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1.
Hum Reprod ; 36(7): 2063-2064, 2021 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-33793791
5.
Basic Clin Androl ; 30: 10, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32685170

RESUMO

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) metamorphosed our medical practice. In early June 2020, more than 6,400,000 COVID-19 (coronavirus-19 disease) cases were diagnosed across the world and more than 380,000 deaths were linked to COVID-19. Many medical symptoms of COVID-19 were reported. We will focus, here, on potential impacts of COVID-19 on men's andrological health. Our society (French-speaking society of andrology, SALF) also emitted some recommendations in the andrological management of men infected by SARS-CoV-2. First, considering the fever and the potential presence of SARS-CoV2 in semen, SALF recommends waiting for 3 months (duration of one spermatogenesis cycle and epididymal transit) before re-starting ART in the case of men diagnosed COVID-19 positive. Whatever the nature of testosterone and COVID-19 relationships, we recommend an andrological examination, sperm parameters, and hormonal evaluation at the time of the COVID-19 is diagnosed, and several months later. Furthermore, we are concerned by the potential morbid-mortality of the COVID-19, which mainly affects men. This "andrological bias", if proven, must be reduced by specific andrological diagnosis, therapeutic and prophylactic measures. Research in this direction must be substantiated and financially supported over the next few months (years).


Le SRAS-CoV-2 (nouveau coronavirus ou coronavirus numéro 2 responsable du syndrome respiratoire aigu sévère) a métamorphosé notre pratique médicale. Début juin 2020, plus de 6,400,000 cas de COVID-19 (maladie à coronavirus 2019) ont été diagnostiqués dans le monde et plus de 380,000 décès ont été reliés à cette maladie. De nombreux symptômes médicaux de cette infection virale ont été signalés. Nous nous concentrerons, ici, sur les impacts potentiels de COVID-19 sur la santé andrologique des hommes. Notre société (Société d'andrologie de langue Française, SALF) émet ici quelques recommandations dans la prise en charge andrologique des hommes infectés par le SRAS-CoV-2. Tout d'abord, compte tenu de la fièvre et de la présence potentielle du SRAS-CoV2 dans le sperme, la SALF recommande d'attendre 3 mois (durée d'un cycle de spermatogenèse et transit épididymaire) avant de recommencer les techniques d'assistance médicale à la procréation pour les hommes diagnostiqués COVID-19 positifs. Quelle que soit la nature des relations entre la testostérone et l'infection à SARS-CoV-2, nous recommandons un examen andrologique, un examen des paramètres du sperme et une évaluation hormonale au moment du diagnostic de l'infection, ainsi qu'à distance (3­6 mois plus tard). De plus, nous sommes préoccupés par la morbidité et la mortalité potentielles de l'infection COVID-19, qui touche principalement les hommes. Ce "biais andrologique", s'il est. prouvé, doit être réduit par un diagnostic andrologique spécifique et des mesures thérapeutiques et prophylactiques. La recherche dans ce sens doit être étayée et soutenue financièrement au cours des prochains mois (années).

6.
Gynecol Obstet Fertil Senol ; 46(1): 47-56, 2018 Jan.
Artigo em Francês | MEDLINE | ID: mdl-29198589

RESUMO

In this last century, an increase of men infertility has been registered. It has been suggested that environmental factors could a negative impact over sperm quality. Among these factors, impact of environmental toxicant has been spread by media. In this review of scientific literature, we identify several environmental factors that could impact men fertility in a negative way. These factors are tobacco, marijuana, weight, body mass index, heat, nutritional state, electromagnetic waves and altitude. For each of these factors, the impact over men fertility, their mechanism, as well their influence over the use of Assisted Reproductive Technics are reported.


