RESUMO
Biofilm has recently been highlighted as a complicating feature of necrotizing soft tissue infections (NSTI) caused by Streptococcus pyogenes (i.e., group A Streptococcus [GAS]) contributing to a persistence of bacteria in tissue despite prolonged antibiotic therapy. Here, we assessed the standard treatment of benzylpenicillin and clindamycin with or without rifampin in a tissue-like setting. Antibiotic efficacy was evaluated by CFU determination in a human organotypic skin model infected for 24 or 48 h with GAS strains isolated from NSTI patients. Antibiotic effect was also evaluated by microcalorimetric metabolic assessment in in vitro infections of cellular monolayers providing continuous measurements over time. Adjunctive rifampin resulted in enhanced antibiotic efficacy of bacterial clearance in an organotypic skin tissue model, 97.5% versus 93.9% (P = 0.006). Through microcalorimetric measurements, adjunctive rifampin resulted in decreased metabolic activity and extended lag phase for all clinical GAS strains tested (P < 0.05). In addition, a case report is presented of adjunctive rifampin treatment in an NSTI case with persistent GAS tissue infection. The findings of this study demonstrate that adjunctive rifampin enhances clearance of GAS biofilm in an in vitro tissue infection model.
Assuntos
Infecções dos Tecidos Moles , Infecções Estreptocócicas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Humanos , Rifampina/farmacologia , Infecções dos Tecidos Moles/tratamento farmacológico , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenesRESUMO
BACKGROUND: Necrotizing soft tissue infections (NSTIs) are rare but carry a high morbidity and mortality. The multicenter INFECT project aims to improve the understanding of the pathogenesis, clinical characteristics, diagnosis, and prognosis of NSTIs. This article describes the study outline and statistical analyses that will be used. METHODS: Within the framework of INFECT project, patients with NSTI at 5 Scandinavian hospitals are enrolled in a prospective observational cohort study. The goal is to evaluate outcome and characteristics for patients with NSTI and diabetes compared to patients with NSTI without diabetes. The primary outcome is mortality at 90 days after inclusion. Secondary outcomes include days alive and out of ICU and hospital, SAPS II, SOFA score, infectious etiology, amputation, affected body area, and renal replacement therapy. Comparison in mortality between patients with diabetes type 1 and 2 as well as between insulin-treated and non-insulin-treated diabetes patients will be made. Clinical data for diabetic patients with NSTI will be reported. CONCLUSION: The study will provide important data on patients with NSTI and diabetes.
RESUMO
BACKGROUND: The INFECT project aims to advance our understanding of the pathophysiological mechanisms in necrotizing soft tissue infections (NSTIs). The INFECT observational study is part of the INFECT project with the aim of studying the clinical profile of patients with NSTIs and correlating these to patient-important outcomes. With this protocol and statistical analysis plan we describe the methods used to obtain data and the details of the planned analyses. METHODS: The INFECT study is a multicentre, prospective observational cohort study. Patients with NSTIs are enrolled in five Scandinavian hospitals, which are all referral centres for NSTIs. The primary outcomes are the descriptive variables of the patients. Secondary outcomes include identification of factors associated with 90-day mortality and amputation; associations between affected body part, maximum skin defect and Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score and 90-day mortality; 90-day mortality in patients with and without acute kidney injury (AKI) and LRINEC score of six and above or below six; and association between affected body part at arrival and microbiological findings. Exploratory outcomes include univariate analyses of baseline characteristics associations with 90-day mortality. The statistical analyses will be conducted in accordance with the predefined statistical analysis plan. CONCLUSION: Necrotizing soft tissue infections result in severe morbidity and mortality. The INFECT study will be the largest prospective study in patients with NSTIs to date and will provide important data for clinicians, researchers and policy makers on the characteristics and outcomes of these patients.
