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2.
Cureus ; 15(5): e39168, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37332408

RESUMO

Bisphenol analogues are widely used in consumer products such as disposable dinnerware, canned food, personal care products, bottled beverages, and more, and dietary exposure is the main pathway. Bisphenol A is used to manufacture synthetic resins and commercial plastics in large quantities. According to epidemiological and animal studies, bisphenols disrupt the reproductive, immunological, and metabolic systems. These analogues are estrogenic like Bisphenol A, although human studies are limited. We did a thorough search of the literature on the toxicity of bisphenol on reproductive and endocrine systems in pregnancy, focusing particularly on human studies. Hence, we present a comprehensive literature review on this topic.​​​​​​​ During our literature search, three epidemiological studies and one human observational study demonstrated a substantial link between bisphenol toxicity and recurrent miscarriages.​​​​​​​ The aforementioned research shows that bisphenol may harm pregnancy and cause miscarriages. We believe this is the first literature review on the topic.

3.
Cureus ; 15(12): e51387, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38292991

RESUMO

AIM/OBJECTIVE: Bisphenols are widely used in the manufacturing of polycarbonate material and epoxy resins which constitute the essential component of plastic. Bisphenol A (BPA) has been reported to produce toxicity on organs in both animal and human studies. Therefore, plastic manufacturers are replacing BPA with other analogues that are considered to be safe, and BPA-free products are now available in the market. However, some studies have reported that bisphenol-S (BPS) also possesses toxic properties. It has been reported to depress ventricular contraction as well as produce ventricular arrhythmia on acute exposure. The present study was performed to examine the effect of BPS on in vitro spontaneously-beating right atria in rats. METHODS: In the present study, in vitro spontaneous contractions of right atria obtained from adult female rats of the Wistar strain were recorded. The atria were exposed to BPS (10-6-10 mM) and its effects on atrial contractions were recorded in the form of cumulative-concentration response with and without administration of antagonists namely atropine, L-NAME, and methylene blue. RESULTS: BPS decreased the rate as well as the force of atrial contractions. The changes produced in the rate and force of atrial contractions were not attributed to ethanol, which was used to prepare BPS solutions. The decrease in right atrial contractility produced by BPS was blocked by L-NAME; however, atropine and methylene blue were not able to antagonize the effects of BPS on atria. CONCLUSIONS: The present study indicates the involvement of NO-dependent but cGMP independent pathway responsible for BPS-induced cardio-toxicity.

4.
Circulation ; 146(22): 1674-1693, 2022 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-36321451

RESUMO

BACKGROUND: ALPK3 encodes α-kinase 3, a muscle-specific protein of unknown function. ALPK3 loss-of-function variants cause cardiomyopathy with distinctive clinical manifestations in both children and adults, but the molecular functions of ALPK3 remain poorly understood. METHODS: We explored the putative kinase activity of ALPK3 and the consequences of damaging variants using isogenic human induced pluripotent stem cell-derived cardiomyocytes, mice, and human patient tissues. RESULTS: Multiple sequence alignment of all human α-kinase domains and their orthologs revealed 4 conserved residues that were variant only in ALPK3, demonstrating evolutionary divergence of the ALPK3 α-kinase domain sequence. Phosphoproteomic evaluation of both ALPK3 kinase domain inhibition and overexpression failed to detect significant changes in catalytic activity, establishing ALPK3 as a pseudokinase. Investigations into alternative functions revealed that ALPK3 colocalized with myomesin proteins (MYOM1, MYOM2) at both the nuclear envelope and the sarcomere M-band. ALPK3 loss-of-function variants caused myomesin proteins to mislocalize and also dysregulated several additional M-band proteins involved in sarcomere protein turnover, which ultimately impaired cardiomyocyte structure and function. CONCLUSIONS: ALPK3 is an essential cardiac pseudokinase that inserts in the nuclear envelope and the sarcomere M-band. Loss of ALPK3 causes mislocalization of myomesins, critical force-buffering proteins in cardiomyocytes, and also dysregulates M-band proteins necessary for sarcomere protein turnover. We conclude that ALPK3 cardiomyopathy induces ventricular dilatation caused by insufficient myomesin-mediated force buffering and hypertrophy by impairment of sarcomere proteostasis.