Assuntos
Meio Ambiente , Infertilidade Masculina/etiologia , Estilo de Vida , Adolescente , Adulto , Idoso , Consumo de Bebidas Alcoólicas/efeitos adversos , Índice de Massa Corporal , Peso Corporal , Cannabis/efeitos adversos , Criança , Radiação Eletromagnética , França , Temperatura Alta , Humanos , Infertilidade Masculina/epidemiologia , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Obesidade/complicações , Fumar/efeitos adversos , Nicotiana/efeitos adversos
7.
Dev Dyn ; 240(3): 605-15, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21290478

RESUMO

Based on our previous observations that clusterin induction accompanies pancreas regeneration in the rat, we sought to determine if regeneration might be impaired in mice that lacked clusterin. We studied the impact of absent clusterin on morphogenic and functional features of regenerating pancreas. Clusterin induction was accompanied in the regenerating pancreas by a robust development of new lobules with ductules, acini, and endocrine islets in wild type after partial pancreatectomy. In clusterin knock-out mice, however, pancreatectomy resulted in a poor formation of regenerating lobule. In particular, regeneration of beta-cells was also significantly reduced and was associated with persistent hyperglycemia. Duct cells obtained from pancreatectomized clusterin knock-out mice exhibited impaired beta-cell formation in vitro; this was restored by administration of exogenous clusterin. We suggest that clusterin plays a critical role to promote both exocrine and endocrine regeneration following pancreas injury, as well as for in vitro beta-cell regeneration.


Assuntos
Clusterina/metabolismo , Pâncreas/metabolismo , Pâncreas/fisiopatologia , Regeneração/fisiologia , Animais , Western Blotting , Clusterina/genética , Clusterina/farmacologia , Teste de Tolerância a Glucose , Imuno-Histoquímica , Técnicas In Vitro , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pâncreas/citologia , Pâncreas/cirurgia , Pancreatectomia , Reação em Cadeia da Polimerase , Regeneração/genética
8.
Cell Death Differ ; 18(3): 549-62, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20966960

RESUMO

The apoptotic program incorporates a paracrine component of importance in fostering tissue repair at sites of apoptotic cell deletion. As this paracrine pathway likely bears special importance in maladaptive intercellular communication leading to vascular remodeling, we aimed at further defining the mediators produced by apoptotic endothelial cells (EC), using comparative and functional proteomics. Apoptotic EC were found to release nanovesicles displaying ultrastructural characteristics, protein markers and functional activity that differed from apoptotic blebs. Tumor susceptibility gene 101 and translationally controlled tumor protein (TCTP) were identified in nanovesicle fractions purified from medium conditioned by apoptotic EC and absent from purified apoptotic blebs. Immunogold labeling identified TCTP on the surface of nanovesicles purified from medium conditioned by apoptotic EC and within multivesicular blebs in apoptotic EC. These nanovesicles induced an extracellular signal-regulated kinases 1/2 (ERK 1/2)-dependent antiapoptotic phenotype in vascular smooth muscle cells (VSMC), whereas apoptotic blebs did not display antiapoptotic activity on VSMC. Caspase-3 biochemical inhibition and caspase-3 RNA interference in EC submitted to a proapoptotic stimulus inhibited the release of nanovesicles. Also, TCTP siRNAs in EC attenuated the antiapoptotic activity of purified nanovesicles on VSMC. Collectively, these results identify TCTP-bearing nanovesicles as a novel component of the paracrine apoptotic program of potential importance in vascular repair.


Assuntos
Apoptose , Biomarcadores Tumorais/metabolismo , Caspase 3/metabolismo , Comunicação Celular , Animais , Células Endoteliais/citologia , Células Endoteliais/enzimologia , Células Endoteliais/ultraestrutura , Ativação Enzimática , Exossomos/ultraestrutura , Humanos , Nanoestruturas/ultraestrutura , Transporte Proteico , Ratos , Soro , Proteína Tumoral 1 Controlada por Tradução , Veias Umbilicais/citologia
9.
Am J Physiol Gastrointest Liver Physiol ; 295(5): G873-85, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18772361