Assuntos
Necrose/patologia , Necrose/terapia , Infecções dos Tecidos Moles/patologia , Infecções dos Tecidos Moles/terapia , Injúria Renal Aguda/complicações , Injúria Renal Aguda/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Amputação Cirúrgica/estatística & dados numéricos , Estudos de Coortes , Comorbidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Necrose/mortalidade , Estudos Prospectivos , Infecções dos Tecidos Moles/mortalidade , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Most studies of sepsis are from intensive care units (ICUs). We aimed to investigate community-acquired severe sepsis in a broader population, in order to compare patients treated in or outside an ICU . METHODS: We performed a 1-year prospective observational study with enrollment of patients from three units; a general ICU, a combined ICU/non-ICU and a medical ward with limited surveillance facilities. Hospital survivors were followed up for 5 years. RESULTS: Overall, 220 patients were included, of which 107 received ICU treatment. The majority of abdominal (77%, P = 0.003) and genitourinary (81%, P < 0.001) infections were found in ICU and non-ICU patients, respectively. Time to first antibiotic administration was longer in ICU-patients (median 3.5 vs. 2.0 h in non-ICU patients, P = 0.011). ICU developed more organ dysfunctions than non-ICU patients (P < 0.001), nevertheless supportive therapy with vasoactive drugs and non-invasive ventilation was documented in 22% and 27% of the latter. Median hospital length of stay was 15 vs. 9 days (P = 0.001), and hospital and 5-year mortality rates 35% vs. 16% (P = 0.002) and 57% vs. 58% (P = 0.892) among ICU and non-ICU patients, respectively. Increasing age (HR 1.06 (1.04, 1.07) per year, P < 0.001), not care level during hospitalization (HR 1.19 (0.70, 2.02), P = 0.514), influenced long-term survival. CONCLUSION: Half of the subjects with community-acquired severe sepsis never received ICU treatment. Still, use of organ supportive therapy outside the ICU was considerable. Hospital mortality was higher, whereas 5-year survival was similar when comparing ICU with non-ICU patients.
Assuntos
Infecções Comunitárias Adquiridas/terapia , Cuidados Críticos , Sepse/terapia , Adolescente , Adulto , Idoso , Infecções Comunitárias Adquiridas/mortalidade , Feminino , Mortalidade Hospitalar , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sepse/mortalidadeRESUMO
Streptococcal inhibitor of complement (SIC) and distantly related to SIC (DRS) are well-characterized extracellular virulence factors produced by only a few emm types among group A streptococci. The prevalence and sequence variations of the sic-like gene (sicG) in clinical samples of group C and G Streptococcus dysgalactiae subspecies equisimilis (SDSE), however, have not been widely investigated. We constructed primers targeting sicG and screened 129 geographically matched and previously emm-typed non-invasive (n = 64) and invasive (n = 65) SDSE isolates for the presence of this gene. sicG was detected in seven non-invasive and eight invasive isolates belonging to eight different emm types. Within five of these emm types, sicG-negative isolates were also detected. All three isolates of stG2078.0 possessed sicG and were associated with severe soft tissue infections. Altogether, six sicG alleles (sicG1-6) were identified, and sequence variations were mainly caused by single nucleotide polymorphisms and deletion/insertion mutations. sicG1-6 were predicted to encode SICG proteins of varying length, composition, and homology with SIC and DRS proteins of group A streptococci. Our findings indicate an unpredictable association between sicG and emm type, a limited distribution and substantial sequence diversity of sicG, and no obvious relation between its presence and disease severity.