Assuntos
Cardiomiopatias , Células-Tronco Pluripotentes Induzidas , Proteínas Musculares , Proteínas Quinases , Adulto , Animais , Criança , Humanos , Camundongos , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Conectina/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Proteínas Musculares/genética , Miócitos Cardíacos/metabolismo , Sarcômeros/metabolismo , Proteínas Quinases/genética
5.
Indian J Pathol Microbiol ; 65(4): 891-894, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36308200

RESUMO

Introduction: Protocol for immunocytochemical (ICC) staining in May-Grünwald Giemsa (MGG)-stained smears has been difficult to establish. It is the need of the hour to be able to use prestained slides for ICC in specific cases to deliver timely diagnoses and reduce inconvenience to patients. Aims and Objectives: To evaluate and compare the use of MGG-stained smears for the purpose of ICC, after de-staining and saline rehydration to that of routine standard ICC. Materials and Methods: A prospective study was conducted on 40 FNAC samples: 25 cases of breast disease and 15 cases of reactive lymphoid hyperplasia known to express pancytokeratin and leukocyte common antigen (LCA)/CD45, respectively. Air-dried smears of each case were stained by standard MGG stain and after the report was dispatched, one smear was selected and sent for ICC. The smears were analyzed to determine the overall result and grade each smear semi-quantitatively with respect to staining-intensity, stain-localization, staining-uniformity, counter-staining, and background-staining. Observations and Results: The proposed protocol was inferior to conventional ICC in all the parameters, more pronounced in pancytokeratin than LCA/CD45. Only 8% of air-dried smears stained for pancytokeratin showed optimal stain intensity (as opposed to 44% of wet-fixed smears), whereas only 14.3% of air-dried smears were optimally stained for LCA (as opposed to 85.7% of wet-fixed smears). Conclusion: The proposed protocol of de-stained Giemsa smears as an alternative to conventional technique for ICC was unsuccessful in giving satisfactory results.


Assuntos
Corantes , Humanos , Corantes Azur , Imuno-Histoquímica , Estudos Prospectivos , Amarelo de Eosina-(YS) , Coloração e Rotulagem
6.
Ann Oper Res ; : 1-24, 2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36091932

RESUMO

The thought to put forward a queuing model proposed in this work was its pertinence in everyday life wherever we can see the uses of computing and networking systems. Industrial software developers and system managers can consider the results of the model to evolve their system for better results. Here we present a novel queueing model having erratic server with delayed repair and balking. Two distinct breakdowns i.e. active and passive breakdown for the system are also considered with their respective amendments. This model is closely related with the smooth functioning of the system during some internal faults (virus attack, electricity failures etc.). The performance indicators which are utilized in enhancing the service standards are obtained using supplementary variable technique. Using ANFIS soft computing technique we have compared the analytical results with those of neuro fuzzy results. Furthermore single and bi-objective minimization problems are considered and minima is obtained using particle swarm optimization and multi objective genetic algorithm respectively. Also, the minimization problems are shown as a convex programming problem to ensure the global optimality of the result. The proposed approach makes it conceivable to accomplish a relevant harmony between operational expenses and administration quality.

