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2.
PLoS One ; 19(2): e0297325, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38346068

RESUMO

BACKGROUND: Pancreatic ductal adenocarcinomas (PDAC) have heterogeneous tumor microenvironments relatively devoid of infiltrating immune cells. We aimed to quantitatively assess infiltrating CD3+ and CD8+ lymphocytes in a treatment-naïve patient cohort and assess associations with overall survival and microenvironment inflammatory proteins. METHODS: Tissue microarrays were immunohistochemically stained for CD3+ and CD8+ lymphocytes and quantitatively assessed using QuPath. Levels of inflammation-associated proteins were quantified by multiplexed, enzyme-linked immunosorbent assay panels on matching tumor and tissue samples. RESULTS: Our findings revealed a significant increase in both CD3+ and CD8+ lymphocytes populations in PDAC compared with non-PDAC tissue, except when comparing CD8+ percentages in PDAC versus intraductal papillary mucinous neoplasms (IPMN) (p = 0.5012). Patients with quantitatively assessed CD3+ low tumors (lower 50%) had shorter survival (median 273 days) compared to CD3+ high tumors (upper 50%) with a median overall survival of 642.5 days (p = 0.2184). Patients with quantitatively assessed CD8+ low tumors had significantly shorter survival (median 240 days) compared to CD8+ high tumors with a median overall survival of 1059 days (p = 0.0003). Of 41 proteins assessed in the inflammation assay, higher levels of IL-1B and IL-2 were significantly associated with decreased CD3+ infiltration (r = -0.3704, p = 0.0187, and r = -0.4275, p = 0.0074, respectively). Higher levels of IL-1B were also significantly associated with decreased CD8+ infiltration (r = -0.4299, p = 0.0045), but not IL-2 (r = -0.0078, p = 0.9616). Principal component analysis of the inflammatory analytes showed diverse inflammatory responses in PDAC. CONCLUSION: In this work, we found a marked heterogeneity in infiltrating CD3+ and CD8+ lymphocytes and individual inflammatory responses in PDAC. Future mechanistic studies should explore personalized therapeutic strategies to target the immune and inflammatory components of the tumor microenvironment.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Linfócitos do Interstício Tumoral , Neoplasias Pancreáticas/patologia , Carcinoma Ductal Pancreático/patologia , Linfócitos T CD8-Positivos , Inflamação/patologia , Prognóstico , Microambiente Tumoral
3.
Mol Cancer Ther ; 21(1): 184-192, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34667112

RESUMO

Pancreatic cancer is the third most common cause of cancer-related deaths in the United States. Although gemcitabine is the standard of care for most patients with pancreatic cancer, its efficacy is limited by the development of resistance. This resistance may be attributable to the evasion of apoptosis caused by the overexpression of BCL-2 family antiapoptotic proteins. In this study, we investigated the role of BCL-XL in gemcitabine resistance to identify a combination therapy to more effectively treat pancreatic cancer. We used CRISPR-Cas9 screening to identify the key genes involved in gemcitabine resistance in pancreatic cancer. Pancreatic cancer cell dependencies on different BCL-2 family proteins and the efficacy of the combination of gemcitabine and DT2216 (a BCL-XL proteolysis targeting chimera or PROTAC) were determined by MTS, Annexin-V/PI, colony formation, and 3D tumor spheroid assays. The therapeutic efficacy of the combination was investigated in several patient-derived xenograft (PDX) mouse models of pancreatic cancer. We identified BCL-XL as a key mediator of gemcitabine resistance. The combination of gemcitabine and DT2216 synergistically induced cell death in multiple pancreatic cancer cell lines in vitro In vivo, the combination significantly inhibited tumor growth and prolonged the survival of tumor-bearing mice compared with the individual agents in pancreatic cancer PDX models. Their synergistic antitumor activity is attributable to DT2216-induced degradation of BCL-XL and concomitant suppression of MCL-1 by gemcitabine. Our results suggest that DT2216-mediated BCL-XL degradation augments the antitumor activity of gemcitabine and their combination could be more effective for pancreatic cancer treatment.


