Heart Biopsies Research Articles

Myocardial SGLT2 expression and cardiac remodeling in patients with severe aortic stenosis: the BIO-AS Study

Abstract Background Cardiac remodeling plays a major role in the prognosis of patients with aortic stenosis (AS) and could impact the benefits of aortic valve replacement. Blood and tissue biomarkers have a differential pattern and expression level in patients with AS, which may retain a pathophysiological role in cardiac remodeling and metabolism. However, the data available are limited and contradictory. Aim Our study aimed to evaluate the expression of sodium-glucose cotransporter 2 (SGLT2) gene and protein in patients with severe AS stratified in high gradient (HG) and low flow-low gradient (LF-LG) AS and its association with cardiac functional impairments. Methods Gene expression and protein levels of main biomarkers of cardiac fibrosis (Galectin-3, sST2, Serpin-4, PINP, PICP, Collagen, TGF-b), inflammation (GDF-15, IL-6, NF-kB), oxidative stress (SOD1, SOD2), and cardiac metabolism (NHE, PPAR-a, PPAR-g, GLUT1, and GLUT4) were evaluated in blood samples and heart biopsies of 45 patients with AS. Results Our study showed SGLT2 gene and protein hyper-expression in patients with LF-LG AS, compared to controls and HG AS (p<0.05). These differences remained significant even after adjusting for age, gender, body mass index, history of diabetes mellitus, arterial hypertension, and coronary artery disease. SGLT2 gene expression was positively correlated with: i) TGF-b (r=0.72, p<0.001) and collagen (r=0.73, p<0.001) as markers of fibrosis; ii) NF-kB (r=0.36, p<0.01) and myocardial IL-6 (r=0.68, p<0.001) as markers of inflammation: iii) SOD2 (r=-0.38, p<0.006) as a marker of oxidative stress; iv) GLUT4 (r= 0.33, p<0.02) and PPAR-a (r=0.36, p<0.01) as markers of cardiac metabolism (Figure 1). Conclusion In patients with LF-LG AS, SGLT2 gene and protein were hyper-expressed in cardiomyocytes and associated with myocardial fibrosis, inflammation, and oxidative stress. The hyper-expression of the SGLT2 gene and protein in patients with LF-LG might pave the way for using SGLT2-Is in this subset population, with the potential to improve the outcomes of AVR and reduce the likelihood of re-hospitalization within one year.Figure 1

Exercise Intolerance in McArdle Disease: A Role for Cardiac Impairment? A Preliminary Study in Humans and Mice.

Whether cardiac impairment can be fully discarded in McArdle disease-the paradigm of 'exercise intolerance', caused by inherited deficiency of the skeletal muscle-specific glycogen phosphorylase isoform ('myophosphorylase')-remains to be determined. Eight patients with McArdle disease and seven age/sex-matched controls performed a 15-minute moderate, constant-load cycle-ergometer exercise bout followed by a maximal ramp test. Electrocardiographic and two-dimensional transthoracic (for cardiac dimension's assessment) and speckle tracking [for left-ventricle global longitudinal (GLS) assessments] echocardiographic evaluations were performed at baseline. Electrocardiographic and GLS assessments were also performed during constant-load exercise and immediately upon maximal exertion. Four human heart biopsies were obtained in individuals without McArdle disease, and in-depth histological/molecular analyses were performed in McArdle and wild-type mouse hearts. Exercise intolerance was confirmed in patients ('second wind' during constant-load exercise, -55% peak power output vs controls). As opposed to controls, patients showed a decrease in GLS during constant-load exercise, especially upon second wind occurrence, but with no other between-group difference in cardiac structure/function. Human cardiac biopsies showed that all three glycogen phosphorylase-myophosphorylase, but also liver and especially brain-isoforms are expressed in the normal adult heart, thereby theoretically compensating for eventual myophosphorylase deficiency. No overall histological (including glycogen depots), cytoskeleton, metabolic or mitochondrial (morphology/network/distribution) differences were found between McArdle and wild-type mouse hearts, except for lower levels of pyruvate kinase M2 and translocase of outer membrane 20 kDa subunit in the former. This study provides preliminary evidence that cardiac structure and function seem to be preserved in patients with McArdle disease. However, the role for an impaired cardiac contractility associated with the second wind phenomenon should be further explored.

