Role of Cardiac Biomarkers in Monitoring Cardiotoxicity in Chemotherapy Patients

PURPOSE

This review aims to highlight the different types of chemotherapy-induced cardiotoxicity and will discuss the evidence base behind the use of different cardiac biomarkers to predict cardiovascular complications. Additionally, we will review the use of cardiac biomarkers to monitor cardiac outcomes and the role of cardioprotective medications in reducing cardiovascular side effects.

RECENT FINDINGS

Chemotherapy has been linked to an increased risk of cardiotoxicity and heart failure. Currently, patients receiving chemotherapy undergo echocardiogram before starting chemotherapy and every 6 months to monitor for any decline in cardiac function. We reviewed the current evidence and practice guidelines of monitoring chemotherapy cardiotoxicity.

SUMMARY

Cardio-oncology is a rapidly evolving subspecialty in cardiology, especially with the advent of new chemotherapeutic agents, which have cardiovascular side effects. Early detection of these effects is crucial to prevent life-threatening and irreversible cardiovascular outcomes. Monitoring troponin, pro-brain natriuretic peptide, and other cardiac biomarkers during chemotherapy will help to early detect cardiotoxicity.

Same-Day Discharge After Left Bundle Area Pacing

BACKGROUND

Left bundle area pacing (LBAP) has emerged as an area that appears to be an attractive alternative to other forms of physiological pacing owing to its ease and favorable pacing parameters. Same-day discharge after conventional pacemakers, implantable cardioverter defibrillators, and more recently leadless pacemakers have become routine, especially after the COVID-19 pandemic. With the advent of LBAP, the safety and feasibility of same-day discharge remain unclear.

METHODS

This is a retrospective, observational case series of consecutive, sequential patients undergoing LBAP at Baystate Medical Center, an academic teaching hospital. We included all patients who underwent LBAP and were discharged on the same day of procedure completion. Safety parameters included any procedure-related complications including pneumothorax, cardiac tamponade, septal perforation, and lead dislodgement. Pacemaker parameters included pacing threshold, R-wave amplitude, and lead impedance pre-discharge the following day of implantation and up to 6 months of follow-up.

RESULTS

A total of 11 patients were included in our analysis, the average age was 70.3 ± 6.74 years. The most common indication for pacemaker insertion was AV block (73%). No complications were seen in any of the patients. The average time between the procedure and discharge was 5.6 hours. Pacemaker and lead parameters were stable after 6 months of follow-up.

CONCLUSIONS

In this case series, we find that same-day discharge after LBAP for any indication is a safe and feasible option. As this mode of pacing becomes increasingly more common, larger prospective studies evaluating the safety and feasibility of early discharge after LBAP will be needed.

Human Obesity Attenuates Cardioprotection Conferred by Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells

To explore the impact of obesity on reparative potency of adipose tissue-derived mesenchymal stromal/stem cells (A-MSC) in hypertensive cardiomyopathy, A-MSC were harvested from subcutaneous fat of obese and age-matched non-obese human subjects during bariatric or kidney donation surgeries, and then injected into mice 2 weeks after inducing renovascular hypertension (RVH) or sham surgery. Two weeks later, left ventricular (LV) function and deformation were estimated in vivo by micro-magnetic resonance imaging and myocardial damage ex vivo. Blood pressure and myocardial wall thickening were elevated in RVH + Vehicle and normalized only by lean-A-MSC. Both A-MSC types reduced LV mass and normalized the reduced LV peak strain radial in RVH, yet obese-A-MSC also impaired LV systolic function. A-MSC alleviated myocardial tissue damage in RVH, but lean-A-MSC decreased oxidative stress more effectively. Obese-A-MSC also showed increased cellular inflammation in vitro. Therefore, obese-A-MSC are less effective than lean-A-MSC in blunting hypertensive cardiomyopathy in mice with RVH.

Prevalence of post-acute COVID-19 syndrome symptoms at different follow-up periods: a systematic review and meta-analysis

BACKGROUND

Post-acute coronavirus 2019 (COVID-19) syndrome is now recognized as a complex systemic disease that is associated with substantial morbidity.

OBJECTIVES

To estimate the prevalence of persistent symptoms and signs at least 12 weeks after acute COVID-19 at different follow-up periods.

DATA SOURCES

Searches were conducted up to October 2021 in Ovid Embase, Ovid Medline, and PubMed.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Articles in English that reported the prevalence of persistent symptoms among individuals with confirmed severe acute respiratory syndrome coronavirus 2 infection and included at least 50 patients with a follow-up of at least 12 weeks after acute illness.

