The neonatal mammalian heart is capable of regeneration for a brief window of time after birth. However, this regenerative capacity is lost within the first week of life, which coincides with a postnatal shift from anaerobic glycolysis to mitochondrial oxidative phosphorylation, particularly towards fatty-acid utilization. Despite the energy advantage of fatty-acid beta-oxidation, cardiac mitochondria produce elevated rates of reactive oxygen species when utilizing fatty acids, which is thought to play a role in cardiomyocyte cell-cycle arrest through induction of DNA damage and activation of DNA-damage response (DDR) pathway. Here we show that inhibiting fatty-acid utilization promotes cardiomyocyte proliferation in the postnatatal heart. First, neonatal mice fed fatty-acid deficient milk showed prolongation of the postnatal cardiomyocyte proliferative window, however cell cycle arrest eventually ensued. Next, we generated a tamoxifen-inducible cardiomyocyte-specific, pyruvate dehydrogenase kinase 4 (PDK4) knockout mouse model to selectively enhance oxidation of glycolytically derived pyruvate in cardiomyocytes. Conditional PDK4 deletion resulted in an increase in pyruvate dehydrogenase activity and consequently an increase in glucose relative to fatty-acid oxidation. Loss of PDK4 also resulted in decreased cardiomyocyte size, decreased DNA damage and expression of DDR markers and an increase in cardiomyocyte proliferation. Following myocardial infarction, inducible deletion of PDK4 improved left ventricular function and decreased remodelling. Collectively, inhibition of fatty-acid utilization in cardiomyocytes promotes proliferation, and may be a viable target for cardiac regenerative therapies.

OBJECTIVEInflammation and dysfunction of the hypothalamus are common features of experimental obesity. However, it is unknown whether obesity and massive loss of body mass can modify the immunologic status or the functional activity of the human brain. Therefore, the aim of this study was to determine the effect of body mass reduction on brain functionality.RESEARCH DESIGN AND METHODSIn humans, changes in hypothalamic activity after a meal or glucose intake can be detected by functional magnetic resonance imaging (fMRI). Distinct fMRI analytic methods have been developed to explore changes in the brain’s activity in several physiologic and pathologic conditions. We used two analytic methods of fMRI to explore the changes in the brain activity after body mass reduction.RESULTSObese patients present distinct functional activity patterns in selected brain regions compared with lean subjects. On massive loss of body mass, after bariatric surgery, increases in the cerebrospinal fluid (CSF) concentrations of interleukin (IL)-10 and IL-6 are accompanied by changes in fMRI patterns, particularly in the hypothalamus.CONCLUSIONSMassive reduction of body mass promotes a partial reversal of hypothalamic dysfunction and increases anti-inflammatory activity in the CSF.

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Focal adhesion kinase (FAK) contributes to cellular homeostasis under stress conditions. Here we show that aB-crystallin interacts with and confers protection to FAK against calpainmediated proteolysis in cardiomyocytes. A hydrophobic patch mapped between helices 1 and 4 of the FAK FAT domain was found to bind to the b4-b8 groove of aB-crystallin. Such an interaction requires FAK tyrosine 925 and is enhanced following its phosphorylation by Src, which occurs upon FAK stimulation. aB-crystallin silencing results in calpain-dependent FAK depletion and in the increased apoptosis of cardiomyocytes in response to mechanical stress. FAK overexpression protects cardiomyocytes depleted of aB-crystallin against the stretch-induced apoptosis. Consistently, load-induced apoptosis is blunted in the hearts from cardiac-specific FAK transgenic mice transiently depleted of aB-crystallin by RNA interference. These studies define a role for aB-crystallin in controlling FAK function and cardiomyocyte survival through the prevention of calpain-mediated degradation of FAK.