Assuntos
Antineoplásicos/uso terapêutico , Desoxicitidina/análogos & derivados , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias Pancreáticas/tratamento farmacológico , Piperazinas/uso terapêutico , Proteína bcl-X/metabolismo , Animais , Antineoplásicos/farmacologia , Desoxicitidina/farmacologia , Desoxicitidina/uso terapêutico , Humanos , Camundongos , Camundongos Endogâmicos NOD , Neoplasias Pancreáticas/patologia , Piperazinas/farmacologia , Gencitabina
4.
Gastrointest Endosc ; 95(4): 626-633, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34906544

RESUMO

BACKGROUND AND AIMS: Data are limited on the role of endoscopic submucosal dissection (ESD) as a potential diagnostic and staging tool in Barrett's esophagus (BE) neoplasia. We aimed to evaluate the frequency and factors associated with change of histologic diagnosis by ESD compared with pre-ESD histology. METHODS: This was a multicenter, prospective cohort study of patients who underwent ESD for BE visible neoplasia. A change in histologic diagnosis was defined as "upstaged" or "downstaged" if the ESD specimen had a higher or lower degree, respectively, of dysplasia or neoplasia when compared with pre-ESD specimens. RESULTS: Two hundred five patients (median age, 69 years; 81% men) with BE visible neoplasia underwent ESD from 2016 to 2021. Baseline histology was obtained using forceps (n = 182) or EMR (n = 23). ESD changed the histologic diagnosis in 55.1% of cases (113/205), of which 68.1% were upstaged and 31.9% downstaged. The frequency of change in diagnosis after ESD was similar whether baseline histology was obtained using forceps (55.5%) or EMR (52.2%) (P = .83). In aggregate, 23.9% of cases (49/205) were upstaged to invasive cancer on ESD histopathology. On multivariate analysis, lesions in the distal esophagus and gastroesophageal junction (odds ratio, 2.1; 95 confidence interval, 1.1-3.9; P = .02) and prior radiofrequency ablation (odds ratio, 2.5; 95% confidence interval, 1.2-5.5; P = .02) were predictors of change in histologic diagnosis. CONCLUSIONS: ESD led to a change of diagnosis in more than half of patients with BE visible neoplasia. Selective ESD can serve as a potential diagnostic and staging tool, particularly in those with suspected invasive disease. (Clinical trial registration number: NCT02989818.).


Assuntos
Adenocarcinoma , Esôfago de Barrett , Ressecção Endoscópica de Mucosa , Neoplasias Esofágicas , Adenocarcinoma/diagnóstico , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Idoso , Esôfago de Barrett/diagnóstico , Esôfago de Barrett/patologia , Esôfago de Barrett/cirurgia , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/patologia , Neoplasias Esofágicas/cirurgia , Feminino , Humanos , Masculino , Estudos Prospectivos , Estudos Retrospectivos
8.
Bioorg Chem ; 109: 104661, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33636438

RESUMO

Microbial metabolite mimicry is a new concept that promises to deliver compounds that have minimal liabilities and enhanced therapeutic effects in a host. In a previous publication, we have shown that microbial metabolites of L-tryptophan, indoles, when chemically altered, yielded potent anti-inflammatory pregnane X Receptor (PXR)-targeting lead compounds, FKK5 and FKK6, targeting intestinal inflammation. Our aim in this study was to further define structure-activity relationships between indole analogs and PXR, we removed the phenyl-sulfonyl group or replaced the pyridyl residue with imidazolopyridyl of FKK6. Our results showed that while removal of the phenyl-sulfonyl group from FKK6 (now called CVK003) shifts agonist activity away from PXR towards the aryl hydrocarbon receptor (AhR), the imidazolopyridyl addition preserves PXR activity in vitro. However, when these compounds are administered to mice, that unlike the parent molecule, FKK6, they exhibit poor induction of PXR target genes in the intestines and the liver. These data suggest that modifications of FKK6 specifically in the pyridyl moiety can result in compounds with weak PXR activity in vivo. These observations are a significant step forward for understanding the structure-activity relationships (SAR) between indole mimics and receptors, PXR and AhR.