RESUMO

Growing evidence suggests that the small intestine may contribute to excessive postprandial lipemia, which is highly prevalent in insulin-resistant/Type 2 diabetic individuals and substantially increases the risk of cardiovascular disease. The aim of the present study was to determine the role of high glucose levels on intestinal cholesterol absorption, cholesterol transporter expression, enzymes controlling cholesterol homeostasis, and the status of transcription factors. To this end, we employed highly differentiated and polarized cells (20 days of culture), plated on permeable polycarbonate filters. In the presence of [(14)C]cholesterol, glucose at 25 mM stimulated cholesterol uptake compared with Caco-2/15 cells supplemented with 5 mM glucose (P < 0.04). Because combination of 5 mM glucose with 20 mM of the structurally related mannitol or sorbitol did not change cholesterol uptake, we conclude that extracellular glucose concentration is uniquely involved in the regulation of intestinal cholesterol transport. The high concentration of glucose enhanced the protein expression of the critical cholesterol transporter NPC1L1 and that of CD36 (P < 0.02) and concomitantly decreased SR-BI protein mass (P < 0.02). No significant changes were observed in the protein expression of ABCA1 and ABCG8, which act as efflux pumps favoring cholesterol export out of absorptive cells. At the same time, 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity was decreased (P < 0.007), whereas ACAT activity remained unchanged. Finally, increases were noted in the transcription factors LXR-alpha, LXR-beta, PPAR-beta, and PPAR-gamma along with a drop in the protein expression of SREBP-2. Collectively, our data indicate that glucose at high concentrations may regulate intestinal cholesterol transport and metabolism in Caco-2/15 cells, thus suggesting a potential influence on the cholesterol absorption process in Type 2 diabetes.


Assuntos
Proteínas de Transporte/metabolismo , Colesterol/metabolismo , Glucose/farmacologia , Mucosa Intestinal/metabolismo , Proteínas de Membrana/metabolismo , Fatores de Transcrição/metabolismo , Western Blotting , Células CACO-2 , Proteínas de Transporte/química , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Humanos , Imuno-Histoquímica , Intestinos/citologia , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas de Membrana Transportadoras , Isoformas de Proteínas
10.
Histol Histopathol ; 22(2): 199-210, 2007 02.
Artigo em Inglês | MEDLINE | ID: mdl-17149693

RESUMO

Leptin is a hormone that plays a central role in the regulation of food intake and energy expenditure. Originally discovered in mature white adipocytes, it was subsequently isolated from the gastric mucosa. This tissue contains a large number of epithelial endocrine and exocrine cells secreting leptin in the blood stream and in the gastric lumen, respectively. Light and electron microscopy have shown that adipocytes and gastric epithelial cells contain leptin along their rough endoplasmic reticulum-Golgi-granules secretory pathway. Both tissues synthesize a soluble form of the leptin receptor that is secreted bound to leptin in the blood and into the gastric juice. This soluble receptor protect leptin and enhances its half-life. Despite the similarities in the mechanisms of leptin secretion by adipocytes and gastric epithelial cells, they are in fact radically different. In gastric cells leptin follows a rapid regulated secretion pathway whereas adipocytes secrete leptin in a constitutive slow fashion. These differences can be explained by the specific roles play by leptin originating from these two different tissues. Gastric leptin is involved in the short-term regulation of digestion, including delay of gastric emptying, absorption of nutrients by the intestinal wall and secretion of gastric, intestinal and pancreatic hormones. On the other hand, leptin secreted by white adipocytes acts primarily on the hypothalamus for the long-term regulation of food intake. Therefore, the coordination of adipose and gastric leptins ensures the proper management of food processing and energy storage.


Assuntos
Adipócitos Brancos/metabolismo , Tecido Adiposo Branco/metabolismo , Mucosa Gástrica/metabolismo , Leptina/metabolismo , Adipócitos Brancos/ultraestrutura , Tecido Adiposo Branco/citologia , Animais , Humanos
11.
Arq. bras. med. vet. zootec ; 58(4): 662-664, ago. 2006. tab
Artigo em Inglês, Português | LILACS | ID: lil-438739

RESUMO

Determinou-se a sobrevida de Campylobacter jejuni subsp. jejuni e C. coli no meio de transporte e enriquecimento TEC, mantido sob diferentes condições de temperatura e concentração de oxigênio. A sobrevida da maioria das amostras foi superior a cinco dias, obtendo-se os períodos de sobrevida mais prolongados (sete a 15 dias), quando o meio foi incubado em microaerofilia à temperatura ambiente, condições nas quais o tempo de sobrevida de C. coli foi superior ao de C. jejuni subsp. jejuni.


