RESUMO
The objective of this work was to identify the nutritional and physiological effects of commercial soy and whey protein preparations. Wistar rats were fed with soy (S), whey (W), or casein (C) preparations as the sole dietary protein source. The nitrogen balance, body composition, changes in caecal microbiota, mucosal and bacterial enzyme activities, and allergenic potential of the preparations were analysed. The whey diet elicited greater skeletal muscle anabolism than the soy diet. Rats from the S group had the lowest values of body weight, fat, and lean mass gain. Compared to casein, soy and whey preparations decreased the protein efficiency ratio, increased N in the urine, and triggered the reduction of ammonia levels in the caecum. Changes in ß-glucuronidase and ß-galactosidase activities in the small intestine, caecum, and colon between experimental groups were observed. Significant differences were noted in the total counts of anaerobic bacteria and sulphite reducing bacteria during soy and whey treatments. This probably affected the short chain fatty acid level in caecal digesta resulting in the lowest propionic acid and total putrefactive short chain fatty acid levels during S treatment. Generally, whey preparations are a good choice for rapid bodybuilding (skeletal muscles), whereas soy preparations are more helpful during mass reduction.
Assuntos
Trato Gastrointestinal/metabolismo , Ratos/metabolismo , Proteínas de Soja/metabolismo , Proteínas do Soro do Leite/metabolismo , Animais , Peso Corporal , Proteínas Alimentares/metabolismo , Digestão , Ácidos Graxos Voláteis/metabolismo , Masculino , Músculo Esquelético/crescimento & desenvolvimento , Músculo Esquelético/metabolismo , Ratos/crescimento & desenvolvimentoRESUMO
Obesity is a serious public health problem and being multifactorial is difficult to tackle. Since the intestinal ecosystem's homeostasis is, at least partially, diet-dependent, its modulation may be triggered by food components that are designed to exert a modulatory action leading to a health-promoting effect. Milk whey proteins, are considered as such promising factors since they influence satiation as well as body weight and constitute the source of biologically active peptides which may modulate health status locally and systemically. This way, whey proteins are associated with obesity. Therefore, this paper is aimed at the estimation of the impact of whey proteins using a commercially available whey protein isolate on the physiological response of mice with diet-induced obesity. The physiological response was evaluated on the local-intestinal level, scrutinizing intestinal microbiota as one of the important factors in obesity and on the systemic level, analyzing the response of the organism. Whey proteins brought about the decrease of the fat mass with a simultaneous increase of the lean mass of animals with diet induced obesity, which is a promising, health-promoting effect. Whey proteins also proved to act beneficially helping restore the number of beneficial bifidobacteria in obese animals and decreasing the calorie intake and fat mass as well as the LDL level. Overall, supplementation of the high fat diet with whey proteins acted locally by restoration of the intestinal ecosystem, thus preventing dysbiosis and its effects and also acted systemically by strengthening the organism increasing the lean mass and thus hindering obesity-related detrimental effects.
Assuntos
Obesidade/dietoterapia , Proteínas do Soro do Leite/metabolismo , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Dieta Hiperlipídica/efeitos adversos , Ingestão de Energia , Microbioma Gastrointestinal , Humanos , Mucosa Intestinal/metabolismo , Intestinos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/genética , Obesidade/metabolismo , Obesidade/microbiologiaRESUMO
The aim of this study was to examine immune adaptive changes, the expression of innate biomarkers and variations in intestinal microbiota composition after horse-milk administration in BALB/c mice, which were sensitized intraperitoneally using cow ß-lactoglobulin and α-casein with aluminum adjuvant. We measured serum antibody IgE levels and the expression of MCP-1, IL-4, and TNF-α in duodenal samples. Changes in immune cell populations in peripheral blood were quantified using flow cytometry, and intestinal microbiota composition was assessed using real-time PCR. We found that horse-milk administration decreased serum IgE levels in sensitized mice. The groups that received horse milk showed an increased population of regulatory T cells (CD4+Foxp3+). Horse-milk administration decreased the mRNA levels of IL-4 and resulted in higher transcripts of TLR-4 in all treatment groups; however, the levels of MCP-1, TNF-α, and TLR-2 were unaltered. After horse-milk treatment, we observed a positive effect, with increased numbers of intestinal Bifidobacterium spp. We observed immune-modulating properties of horse milk, but future studies should focus on testing horse-milk processing, such as fermentation and destroying most allergenic epitopes to continue research under clinical conditions.