Viral Myocarditis as a Factor Leading to the Development of Heart Failure Symptoms, Including the Role of Parvovirus B19 Infection-Systematic Review.

Myocarditis (MC) is defined as an immunological inflammatory reaction with various etiologies, clinical presentations and prognoses within the myocardium. Currently, parvovirus B19 (PVB19) has become the main factor leading to this disease, replacing the previously dominant viruses A and B. In the case of chronic heart failure with subsequent dilated cardiomyopathy, approximately 67% have a viral etiology, and most of them are the result of PVB19 infection. However, the analysis showed a correlation between PVB19 infection and the risk of developing inflammatory dilated cardiomyopathy (DCMi). PVB19 is detected in 23% of patients with DCMi. Chronic infection may also contribute to progressive left ventricular failure in patients with a history of MC. The above effect suggests the active replication of PVB19 only in heart biopsies with inflammation due to MC or DCMi. Moreover, the supply of IFN-β to suppress the active transcription of PVB19 accompanied by DCMi over a period of 6 months results in the normalization of NT-proBNP and an improvement in LVEF along with NYHA performance. The small number of reports on this topic and inaccuracies resulting from constantly conducted research and ongoing changes make it impossible to clearly answer the question of whether PVB19 is a factor inducing de novo MC and DCM or only accompanies the above conditions. However, large clinical cohort studies lead to the perception of PVB19 as a viral etiological agent capable of causing de novo MC together with DCMi.

Molecular Pathways and Cellular Subsets Associated with Adverse Clinical Outcomes in Overlapping Immune-Related Myocarditis and Myositis.

Immune checkpoint therapies (ICT) can induce life-threatening immune-related adverse events, including myocarditis and myositis, which are rare but often concurrent. The molecular pathways and immune subsets underlying these toxicities remain poorly understood. To address this need, we performed single-cell RNA sequencing of heart and skeletal muscle biopsies obtained from living patients with cancers treated with ICTs and admitted to the hospital with myocarditis and/or myositis (overlapping myocarditis plus myositis, n = 10; myocarditis-only, n = 1) or ICT-exposed patients ruled out for toxicity utilized as controls (n = 9). All biopsies were obtained within 96 hours of clinical presentation. Analyses of 58,523 cells revealed CD8+ T cells with a cytotoxic phenotype expressing activation/exhaustion markers in both myocarditis and myositis. Furthermore, the analyses identified a population of myeloid cells expressing tissue-resident signatures and FcγRIIIa (CD16a), which is known to bind IgG and regulate complement activation. Immunohistochemistry of affected cardiac and skeletal muscle tissues revealed protein expression of pan-IgG and complement product C4d, which were associated with the presence of high-titer serum autoantibodies against muscle antigens in a subset of patients. We further identified a population of inflammatory IL1B+TNF+ myeloid cells specifically enriched in myocarditis and associated with greater toxicity severity and poorer clinical outcomes. These results provide insight into the myeloid subsets present in human immune-related myocarditis and myositis tissues and nominate new targets for investigation into rational treatments to overcome these high-mortality toxicities. See related Spotlight by Fankhauser et al., p. 954.