Assuntos
Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Indóis/química , Indóis/farmacologia , Receptor de Pregnano X/metabolismo , Adenocarcinoma , Animais , Linhagem Celular Tumoral , Neoplasias do Colo , Desenho de Fármacos , Feminino , Hepatócitos , Humanos , Intestinos , Fígado , Masculino , Camundongos , Pessoa de Meia-Idade , Modelos Moleculares , Mimetismo Molecular , Estrutura Molecular , Receptor de Pregnano X/química , Conformação Proteica , Relação Estrutura-Atividade
12.
Am J Surg Pathol ; 43(12): 1668-1673, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31464710

RESUMO

Many gallbladder adenocarcinomas (ACs) are detected incidentally in routine cholecystectomy specimens, yet sampling practices vary when intestinal metaplasia (IM) or dysplasia are found via routine sampling. Our practice has been to submit 5 additional sections when IM is found, but cases with dysplasia are entirely submitted. We sought to determine an appropriate sampling protocol when encountering these findings. We retrospectively identified cholecystectomy specimens with these features over a 26-month period, yielding 48 of 4059 (1%) cases. Four pathologists independently classified the (2 longitudinal and 1 cystic duct margin) original sections into 1 of 3 categories (IM, low-grade dysplasia [LGD] or high-grade dysplasia [HGD]); initial findings were correlated with final diagnoses. Sixteen (33%) cases had additional findings upon further sampling, including LGD (n=10) or HGD (n=4) and AC (n=2). HGD always accompanied malignancy. We prospectively analyzed 39 of 3133 (1%) additional cholecystectomy specimens, initially submitting the same routine sections. We submitted 5 random sections from cases with IM. Cases with LGD were first examined with 1 additional section per centimeter. All remaining tissue was submitted in all of these cases and separately reviewed. Cases with HGD were entirely submitted as both test cases with HGD in initial sections ultimately showed carcinoma. This protocol detected all cases of HGD and AC. Patients with clear cystic duct margins did not experience neoplastic progression, even if dysplasia was present elsewhere. We conclude gallbladders with HGD should be entirely submitted, LGD may be representatively sampled, and routine sampling is adequate for IM.


Assuntos
Adenocarcinoma/patologia , Colecistectomia , Neoplasias da Vesícula Biliar/patologia , Achados Incidentais , Adenocarcinoma/terapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Feminino , Neoplasias da Vesícula Biliar/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Variações Dependentes do Observador , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Adulto Jovem
13.
Gastroenterology Res ; 12(2): 72-77, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31019616

RESUMO

BACKGROUND: Desmoplasia and detached papillae were only rarely mentioned in intramucosal adenocarcinoma of esophagus or stomach. This study aimed to examine these two features in early esophageal adenocarcinoma. METHODS: All endoscopic submucosal dissections specimens performed for Barrett's esophagus neoplasm during the year 2013 to 2016 were reviewed. These 44 cases included in this study were eight Barrett's esophagus with high-grade dysplasia, 21 intramucosal adenocarcinoma, and 15 submucosally or beyond invasive adenocarcinoma. RESULTS: Desmoplasia occurred in 73% submucosally or beyond invasive adenocarcinoma, higher than intramucosal adenocarcinoma (24%) and high-grade dysplasia (0%) (P < 0.00001 for each). The frequency of detached papillae in intramucosal adenocarcinoma and submucosally or beyond invasive adenocarcinoma specimens was 71.4% and 73.3%, higher than high-grade dysplasia (0%, P < 0.0001 for both). Univariate analysis identified desmoplasia as risk factors for lymphovascular invasion in intramucosal adenocarcinoma specimens (odds ratio 12, P = 0.048), and desmoplasia and tumor thickness for lymphovascular invasion in intramucosal adenocarcinoma and submucosally or beyond invasive adenocarcinoma specimens combined (odds ratio 9.0, P = 0.005; odds ratio 2.7, P = 0.01, respectively). Age, gender, the largest dimension and the average thickness of endoscopic submucosal dissection specimens, tumor size, detached papillae, and poor differentiation were not associated with lymphovascular invasion (P ≥ 0.05 for all). Multivariate analysis confirmed that only desmoplasia was predictive of lymphovascular invasion (odds ratio 8.0, P = 0.02) in intramucosal adenocarcinoma and submucosally or beyond invasive adenocarcinoma specimens combined. CONCLUSIONS: In conclusion, desmoplasia occurs in about a quarter of esophageal intramucosal adenocarcinomas and three quarters of submucosally or beyond invasive adenocarcinomas, and is associated with lymphovascular invasion in early esophageal adenocarcinoma.