Assuntos
Lactoglobulinas/imunologia , Leite , Animais , Caseínas/genética , Bovinos , Feminino , Imunoglobulina E/sangue , Camundongos , Hipersensibilidade a Leite/imunologiaRESUMO
DNA oxidative lesions are widely considered as a potential risk factor for colorectal cancer development. The aim of this work was to determine the role of the efficiency of base excision repair, both in lymphocytes and in epithelial tissue, in patients with CRC and healthy subjects. SNPs were identified within genes responsible for steps following glycosylase action in BER, and patients and healthy subjects were genotyped. A radioisotopic BER assay was used for assessing repair efficiency and TaqMan for genotyping. Decreased BER activity was observed in lymphocyte extract from CRC patients and in cancer tissue extract, compared to healthy subjects. In addition, polymorphisms of EXO1, LIG3, and PolB may modulate the risk of colorectal cancer by decreasing (PolB) or increasing (LIG3 and EXO1) the chance of malignant transformation.
Assuntos
Neoplasias Colorretais/genética , Dano ao DNA , Reparo do DNA , Proteínas de Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , PolôniaRESUMO
AIMS: Investigation of intestinal bacterial groups involved in phytate degradation and the impact of diets with different phytate contents on phytase activity. METHODS AND RESULTS: Faecal samples of adults on conventional (n = 8) or vegetarian (n = 8) diets and breastfed infants (n = 6) were used as an inoculum for modified media supplemented with phytate. Populations of Gram-positive anaerobes (GPA), lactic acid bacteria (LAB), Proteobacteria-Bacteroides (P-B), coliforms and anaerobes were studied. The PCR-DGGE analysis revealed a random distribution of DGGE profiles in the dendrograms of GPA, P-B and coliforms, and a partially diet-specific distribution in the DGGE dendrograms of LAB and anaerobes. The degradation of phytic acid (PA) was determined with HPLC method in supernatants of the cultures. Regardless of the diet, the Gram-positive anaerobes and LAB displayed the lowest ability to degrade phytate, whereas the coliforms and P-B cultures produced higher amounts of intermediate myo-inositol phosphates. Bacterial populations grown in a nonselective medium were the most effective ones in phytate degradation. It was the vegetarians' microbiota that particularly degraded up to 100% phytate to myo-inositol phosphate products lower than InsP3. CONCLUSIONS: A diet rich in phytate increases the potential of intestinal microbiota to degrade phytate. The co-operation of aerobic and anaerobic bacteria is essential for the complete phytate degradation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides insights on the effect of diet on specific metabolic activity of human intestinal microbiota.
