: .7-1.1) and $1200 in hospitalization costs (95% CI: 400-1900), but no significant difference in odds of 30-day readmission.

CONCLUSIONS

Bariatric surgery is associated with reduced admissions for acute HF. Among acute HF hospitalizations, bariatric surgery is linked to significantly improved clinical and financial outcomes. Given its potential benefits in obesity and related diseases, bariatric surgery holds promise for promoting value-based healthcare for HF.

Adipokines at the crossroads of obesity and mesenchymal stem cell therapy

Mesenchymal stem cell (MSC) therapy is an emerging treatment strategy to counteract metabolic syndromes, including obesity and its comorbid disorders. However, its effectiveness is challenged by various factors in the obese environment that negatively impact MSC survival and function. The identification of these detrimental factors will provide opportunities to optimize MSC therapy for the treatment of obesity and its comorbidities. Dysregulated production of adipokines, a group of cytokines and hormones derived from adipose tissue, has been postulated to play a pivotal role in the development of obesity-associated complications. Intriguingly, adipokines have also been implicated in the modulation of viability, self-renewal, proliferation, and other properties of MSC. However, the involvement of adipokine imbalance in impaired MSC functionality has not been completely understood. On the other hand, treatment of obese individuals with MSC can restore the serum adipokine profile, suggesting the bidirectionality of the adipokine-MSC relationship. In this review, we aim to discuss the current knowledge on the central role of adipokines in the crosstalk between obesity and MSC dysfunction. We also summarize recent advances in the use of MSC for the treatment of obesity-associated diseases to support the hypothesis that adipokines modulate the benefits of MSC therapy in obese patients.

Direct cardio-protection of Dapagliflozin against obesity-related cardiomyopathy via NHE1/MAPK signaling

Obesity is an important independent risk factor for cardiovascular diseases, remaining an important health concern worldwide. Evidence shows that saturated fatty acid-induced inflammation in cardiomyocytes contributes to obesity-related cardiomyopathy. Dapagliflozin (Dapa), a selective SGLT2 inhibitor, exerts a favorable preventive activity in heart failure. In this study, we investigated the protective effect of Dapa against cardiomyopathy caused by high fat diet-induced obesity in vitro and in vivo. Cultured rat cardiomyocyte H9c2 cells were pretreated with Dapa (1, 2.5 μM) for 1.5 h, followed by treatment with palmitic acid (PA, 200 μM) for 24 h. We showed that Dapa pretreatment concentration-dependently attenuated PA-induced cell hypertrophy, fibrosis and apoptosis. Transcriptome analysis revealed that inhibition of PA-activated MAPK/AP-1 pathway contributed to the protective effect of Dapa in H9c2 cells, and this was confirmed by anti-p-cJUN fluorescence staining assay. Using surface plasmon resonance analysis we found the direct binding of Dapa with NHE1. Gain and loss of function experiments further demonstrated the role of NHE1 in the protection of Dapa. In vivo experiments were conducted in mice fed a high fat diet for 5 months. The mice were administered Dapa (1 mg·kg-1·d-1, i.g.) in the last 2 months. Dapa administration significantly reduced the body weight and improved the serum lipid profiles. Dapa administration also alleviated HFD-induced cardiac dysfunction and cardiac aberrant remodeling via inhibiting MAPK/AP-1 pathway and ameliorating cardiac inflammation. In conclusion, Dapa exerts a direct protective effect against saturated fatty acid-induced cardiomyocyte injury in addition to the lowering effect on serum lipids. The protective effect results from negative regulating MAPK/AP-1 pathway in a NHE1-dependent way. The current study highlights the potential of clinical use of Dapa in the prevention of obesity-related cardiac dysfunction.

FUNDC1 insufficiency sensitizes high fat diet intake-induced cardiac remodeling and contractile anomaly through ACSL4-mediated ferroptosis

OBJECTIVE

Ferroptosis is indicated in cardiovascular diseases. Given the prominent role of mitophagy in the governance of ferroptosis and our recent finding for FUN14 domain containing 1 (FUNDC1) in obesity anomalies, this study evaluated the impact of FUNDC1 deficiency in high fat diet (HFD)-induced cardiac anomalies.

METHODS AND MATERIALS

WT and FUNDC1-/- mice were fed HFD (45% calorie from fat) or low fat diet (LFD, 10% calorie from fat) for 10 weeks in the presence of the ferroptosis inhibitor liproxstatin-1 (LIP-1, 10 mg/kg, i.p.).

RESULTS

RNAseq analysis for differentially expressed genes (DEGs) reported gene ontology term related to ferroptosis and mitophagy in obese rat hearts, which was validated in obese rodent and human hearts. Although 10-week HFD intake did not alter global metabolism, cardiac geometry and function, ablation of FUNDC1 unmasked metabolic derangement, pronounced cardiac remodeling, contractile, intracellular Ca2+ and mitochondrial anomalies upon HFD challenge, the effects of which with exception of global metabolism were attenuated or mitigated by LIP-1. FUNDC1 ablation unmasked HFD-evoked rises in fatty acid synthase ACSL4, necroptosis, inflammation, ferroptosis, mitochondrial O2- production, and mitochondrial injury as well as dampened autophagy and DNA repair enzyme 8-oxoG DNA glycosylase 1 (OGG1) but not apoptosis, the effect of which except ACSL4 and its regulator SP1 was reversed by LIP-1. In vitro data noted that arachidonic acid, an ACSL4 substrate, provoked cytochrome C release, cardiomyocyte defect, and lipid peroxidation under FUNDC1 deficiency, the effects were interrupted by inhibitors of SP1, ACSL4 and ferroptosis.

CONCLUSIONS

These data suggest that FUNDC1 deficiency sensitized cardiac remodeling and dysfunction with short-term HFD exposure, likely through ACSL4-mediated regulation of ferroptosis.