Assuntos
Campylobacter jejuni/isolamento & purificação , Sobrevida , Meios de Transporte/instrumentação , Meios de Transporte/métodos
12.
Kidney Int ; 69(9): 1570-7, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16541018

RESUMO

Diabetic glomerulopathy has been linked to shifts in balance between the synthetic and degradative pathways of the glomerular basement membrane (GBM), a key player in the permselectivity properties of the glomerular wall. The goal of this study was to trace the expression and localization of membrane type-1 metalloprotease (MT1-MMP) and its activating enzyme furin, key proteins involved in basement membrane turnover, in short- and long-term diabetic rat renal tissues. Quantitative immunogold was carried out for MT1-MMP and furin and their expression was evaluated in renal tissues of young and old, control and diabetic rats. To corroborate immunocytochemical findings, Western blots were performed on glomerular lysates. Electron microscopy revealed that the overall expression of MT1-MMP and furin is reduced in plasma membranes of all glomerular cell types of old normoglycemic animals, a phenomenon that is exacerbated in long-term diabetic animals. This observation supports the prevailing theory that diabetes fosters acceleration in the aging process. Interestingly, while biochemical results confirmed a decrease in MT1-MMP expression, an increase in furin was observed. Immunocytochemical studies resolved this discrepancy by tracing the increased furin expression in endoplasmic reticulum and Golgi membranes of podocytes, indicating that furin is retained in the secretory pathway in a diabetic environment. Disturbances at the molecular level of the otherwise tightly regulated MT1-MMP/furin interactions found at the cell surface must account for a lack in extracellular matrix remodeling, increased deposition of GBM material, and loss of glomerular filtration integrity.


Assuntos
Nefropatias Diabéticas/enzimologia , Furina/metabolismo , Membrana Basal Glomerular/enzimologia , Glomérulos Renais/enzimologia , Metaloproteinases da Matriz/metabolismo , Animais , Retículo Endoplasmático/enzimologia , Furina/análise , Membrana Basal Glomerular/ultraestrutura , Complexo de Golgi/enzimologia , Glomérulos Renais/ultraestrutura , Masculino , Metaloproteinases da Matriz/análise , Metaloproteinases da Matriz Associadas à Membrana , Ratos , Ratos Sprague-Dawley
13.
Diabetologia ; 49(2): 311-20, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16411126

RESUMO

AIMS/HYPOTHESIS: We recently reported that expression of the gene encoding clusterin (Clu) is upregulated in the regenerating pancreas, particularly in tissues undergoing differentiation. This led us to propose that clusterin participates in the cytodifferentiation of pancreatic tissue, particularly the endocrine islet cells. The aim of this study was to investigate whether clusterin induces the differentiation of duct-lining cells into insulin-secreting cells. METHODS: We isolated ductal tissue from rat pancreas and cultured it to develop epithelial cell explants for transfection of the Clu cDNA as well as for treatment of clusterin protein. RESULTS: The number of newly differentiated insulin cells increased 6.9-fold upon Clu overexpression compared with controls. Ins1 mRNA and peptide levels were also increased. Furthermore, glucose-stimulated insulin secretion was observed in the differentiated insulin cells. These cells were immunoreactive for insulin and C-peptide, but negative for other islet hormones and for cytokeratin-20, which indicates a fully differentiated state. Insulin cell differentiation was also increased in a dose-dependent manner by treating duct cells in culture with clusterin, indicating a growth-factor-like action of clusterin in insulin cell differentiation. CONCLUSIONS/INTERPRETATION: These results suggest that clusterin can be considered as a potential morphogenic factor that promotes differentiation of pancreatic beta cells.


Assuntos
Diferenciação Celular , Clusterina/fisiologia , Células Secretoras de Insulina/citologia , Ductos Pancreáticos/citologia , Animais , Peptídeo C/metabolismo , Células Cultivadas , Clusterina/genética , Clusterina/farmacologia , DNA Complementar/genética , Regulação da Expressão Gênica , Glucose/farmacologia , Imuno-Histoquímica , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/química , Células Secretoras de Insulina/metabolismo , Masculino , Ductos Pancreáticos/química , Ductos Pancreáticos/metabolismo , RNA Mensageiro/análise , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Técnicas de Cultura de Tecidos , Transfecção
14.
Am J Physiol Renal Physiol ; 289(6): F1201-9, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16014576

