bims-hafaim Biomed News
on Heart failure metabolism
Issue of 2021‒08‒08
seven papers selected by
Kyle McCommis
Saint Louis University

  1. Physiol Rep. 2021 Aug;9(15): e14965
      Protein posttranslational modifications (PTMs) by O-linked β-N-acetylglucosamine (O-GlcNAc) rise during pressure-overload hypertrophy (POH) to affect hypertrophic growth. The hexosamine biosynthesis pathway (HBP) branches from glycolysis to make the moiety for O-GlcNAcylation. It is speculated that greater glucose utilization during POH augments HBP flux to increase O-GlcNAc levels; however, recent results suggest glucose availability does not primarily regulate cardiac O-GlcNAc levels. We hypothesize that induction of key enzymes augment protein O-GlcNAc levels primarily during active myocardial hypertrophic growth and remodeling with early pressure overload. We further speculate that downregulation of protein O-GlcNAcylation inhibits ongoing hypertrophic growth during prolonged pressure overload with established hypertrophy. We used transverse aortic constriction (TAC) to create POH in C57/Bl6 mice. Experimental groups were sham, 1-week TAC (1wTAC) for early hypertrophy, or 6-week TAC (6wTAC) for established hypertrophy. We used western blots to determine O-GlcNAc regulation. To assess the effect of increased protein O-GlcNAcylation with established hypertrophy, mice received thiamet-g (TG) starting 4 weeks after TAC. Protein O-GlcNAc levels were significantly elevated in 1wTAC versus Sham with a fall in 6wTAC. OGA, which removes O-GlcNAc from proteins, fell in 1wTAC versus sham. GFAT is the rate-limiting HBP enzyme and the isoform GFAT1 substantially rose in 1wTAC. With established hypertrophy, TG increased protein O-GlcNAc levels but did not affect cardiac mass. In summary, protein O-GlcNAc levels vary during POH with elevations occurring during active hypertrophic growth early after TAC. O-GlcNAc levels appear to be regulated by changes in key enzyme levels. Increasing O-GlcNAc levels during established hypertrophy did not restart hypertrophic growth.
    Keywords:  Cardiac hypertrophy; GFAT; O-GlcNAc; glucose metabolism; hexosamine biosynthesis pathway; pressure-overload hypertrophy; thiamet-g; transverse aortic constriction
  2. Int J Biol Sci. 2021 ;17(11): 2871-2883
      Obesity is often associated with metabolic dysregulation and oxidative stress with the latter serving as a possible unifying link between obesity and cardiovascular complications. Glutaredoxins (Grxs) comprise one of the major antioxidant systems in the heart. Although Grx3 has been shown to act as an endogenous negative regulator of cardiac hypertrophy and heart failure, its metabolic impact on cardiac function in diet-induced obese (DIO) mice remains largely unknown. In the present study, analysis of Grx3 expression indicated that Grx3 protein levels, but not mRNA levels, were significantly increased in the hearts of DIO mice. Cardiac-specific Grx3 deletion (Grx3 CKO) mice were viable and grew indistinguishably from their littermates after being fed a high fat diet (HFD) for one month, starting at 2 months of age. After being fed with a HFD for 8 months (starting at 2 months of age); however, Grx3 CKO DIO mice displayed left ventricular systolic dysfunction with a significant decrease in ejection fraction and fractional shortening that was associated with heart failure. ROS production was significantly increased in Grx3 CKO DIO cardiomyocytes compared to control cells. Gene expression analysis revealed a significant decline in the level of transcripts corresponding to genes associated with processes such as fatty acid uptake, mitochondrial fatty acid transport and oxidation, and citrate cycle in Grx3 CKO DIO mice compared to DIO controls. In contrast, an increase in the level of transcripts corresponding to genes associated with glucose uptake and utilization were found in Grx3 CKO DIO mice compared to DIO controls. Taken together, these findings indicate that Grx3 may play a critical role in redox balance and as a metabolic switch in cardiomyocytes contributing to the development and progression of heart failure.
    Keywords:  Heart failure; cardiac energy metabolism; glutaredoxin; oxidative stress; transcriptome
  3. Metabolism. 2021 Jul 29. pii: S0026-0495(21)00140-2. [Epub ahead of print]122 154840
      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.
