Anatomy of the liver (a05.8. 01. 001): worldwide review, 2019: new findings, concepts and definitions support a division of the liver into seven portal segments / Anatomía del hígado (a05. 8.01. 001): revisión mundial, 2019: nuevos hallazgos, conceptos y definiciones respaldan una división del hígado en siete segmentos portales

Due to a lack of consensus on the description of the human liver anatomy, we decided to explore different researches worldwide. Studies are focused on the hepatic vascularization. The results obtained through serial dissections in embryos, fetuses and adults have contributed to new definitions. Researchers around the world have agreed on finding the bases to propose a liver segmentation with seven portal segments.

La confusión existente en la descripción de la anatomía del hígado humano nos llevó a realizar esta revisión a nivel mundial. Las investigaciones se centran en la vascularización del hígado, el conocimiento obtenido mediante disecciones seriadas en embriones, fetos y adultos han aportado nuevos conocimientos que fundamentan nuevas definiciones. Investigadores de países distantes han coincidido en encontrar las bases para proponer una segmentación del hígado con siete segmentos portales.

Fetal hematopoietic stem cells express MFG-E8 during mouse embryogenesis

The milk fat globule-EGF-factor 8 protein (MFG-E8) has been identified in various tissues, where it has an important role in intercellular interactions, cellular migration, and neovascularization. Previous studies showed that MFG-E8 is expressed in different cell types under normal and pathophysiological conditions, but its expression in hematopoietic stem cells (HSCs) during hematopoiesis has not been reported. In the present study, we investigated MFG-E8 expression in multiple hematopoietic tissues at different stages of mouse embryogenesis. Using immunohistochemistry, we showed that MFG-E8 was specifically expressed in CD34+ HSCs at all hematopoietic sites, including the yolk sac, aorta-gonad-mesonephros region, placenta and fetal liver, during embryogenesis. Fluorescence-activated cell sorting and polymerase chain reaction analyses demonstrated that CD34+ cells, purified from the fetal liver, expressed additional HSC markers, c-Kit and Sca-1, and that these CD34+ cells, but not CD34- cells, highly expressed MFG-E8. We also found that MFG-E8 was not expressed in HSCs in adult mouse bone marrow, and that its expression was confined to F4/80+ macrophages. Together, this study demonstrates, for the first time, that MFG-8 is expressed in fetal HSC populations, and that MFG-E8 may have a role in embryonic hematopoiesis.

Modelo experimental para restrição do crescimento fetal em ratos: efeito sobre o glicogênio hepático e morfometria intestinal e renal / Experimental rat model for fetal growth restriction: effects on liver glycogen and intestinal and renal morphometry

OBJETIVO: avaliar a eficácia do modelo de RCIU por ligadura da artéria uterina simulando insuficiência placentária em ratos. MÉTODOS: fetos de ratas prenhes Sprague-Dawley foram divididos em três grupos: RCIU (restrição de crescimento intrauterino), com fetos submetidos à ligadura da artéria uterina com 18,5 dias de gestação (termo = 22 dias), C-RCIU (controle da restrição), com fetos do corno contralateral à ligadura, CE (Controle Externo), com fetos de ratas sem manipulação. Com 21,5 dias de gestação, foi realizada cesárea, os fetos foram pesados e dissecados para análise morfométrica e histológica do fígado, intestino e rins. RESULTADOS: os dados morfométricos avaliados mostraram o peso corpóreo (PC), hepático (PH) e intestinal (PI) dos fetos com RCIU menor que C-RCIU e CE (p<0,001). O peso placentário (PP), renal (PR) e as relações PH/PC, PI/PC e PR/PC não se alteraram. A espessura renal foi menor nos fetos com RCIU (p<0,001) e houve diminuição da camada mucosa e submucosa intestinal (p<0,05). A avaliação histológica mostrou diminuição do glicogênio hepático nos fetos com RCIU em relação aos grupos C-RCIU e CE. CONCLUSÕES: o modelo descrito foi eficiente e causou RCIU fetal simétrica com diminuição da maioria dos órgãos, especialmente do peso hepático, e alteração nos depósitos de glicogênio.