METHODS

Random-effect meta-analysis was performed to produce a pooled prevalence for each symptom at four different follow-up time intervals. Between-study heterogeneity was evaluated using the I2 statistic and was explored via meta-regression, considering several a priori study-level variables. Risk of bias was assessed using the Joanna Briggs Institute tool and the Newcastle-Ottawa Scale for prevalence studies and comparative studies, respectively.

RESULTS

After screening 3209 studies, a total of 63 studies were eligible, with a total COVID-19 population of 257 348. The most commonly reported symptoms were fatigue, dyspnea, sleep disorder, and difficulty concentrating (32%, 25%, 24%, and 22%, respectively, at 3- to <6-month follow-up); effort intolerance, fatigue, sleep disorder, and dyspnea (45%, 36%, 29%, and 25%, respectively, at 6- to <9-month follow-up); fatigue (37%) and dyspnea (21%) at 9 to <12 months; and fatigue, dyspnea, sleep disorder, and myalgia (41%, 31%, 30%, and 22%, respectively, at >12-month follow-up). There was substantial between-study heterogeneity for all reported symptom prevalences. Meta-regressions identified statistically significant effect modifiers: world region, male sex, diabetes mellitus, disease severity, and overall study quality score. Five of six studies including a comparator group consisting of COVID-19-negative cases observed significant adjusted associations between COVID-19 and several long-term symptoms.

CONCLUSIONS

This systematic review found that a large proportion of patients experience post-acute COVID-19 syndrome 3 to 12 months after recovery from the acute phase of COVID-19. However, available studies of post-acute COVID-19 syndrome are highly heterogeneous. Future studies need to have appropriate comparator groups, standardized symptom definitions and measurements, and longer follow-up.

Global epigenetic alterations of mesenchymal stem cells in obesity: the role of vitamin C reprogramming

Obesity promotes dysfunction and impairs the reparative capacity of mesenchymal stem/stromal cells (MSCs), and alters their transcription, protein content, and paracrine function. Whether these adverse effects are mediated by chromatin-modifying epigenetic changes remains unclear. We tested the hypothesis that obesity imposes global DNA hydroxymethylation and histone tri-methylation alterations in obese swine abdominal adipose tissue-derived MSCs compared to lean pig MSCs. MSCs from female lean (n = 7) and high-fat-diet fed obese (n = 7) domestic pigs were assessed using global epigenetic assays, before and after in-vitro co-incubation with the epigenetic modulator vitamin-C (VIT-C) (50 μg/ml). Dot blotting was used to measure across the whole genome 5-hydroxyemthycytosine (5hmC) residues, and Western blotting to quantify in genomic histone-3 protein tri-methylated lysine-4 (H3K4me3), lysine-9 (H3K9me3), and lysine-27 (H3K27me3) residues. MSC migration and proliferation were studied in-vitro. Obese MSCs displayed reduced global 5hmC and H3K4m3 levels, but comparable H3K9me3 and H3K27me3, compared to lean MSCs. Global 5hmC, H3K4me3, and HK9me3 marks correlated with MSC migration and reduced proliferation, as well as clinical and metabolic characteristics of obesity. Co-incubation of obese MSCs with VIT-C enhanced 5hmC marks, and reduced their global levels of H3K9me3 and H3K27me3. Contrarily, VIT-C did not affect 5hmC, and decreased H3K4me3 in lean MSCs. Obesity induces global genomic epigenetic alterations in swine MSCs, involving primarily genomic transcriptional repression, which are associated with MSC function and clinical features of obesity. Some of these alterations might be reversible using the epigenetic modulator VIT-C, suggesting epigenetic modifications as therapeutic targets in obesity.