7.
J Cytol ; 39(1): 9-13, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35341110

RESUMO

Aims and Objectives: To study the diagnostic utility of fine-needle aspiration cytology (FNAC) and immunocytochemistry in diagnosing primary malignant mixed Mullerian tumors (MMMT). Materials and Methods: A 3-year retrospective study carried out in a tertiary care hospital, which included all the gynecological patients who underwent USG-guided FNAC of their abdominopelvic masses. Observations and Results: Out of the 324 total cases, 05 (1.5%) were reported as primary malignant mixed Mullerian tumors. Out of these 05 cases, 03 were ovarian, 01 was uterine, and 01 involved both uterus and one-sided adnexa. The FNA smears from the masses revealed cytomorphological features of a biphasic neoplasm with elongated pleomorphic spindle cells and dispersed, focal attempted acinar pattern, thus indicating the possibility of MMMT. Immunocytochemistry was further carried out which showed both vimentin and cytokeratin positivity. The diagnosis was confirmed on subsequent biopsy and immunohistochemistry (without any histopathological-cytological discrepancy). Conclusion: Though the literature is replete in establishing a histo-pathological diagnosis of MMMT, the diagnosis on USG-guided FNAC has been rarely described. Emphasis should be made on the careful examination of small sarcomatous elements in smears. Utilization of cell block and immunocytochemistry with histopathological correlation should be done to avoid misdiagnosis.

8.
Int J Legal Med ; 136(2): 465-473, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34748086

RESUMO

With the advent of next-generation sequencing technology, SNP markers are being explored as a useful alternative to conventional capillary electrophoresis-based STR typing. Low mutation rate and short-sized amplicons are added advantages of SNP markers over the STRs. However, to achieve a sufficient level of discrimination among individuals, a higher number of SNPs need to be characterized simultaneously. Hence, the NGS technique is highly useful to analyze a sufficiently higher number of SNPs simultaneously. Though the technique is in its nascent stage, an attempt has been made to assess its usability in the central Indian population by analyzing 124 SNPs (90 autosomal and 34 Y-chromosome) in 95 individuals. Various quality parameters such as locus balance, locus strand balance, heterozygosity balance, and noise level showed a good quality sequence obtained from the Ion GeneStudio S5 instrument. Obtained frequency of SNP alleles ranged from 0.001 to 0.377 in autosomal SNPs. rs9951171 was found to be the most informative SNP in the studied population with the highest PD and lowest MP value. The cumulative MP of 90 SNPs was found to be 4.76698 × 10-37. Analysis of 34 Y-chromosome SNPs reveals 11 unique haplogroups in 54 male samples with R1a1 as the most frequent haplogroup found in 22.22% of samples. Interpopulation comparison by FST analysis, PCA plot, and STRUCTURE analysis showed genetic stratification of the studied population suggesting the utility of SNP markers present in the Precision ID Identity Panel for forensic demands of the Indian population.


Assuntos
Repetições de Microssatélites , Polimorfismo de Nucleotídeo Único , Povo Asiático , Cromossomos Humanos Y , Impressões Digitais de DNA , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Análise de Sequência de DNA
9.
Ann Hum Biol ; 48(7-8): 605-613, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34866517

RESUMO

BACKGROUND: Most of the forensic DNA laboratories have migrated to new generation STR kits of 6 dye chemistry with more than 20 autosomal STRs. The population-specific databases of such STR markers are lacking in many regions. AIM: To evaluate the effect of the inter-population database in 100 paternity trios with no inconsistencies at 23 STRs. SUBJECTS AND METHODS: 100 paternity trios were evaluated considering inter-population allelic frequency values for calculation of Combined Paternity Index (CPI) and Probability of Paternity (POP). RESULTS: No significant variation (p < 0.05) among the allele frequencies at the interpopulation level was observed. The number of obligate alleles and the likelihood of transferring obligate alleles from the putative father showed a positive correlation (p < 0.005) with Power of Discrimination (PD), Polymorphic Information Content (PIC), Power of Exclusion (PE), Paternity Index (PI), Observed and Expected Heterozygosity (Ho and He), and a statistically significant negative correlation (p < 0.005) with Matching Probability (Pm). The average Combined Paternity Index (CPI) and Probability of Paternity (POP) did not show any statistically significant difference (p < 0.05) at the interpopulation level. CONCLUSION: The allelic database showed no effect on the CPI and POP in 100 paternity trios. This suggests no urgent need for using population-specific databases for statistical evaluation of paternity trios without inconsistencies.