Reprogramming cardiac macrophages with circular RNAs to attenuate post-MI adverse remodeling

Cardiac macrophages (cMφ) play a critical role in cardiac remodeling following myocardial infarction (MI). Reprogramming cMφ towards a favorable wound-healing phenotype is emerging as a promising therapeutic strategy for MI patients. Circular RNAs (circRNAs) are a unique class of non-coding RNAs with high stability and abundance, making them attractive therapeutic targets. However, the role of circRNAs in cMφ physiology during heart failure (HF) progression is poorly understood. To identify circRNAs as key regulators of cMφ dynamics, we performed RNA sequencing and bioinformatics analysis on heart biopsies from healthy donors and patients with ischemic HF. We identified a promising circRNA, circMJ1, as a regulator of Mφ polarization and inflammatory response. CircMJ1 was highly expressed in cMφ and its expression was associated with cMφ polarization. Knockdown of circMJ1 significantly inhibited inflammatory signaling pathways in cMφ and reduced the secretion of pro-inflammatory cytokines. The secretome from circMJ1-silenced cMφ (circMJ1-KD cMφ) also significantly suppressed the migration of cardiac fibroblasts and apoptosis of cardiomyocytes. To further assess the therapeutic effcacy of circMJ1-KD Mφ in cardiac remodeling in the context of MI, we employed a novel multicellular 3D ex vivo model, called living myocardial slices (LMS). We applied circMJ1-KD Mφ to both rat LMS subjected to cryo-injury mimicking MI and HF patient-derived LMS. Interestingly, co-culture with circMJ1-KD Mφ demonstrated a remarkable reduction in inflammation and fibrosis, alongside notable improvement in cardiac function in both cryo-injured rat LMS and HF patient-derived LMS. Overall, our findings reveal circMJ1 as a crucial "switch" for Mφ dynamics and suggest the therapeutic potential of engineered circMJ1-silenced Mφ to improve post-MI healing. Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) –465131031. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Coronavirus Disease 2019 (COVID-19) in Heart Transplant Recipients and Anti-SARS-CoV-2 Monoclonal Antibodies: Experience, Lessons Learnt, and Future Challenges

Solid organ transplant recipients (SOTRs), including heart transplant (HT) recipients, infected with Coronavirus disease 2019 (COVID-19) are at higher risk of hospitalization, mechanical ventilation, or death when compared with general population. Advances in diagnosis and treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have reduced COVID-19-related mortality rates from ~30% in the early pandemic to <3% in 2022 among HT recipients. We performed a retrospective chart review including adult HT recipients at Westchester Medical Center from January 1, 2020 to December 10, 2022, who received anti-SARS-CoV-2 monoclonal antibodies (mAbs) for treatment of mild-to-moderate COVID-19, and those who received tixagevimab/cilgavimab for preexposure prophylaxis. Additionally, a comprehensive review of the literature involving SOTRs who received mAbs for COVID-19 was conducted. In this largest single-center study in this population, 42 adult HT recipients received casirivimab/imdevimab (36%), sotrovimab (31%), or bebtelovimab (29%) for treatment of mild-to-moderate COVID-19. Among these recipients, no infusion-associated adverse effects, progression of disease, COVID-19-associated hospitalizations, or death were noted. Preexposure prophylaxis with tixagevimab/cilgavimab was given to 63 HT recipients in a dedicated infusion center (40%), inpatient setting (33%), or at time of annual heart biopsy (27%). No immediate adverse events were noted. There were 11 breakthrough infections, all mild. Overall, the data suggests that HT recipients receiving mAbs have reduced rates of hospitalization, need for intensive care unit care, or death. Use of anti-SARS-CoV-2 mAbs in SOTRs is resource intensive and requires a programmatic team approach for optimal administration and to minimize any risk of disparities in their use.

Caveats in Interpretation of Molecular Diagnostics in Heart Allografts.