Assuntos
6-Fitase/metabolismo , Bactérias/enzimologia , Intestinos/microbiologia , Microbiota , Ácido Fítico/metabolismo , Adulto , Animais , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Dieta , Fezes/microbiologia , Feminino , Humanos , Lactente , MasculinoRESUMO
Methotrexate (MTX) and 6-mercaptopurine (6MP) are the most commonly used drugs in the therapy of childhood acute lymphoblastic leukaemia (ALL). The main genotoxic effect of MTX resulting from inhibition of thymidylate synthase is mis-incorporation of uracil into DNA, which is considered essential for the effectiveness of the Protocol M in ALL IC BFM 2002/EURO LB 2002 regimens. In this study, we investigated the level of basal and induced DNA damage as well as the effectiveness of DNA repair in lymphocytes of children with ALL at four time-points during therapy with MTX and 6MP. To assess DNA damage and the efficacy of DNA repair we used the modified alkaline comet assay with uracil DNA glycosylase (Udg) and endonuclease III (EndoIII). In addition, we examined the induction of apoptosis in the lymphocytes of the patients during treatment. Finally, we compared the activity of base-excision repair (BER), involved in removal of both uracil and oxidized bases from DNA in lymphocytes of children with ALL and lymphocytes of healthy children. BER efficiency was estimated in an in vitro assay with cellular extracts and plasmid substrates of heteroduplex DNA with an AP-site. Our results indicate that there is a significant decrease in the efficacy of DNA repair associated with an increased level of uracil in DNA and induction of apoptosis during therapy. Moreover, it was found that the BER capacity was decreased in the lymphocytes of ALL patients in contrast to that in lymphocytes of healthy children. Thus, we suggest that an impairment of the BER pathway may play a role in the pathogenesis and therapy of childhood ALL.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Dano ao DNA , Reparo do DNA , Mercaptopurina/administração & dosagem , Metotrexato/administração & dosagem , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Adolescente , Apoptose , Criança , Pré-Escolar , Ensaio Cometa , Humanos , Peróxido de Hidrogênio/farmacologia , Linfócitos/efeitos dos fármacos , Masculino , Oxirredução , Uracila/metabolismo , Adulto JovemRESUMO
Tobacco smoking is one of the major risk factors in pathogenesis of head and neck squamous cell carcinomas (HNSCC). Many of the chemical compounds present in tobacco are well-known carcinogens which form adducts with DNA. Cells remove these adducts mainly by the nucleotide excision repair pathway (NER). NER also eliminates a broad spectrum of pyrimidine dimers (CPD) and photo-products (6-4PP) induced by UV-radiation or DNA cross-links after cisplatin anti-cancer treatment. In this study DNA damage and repair was examined in peripheral blood lymphocytes obtained from 20 HNSCC patients and 20 healthy controls as well as HTB-43 larynx and SSC-25 tongue cancer cell lines. DNA repair kinetics in the examined cells after cisplatin or UV-radiation treatment were investigated using alkaline comet assay during 240min of post-treatment incubation. MTT assay was used to analyse cell viability and the Annexin V-FITC kit specific for kinase-3 was employed to determine apoptosis after treating the cells with UV-radiation at dose range from 0.5 to 60J/m(2). NER capability was assessed in vitro with cell extracts by the use of a bacterial plasmid irradiated with UV-light as a substrate for the repair. The results show that lymphocytes from HNSCC patients and HTB-43 or SSC-25 cancer cells were more sensitive to genotoxic treatment with UV-radiation and displayed impaired DNA repair. Also evidenced was a higher rate of apoptosis induction after UV-radiation treatment of lymphocytes from the HNSCC patients and the HTB-43 cancer cells than after treatment of those from healthy donors. Finally, our results showed that there was a significant decrease in NER capacity in HTB-43 or SSC-25 cancer cells as well as in peripheral blood lymphocytes of HNSCC patients compared to controls. In conclusion, we suggest that the impaired NER pathway might be a critical factor in pathogenesis of head and neck cancer.
Assuntos
Carcinoma de Células Escamosas/genética , Dano ao DNA , Reparo do DNA , Neoplasias de Cabeça e Pescoço/genética , Apoptose , Estudos de Casos e Controles , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Cisplatino/farmacologia , Feminino , Humanos , Neoplasias Laríngeas/genética , Linfócitos/patologia , Masculino , Pessoa de Meia-Idade , Carcinoma de Células Escamosas de Cabeça e Pescoço , Raios Ultravioleta/efeitos adversosRESUMO
Eleven type strains and 24 Lactobacillus isolates, preliminarily classified to the species due to phenotypic features, were investigated. Standard methods of identification with species-specific PCRs and typing with PFGE (with ApaI, NotI and SmaI restriction enzymes) allowed us to distinguish 16 unique strains belonging to 5 species (L. acidophilus, L. delbrueckii ssp. bulgaricus, L. plantarum, L. rhamnosus, L. salivarius). Alternative approach with 16S-23S rDNA ARDRA identification (with merely two restrictases, BsuRI and TaqI) and PCR-based typing (RAPD with two random- and rep-PCR with (GTG)(5) primers) showed to be more discriminative, i.e. 21 unique strains were classified in the same species as above. As a result, 7 out of 24 phenotypically species-assigned isolates were reclassified. The alternative procedure of rapid identification and typing of Lactobacillus isolates appeared to be equally effective and shortened from 1 week to 2-3 d (in comparison to the standard methods).