14.
Lab Med ; 49(4): 377-384, 2018 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-29982809

RESUMO

BACKGROUND: We describe the differential diagnosis of an obese 12-year-old boy of Mexican origin who presented with a 6-year history of abnormal lipid profile and elevated liver transaminase levels. METHODS: The patient underwent routine clinical testing, an abdominal ultrasound and, ultimately, a liver biopsy. Based on the histologic findings, a serum leukocyte lysosomal acid lipase (LAL) assay and DNA sequencing of the lipase A (LIPA) gene were performed. RESULTS: Liver biopsy revealed diffuse microvesicular steatosis with clusters of foamy histiocytes in the lobules and portal areas. Our differential diagnosis included nonalcoholic fatty liver disease; medication-induced hepatotoxicity; glycogenic hepatopathy; medium-chain acyl coenzyme A dehydrogenase or long-chain acyl coenzyme A dehydrogenase deficiency; and lysosomal storage disorders, including Niemann-Pick disease and lysosomal acid lipase deficiency (LAL-D). Serum LAL activity was absent, and DNA sequencing confirmed homozygous mutation in LIPA. CONCLUSIONS: Although it occurs rarely, LAL-D should be considered in the differential diagnosis of microvesicular steatosis for a timely diagnosis.


Assuntos
Doença de Wolman , Criança , Análise Mutacional de DNA , Diagnóstico Diferencial , Humanos , Fígado/patologia , Masculino , Esterol Esterase/genética , Doença de Wolman/diagnóstico , Doença de Wolman/genética , Doença de Wolman
15.
Ann Gastroenterol ; 30(5): 581-582, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28845118

RESUMO

Primary cutaneous adnexal neoplasms are mostly benign in nature; however, there have been reports of malignant adnexal tumors with distant metastasis to lymph nodes. Adnexal cutaneous malignancy with metastasis to the gastrointestinal tract has never been reported. Here, we present a rare case of a man with primary adnexal cutaneous adenocarcinoma who presented with symptomatic anemia secondary to occult gastrointestinal bleeding, found to be from gastrointestinal metastasis of the adnexal malignancy.

16.
J Investig Med High Impact Case Rep ; 5(1): 2324709617690742, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28491877

RESUMO

Introduction: Nodular regenerative hyperplasia (NRH) is a known etiology of noncirrhotic portal hypertension. Cases of biopsy-proven NRH in human immunodeficiency virus (HIV)-positive patients have been described. While these patients often have normal synthetic liver function, several reports described disease progression to liver failure. Case: We here present a 26-year-old woman with history of congenital HIV on antiretroviral therapy complicated by Pneumocystis carinii pneumonia at age 14. CD4 counts have been >300 with undetectable viral load. She was referred to our Hepatology service for evaluation of splenomegaly, elevated liver tests, and thrombocytopenia. On initial presentation, she reported easy bruising and gingival bleeding, and abdominal imaging showed evidence of portal hypertension without associated cirrhosis. Upper endoscopy was significant for large esophageal varices without bleeding stigmata. Liver biopsy showed minimal fibrosis around the portal areas without significant inflammation. The lobules showed focal zones of thin hepatocyte plates on reticulin stain with adjacent areas showing mild regenerative changes. The diagnosis of NRH was made and patient was placed on propranolol for variceal bleeding prophylaxis. Two years later, the patient presented with bleeding gastric varices warranting transjugular intrahepatic portosystemic shunt. Postprocedure course was complicated by mild encephalopathy. Subsequent magnetic resonance imaging showed a 1.7 × 1.3 cm lesion suggestive of hepatocellular carcinoma (HCC). The patient was deemed to be a candidate for liver transplantation, and she is now delisted due to ongoing pregnancy. Conclusion: This report describes the first case of HCC in an HIV patient with NRH. The possible association of NRH with HCC warrants further investigation.