Histologic separation of injury, T cell-mediated rejection, or antibody-mediated rejection in allograft heart biopsies is difficult. A critical review of publications was performed to evaluate the caveats of using molecular diagnostics (MDX) to distinguish between these entities. Typically, only 1 to 2 fragments of unknown histologic appearance are evaluated. Archetype and molecular classifier analyses use gene lists derived from histologic labels and associated reproducibility issues influence the accuracy of the derived MDX classes. Archetypes A1, A2, and A3 archetypes created by bioinformatics were renamed no rejection, T cell-mediated rejection, and antibody-mediated rejection despite as little as 40% concordance with histologic diagnoses and overlapping archetype scores. Additional archetypes S4 and minor injury were created using arbitrary cutoffs based on visual examination of principal component analysis plots. Therapeutic implications of the numerous discrepancies with histology remain unexplored. Many MDX-derived observations are ambiguous and open to alternate logical explanations. Better molecular methods and more rigorous validation studies are needed to advance the field. Ideally, these methods should analyze all available biopsy fragments to minimize sampling issues. It is also desirable to incorporate spatial transcriptomics into the workflow, so that gene expression data can be directly compared with the underlying histology lesions.

Myocardial sodium-glucose cotransporter 2 expression and cardiac remodelling in patients with severe aortic stenosis: The BIO-AS study.

Cardiac remodelling plays a major role in the prognosis of patients with aortic stenosis (AS) and could impact the benefits of aortic valve replacement. Our study aimed to evaluate the expression of sodium-glucose cotransporter 2 (SGLT2) gene and protein in patients with severe AS stratified in high gradient (HG) and low flow-low gradient (LF-LG) AS and its association with cardiac functional impairments. Gene expression and protein levels of main biomarkers of cardiac fibrosis (galectin-3, sST2, serpin-4, procollagen type I amino-terminal peptide, procollagen type I carboxy-terminal propeptide, collagen, transforming growth factor [TGF]-β), inflammation (growth differentiation factor-15, interleukin-6, nuclear factor-κB [NF-κB]), oxidative stress (superoxide dismutase 1 [SOD1] and 2 [SOD2]), and cardiac metabolism (sodium-hydrogen exchanger, peroxisome proliferator-activated receptor [PPAR]-α, PPAR-γ, glucose transporter 1 [GLUT1] and 4 [GLUT4]) were evaluated in blood samples and heart biopsies of 45 patients with AS. Our study showed SGLT2 gene and protein hyper-expression in patients with LF-LG AS, compared to controls and HG AS (p < 0.05). These differences remained significant even after adjusting for age, gender, body mass index, history of diabetes mellitus, arterial hypertension, and coronary artery disease. SGLT2 gene expression was positively correlated with: (i) TGF-β (r = 0.72, p < 0.001) and collagen (r = 0.73, p < 0.001) as markers of fibrosis; (ii) NF-κB (r = 0.36, p < 0.01) and myocardial interleukin-6 (r = 0.68, p < 0.001) as markers of inflammation: (iii) SOD2 (r = -0.38, p < 0.006) as a marker of oxidative stress; (iv) GLUT4 (r = 0.33, p < 0.02) and PPAR-α (r = 0.36, p < 0.01) as markers of cardiac metabolism. In patients with LF-LG AS, SGLT2 gene and protein were hyper-expressed in cardiomyocytes and associated with myocardial fibrosis, inflammation, and oxidative stress.

Critical contribution of mitochondria in the development of cardiomyopathy linked to desmin mutation.

Beyond the observed alterations in cellular structure and mitochondria, the mechanisms linking rare genetic mutations to the development of heart failure in patients affected by desmin mutations remain unclear due in part, to the lack of relevant human cardiomyocyte models. To shed light on the role of mitochondria in these mechanisms, we investigated cardiomyocytes derived from human induced pluripotent stem cells carrying the heterozygous DESE439K mutation that were either isolated from a patient or generated by gene editing. To increase physiological relevance, cardiomyocytes were either cultured on an anisotropic micropatterned surface to obtain elongated and aligned cardiomyocytes, or as a cardiac spheroid to create a micro-tissue. Moreover, when applicable, results from cardiomyocytes were confirmed with heart biopsies of suddenly died patient of the same family harboring DESE439K mutation, and post-mortem heart samples from five control healthy donors. The heterozygous DESE439K mutation leads to dramatic changes in the overall cytoarchitecture of cardiomyocytes, including cell size and morphology. Most importantly, mutant cardiomyocytes display altered mitochondrial architecture, mitochondrial respiratory capacity and metabolic activity reminiscent of defects observed in patient's heart tissue. Finally, to challenge the pathological mechanism, we transferred normal mitochondria inside the mutant cardiomyocytes and demonstrated that this treatment was able to restore mitochondrial and contractile functions of cardiomyocytes. This work highlights the deleterious effects ofDESE439Kmutation, demonstrates the crucial role of mitochondrial abnormalities in the pathophysiology of desmin-related cardiomyopathy, and opens up new potential therapeutic perspectives for this disease.