Assuntos
Lactobacillus/classificação , Lactobacillus/genética , Reação em Cadeia da Polimerase/métodos , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Mapeamento por Restrição/métodos , Técnicas de Tipagem Bacteriana/métodos , Primers do DNA , DNA Bacteriano/análise , DNA Bacteriano/genética , Eletroforese em Gel de Poliacrilamida , Lactobacillus/isolamento & purificação , Fenótipo , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética , Especificidade da Espécie , Fatores de TempoRESUMO
AIM: To evaluate the generation and repair of DNA double strand breaks (DSBs) as a critical factors that define the efficiency of radiation therapy of cancer patients. METHODS: Peripheral blood lymphocytes obtained from 18 patients with head and neck squamous cell carcinoma (HNSCC) and 18 healthy donors were studied. The efficiency of DSBs repair after genotoxic treatment with hydrogen peroxide and gamma-radiation were examined by neutral comet assay. MTT assay was used for cell viability analysis and Annexin V-FITC kit specific for kinase-3 was employed to determine apoptosis. RESULTS: Lymphocytes from HNSCC patients were sensitive to genotoxic treatment and displayed impaired DSBs repair. Finally, as a consequence of this finding we have evidenced higher rate of apoptosis induction after gamma-radiation treatment of lymphocytes from HNSCC patients than those from healthy controls. CONCLUSIONS: DSBs repair and increased apoptosis in cells of patients with head and neck cancer is relevant for efficient therapy of HNSCC.
Assuntos
Apoptose , Carcinoma de Células Escamosas/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA/genética , Neoplasias de Cabeça e Pescoço/genética , Linfócitos/patologia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Células Cultivadas , Ensaio Cometa , Feminino , Raios gama , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Peróxido de Hidrogênio/uso terapêutico , Linfócitos/efeitos dos fármacos , Linfócitos/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Oxidantes/uso terapêuticoRESUMO
BACKGROUND: Head and neck squamous cell carcinomas (HNSCC) comprise about 6% of all malignant neoplasms. The major risk factors of -HNSCC are smoking and alcohol consumption. Genetic polymorphisms of DNA repair enzymes may lead to genetic instability and carcinogenesis. MUTYH gene encodes a DNA glycosylase that can initiate the base excision repair (BER) pathway and prevent G:C > T:A transversion by excising adenine mispaired with 8-hydroxyguanine produced by reactive oxygen species (ROS). AIM: to perform a case-control study to test the association between polymorphism in the MUTYH gene: Tyr165Cys and head and neck cancer risk progression. METHODS: Genotypes were determined in DNA from peripheral blood lymphocytes of 193 patients (among them 97 subjects with precancerous hyperplastic laryngeal lesions and 96 subjects with head and neck cancer) and 140 age, sex and ethnic-matched cancer-free controls by tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR). RESULTS: We found an association between head and neck cancer risk and the Tyr165Tyr variant of the MUTYH gene (OR 2.18; 95% CI 1.19-3.97). For Tyr165Tyr genotype we also observed positive correlation with cancer progression assessed by tumor size (OR 4.56; 95% CI 1.60-12.95). We did not observe any correlation between Tyr165Cys polymorphism of MUTYH gene and precancerous hyperplastic laryngeal lesions risk. CONCLUSION: The Tyr165Tyr polymorphic variant of the MUTYH gene may be associated with head and neck cancer in Polish population.
Assuntos
DNA Glicosilases/genética , DNA/genética , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/patologia , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Progressão da Doença , Feminino , Genótipo , Neoplasias de Cabeça e Pescoço/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , População BrancaRESUMO
The goal of this paper was studying the effectiveness of frequently repeated low values of long duration acceleration on circulatory system response during gradual onset rate of acceleration on a human centrifuge.