17.
Am J Surg Pathol ; 38(9): 1251-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25133708

RESUMO

The pseudoangiosarcomatous pattern has been described mostly in cutaneous and some visceral squamous cell carcinomas and is unique for its striking morphologic resemblance to angiosarcoma. Herein, we describe the clinicopathologic features of 7 pseudoangiosarcomatous urothelial carcinomas that occurred in the urinary bladder. The patients included 6 men and 1 woman ranging in age from 47 to 87 years (median 70 y). The pseudoangiosarcomatous morphology was observed in 7 urothelial carcinomas including 3 with squamous differentiation and comprised 35% to 85% of the invasive tumor. Histologically, the pseudoangiosarcomatous carcinomas were characterized by tumor cell discohesion and lysis that created pseudolumina formations surrounded by attached residual tumor cells. Detached degenerating tumor cells variably admixed with inflammatory cells were common in the false lumina. Partly intact urothelial carcinoma nests contained irregular or cleft-like spaces and disintegrating tumor cells with stretched intercellular bridges. The tumor was commonly associated with a dense collagenous matrix, often surrounding the lytic nests. Similar tumor cell discohesion and breakdown were observed in 3 tumors with foci of squamous cell differentiation, distinguished by the presence of dyskeratosis and keratin formation. All 7 tumors contained other nonpseudoangiosarcomatous carcinoma components such as conventional urothelial carcinoma (5), squamous differentiation (4), sarcomatoid spindle cell carcinoma (2), small cell carcinoma (1), micropapillary carcinoma (1), and glandular differentiation (1). The pseudoangiosarcomatous urothelial carcinomas were all (7/7) diffusely CK7 positive, most (6/7) were GATA3 positive, and none (0/7) expressed vascular-associated markers. There was no evidence to suggest that apoptosis (by TUNEL assay and cleaved caspase-3 immunostaining) or loss of the adhesion molecules CD138 and e-cadherin were possible causes for the tumor cell discohesion and breakdown. All 7 tumors were high stage at cystectomy and included 1 pT3a, 2 pT3b, and 4 pT4a tumors, and 3 had pelvic lymph node involvement. Follow-up data available in 6 cases revealed a poor outcome with an overall median survival of 8.5 months. In conclusion, we present an unusual morphology of bladder carcinoma that has a striking resemblance to a malignant vasoformative tumor. Our series showed that bladder pseudoangiosarcomatous carcinoma morphology is associated with a higher tumor stage at cystectomy, commonly admixed with other aggressive carcinoma variant morphologies, and portend a poorer outcome. Knowledge of this pattern is also important to avoid misdiagnosis, particularly in limited tissue samples.


Assuntos
Carcinoma/patologia , Hemangiossarcoma/patologia , Neoplasias da Bexiga Urinária/patologia , Urotélio/patologia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/análise , Biópsia , Carcinoma/química , Carcinoma/classificação , Carcinoma/mortalidade , Diferenciação Celular , Feminino , Hemangiossarcoma/química , Hemangiossarcoma/classificação , Hemangiossarcoma/mortalidade , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Análise de Sobrevida , Terminologia como Assunto , Fatores de Tempo , Neoplasias da Bexiga Urinária/química , Neoplasias da Bexiga Urinária/classificação , Neoplasias da Bexiga Urinária/mortalidade , Urotélio/química
18.
Age (Dordr) ; 36(1): 21-30, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23695949

RESUMO

The interleukin-10 knockout mouse (IL10(tm/tm)) has been proposed as a model for human frailty, a geriatric syndrome characterized by skeletal muscle (SM) weakness, because it develops an age-related decline in SM strength compared to control (C57BL/6J) mice. Compromised energy metabolism and energy deprivation appear to play a central role in muscle weakness in metabolic myopathies and muscular dystrophies. Nonetheless, it is not known whether SM energy metabolism is altered in frailty. A combination of in vivo (31)P nuclear magnetic resonance experiments and biochemical assays was used to measure high-energy phosphate concentrations, the rate of ATP synthesis via creatine kinase (CK), the primary energy reserve reaction in SM, as well as the unidirectional rates of ATP synthesis from inorganic phosphate (Pi) in hind limb SM of 92-week-old control (n = 7) and IL10(tm/tm) (n = 6) mice. SM Phosphocreatine (20.2 ± 2.3 vs. 16.8 ± 2.3 µmol/g, control vs. IL10(tm/tm), p < 0.05), ATP flux via CK (5.0 ± 0.9 vs. 3.1 ± 1.1 µmol/g/s, p < 0.01), ATP synthesis from inorganic phosphate (Pi → ATP) (0.58 ± 0.3 vs. 0.26 ± 0.2 µmol/g/s, p < 0.05) and the free energy released from ATP hydrolysis (∆G ∼ATP) were significantly lower and [Pi] (2.8 ± 1.0 vs. 5.3 ± 2.0 µmol/g, control vs. IL10(tm/tm), p < 0.05) markedly higher in IL10(tm/tm) than in control mice. These observations demonstrate that, despite normal in vitro metabolic enzyme activities, in vivo SM ATP kinetics, high-energy phosphate levels and energy release from ATP hydrolysis are reduced and inorganic phosphate is elevated in a murine model of frailty. These observations do not prove, but are consistent with the premise, that energetic abnormalities may contribute metabolically to SM weakness in this geriatric syndrome.