YB-1 Is a Novel Target for the Inhibition of α-Adrenergic-Induced Hypertrophy.

Cardiac hypertrophy resulting from sympathetic nervous system activation triggers the development of heart failure. The transcription factor Y-box binding protein 1 (YB-1) can interact with transcription factors involved in cardiac hypertrophy and may thereby interfere with the hypertrophy growth process. Therefore, the question arises as to whether YB-1 influences cardiomyocyte hypertrophy and might thereby influence the development of heart failure. YB-1 expression is downregulated in human heart biopsies of patients with ischemic cardiomyopathy (n = 8), leading to heart failure. To study the impact of reduced YB-1 in cardiac cells, we performed small interfering RNA (siRNA) experiments in H9C2 cells as well as in adult cardiomyocytes (CMs) of rats. The specificity of YB-1 siRNA was analyzed by a miRNA-like off-target prediction assay identifying potential genes. Testing three high-scoring genes by transfecting cardiac cells with YB-1 siRNA did not result in downregulation of these genes in contrast to YB-1, whose downregulation increased hypertrophic growth. Hypertrophic growth was mediated by PI3K under PE stimulation, as well by downregulation with YB-1 siRNA. On the other hand, overexpression of YB-1 in CMs, caused by infection with an adenovirus encoding YB-1 (AdYB-1), prevented hypertrophic growth under α-adrenergic stimulation with phenylephrine (PE), but not under stimulation with growth differentiation factor 15 (GDF15; n = 10-16). An adenovirus encoding the green fluorescent protein (AdGFP) served as the control. YB-1 overexpression enhanced the mRNA expression of the Gq inhibitor regulator of G-protein signaling 2 (RGS2) under PE stimulation (n = 6), potentially explaining its inhibitory effect on PE-induced hypertrophic growth. This study shows that YB-1 protects cardiomyocytes against PE-induced hypertrophic growth. Like in human end-stage heart failure, YB-1 downregulation may cause the heart to lose its protection against hypertrophic stimuli and progress to heart failure. Therefore, the transcription factor YB-1 is a pivotal signaling molecule, providing perspectives for therapeutic approaches.

E3 ubiquitin ligase COP1-mediated CEBPB ubiquitination regulates the inflammatory response of macrophages in sepsis-induced myocardial injury.

CCAAT/enhancer-binding protein beta (CEBPB) has been associated with sepsis. However, its role in sepsis-induced myocardial injury (SIMI) remains ill-defined. This research was designed to illustrate the involvement of CEBPB in SIMI and its upstream modifier. The transcriptomic changes in heart biopsies of mice that had undergone polymicrobial sepsis were downloaded from the GEO dataset for KEGG enrichment analysis. CEBPB, on the TNF signaling pathway, was significantly enhanced in the myocardial tissues of mice with SIMI. Downregulation of CEBPB alleviated SIMI, as evidenced by minor myocardial injury and inflammatory manifestations. Moreover, ubiquitination modification of CEBPB by constitutive photomorphogenesis protein 1 homolog (COP1) led to the degradation of CEBPB and inhibited inflammatory responses in macrophages. Upregulation of COP1 protected against SIMI in mice overexpressing CEBPB. Collectively, our findings demonstrated that COP1 protected the heart against SIMI through the ubiquitination modification of CEBPB, which might be a novel therapeutic approach in the future.