Assuntos
Repetições de Microssatélites , Paternidade , Alelos , Frequência do Gene , Genética Populacional , Humanos , Masculino , Repetições de Microssatélites/genética
10.
Curr Pharm Des ; 27(45): 4578-4592, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34620056

RESUMO

The field of oncology is vast and ever-growing. The present cancer therapeutics is continually exhibiting various drawbacks, which opens the door for exploring better novel therapeutic techniques. One such emerging technique is the manipulation of gut microbiota to induce a positive curative effect in the body. The dynamic gut microbiota of our body houses an astonishing number of microorganisms, mainly bacteria. The balance of the gut microbiota is essential for good health as imbalances may result in dysbiosis leading to various diseases such as cancer. The gut microbiota can be manipulated by using prebiotics, probiotics, synbiotics, postbiotics, and antibiotics for better therapeutic outcomes, as well as to improve the quality of life of patients undergoing conventional cancer treatment. Administration of bacteria as a probiotic agent accompanied with prebiotics obtained from a wide variety of herbs has been used effectively to enhance the treatment of various cancers. Although the theoretical basis of Gut therapy can be ascertained, further clinical trials will be essential to determine the scope and limitations fully. The present review provides a glimpse of conventional and novel cancer therapeutics and their drawbacks, along with the role of the gut microbiome and its modulation to design new pharmaceutics against cancer.


Assuntos
Microbioma Gastrointestinal , Neoplasias , Probióticos , Simbióticos , Disbiose , Humanos , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Prebióticos , Probióticos/uso terapêutico , Qualidade de Vida
11.
J Cancer Res Ther ; 17(4): 1059-1063, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34528564

RESUMO

BACKGROUND: Hepatoblastoma (HB), rare malignancy in itself, is the most common primary liver tumor in children. Most common presenting features are abdominal distension or abdominal mass. Several patterns are associated with HB with different prognosis. Furthermore, some patterns have overlapping features with other childhood tumors. AIMS AND OBJECTIVES: The aim of this study is to discuss various patterns of HB which we came across in a tertiary care hospital during our study. H and E slides were reviewed with respect to different patterns, postchemotherapy changes including extramedullary hematopoiesis, necrosis, osteoid metaplasia, necrosis, and fibrosis. CONCLUSION: Different patterns of HB should be kept in mind by the pathologists to avoid any misdiagnosis.


Assuntos
Hepatoblastoma/patologia , Neoplasias Hepáticas/patologia , Centros de Atenção Terciária/estatística & dados numéricos , Criança , Pré-Escolar , Feminino , Seguimentos , Hepatoblastoma/cirurgia , Humanos , Lactente , Neoplasias Hepáticas/cirurgia , Masculino , Prognóstico , Estudos Retrospectivos
12.
J Cancer Res Ther ; 17(4): 1115-1118, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34528574

RESUMO

Acinic cell carcinoma (ACC) is a malignant salivary gland tumor characterized by tumor cells displaying acinar features. Usually presenting as a slow-growing tumor, ACC, however, may show dedifferentiation to a higher grade including neuroendocrine carcinoma. In addition, ACC may rarely show focal neuroendocrine differentiation without any frank evidence of neuroendocrine carcinoma. We describe such a case of ACC of the parotid gland in a 65-year-old female, which showed neuroendocrine differentiation. The diagnostic clues, immunohistochemistry panel, and prognostic and treatment aspects are also presented.