RESUMO

Persistent hyperglycemia, as occurring in diabetes, induces changes in circulating as well as in structural proteins. These changes involve substitution of lysine residues by glucose adducts resulting in early Amadori products that evolve into toxic and active substances, the advanced glycation end adducts. In previous studies, we demonstrated that early glycated (Amadori) albumin infused into the circulation of normal animals induces transitory alterations of glomerular filtration. Attempting to elucidate the mechanisms underlying these changes, various molecular modifications were introduced in vitro to serum albumin. Glycation, acetylation, carboxymethylation, methylation, and succinylation, involving either a few or a significant number of amino acid residues, produced heavier and more anionic albumin molecules compared with the native one. Native and each of the modified albumin molecules were injected intravenously into normal rats, followed, 30 min later, by hapten-tagged native BSA. Changes in glomerular filtration were evaluated by morphometrical analysis of gold immunolabelings. Compared with native albumin, all the modified forms of albumin induced a deeper penetration of the tracer through the glomerular basement membrane revealing alterations in glomerular permselectivity. This was more evident for severely modified albumin molecules which displayed high labelings in the urinary space and endocytic compartments of proximal tubule epithelial cells. These results indicate that modifications of serum albumin, even minimal, as those occurring in early diabetes, could immediately affect the permselectivity properties of the glomerular wall leading, with time, to severe glomerulopathies.


Assuntos
Glomérulos Renais/fisiologia , Albumina Sérica/metabolismo , Animais , Bilirrubina/metabolismo , Eletroforese em Gel de Poliacrilamida , Fluoresceína-5-Isotiocianato/análogos & derivados , Fluoresceína-5-Isotiocianato/metabolismo , Fluorescência , Produtos Finais de Glicação Avançada , Glicosilação , Focalização Isoelétrica , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Soroalbumina Bovina/metabolismo , Albumina Sérica Glicada
15.
Dev Dyn ; 230(1): 1-11, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15108304

RESUMO

Stem cells in adult pancreas and their specific marker are poorly characterized. We hypothesized that pancreatic stem cells could evolve from the duct system in response to neogenic stimulation and may transiently express nestin during tissue regeneration. After partial pancreatectomy (Px), we found extensive formation of ductules consisting of nestin-positive epithelial cells with higher replicating ability in the neogenic foci, particularly at day 3 after Px. Nestin was highly expressed in the earlier stages of ductule morphogenesis and then regressed as the cells evolved toward differentiated pancreatic cell types. The neogenic ductules were isolated for the culture of nestin-positive duct stem cells. These nestin-positive duct cells were numerous and displayed extensive self-replication in the duct cell explants after 2-3 days of culture, thus depicted as nestin-positive duct stem (NPDS) cells. As seen in the tissue of neogenic foci, NPDS cells were negative for cytokeratin-20 and vimentin, the marker for duct epithelial and mesenchymal cells, respectively. Endocrine cells, mostly insulin cells, were present in the explants at day 2 as single cells or as small clusters adjacent to the NPDS cells, and formed islet-like masses at day 3 of culture, suggesting islet cell differentiation from NPDS cells. In addition, insulin secretion from these beta cells responded to glucose stimulation. We found transient up-regulation of PDX-1 expression by reverse transcriptase-polymerase chain reaction at day 3 after Px in pancreatic tissue. Higher expression of PDX-1 was seen in the culture of neogenic ductules than that of ducts isolated from the sham-operated pancreas. In particular, a subpopulation of nestin-positive cells in the duct cell explants formed from the neogenic ductules expressed PDX-1 in their nuclei. Taken together, this information suggests that NPDS cells could be generated from adult pancreas by neogenic motivations and they may differentiate into insulin-secreting cells.


Assuntos
Insulina/metabolismo , Proteínas de Filamentos Intermediários/biossíntese , Proteínas do Tecido Nervoso/biossíntese , Pâncreas/citologia , Células-Tronco/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Proteínas de Homeodomínio/biossíntese , Imuno-Histoquímica , Secreção de Insulina , Proteínas de Filamentos Intermediários/metabolismo , Ilhotas Pancreáticas/metabolismo , Queratina-20 , Masculino , Proteínas do Tecido Nervoso/metabolismo , Nestina , Pâncreas/metabolismo , Ductos Pancreáticos/patologia , Ratos , Ratos Sprague-Dawley , Regeneração , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transativadores/biossíntese , Vimentina/metabolismo
16.
Exp Diabesity Res ; 4(2): 83-92, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14630570