Sex differences and estrogen effects in cardiac mitochondria in human aortic stenosis and in the mouse heart.

Sex differences in the adaptation to pressure overload have been described in humans, as well as animal models, and have been related to sex-specific expression of mitochondrial genes. We therefore tested whether sex differences in cardiac mitochondrial respiration exist in humans with aortic stenosis (AS). We also examined whether these potential differences may be at least partially due to sex hormones by testing if mitochondrial respiration is affected by estrogen (17ß-estradiol (E2)). Consecutive patients undergoing transapical aortic valve implantation (TAVI) (women, n = 7; men, n = 10) were included. Cardiac biopsies were obtained during TAVI and used directly for mitochondrial function measurements. Male and female C57BL/6J mice (n = 8/group) underwent sham surgery or gonadectomy (GDX) at the age of 2 months. After 14 days, mice were treated once with intraperitoneally injected vehicle (placebo), 17ß-estradiol (E2), estrogen receptor alpha (ERα) agonist [propyl pyrazole triol (PPT)], or ER beta (ERβ) agonist (BAY-1214257). Thereafter, mitochondrial measurements were performed directly in cardiac skinned fibers from isolated left ventricles and musculus solei. Mitochondrial State-3 respiration was higher in female than that in male human heart biopsies (15.0 ± 2.30 vs. 10.3 ± 2.05 nmol/mL/min/mg, p< 0.05). In the mouse model, mitochondrial State-3 respiration decreased significantly after GDX in female (27.6 ± 1.55 vs. 21.4 ± 1.71 nmol/mL/min/mg; p< 0.05) and male hearts (30.7 ± 1,48 vs. 23.7 ± 2,23 nmol/mL/min/mg; p< 0.05). In ovariectomized female mice, E2 and ERβ-agonist treatment restored the State-3 respiration to intact placebo level, whereas ERα-agonist treatment did not modulate State-3 respiration. The treatment with E2, ERα-, or ERβ-agonist did not modulate the State-3 respiration in GDX male mice. We identified sex differences in mitochondrial respiration in the diseased human heart. This is in alignment with known sex differences in the gene expression and proteome level at the functional level. E2 and ERβ affect cardiac mitochondrial function in the mouse model, suggesting that they may also contribute to the sex differences in the human heart. Their roles should be further investigated.

Heart biopsy in follow-up of patients after transplantation

Heart biopsy in follow-up of patients after transplantation

Mapping of SARS-CoV-2 in Waldeyer’s lymphatic ring and visceral biopsies: the age and the illness duration’s impact

ObjectiveTo study the impact of age and the interval between disease diagnosis and death on the organotropism of SARS-CoV-2. MethodPatients underwent post-mortem biopsies from lungs, Waldeyer ring, heart, liver, kidneys and bone marrow between 2020‒2021. SARS-CoV-2 organotropism was mapped by using molecular RT-PCR analyses for SARS-CoV2 targeting the Envelope gene (E), the RNA Polymerase Gene (RdRp), and the Nucleocapsid gene (N). Statistical and linear regression analysis was performed to study the impact of age and illness duration in SARS-CoV-2 organotropism. ResultsWe performed 158 postmortem biopsies in 21 patients, with a mean age of 76 years old. The mean interval between the diagnosis of the infection to the death was 23 days. The RNA of the SARS-CoV-2 was detected in 100% of lung biopsies, 76%‒82% of Waldeyer’s ring biopsies, 55% of heart biopsies, 40% of kidney biopsies, 33% of liver and 25% of bone marrow biopsies. Patients who died before the day 9, presented extensive visceral dissemination of SARS-CoV-2 RNA. Most of the patients older than 80 years (90%) presented visceral dissemination of SARS-CoV-2 RNA, while among younger patients, only 3/11 patients presented visceral dissemination of the virus. The relationship between “age” and “illness duration” and multitropism of the virus was statistically significant (p<0.001). ConclusionDisease interval and age were factors that were significantly associated with RT-PCR positive results in multiple organs. Critical COVID-19 patients have multiorganic viral dissemination in early stages. In the critical older patients, multiorganic viral dissemination is the rule. Level of evidence4. Case Series.