Assuntos
Carcinoma de Células Acinares/patologia , Carcinoma Neuroendócrino/patologia , Diferenciação Celular , Neoplasias Parotídeas/patologia , Idoso , Feminino , Humanos , Prognóstico
14.
Diagn Cytopathol ; 49(4): 487-493, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33492721

RESUMO

OBJECTIVE: Fine needle aspiration (FNA) cytology has been successfully utilized in the preoperative diagnosis of oral masses. Lymphoma involving other sites has also been diagnosed frequently on FNA. Oral cavity lymphoma (OL) is rare and is clinically indistinguishable from other lesions of the mouth. A complete excision of these may be difficult. Our experience with FNA diagnosis of 11 OLs along with histopathological correlation is reported herein in a tertiary health care setting. METHODS: In this retrospective study, clinico pathological characteristics of patients with final diagnosis of non-Hodgkin's lymphoma (NHL) were reviewed over a 7 year period. Routine cytological giemsa staining was performed in all cases along with immunocytochemistry (ICC) wherever possible. The gold standard for diagnosis of NHL was based on: (1) Histopathology and immunohistochemistry and/or (2) Flow cytometry (FC). RESULTS: A total of 11 cases were diagnosed as NHL. All showed B cell immunophenotype. Two of them were diagnosed as follicular lymphoma on histopathology. Male to female ratio was 7:4 and ranged in age from 37 to 70 years. The most common site was tonsillar fossa (N = 5), followed by hard palate (N = 3), soft palate (N = 2), and buccal mucosa (N = 1). Size ranged from 1 to 6 cm. CONCLUSIONS: Diagnosis of OLs may be hampered by its rarity and difficulties in obtaining sufficient cellularity in oral FNA but there is need for immediate and accurate diagnostic procedures, including immunohistochemical analysis to avoid delay in treatment. FNA along with ICC helps in early diagnosis of this rare entity and can also provide sample for FC.


Assuntos
Linfoma/patologia , Neoplasias Bucais/patologia , Adulto , Idoso , Biópsia por Agulha Fina/métodos , Biópsia por Agulha Fina/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mucosa Bucal/patologia , Palato/patologia , Tonsila Palatina/patologia , Valor Preditivo dos Testes , Centros de Atenção Terciária
15.
Diagn Cytopathol ; 49(4): E187-E189, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33074579

RESUMO

Scedosporium apiospermum (also known as Pseudallescheria boydii) is a ubiquitous filamentous fungus. This fungus is known as a cause of mycetoma, which may occur in a normal immune host following trauma and nonmycetoma-localized skin infections without grain production which are much rarer. However, in an immunocompromised host, S. apiospermum may cause a life-threatening infection. We describe a case of S. apiospermum infection of the left middle finger in an immunocompetent patient, which was diagnosed on cytology and later confirmed on culture.


Assuntos
Dermatomicoses/patologia , Infecções Fúngicas Invasivas/patologia , Dermatomicoses/microbiologia , Dedos/microbiologia , Dedos/patologia , Humanos , Infecções Fúngicas Invasivas/microbiologia , Masculino , Pessoa de Meia-Idade , Scedosporium/patogenicidade , Pele/microbiologia , Pele/patologia
16.
J Cancer Res Ther ; 16(6): 1408-1411, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33342805

RESUMO

INTRODUCTION: Phyllodes tumor is a group of biphasic fibroepithelial tumors of the breast, graded as benign, borderline, and malignant. The grading of breast phyllodes remains a challenging task for the pathologists as the prognosis, and further treatment depends on it. In this study, an effort has been made to grade phyllodes tumor on the basis of immunohistochemistry. AIMS AND OBJECTIVES: Vascular endothelial growth factor, CD10, and factor 8 have been used as immunohistochemical markers for grading. RESULTS AND CONCLUSION: We have found a significant correlation between the expression of these markers and grading of phyllodes tumor. Positive correlation was also found amongst expression of all three markers. To conclude, increased expression of these markers with increasing grade can aid in diagnosis and guide treatment.