Assuntos
Trifosfato de Adenosina/metabolismo , Envelhecimento/metabolismo , Debilidade Muscular/metabolismo , Músculo Esquelético/metabolismo , Animais , Creatina Quinase/metabolismo , Modelos Animais de Doenças , Metabolismo Energético , Hidrólise , Cinética , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Fosfocreatina/metabolismo
19.
Am J Physiol Heart Circ Physiol ; 304(5): H633-48, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23292717

RESUMO

Magnetic resonance imaging (MRI) has emerged as a powerful and reliable tool to noninvasively study the cardiovascular system in clinical practice. Because transgenic mouse models have assumed a critical role in cardiovascular research, technological advances in MRI have been extended to mice over the last decade. These have provided critical insights into cardiac and vascular morphology, function, and physiology/pathophysiology in many murine models of heart disease. Furthermore, magnetic resonance spectroscopy (MRS) has allowed the nondestructive study of myocardial metabolism in both isolated hearts and in intact mice. This article reviews the current techniques and important pathophysiological insights from the application of MRI/MRS technology to murine models of cardiovascular disease.


Assuntos
Doenças Cardiovasculares/patologia , Doenças Cardiovasculares/fisiopatologia , Sistema Cardiovascular/patologia , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Animais , Fenômenos Fisiológicos Cardiovasculares , Sistema Cardiovascular/anatomia & histologia , Modelos Animais de Doenças , Camundongos
20.
Am J Physiol Heart Circ Physiol ; 303(7): H844-52, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22886411

RESUMO

Reduced myofibrillar ATP availability during prolonged myocardial ischemia may limit post-ischemic mechanical function. Because creatine kinase (CK) is the prime energy reserve reaction of the heart and because it has been difficult to augment ATP synthesis during and after ischemia, we used mice that overexpress the myofibrillar isoform of creatine kinase (CKM) in cardiac-specific, conditional fashion to test the hypothesis that CKM overexpression increases ATP delivery in ischemic-reperfused hearts and improves functional recovery. Isolated, retrograde-perfused hearts from control and CKM mice were subjected to 25 min of global, no-flow ischemia and 40 min of reperfusion while cardiac function [rate pressure product (RPP)] was monitored. A combination of (31)P-nuclear magnetic resonance experiments at 11.7T and biochemical assays was used to measure the myocardial rate of ATP synthesis via CK (CK flux) and intracellular pH (pH(i)). Baseline CK flux was severalfold higher in CKM hearts (8.1 ± 1.0 vs. 32.9 ± 3.8, mM/s, control vs. CKM; P < 0.001) with no differences in phosphocreatine concentration [PCr] and RPP. End-ischemic pH(i) was higher in CKM hearts than in control hearts (6.04 ± 0.12 vs. 6.37 ± 0.04, control vs. CKM; P < 0.05) with no differences in [PCr] and [ATP] between the two groups. Post-ischemic PCr (66.2 ± 1.3 vs. 99.1 ± 8.0, %preischemic levels; P < 0.01), CK flux (3.2 ± 0.4 vs. 14.0 ± 1.2 mM/s; P < 0.001) and functional recovery (13.7 ± 3.4 vs. 64.9 ± 13.2%preischemic RPP; P < 0.01) were significantly higher and lactate dehydrogenase release was lower in CKM than in control hearts. Thus augmenting cardiac CKM expression attenuates ischemic acidosis, reduces injury, and improves not only high-energy phosphate content and the rate of CK ATP synthesis in postischemic myocardium but also recovery of contractile function.


Assuntos
Trifosfato de Adenosina/metabolismo , Creatina Quinase Forma MM/metabolismo , Metabolismo Energético , Contração Miocárdica , Isquemia Miocárdica/enzimologia , Traumatismo por Reperfusão Miocárdica/enzimologia , Miocárdio/enzimologia , Acidose/enzimologia , Acidose/fisiopatologia , Animais , Creatina Quinase Forma MM/genética , Modelos Animais de Doenças , Metabolismo Energético/genética , Concentração de Íons de Hidrogênio , Cinética , L-Lactato Desidrogenase/metabolismo , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Contração Miocárdica/genética , Isquemia Miocárdica/genética , Isquemia Miocárdica/fisiopatologia , Traumatismo por Reperfusão Miocárdica/genética , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Fosfocreatina/metabolismo , Regulação para Cima
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