    Keywords:  ACSL4; FUNDC1; Ferroptosis; Heart; High fat diet intake; Mitochondria
  4. Antioxidants (Basel). 2021 Jul 20. pii: 1153. [Epub ahead of print]10(7):
      Thioredoxin 1 (Trx1) is a major antioxidant that acts adaptively to protect the heart during the development of diabetic cardiomyopathy. The molecular mechanism(s) responsible for regulating the Trx1 level and/or activity during diabetic cardiomyopathy is unknown. β-hydroxybutyrate (βHB), a major ketone body in mammals, acts as an alternative energy source in cardiomyocytes under stress, but it also appears to be involved in additional mechanisms that protect the heart against stress. βHB upregulated Trx1 in primary cultured cardiomyocytes in a dose- and a time-dependent manner and a ketogenic diet upregulated Trx1 in the heart. βHB protected cardiomyocytes against H2O2-induced death, an effect that was abolished in the presence of Trx1 knockdown. βHB also alleviated the H2O2-induced inhibition of mTOR and AMPK, known targets of Trx1, in a Trx1-dependent manner, suggesting that βHB potentiates Trx1 function. It has been shown that βHB is a natural inhibitor of HDAC1 and knockdown of HDAC1 upregulated Trx1 in cardiomyocytes, suggesting that βHB may upregulate Trx1 through HDAC inhibition. βHB induced Trx1 acetylation and inhibited Trx1 degradation, suggesting that βHB-induced inhibition of HDAC1 may stabilize Trx1 through protein acetylation. These results suggest that βHB potentiates the antioxidant defense in cardiomyocytes through the inhibition of HDAC1 and the increased acetylation and consequent stabilization of Trx1. Thus, modest upregulation of ketone bodies in diabetic hearts may protect the heart through the upregulation of Trx1.
    Keywords:  cardiomyocytes; thioredoxin 1 (Trx1); β-hydroxybutyrate (βHB)
  5. Cardiovasc Diabetol. 2021 Jul 31. 20(1): 159
      BACKGROUND: Randomized, controlled cardiovascular outcome trials may not be fully representative of the management of patients with type 2 diabetes across different geographic regions. We conducted analyses of data from the multinational CVD-REAL consortium to determine the association between initiation of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and cardiovascular outcomes, including subgroup analyses based on patient characteristics.METHODS: De-identified health records from 13 countries across three continents were used to identify patients newly-initiated on SGLT-2i or other glucose-lowering drugs (oGLDs). Propensity scores for SGLT-2i initiation were developed in each country, with 1:1 matching for oGLD initiation. In the matched groups hazard ratios (HRs) for hospitalization for heart failure (HHF), all-cause death (ACD), the composite of HHF or ACD, myocardial infarction (MI) and stroke were estimated by country, and pooled using a weighted meta-analysis. Multiple subgroup analyses were conducted across patient demographic and clinical characteristics to examine any heterogeneity in treatment effects.
    RESULTS: Following matching, 440,599 new users of SGLT-2i and oGLDs were included in each group. Mean follow-up time was 396 days for SGLT-2i initiation and 406 days for oGLDs initiation. SGLT-2i initiation was associated with a lower risk of HHF (HR: 0.66, 95%CI 0.58-0.75; p < 0.001), ACD (HR: 0.52, 95%CI 0.45-0.60; p < 0.001), the composite of HHF or ACD (HR: 0.60, 95%CI 0.53-0.68; p < 0.001), MI (HR: 0.85, 95%CI 0.78-0.92; p < 0.001), and stroke (HR: 0.78, 95%CI 0.72-0.85; p < 0.001); regardless of patient characteristics, including established cardiovascular disease, or geographic region.
    CONCLUSIONS: This CVD-REAL study extends the findings from the SGLT-2i clinical trials to the broader setting of an ethnically and geographically diverse population, and across multiple subgroups. Trial registration NCT02993614.
    Keywords:  Cardiovascular outcomes; Heart failure; Sodium–glucose cotransporter-2 inhibitors; Type 2 diabetes
  6. Cardiovasc Diabetol. 2021 Aug 03. 20(1): 161
      BACKGROUND: Whether differences in circulating long chain acylcarnitines (LCAC) are seen in heart failure (HF) patients with and without diabetes mellitus (DM), and whether these biomarkers report on exercise capacity and clinical outcomes, remains unknown. The objective of the current study was to use metabolomic profiling to identify biomarkers that report on exercise capacity, clinical outcomes, and differential response to exercise in HF patients with and without DM.METHODS: Targeted mass spectrometry was used to quantify metabolites in plasma from participants in the heart failure: a controlled trial investigating outcomes of exercise training (HF-ACTION) trial. Principal components analysis was used to identify 12 uncorrelated factors. The association between metabolite factors, diabetes status, exercise capacity, and time to the primary clinical outcome of all-cause mortality or all-cause hospitalization was assessed.