A Case Report of Triple Organ Transplantation From a Donor After Circulatory Death Using Thoraco-Abdominal Normothermic Regional Perfusion

Organ transplantation with donation after circulatory death can potentially increase the donor pool. Here, we report the rare case of triple-organ (heart/liver/kidney) transplantation from a donor after circulatory death using thoraco-abdominal normothermic regional perfusion. The recipient was a 61-year-old man with end-stage heart failure, liver failure, and kidney failure secondary to arrhythmogenic right ventricular dysplasia. He received a heart/liver/kidney transplantation from a donor after circulatory death. The course was complicated with primary graft dysfunction of the heart that resolved on postoperative day 3. The patient was discharged on postoperative day 39. He has no evidence for rejection on heart biopsy, and all 3 organs exhibit stable function. The use of donation after cardiac death donors greatly increases the donor pool and should be considered for patients requiring multiorgan transplantation. The use of thoraco-abdominal normothermic reperfusion is not only a feasible method for multiorgan procurement but also provides enhanced protection for all transplanted organs.

Investigation of the Role of BMP2 and -4 in ASD, VSD and Complex Congenital Heart Disease.

Congenital heart malformations (CHMs) make up between 2 and 3% of annual human births. Bone morphogenetic proteins (BMPs) signalling is required for chamber myocardium development. We examined for possible molecular defects in the bone morphogenetic protein 2 and 4 (BMP2, -4) genes by sequencing analysis of all coding exons, as well as possible transcription or protein expression deregulation by real-time PCR and ELISA, respectively, in 52 heart biopsies with congenital malformations (atrial septal defect (ASD), ventricular septal defect (VSD), tetralogy ofFallot (ToF) and complex cases) compared to 10 non-congenital heart disease (CHD) hearts. No loss of function mutations was found; only synonymous single nucleotide polymorphisms (SNPs) in the BMP2 and BMP4 genes were found. Deregulation of the mRNA expression and co-expression profile of the two genes (BMP2/BMP4) was observed in the affected compared to the normal hearts. BMP2 and -4 protein expression levels were similar in normal and affected hearts. This is the first study assessing the role of BMP-2 and 4 in congenital heart malformations. Our analysis did not reveal molecular defects in the BMP2 and -4 genes that could support a causal relationship with the congenital defects present in our patients. Importantly, sustained mRNA and protein expression of BMP2 and -4 in CHD cases compared to controls indicates possible temporal epigenetic, microRNA or post-transcriptional regulation mechanisms governing the initial stages of cardiac malformation.

Development of a Method for Isolation of Mature Cardiomyocytes from Human Heart Biopsy Specimens.

To increase the yield of living cells and their survival, studies were carried out to optimize the method for isolating cardiomyocytes from biopsy specimens excised from the right atrial appendages. It was found that creatine, blebbistatin, and taurine are necessary components of the buffer solution during cardiomyocyte isolation, and that composition of the solutions is a more important factor than their oxygenation.

Hydroxychloroquine Toxicity in the Vital Organs of the Body: In Vivo Study.