Assuntos
Biomarcadores Tumorais/análise , Neoplasias da Mama/diagnóstico , Fator VIII/análise , Neprilisina/análise , Tumor Filoide/diagnóstico , Fator A de Crescimento do Endotélio Vascular/análise , Adolescente , Adulto , Idoso , Biomarcadores Tumorais/metabolismo , Biópsia , Mama/diagnóstico por imagem , Mama/patologia , Mama/cirurgia , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Criança , Fator VIII/metabolismo , Estudos de Viabilidade , Feminino , Humanos , Imuno-Histoquímica , Mamografia , Pessoa de Meia-Idade , Gradação de Tumores/métodos , Neprilisina/metabolismo , Tumor Filoide/patologia , Tumor Filoide/cirurgia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Adulto Jovem
17.
Elife ; 92020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-33054971

RESUMO

Damaging GATA6 variants cause cardiac outflow tract defects, sometimes with pancreatic and diaphragmic malformations. To define molecular mechanisms for these diverse developmental defects, we studied transcriptional and epigenetic responses to GATA6 loss of function (LoF) and missense variants during cardiomyocyte differentiation of isogenic human induced pluripotent stem cells. We show that GATA6 is a pioneer factor in cardiac development, regulating SMYD1 that activates HAND2, and KDR that with HAND2 orchestrates outflow tract formation. LoF variants perturbed cardiac genes and also endoderm lineage genes that direct PDX1 expression and pancreatic development. Remarkably, an exon 4 GATA6 missense variant, highly associated with extra-cardiac malformations, caused ectopic pioneer activities, profoundly diminishing GATA4, FOXA1/2, and PDX1 expression and increasing normal retinoic acid signaling that promotes diaphragm development. These aberrant epigenetic and transcriptional signatures illuminate the molecular mechanisms for cardiovascular malformations, pancreas and diaphragm dysgenesis that arise in patients with distinct GATA6 variants.


Assuntos
Diafragma/crescimento & desenvolvimento , Fator de Transcrição GATA6/genética , Coração/crescimento & desenvolvimento , Células-Tronco Pluripotentes Induzidas/metabolismo , Pâncreas/crescimento & desenvolvimento , Diferenciação Celular/genética , Epigênese Genética/genética , Perfilação da Expressão Gênica , Humanos , Mutação de Sentido Incorreto/genética , Miócitos Cardíacos/metabolismo
18.
Am Heart J ; 225: 108-119, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32480058

RESUMO

INTRODUCTION: Biallelic damaging variants in ALPK3, encoding alpha-protein kinase 3, cause pediatric-onset cardiomyopathy with manifestations that are incompletely defined. METHODS AND RESULTS: We analyzed clinical manifestations of damaging biallelic ALPK3 variants in 19 pediatric patients, including nine previously published cases. Among these, 11 loss-of-function (LoF) variants, seven compound LoF and deleterious missense variants, and one homozygous deleterious missense variant were identified. Among 18 live-born patients, 8 exhibited neonatal dilated cardiomyopathy (44.4%; 95% CI: 21.5%-69.2%) that subsequently transitioned into ventricular hypertrophy. The majority of patients had extracardiac phenotypes, including contractures, scoliosis, cleft palate, and facial dysmorphisms. We observed no association between variant type or location, disease severity, and/or extracardiac manifestations. Myocardial histopathology showed focal cardiomyocyte hypertrophy, subendocardial fibroelastosis in patients under 4 years of age, and myofibrillar disarray in adults. Rare heterozygous ALPK3 variants were also assessed in adult-onset cardiomyopathy patients. Among 1548 Dutch patients referred for initial genetic analyses, we identified 39 individuals with rare heterozygous ALPK3 variants (2.5%; 95% CI: 1.8%-3.4%), including 26 missense and 10 LoF variants. Among 149 U.S. patients without pathogenic variants in 83 cardiomyopathy-related genes, we identified six missense and nine LoF ALPK3 variants (10.1%; 95% CI: 5.7%-16.1%). LoF ALPK3 variants were increased in comparison to matched controls (Dutch cohort, P = 1.6×10-5; U.S. cohort, P = 2.2×10-13). CONCLUSION: Biallelic damaging ALPK3 variants cause pediatric cardiomyopathy manifested by DCM transitioning to hypertrophy, often with poor contractile function. Additional extracardiac features occur in most patients, including musculoskeletal abnormalities and cleft palate. Heterozygous LoF ALPK3 variants are enriched in adults with cardiomyopathy and may contribute to their cardiomyopathy. Adults with ALPK3 LoF variants therefore warrant evaluations for cardiomyopathy.