98 Effects of maternal age on oxygen consumption of oocytes and invitro-produced equine embryos

Mitochondrial replication is arrested during early cleavage stages, leaving the embryo dependent on maternally derived mitochondria for oxidative phosphorylation. Numbers of mitochondrial DNA (mtDNA) are used as indicators of functional mitochondria; however, direct comparisons for mtDNA and oxygen consumption rate (OCR) have not been performed for horses. The objectives of this study were to compare equine oocyte mtDNA copy numbers with a measure of mitochondrial function (OCR) and to determine whether maternal age of the oocyte donor impacts OCR of early-stage embryos. We hypothesised that (1) OCR in oocytes is not directly associated with mitochondrial numbers and (2) aerobic metabolism (OCR) is lower in early embryos from old than from young mares. Mares ages 6-13 years (Young, n=7) and=20 years (Old, n=8) were used as oocyte donors. Oocytes were collected from dominant follicles (=35mm) during oestrus and at 16±2h after induction of follicular maturation. Recovered oocytes were incubated in tissue culture medium 199 with 10% fetal calf serum, 25mgmL−1 of gentamicin, and 0.2mM pyruvate for 26±2h. Metaphase II oocytes (Young, n=14; Old, n=15) were fertilized by intracytoplasmic sperm injection (ICSI) using frozen-thawed sperm from one stallion. Presumptive zygotes were cultured in global medium (LifeGlobal Group). Other oocytes and early embryos were used for OCR. A microchamber containing an electrochemical sensor was used to measure OCR from individual oocytes (Young, n=9; Old, n=14) and early embryos (Young, n=8; Old, n=10). After analyses, oocytes were snap frozen, and mtDNA was later quantified by qPCR. Metabolic assays of embryos that cleaved were performed at Day 2 after ICSI. After the assay, embryos were placed back to culture until blastocyst formation at Day 7 or 8. Two-tailed Student's t-tests were used for OCR and mtDNA comparisons, and Fisher's exact tests were used to compare development rates. We found that OCR was higher (P=0.007) for oocytes from Young (mean±s.e.m.: 1.8±0.2) than from Old (1.3±0.1 fmol s−1). However, mtDNA numbers were not different (P=0.3) for Young (5.6±0.4×105) and Old (6.2±0.4×105). Cleavage rates were similar (P=0.6) between Young (11 out of 14, 79%) and Old (13 of 15, 87%). Day 2 embryos from Young had higher basal OCR compared with Old (3.8±0.1 and 3.2±0.2 fmol s−1, respectively; P=0.05). Blastocyst rates per cleaved oocytes were similar for Young (5 of 11, 45%) and Old (4 of 13, 31%; P=0.7). Lower OCR was observed in oocytes and early embryos from Old, which indicates that mitochondrial metabolic function is reduced for mitochondria originating in the oocytes of Old compared with Young. Use of mtDNA was not indicative of mitochondrial metabolic function. Although sample numbers were limited, cleavage and blastocyst development were not significantly different between Young and Old. Further developmental competence was not determined, although the compromised metabolic capacity of oocytes and embryos from old mares could ultimately contribute to lower fertility outcomes.

167 Basal and maximal oxygen consumption of oocytes from young and old mares

Mitochondria play a critical role in oocyte developmental competence by providing energy to the oocyte through oxidative phosphorylation. We hypothesised that oxygen consumption, a measure of mitochondrial function, would be lower in the oocytes of old versus young mares as a potential mechanism of reduced developmental competence associated with equine aging. To test this hypothesis, we used a novel electrochemical sensor device to compare basal and maximal oxygen consumption rates of oocytes obtained from mares aged 6 to 12 years (Young, n=8 from 7 mares) and=20 years (Old, n=12 from 8 mares). Cumulus-oocyte complexes (COC) were collected by transvaginal, ultrasound-guided follicular aspirations of dominant follicles (35mm) during oestrus and at 16±2h after induction of follicular maturation (2000IU of hCG and 0.75mg of deslorelin acetate). Recovered COC were incubated in medium [TCM-199; Life Technologies, Grand Island, NY, USA) with 10% fetal calf serum, 25mg mL−1 gentamicin, and 0.2mM pyruvate] at 38.5°C in 5% CO2 and air for 26±2h. After maturation, COC were stripped of cumulus cells and checked for the presence of an extruded polar body before electrochemical measurements using amperometry. A microchamber with a 3-electrode system (working, counter, and reference electrodes) was filled with 120µL of medium (G-MOPS™, Vitrolife, Englewood, CO, USA) and overlaid with 120µL of paraffin oil (OVOIL™, Vitrolife). The baseline current was measured before adding the oocyte through the oil layer and over the centre of the working electrode. Oxygen consumption was monitored as the linear decrease in the oxygen reduction current over time, which was converted to femtomoles of O2 consumed per second (fmol s−1) using a calibration curve for the sensor. Basal (nonstimulated) oxygen consumption was measured for 5min, followed by assessment of maximal noncoupled respiratory capacity obtained by titrating 1 µM carbonyl cyanide m-chlorophenyl hydrazone (CCCP) at 8-min intervals. The highest value observed during CCCP titrations was considered the maximal oxygen consumption. Two-tailed Student’s t-tests were used to analyse data. Oocytes from young mares had higher basal oxygen consumption compared with old mares, respectively (mean±s.e.m., 1.74±0.18 and 1.27±0.09 fmol s−1; P=0.04) as well as higher maximal oxygen consumption (2.67±0.19 and 2.05±0.12 fmol s−1; P=0.016). Mitochondrial efficiency (maximal/basal oxygen consumption) was not different for Young and Old, respectively (1.62±0.13 and 1.65±0.07; P=0.9). In summary, we used a novel electrochemical sensor device to measure basal and maximal oxygen consumption of oocytes and to confirm our hypothesis that aging impairs mitochondrial respiratory capacity in equine oocytes, which may contribute to age-associated changes in equine fertility.