Hydroxychloroquine (HCQ) toxicity can adversely affect vital organs, cause pathologic ocular damage, and can have direct cardiovascular effects. This study aims to identify the biochemical, hematological, and histological alterations of the vital organs associated with the effects of HCQ. Male albino rats were exposed to the equivalent of HCQ therapeutic doses given to human patients being affected by malaria, lupus erythematosus, and COVID-19. The animal blood samples were subjected to hematological analysis, biochemical analysis, liver function tests, kidney function tests, and cardiac biomarkers. Liver, kidney, heart, spleen, and testis biopsies were subjected to histological examination. HCQ significantly lowered the values of erythrocytes, hemoglobin, hematocrit, platelets, leucocytes, and lymphocytes but significantly increased the values of aspartate aminotransferase (AST), alanine aminotransferase (ALT), amylase, alkaline phosphatase, lactate dehydrogenase, cholesterol, and chlorine ions. The renal tissues of HCQ-treated animals demonstrated glomerular fragmentation, partial atrophy degeneration, renal tubules hydropic degeneration, hyaline cast formation, and interstitial edema formation. Additionally, the heart exhibited myofiber necrosis, myolysis, wavy appearance, disorganization, and disarray. The testicular tissues also demonstrated spermatocyte degeneration, spermatogenic cell sloughing, testicular interstitial edema, and occasional spermatogenic arrest. Additionally, the spleen showed a decrease in the number and size of the white pulp follicles, a decrease in the number of apoptotic activity, and a decline in the number of T-rich cells. However, the red pulp demonstrated a diffuse decline in B rich-lymphocytes and macrophages. The liver was also the least affected but showed Kupffer cell hyperplasia and occasional hepatocyte dysplasia. The results indicate that chronic exposure to HCQ could alter the structures and functions of the vital organs.

Capillary rarefaction: a missing link in renal and cardiovascular disease?

Patients with chronic kidney disease (CKD) have an increased risk for cardiovascular morbidity and mortality. Capillary rarefaction may be both one of the causes as well as a consequence of CKD and cardiovascular disease. We reviewed the published literature on human biopsy studies and conclude that renal capillary rarefaction occurs independently of the cause of renal function decline. Moreover, glomerular hypertrophy may be an early sign of generalized endothelial dysfunction, while peritubular capillary loss occurs in advanced renal disease. Recent studies with non-invasive measurements show that capillary rarefaction is detected systemically (e.g., in the skin) in individuals with albuminuria, as sign of early CKD and/or generalized endothelial dysfunction. Decreased capillary density is found in omental fat, muscle and heart biopsies of patients with advanced CKD as well as in skin, fat, muscle, brain and heart biopsies of individuals with cardiovascular risk factors. No biopsy studies have yet been performed on capillary rarefaction in individuals with early CKD. At present it is unknown whether individuals with CKD and cardiovascular disease merely share the same risk factors for capillary rarefaction, or whether there is a causal relationship between rarefaction in renal and systemic capillaries. Further studies on renal and systemic capillary rarefaction, including their temporal relationship and underlying mechanisms are needed. This review stresses the importance of preserving and maintaining capillary integrity and homeostasis in the prevention and management of renal and cardiovascular disease.

Current Utilization of Electron Microscopy in the Pediatric Pathology Setting: A Survey by the SPP Practice Committee.

Electron microscopy (EM), once an important component in diagnosing pediatric diseases, has experienced a decline in its use. To assess the impact of this, pediatric pathology practices were surveyed regarding EM services. The Society of Pediatric Pathology Practice Committee surveyed 113 society members from 74 hospitals. Settings included 36 academic tertiary, 32 free-standing children's, and 6 community hospitals. Over 60% maintained in-house EM services and had more than 2 pathologists interpreting EM while reporting a shortage of EM technologists. Freestanding children's hospitals had the most specimens (100-200 per year) and more diverse specimen types. Hospitals with fewer than 50 yearly specimens often used reference laboratories. Seventeen had terminated all in-house EM services. Challenges included decreasing caseloads due to alternative diagnostic methods, high operating costs, and shortages of EM technologists and EM-proficient pathologists. Kidney, liver, cilia, heart, and muscle biopsies most often required EM. Lung/bronchoalveolar lavage, tumor, skin, gastrointestinal, nerve, platelet, and autopsy samples less commonly needed EM. The survey revealed challenges in maintaining EM services but demonstrated its sustained value in pediatric pathology. Pediatric pathologists may need to address the centralization of services and training to preserve EM diagnostic proficiency among pathologists who perform ultrastructural interpretations.