    RESULTS: A total of 664 participants were included: 359 (54%) with DM. LCAC factor levels were associated with baseline exercise capacity as measured by peak oxygen consumption (beta 0.86, p  =  2 × 10-7, and were differentially associated in participants with and without DM (beta 1.58, p  =  8  ×  10-8 vs. 0.67, p  =  9  ×  10-4, respectively; p value for interaction  =  0.012). LCAC levels changed to a lesser extent in participants with DM after exercise (mean ∆ 0.09, p  =  0.24) than in those without DM (mean ∆ 0.16, p  =  0.08). In univariate and multivariate modeling, LCAC factor levels were associated with time to the primary outcome (multivariate HR 0.80, p  =  2.74  ×  10-8), and were more strongly linked to outcomes in diabetic participants (HR 0.64, p  =  3.21  ×  10-9 v. HR 0.90, p  =  0.104, p value for interaction  =  0.001). When analysis was performed at the level of individual metabolites, C16, C16:1, C18, and C18:1 had the greatest associations with both exercise capacity and outcomes, with higher levels associated with worse outcomes. Similar associations with time to the primary clinical outcome were not found in a control group of patients without HF from the CATHeterization GENetics (CATHGEN) study.
    CONCLUSIONS: LCAC biomarkers are associated with exercise status and clinical outcomes differentially in HF patients with and without DM. Impaired fatty acid substrate utilization and mitochondrial dysfunction both at the level of the skeletal muscle and the myocardium may explain the decreased exercise capacity, attenuated response to exercise training, and poor clinical outcomes seen in patients with HF and DM. Trial Registration Identifier: NCT00047437.
    Keywords:  Diabetes; Exercise; Heart failure; Long chain acylcarnitines
  7. Front Cardiovasc Med. 2021 ;8 691907
      Background: Sodium-glucose co-transporter 2 (SGLT2) inhibitors are an emerging class of glucose-lowering drugs that have become increasingly relevant for the treatment and prevention of heart failure (HF). Therefore, we aimed to investigate various SGLT2 inhibitors in patients with established HF at baseline and focused on the different types of HF. Methods: An extensive search of PubMed and Web of Science until January 2021 was done. Two reviewers, independently and in duplicate, applied the selection criteria. This meta-analysis was conducted according to the PRISMA guidelines. Data were pooled using a random-effects model. Randomized controlled trials (RCTs) of SGLT2 inhibitors vs. a comparator in patients with HF reporting clinical outcomes were included. The primary efficacy outcome was the composite of hospitalization for HF (HHF) or cardiovascular (CV) mortality. All-cause mortality, CV mortality, and HHF were considered as secondary endpoints. Subgroup analyses involving the status of diabetes, type of HF, administered type of SGLT2 inhibitor, sex, age, body mass index (BMI), estimated glomerular filtration rate (eGFR), cause of HF, and concomitant medication were performed. Results: Seventeen RCTs, comprising a total of 20,749 participants, were included (n = 10,848 treated with SGLT2 inhibitors and n = 9,901 treated with a comparator). Treatment with SGLT2 inhibitors in a HF population was associated with a 27% relative risk reduction (RRR) of HHF or CV mortality [risk ratio (RR) = 0.73, 95% CI = 0.68-0.78], 32% RRR of HHF (RR = 0.68, 95% CI = 0.62-074), 18% RRR of CV mortality (RR = 0.82, 95% CI = 0.73-0.91), and 17% RRR of all-cause mortality (RR = 0.83, 95% CI = 0.75-0.91). The effect of SGLT2 inhibitors on the primary endpoint was consistent among the different gliflozines. The effect of SGLT2 inhibitors on the primary endpoint was independent of underlying diabetes mellitus, age, sex, BMI, renal function, and HF type. Conclusions: SGLT2 inhibitors are associated with improved CV outcomes in patients with HF.
    Keywords:  SGLT2 inhibitors; clinical outcome; heart failure; meta-analysis; pharmacotherapy