Assuntos
Aceleração/efeitos adversos , Adaptação Fisiológica , Circulação Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Hipergravidade , Adulto , Medicina Aeroespacial , Aviação/educação , Centrifugação , Humanos , Militares/educação , PolôniaRESUMO
Estrogenic activities of testosterone (T) and 5a-dihydrotestosterone (DHT) were detected and measured by using their specific stimulatory effects on alkaline phosphatase (AP) activity in human endometrial adenocarcinoma cells of the Ishikawa Var-1 line. These two physiologic androgens were able to induce, at microM concentrations, estrogenic effect believed to be mediated by the estrogen receptor (ER) since the antiestrogens ICI-164384 and 4-hydroxytamoxifen (OHTam), but not the antiandrogens hydroxyflutamide (OHFl) or cyproterone acetate (CPA), reversed that effect. By using another in vitro bioassay, based on the progestin-specific stimulation of AP activity in cells of the T47D human breast cancer line, progestagenic activity was detected and measured in T, DHT and three synthetic androgens: nandrolone (19-nortestosterone). 7 alpha-methyl 19-nortestosterone (MENT) and mibolerone (7 alpha, 17 alpha-dimethyl 19-nortestosterone) (DMNT). While progestagenic effects of T and DHT required relatively high concentrations (microM levels), the synthetic androgens stimulated AP activity at nM or pM levels. These effects seem to be mediated by the progesterone receptor (PR), since they are completely abolished by the antiprogestins RU-486, ZK-98299 and ZK-112993, but not by the antiandrogen OHFl. These simple in vitro bioassays, expressing biological effects of the test compounds in human cells in culture, revealed dual or multiple hormonal activities coexisting in a single compound and provide quantitative information of considerable pharmacological importance concerning the complex actions of drugs.
Assuntos
Adenocarcinoma/fisiopatologia , Fosfatase Alcalina/metabolismo , Androgênios/fisiologia , Neoplasias da Mama/fisiopatologia , Neoplasias do Endométrio/fisiopatologia , Antagonistas de Estrogênios/farmacologia , Progestinas/antagonistas & inibidores , Congêneres da Testosterona/farmacologia , Adenocarcinoma/enzimologia , Fosfatase Alcalina/efeitos dos fármacos , Antagonistas de Androgênios/farmacologia , Neoplasias da Mama/enzimologia , Acetato de Ciproterona/farmacologia , Neoplasias do Endométrio/enzimologia , Estradiol/análogos & derivados , Estradiol/farmacologia , Feminino , Flutamida/análogos & derivados , Flutamida/farmacologia , Gonanos/farmacologia , Humanos , Mifepristona/análogos & derivados , Mifepristona/farmacologia , Alcamidas Poli-Insaturadas , Tamoxifeno/análogos & derivados , Tamoxifeno/farmacologia , Testosterona/farmacologia , Testosterona/fisiologia , Células Tumorais CultivadasRESUMO
NASA: Two different anti-G flight suits are compared. The first suit uses a bladder system to compress the lower limbs and abdomen and the second uses a tightening system to produce compression evenly for the lower body. Studies were performed using a centrifuge cabin with exposure to acceleration forces up to 2.5 G. Suits were compared for protection efficiency, comfort, complaints, and put on ease. Results of the study, including heart rate dynamics, ear vascular pulsation amplitude, and peripheral vision loss are presented.^ieng
Assuntos
Aceleração/efeitos adversos , Trajes Gravitacionais , Adaptação Fisiológica , Medicina Aeroespacial , Altitude , Aviação/educação , Centrifugação , Desenho de Equipamento , Frequência Cardíaca/fisiologia , Humanos , PolôniaRESUMO
In the years 1986-1990 within Upper Silesia Region (Katowice Voivodeship) 1240 larynx cancer cases were diagnosed. Larynx cancer standardized incidence rates there are: 12,5 cases per 100 thousand on the whole area, maximal--28.6 and minimal--2.2 per 100 thousand, taking into consideration 93 administrative units (45 towns and 48 community councils). Larynx cancer incidence rates were dynamically increasing every year by 3%. There has not been attained geographic correlation between highest larynx cancer incidence level and highest ambient air pollution.