Assuntos
Proteínas de Bactérias/genética , Variação Genética , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/microbiologia , Streptococcus/genética , Alelos , Sequência de Aminoácidos , Primers do DNA/genética , DNA Bacteriano/genética , Genótipo , Humanos , Dados de Sequência Molecular , Mutagênese Insercional , Noruega/epidemiologia , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Alinhamento de Sequência , Análise de Sequência de DNA , Deleção de SequênciaRESUMO
The prevalence of overweight and obesity in most developed countries has markedly increased during the last decades. In addition to genetic, hormonal, and metabolic influences, environmental factors like fetal and neonatal nutrition play key roles in the development of obesity. Interestingly, overweight during critical developmental periods of fetal and/or neonatal life has been demonstrated to increase the risk of obesity throughout juvenile life into adulthood. In spite of this evidence, the specific mechanisms underlying this fetal/neonatal programming are not perfectly understood. However, it is clear that circulating hormones such as insulin and leptin play a critical role in the development and programming of hypothalamic circuits regulating energy balance. Here, we review what is currently known about the impact of perinatal malnutrition on the mechanisms regulating body weight homeostasis. Understanding these molecular mechanisms may provide new targets for the treatment of obesity.
Assuntos
Metabolismo Energético , Hipotálamo/metabolismo , Hipotálamo/fisiopatologia , Transtornos da Nutrição do Lactente/metabolismo , Transtornos da Nutrição do Lactente/fisiopatologia , Obesidade/metabolismo , Obesidade/fisiopatologia , Adulto , Animais , Feminino , Humanos , Hipotálamo/patologia , Lactente , Transtornos da Nutrição do Lactente/complicações , Transtornos da Nutrição do Lactente/patologia , Recém-Nascido , Masculino , Obesidade/etiologia , Obesidade/patologiaRESUMO
In order to investigate molecular characteristics of beta-hemolytic streptococcal isolates from western Norway, we analysed the entire emm gene sequences, obtained superantigen gene profiles and determined the prevalence of the gene encoding streptococcal phospholipase A2 (SlaA) of 165 non-invasive and 34 contemporary invasive group A, C and G streptococci (GAS, GCS and GGS). Among the 25 GAS and 26 GCS/GGS emm subtypes identified, only emm3.1 was significantly associated with invasive disease. M protein size variation within GAS and GCS/GGS emm types was frequently identified. Two non-invasive and one invasive GGS possessed emm genes that translated to truncated M proteins as a result of frameshift mutations. Results suggestive of recombinations between emm or emm-like gene segments were found in isolates of emm4 and stG485 types. One non-invasive GGS possessed speC, speG, speH, speI and smeZ, and another non-invasive GGS harboured SlaA. speA and SlaA were over-represented among invasive GAS, probably because they were associated with emm3. speG(dys) was identified in 83% of invasive and 63% of non-invasive GCS/GGS and correlated with certain emm subtypes. Our results indicate the invasive potential of isolates belonging to emm3, and show substantial emm gene diversity and possible lateral gene transfers in our streptococcal population.
Assuntos
Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Transporte/genética , Fosfolipases A2/genética , Streptococcus pyogenes/genética , Streptococcus/genética , Superantígenos/genética , Sequência de Aminoácidos , Antígenos de Bactérias/química , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Transporte/química , Mutação da Fase de Leitura , Transferência Genética Horizontal , Variação Genética , Humanos , Dados de Sequência Molecular , Noruega , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Recombinação Genética , Análise de Sequência de Proteína , Infecções Estreptocócicas/microbiologia , Streptococcus/imunologia , Streptococcus/patogenicidade , Streptococcus pyogenes/imunologia , Streptococcus pyogenes/isolamento & purificação , Streptococcus pyogenes/patogenicidade , Superantígenos/imunologiaRESUMO
BACKGROUND: Necrotizing skin and soft-tissue infections (NSTI) are rare but potentially life-threatening and disabling infections that often require intensive care unit admission. OBJECTIVES: To review all aspects of care for a critically ill individual with NSTI. SOURCES: Literature search using Medline and Cochrane library, multidisciplinary panel of experts. CONTENT: The initial presentation of a patient with NSTI can be misleading, as features of severe systemic toxicity can obscure sometimes less impressive skin findings. The infection can spread rapidly, and delayed surgery worsens prognosis, hence there is a limited role for additional imaging in the critically ill patient. Also, the utility of clinical scores is contested. Prompt surgery with aggressive debridement of necrotic tissue is required for source control and allows for microbiological sampling. Also, prompt administration of broad-spectrum antimicrobial therapy is warranted, with the addition of clindamycin for its effect on toxin production, both in empirical therapy, and in targeted therapy for monomicrobial group A streptococcal and clostridial NSTI. The role of immunoglobulins and hyperbaric oxygen therapy remains controversial. IMPLICATIONS: Close collaboration between intensive care, surgery, microbiology and infectious diseases, and centralization of care is fundamental in the approach to the severely ill patient with NSTI. As many aspects of management of these rare infections are supported by low-quality data only, multicentre trials are urgently needed.