PURPOSE: to evaluate the effectiveness of the IUGR model by uterine artery ligation mimicking placental insufficiency in rats. METHODS: sprague-Dawley rat fetuses were divided into three groups: IUGR (intrauterine growth restriction), with fetuses in the right horn of pregnant rats subjected to right uterine artery ligation at 18.5 days of gestation (term = 22 days); C-IUGR (control of restriction), with control fetuses in the left horn, and EC (external control), with fetuses of intact rats. Animals were harvested by cesarean section at day 21.5 days of gestation. Fetuses were weighed and then sacrificed. The intestine, liver, kidney and placenta were weighed and dissected for morphometric and histological analysis. RESULTS: the morphometric data showed decreased body weight (BW), liver weight (LW) and intestinal weight (IW) of fetuses with IUGR compared to C-IUGR and EC (p<0.001). The placental weight (PW), renal weight (RW) and LW/BW, IW/BW, and RW/BW ratios did not change. IUGR fetuses had decreased kidney thickness (p<0.001) and decreased thickness of the intestinal mucosa and submucosa (p<0.05). Histological evaluation showed reduction of liver glycogen storage in fetuses with IUGR compared to C-IUGR and CE. CONCLUSIONS: the model described was efficient and caused symmetric fetal IUGR with decreased size of most organs, especially the liver, and changes in glycogen stores.

Estudios morfológico y morfométrico del hígado de fetos de ratas con enfermedad de Chagas aguda / Morphologic and morphometric study of the fetus liver from mice with acute Chagas' disease

Fueron estudiados los fetos de la enfermedad de Chagas aguda, durante la preñez en fetos de ratas, particularmente las posibles alteraciones provocadas en las células hepáticas. Fue demostrado un retardo en el crecimiento intrauterino de los fetos, que presentaron peso y longitud menores que el grupo control. A nivel hepático no fue identificada la presencia de nidos de parásitos. Sin embargo, el hígado de los fetos del grupo inoculado presentaba algunos hepatocitos degenerados y con desorganización arquitectural, mientras que los capilares sinusoides estaban congestivos y dilatados. Morfométricamente se verificó la ausencia de alteraciones nucleares en los hepatocitos de los fetos del grupo inoculado. El volumen relativo ocupado por hepatocitos, fue significativamente mayor en el hígado de los fetos del grupo inoculado que en el grupo control, al contrario de lo observado con el volumen relativo de los sinusoides. Así, aún dilatados y congestionados, el volumen relativo de los sinusoides hepáticos en los fetos del grupo inoculado, fue menor que en los controles, reflejando una disminución del número de capilares sinusoides

Intrahepatic bile duct development in the human foetus

This study included twenty human foetuses during various periods of gestation ranging from 9 to 40 weeks. The age of the foetus was approximately determined. Specimens from the liver were obtained and subjected to the appropriate histological and histochemical techniques. The data revealed that the bile duct system was immature at 9 weeks-old foetuses. Then at the 11th week, groups of hepatic cells were arranged in close contact with portal vein branches. At 12 weeks-old foetuses, the biliary ducts started to appear as small spaces among these groups of hepatic cells. At 18 to 20 weeks, portal spaces became obvious and duct-like structures were observed in the parenchyma-connective tissue contact area around these portal spaces. From the 21st week onwards, developing biliary structures were observed at the margins of the portal spaces. Then the portal mesenchymal tissue successively surrounded the bile ducts and pushed them inside portal spaces. At week 40, the number of large individual bile ducts increased in each portal area. The present results suggested that the cells lining the developing biliary structures originated from the hepatoblasts. The number of ductular structures per portal tract increased in full term foetal liver. Nevertheless, the bile canalicular system was less conspicuous till the full term gestational period suggesting that development will continue in the postantal life

Cytochemical localization of sorbitol dehydrogenase in kidney and liver from Myiopsitta m. monachus (Boddaert, 1783), during embryonic development

A histochemical study to determine the localization of sorbitol dehydrogenase (SDH) in kidney and liver from embryionic, young and adult Myiopsitta m. monachus was performed. The enzyme activity increased with age in both organs. In the kidney, the enzyme appeared at the proximal convoluted tubules, and increased in the basal cytoplasm of the tubular cells. In the liver the localization was diffuse in the lobule but more intense in the cytoplasm of hepatocytes, especially in the perinuclear areas. These studies indicate that the cytochemical enzyme localization differs in this species, which is more evolutioned than Gallus gallus, and would be related to ontogenetic and phylogenetic differentiation.