Assuntos
Neoplasias Laríngeas/epidemiologia , Neoplasias Laríngeas/patologia , Laringe/patologia , Poluição do Ar/efeitos adversos , Feminino , Humanos , Incidência , Indústrias , Neoplasias Laríngeas/etiologia , Masculino , Polônia/epidemiologia , Estudos RetrospectivosAssuntos
Bioensaio , Estrogênios/farmacologia , Progestinas/farmacologia , Adenocarcinoma , Fosfatase Alcalina/metabolismo , Dinoprosta/biossíntese , Neoplasias do Endométrio , Endométrio/efeitos dos fármacos , Endométrio/metabolismo , Feminino , Humanos , Técnicas de Cultura de Órgãos , Células Tumorais CultivadasAssuntos
Decídua/fisiologia , Endométrio/enzimologia , Endopeptidases/metabolismo , Inibidores de Proteases/metabolismo , Células Cultivadas , Endométrio/citologia , Endométrio/fisiologia , Matriz Extracelular/enzimologia , Feminino , Humanos , Metaloendopeptidases/metabolismo , Ativadores de Plasminogênio/metabolismo , Inativadores de Plasminogênio/metabolismo , GravidezRESUMO
The physiologic mechanisms whereby the human endometrium maintains hemostasis during endovascular trophoblast invasion, yet permits menstrual hemorrhage, are unknown. This paradoxical relationship was investigated by evaluating endometrial expression of tissue factor (TF), the primary initiator of hemostasis, and plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of fibrinolysis. We observed increased immunostaining for TF and PAI-1 in sections of decidualized stromal cells from luteal phase and gestational endometrium. To determine whether TF and PAI-1 expression are directly linked to decidualization, both endpoints were monitored in a well described in vitro model of decidualization. Thus, confluent stromal cell cultures were exposed to vehicle control, 10(-8) M estradiol (E2), 10(-8) to 10(-6) M medroxyprogesterone acetate (MPA) or both E2 + MPA for 2-24 days in serum-containing or defined media. The progestin enhanced the content of stromal cell-associated immunoreactive and functionally active TF and PAI-1 released into the medium and elevated levels of stromal cell TF and PAI-1 mRNA. While E2 alone was ineffective, it greatly augmented MPA-enhanced TF and PAI-1 protein and mRNA content. Dose-dependent effects on TF and PAI-1 content were observed between 10(-8) to 10(-6) M MPA +/- E2. Similar results were observed for decidual cells derived from first trimester endometrium and cultured in type 1 collagen gels. Following optimal induction of TF and PAI-1 expression by E2 + MPA in stromal cell cultures, removal of these steroids greatly reduced levels of both TF and PAI-1 protein and mRNA within 4 days. These studies suggest a mechanism whereby endometrial hemostasis is maintained during trophoblast invasion yet reduced at the end of nonfertile cycles to permit menses.