RESUMO

Aiming to discern the mechanisms by which circulating glycated albumin alters the glomerular filtration properties that lead to glomerular dysfunction in diabetes, the authors studied the distribution and densities of anionic charges through the rat glomerular wall upon intravascular infusion of Amadori products, as well as in various conditions of increased glomerular permselectivity. Polylysine-gold was used as the probe to reveal the anionic charges. The study was carried on renal tissue sections of bovine serum albumin (BSA)- and glycated BSA-injected, normoglycemic animals. Results were generated through morphometrical evaluations of the gold labeling. Changes in glomerular anionic distribution were corroborated on renal tissue sections of short- and long-term diabetic rats and of normal newborn rats, situations known for abnormal glomerular filtration. Altered renal function in these conditions was clearly associated with changes in glomerular anionic charges. On the other hand, the infusion of glycated albumin in the circulation of normal rats, though altering glomerular filtration properties, did not modify the distribution and density of the polylysine-gold labeling through the glomerular basement membrane. Thus, anionic charges seem not to be the factor involved in the early changes of glomerular permeability induced by circulating glycated albumin.


Assuntos
Diabetes Mellitus Experimental/sangue , Taxa de Filtração Glomerular/fisiologia , Glomérulos Renais/efeitos dos fármacos , Albumina Sérica/farmacologia , Albumina Sérica/farmacocinética , Animais , Animais Recém-Nascidos , Membrana Basal/efeitos dos fármacos , Membrana Basal/fisiologia , Taxa de Filtração Glomerular/efeitos dos fármacos , Produtos Finais de Glicação Avançada , Injeções Intravenosas , Glomérulos Renais/fisiologia , Glomérulos Renais/fisiopatologia , Masculino , Ratos , Ratos Sprague-Dawley , Valores de Referência , Albumina Sérica/administração & dosagem , Soroalbumina Bovina/administração & dosagem , Soroalbumina Bovina/farmacocinética , Soroalbumina Bovina/farmacologia , Albumina Sérica Glicada
17.
J Endocrinol ; 179(1): 81-9, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14529568

RESUMO

Renin and angiotensinogen have been previously found in the rat pancreas, and angiotensin receptors have been located in the apical domain of duct cells. To evaluate the possibility that angiotensin II could be generated within the duct system, we decided to determine whether angiotensinogen is present in rat pancreatic juice and the angiotensinogen-immunoreactive pancreatic cell types that could be responsible for its production. Angiotensinogen was detected in significant amounts by Western blotting in pancreatic juice collected from several individual rats. Different isoforms between plasma and pancreatic juice angiotensinogens were demonstrated by isoelectric focusing. Immunocytochemical experiments revealed angiotensinogen-immunoreactive cells at the periphery of the islets of Langerhans, and confocal microscopy demonstrated that most angiotensinogen-immunoreactive cells were glucagon-secreting cells. Secretion of angiotensinogen did not follow the regulated secretory pathway since it was absent from the glucagon-containing granules. This was confirmed by electron microscopy immunocytochemistry. Duct and acinar cells did not express angiotensinogen at an immunocytochemical detectable level. The present findings indicated an exocrine secretion of angiotensinogen by glucagon-secreting cells and suggest that one of the final targets of the local pancreatic renin-angiotensin system may be the duct epithelium.


Assuntos
Angiotensinogênio/análise , Suco Pancreático/química , Angiotensinogênio/metabolismo , Animais , Western Blotting , Glucagon/metabolismo , Ilhotas Pancreáticas/metabolismo , Masculino , Microscopia Confocal , Microscopia Eletrônica , Pâncreas/metabolismo , Pâncreas/ultraestrutura , Ratos , Ratos Sprague-Dawley
18.
Cell Stress Chaperones ; 8(3): 287-94, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14984062