Assuntos
Cardiomiopatias/genética , Heterozigoto , Mutação com Perda de Função , Proteínas Musculares/genética , Mutação de Sentido Incorreto , Proteínas Quinases/genética , Anormalidades Múltiplas/genética , Adulto , Idade de Início , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/fisiopatologia , Cardiomiopatia Dilatada/genética , Cardiomiopatia Hipertrófica/genética , Criança , Pré-Escolar , Cromossomos Humanos Par 15/genética , Ecocardiografia , Eletrocardiografia , Humanos , Lactente , Fenótipo
20.
Circulation ; 141(10): 828-842, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-31983222

RESUMO

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is caused by pathogenic variants in sarcomere protein genes that evoke hypercontractility, poor relaxation, and increased energy consumption by the heart and increased patient risks for arrhythmias and heart failure. Recent studies show that pathogenic missense variants in myosin, the molecular motor of the sarcomere, are clustered in residues that participate in dynamic conformational states of sarcomere proteins. We hypothesized that these conformations are essential to adapt contractile output for energy conservation and that pathophysiology of HCM results from destabilization of these conformations. METHODS: We assayed myosin ATP binding to define the proportion of myosins in the super relaxed state (SRX) conformation or the disordered relaxed state (DRX) conformation in healthy rodent and human hearts, at baseline and in response to reduced hemodynamic demands of hibernation or pathogenic HCM variants. To determine the relationships between myosin conformations, sarcomere function, and cell biology, we assessed contractility, relaxation, and cardiomyocyte morphology and metabolism, with and without an allosteric modulator of myosin ATPase activity. We then tested whether the positions of myosin variants of unknown clinical significance that were identified in patients with HCM, predicted functional consequences and associations with heart failure and arrhythmias. RESULTS: Myosins undergo physiological shifts between the SRX conformation that maximizes energy conservation and the DRX conformation that enables cross-bridge formation with greater ATP consumption. Systemic hemodynamic requirements, pharmacological modulators of myosin, and pathogenic myosin missense mutations influenced the proportions of these conformations. Hibernation increased the proportion of myosins in the SRX conformation, whereas pathogenic variants destabilized these and increased the proportion of myosins in the DRX conformation, which enhanced cardiomyocyte contractility, but impaired relaxation and evoked hypertrophic remodeling with increased energetic stress. Using structural locations to stratify variants of unknown clinical significance, we showed that the variants that destabilized myosin conformations were associated with higher rates of heart failure and arrhythmias in patients with HCM. CONCLUSIONS: Myosin conformations establish work-energy equipoise that is essential for life-long cellular homeostasis and heart function. Destabilization of myosin energy-conserving states promotes contractile abnormalities, morphological and metabolic remodeling, and adverse clinical outcomes in patients with HCM. Therapeutic restabilization corrects cellular contractile and metabolic phenotypes and may limit these adverse clinical outcomes in patients with HCM.


Assuntos
Miosinas Cardíacas/genética , Cardiomiopatia Hipertrófica/metabolismo , Mutação de Sentido Incorreto/genética , Miócitos Cardíacos/fisiologia , Cadeias Pesadas de Miosina/genética , Sarcômeros/metabolismo , Adenosina Trifosfatases , Animais , Cardiomiopatia Hipertrófica/genética , Células Cultivadas , Metabolismo Energético , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Camundongos , Simulação de Dinâmica Molecular , Relaxamento Muscular , Contração Miocárdica , Miócitos Cardíacos/citologia , Conformação Proteica , Sarcômeros/genética
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