Assuntos
Endométrio/irrigação sanguínea , Hemostasia , Menstruação/fisiologia , Inibidor 1 de Ativador de Plasminogênio/fisiologia , Progesterona/fisiologia , Tromboplastina/fisiologia , Células Cultivadas , Decídua/fisiologia , Endométrio/efeitos dos fármacos , Endométrio/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Fase Luteal , Acetato de Medroxiprogesterona/farmacologia , Inibidor 1 de Ativador de Plasminogênio/análise , Inibidor 1 de Ativador de Plasminogênio/genética , Gravidez , RNA Mensageiro/metabolismo , Tromboplastina/análise , Tromboplastina/genéticaRESUMO
The extracellular matrix (ECM) protein fibronectin (FN) is a critical regulator of uterine-placental adherence. In the present report we compared the effects of glucocorticoids on FN expression in cytotrophoblast cultures isolated from human first trimester and term placentas to elucidate potential steroid-dependent cellular mechanisms associated with human parturition. Based on immunoassays, treatment of first trimester cytotrophoblasts with 10(-7) M dexamethasone (DEX) for 2 cr 4 days reduced medium levels of oncofetal FN (onfFN; i.e. FNs bearing an oncofetal epitope) to approximately 80% of control levels. Conversely, treatment of cytotrophoblasts isolated from term placentas with DEX dramatically reduced medium levels of onfFN to approximately 12% of control values. Treatment of both first trimester and term cells with 10(-6) M progestin, mineralocorticoid, or estrogen had no significant effect on onfFN expression in either cell type. Glucocorticoids specifically down-regulated medium levels of onfFN in term cells, but not in first trimester cells. In contrast, DEX treatment promoted an approximately 3- to 7-fold increase in levels of hCG in both first trimester and term cytotrophoblasts, suggesting that the effects of glucocorticoid on FN and hCG expression are elicited through independent cell-signaling pathways. In first trimester cells, DEX promoted a reduction in rates of FN and laminin synthesis to 60-70% of control levels. In term cells, DEX treatment reduced levels of FN and laminin synthesis to approximately 10% of control levels. Similarly, DEX treatment down-regulated levels of FN mRNA to approximately 60% and 10% of control values in first trimester and term cells, respectively. The first trimester of human pregnancy is associated with low levels of glucocorticoids and reduced glucocorticoid responsiveness. These conditions would favor high levels of placental ECM protein synthesis, thus stabilizing uterine-placental adherence. Conversely, elevated levels of glucocorticoids near parturition and increased glucocorticoid responsiveness would inhibit placental ECM protein synthesis, reducing uterine-placental adherence and promoting the separation of placenta from uterus.
Assuntos
Dexametasona/farmacologia , Proteínas da Matriz Extracelular/genética , Expressão Gênica/efeitos dos fármacos , Placenta/metabolismo , Células Cultivadas , Gonadotropina Coriônica/genética , Desenvolvimento Embrionário e Fetal , Proteínas da Matriz Extracelular/biossíntese , Feminino , Fibronectinas/genética , Humanos , Laminina/genética , Gravidez , RNA Mensageiro/metabolismo , Trofoblastos/metabolismoRESUMO
The progestin-specific stimulation of alkaline phosphatase (AP) activity in cells of the T47D human breast cancer line was applied to the development of a sensitive microtiter plate bioassay for the quantitative evaluation of progestagenic and antiprogestagenic potencies of natural and synthetic compounds. Some of the steroids tested (viz. progesterone, medroxyprogesterone acetate, norethynodrel) behaved as full-agonists, capable of inducing AP activities to the same maximal levels (equal efficacy), while others (norethindrone, gestrinone, R5020, norgestrel, Org OD 14 and its 4-ene metabolite) behaved as partial agonists, eliciting lower maximal effects. Efficacy, EC50 values (concentrations at which they induce one-half of the maximal response) and "slope factors" serve to characterize agonistic effects. Relative progestagenic potencies among the full-agonists were evaluated by comparing EC50 concentrations. Several 19-nor synthetic progestins (norethynodrel, norethindrone, Org OD 14 and its 4-ene isomer, dl-norgestrel, levo-norgestrel, RU2323), but none of the tested progestins with the pregnane structure, showed intrinsic estrogenic activity, as evaluated by using a similar in vitro bioassay based on a previously reported estrogen-specific induction of AP in human endometrial adenocarcinoma cells of the Ishikawa Var-1 line. Maximal estrogenic effects of all the tested progestins with dual activity were as high as those of estradiol. However, these compounds widely varied in their EC50 values for estrogenic activity. Consequently, the in vitro bioassays can reveal differences in the ratio of progestagenic and estrogenic activities intrinsic to these compounds. The reduced capability of the partial agonists to exert progestagenic or estrogenic effects on AP expression may reflect an impeded, receptor-mediated action, a mechanism that would also account for their inhibitory effects on the induction of AP activity by full agonists. Partial progestagenic agonists were able to reduce the efficacy of a full agonist to their own partial maximal activity.