Physalaemus biligonigerus, P. fuscomaculatus and P. sp. have 2n=2 chromosomes, consistent with the number of chromosomal pairs found in the genus. There were no substantial differences in the karyotypes of the three species, except for chromosome 3 which was submetacentric in P. fuscomaculatus and metacentric in P. biligonigerus and P. sp. All chromosomes were characterised by the presence of a C-band in the pericentromeric region. Some interstitial bands were also detected at the same position in all karyotypes, but the band located on the short arm of chromosome 3 was larger in P. biligonigerus and P. sp. than in P. fuscomaculatus. Also, only P. sp. had a large block of pericentromeric heterochro-matin in the short arm of chromosome 9 and another one in the telomeric band on the long arm. The NOR was located on the long arm of chromosome 9 in the three species. These findings confirmed that the three species are indeed closely related cytogenetically.

The teratogenic mechanisms triggered by ZIKV are still obscure due to the lack of a suitable animal model. Here we present a mouse model of developmental disruption induced by ZIKV hematogenic infection. The model utilizes immunocompetent animals from wild-type FVB/NJ and C57BL/6J strains, providing a better analogy to the human condition than approaches involving immunodeficient, genetically modified animals, or direct ZIKV injection into the brain. When injected via the jugular vein into the blood of pregnant females harboring conceptuses from early gastrulation to organogenesis stages, akin to the human second and fifth week of pregnancy, ZIKV infects maternal tissues, placentas and embryos/fetuses. Early exposure to ZIKV at developmental day 5 (second week in humans) produced complex manifestations of anterior and posterior dysraphia and hydrocephalus, as well as severe malformations and delayed development in 10.5 days post-coitum (dpc) embryos. Exposure to the virus at 7.5–9.5 dpc induces intra-amniotic hemorrhage, widespread edema, and vascular rarefaction, often prominent in the cephalic region. At these stages, most affected embryos/fetuses displayed gross malformations and/or intrauterine growth restriction (IUGR), rather than isolated microcephaly. Disrupted conceptuses failed to achieve normal developmental landmarks and died in utero. Importantly, this is the only model so far to display dysraphia and hydrocephalus, the harbinger of microcephaly in humans, as well as arthrogryposis, a set of abnormal joint postures observed in the human setting. Late exposure to ZIKV at 12.5 dpc failed to produce noticeable malformations. We have thus characterized a developmental window of opportunity for ZIKV-induced teratogenesis encompassing early gastrulation, neurulation and early organogenesis stages. This should not, however, be interpreted as evidence for any safe developmental windows for ZIKV exposure. Late developmental abnormalities correlated with damage to the placenta, particularly to the labyrinthine layer, suggesting that circulatory changes are integral to the altered phenotypes.

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Obstruction of the portal vein may be related to constriction by malignant tumors or thrombosis associated with liver disease. We herein have reported our experience with patients undergoing liver transplantation with portal vein thrombosis (PVT) whose diagnosis was made intraoperatively. From September 1991 to May 2009, we studied 27/419 (6.4%) patients with PVT who were evaluated according to the presence of esophagogastric varices, underlying disease, malignancy, and if there was previous surgery, review of medical records on data collected prospectively. We observed 24 (88.9%) patients with PVT grade 1, 2 (7.4%) with grade 2, and 1 (3.7%) with grade 3. The average age of the PVT patients was 47.5 years; the average model for End-Stage Liver Discase score was 18.3, and the predominant diagnosis, hepatitis C cirrhosis. Eighteen underwent a sclerotherapy/ligature. The sensitivity of ultrasound for grade 1 thrombosis was 39.1%; for grade 2, 50%; and for grade 3, 100%. Portal vein thrombectomy was performed in 24 patients. In other patients (grade 2), we performed an anastomosis of the donor portal vein to the recipient gastric vein or to a greater splanchnic collateral vein. In only 1 patient was the graft performed using the donor portal vein-donor iliac vein-recipient superior mesenteric vein. None of the patients displayed PVT in the immediate postoperative period. Actuarial survivals at the years 1, 3, and 5 were 85%, 74%, and 63%, respectively. We concluded that PVT cannot be considered to be a contraindication for liver transplantation.