RESUMO

In pancreatic acinar cells, chaperonin Cpn60 is present in all the cellular compartments involved in protein secretion as well as in mitochondria. To better understand the role Cpn60 plays in pancreatic secretion, we have evaluated its changes under experimental conditions known to alter pancreatic secretion. Quantitative protein A-gold immunocytochemistry was used to reveal Cpn60 in pancreatic acinar cells. Cpn60 immunolabelings in cellular compartments involved in secretion were found to decrease in acute pancreatitis as well as upon stimulation of secretion and in starvation conditions. A major increase in Cpn60 was recorded in diabetic condition. This was normalized by insulin treatment. Although in certain situations changes in secretory enzymes and in Cpn60 correlate well, in others, nonparallel secretion seemed to take place. In contrast, expression of mitochondrial Cpn60 in acinar cells appeared to remain stable in all conditions except starvation, where its levels decreased. Expression of Cpn60 in the secretory pathway and in mitochondria thus appears to behave differently, and Cpn60 in the secretory pathway must be important for quality control and integrity of secretion.


Assuntos
Chaperonina 60/metabolismo , Mitocôndrias/metabolismo , Pâncreas/metabolismo , Animais , Masculino , Pâncreas/citologia , Ratos , Ratos Sprague-Dawley
19.
Diabetologia ; 45(7): 1017-25, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12136401

RESUMO

AIMS/HYPOTHESIS: We undertook the characterization of the capillary bed of the rat frontal cortex and their permeability properties in short-term and long-term diabetic rats. METHODS: Diabetes was induced by strepozotocin injection. Rats were maintained hyperglycaemic without insulin treatment during 4 to 5 months (short-term) and 8 to 13 months (long-term). Rats from an additional short-term hyperglycaemic group received an injection of exogenous dinitrophenylated albumin 15 min before being killed. Tissues were processed for electron microscopy and quantitative immunocytochemistry. Endogenous and dinitrophenylated exogenous albumin were revealed with high resolution over the capillary wall using specific antibodies and the protein A-gold complex. Morphometrical analyses were carried out. RESULTS: Albumin is transported across endothelial cells by plasmalemmal vesicles or caveolae and larger vacuolar structures. This transport increased in diabetic rats by an increment in the number of vesicles. Albumin distribution across the capillary basement membrane showed that the restrictive properties of the basement membrane present in normoglycaemic rats are altered in the diabetic condition, as was its thickness. Similar alterations of the basement membrane structure and function were encountered in old normoglycaemic rats but to a lesser extent. CONCLUSION/INTERPRETATION: The results indicate that diabetes seems to accelerate the ageing process of the vascular wall and that the central nervous system capillary bed is also a target for diabetic microangiopathy.


Assuntos
Barreira Hematoencefálica/fisiologia , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Experimental/fisiopatologia , Lobo Frontal/irrigação sanguínea , Animais , Capilares/patologia , Capilares/fisiologia , Capilares/fisiopatologia , Permeabilidade da Membrana Celular , Lobo Frontal/patologia , Ratos , Ratos Sprague-Dawley , Valores de Referência , Albumina Sérica/metabolismo , Fatores de Tempo
20.
Microsc Res Tech ; 57(5): 408-17, 2002 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-12112446

RESUMO

With the rete model of the eel swimbladder, we have studied the appearance and development of a microangiopathy during a 2-year period of hyperglycaemia. Hyperglycaemia was induced in the eel by chronic exposure to cold water. At 3-5 months, basement membrane thickness was twice the normal value and increased only slightly thereafter. Diffusion coefficients of permeability were measured in counter-current perfusion experiments for a variety of tracers that are believed to use different pathways of transcapillary transport. The permeability to sucrose was the first to significantly increase, at 6-8 months, followed by that of albumin, insulin, and inulin, at 9-11 months and that of sodium, at 18-24 months. The permeability to water and antipyrine remained stable throughout the study. The results indicate that in the rete model, chronic hyperglycaemia induces a rapid thickening of the capillary basement membrane and selective permeability increments in the various paths of transcapillary transport.


Assuntos
Sacos Aéreos/irrigação sanguínea , Capilares/ultraestrutura , Permeabilidade Capilar/fisiologia , Hiperglicemia/fisiopatologia , Sacos Aéreos/ultraestrutura , Animais , Membrana Basal/ultraestrutura , Capilares/fisiopatologia , Angiopatias Diabéticas/patologia , Angiopatias Diabéticas/fisiopatologia , Modelos Animais de Doenças , Enguias , Feminino , Humanos , Hiperglicemia/patologia , Distribuição Aleatória , Temperatura
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