Assuntos
Fasciite Necrosante/microbiologia , Unidades de Terapia Intensiva/estatística & dados numéricos , Pele/microbiologia , Infecções dos Tecidos Moles/microbiologia , Antibacterianos/uso terapêutico , Bactérias/efeitos dos fármacos , Estado Terminal , Desbridamento , Gerenciamento Clínico , Fasciite Necrosante/tratamento farmacológico , Fasciite Necrosante/cirurgia , Humanos , Pele/patologia , Infecções dos Tecidos Moles/tratamento farmacológico , Infecções dos Tecidos Moles/cirurgiaRESUMO
A mixture of 7 alpha-3H- and 4-14C-labeled cholesterol was administered intravenously to rats. Cholestanol with 20-30% lower ratio between 3H and 14C than in cholesterol could be isolated from different organs. In a healthy human control, cholestanol isolated from feces had a 3H/14C ratio which was 28% lower than in administered cholesterol. Cholesterol and coprostanol reisolated in these experiments had the same ratio between 3H and 14C as in the precursor. A previously unknown pathway for formation of cholestanol, involving 7 alpha-hydroxylated intermediates, may explain these results. Under normal conditions, this pathway is responsible for at most 30% of the cholestanol synthesized from cholesterol. Intravenous administration of the 7 alpha-3H- and 4-14C-labeled cholesterol to a patient with cerebrotendinous xanthomatosis (CTX) resulted in formation of cholestanol which had 70-75% lower 3H/14C ratio. It is concluded that the novel pathway involving 7 alpha-hydroxylated intermediates is accelerated in patients with CTX. This acceleration may contribute essentially to the accumulation of cholestanol, which is a predominant feature of this disease. 7 alpha-Hydroxycholesterol and 7 alpha-hydroxy-4-cholesten-3-one might be intermediates in the novel pathway to cholestanol. After intravenous administration of 7 beta-3H-labeled 7 alpha-hydroxycholesterol in a patient with CTX, significant amounts of 3H were incorporated into plasma and fecal cholestanol. Only small amounts of 7 alpha-hydroxycholesterol and 7 alpha-hydroxy-4-cholesten-3-one are excreted into the intestine, and we therefore conclude that the 7 alpha-dehydroxylation step mainly occurs in the liver. In CTX, the synthesis of cholestanol may be accelerated because the concentrations of 7 alpha-hydroxylated bile acid intermediates in the liver are increased. A possible mechanism for the conversion of a minor fraction of 7 alpha-hydroxycholesterol into cholestanol is suggested.
Assuntos
Encefalopatias/metabolismo , Colestanol/biossíntese , Colestanóis/biossíntese , Colesterol/análogos & derivados , Doenças Musculares/metabolismo , Xantomatose/metabolismo , Adulto , Ácidos e Sais Biliares/metabolismo , Fenômenos Químicos , Química , Colestanol/metabolismo , Fezes/análise , Feminino , Humanos , Hidroxilação , Pessoa de Meia-IdadeRESUMO
On the basis of different in vitro studies, we have previously suggested that the basic metabolic defect in the rare inherited disease cerebrotendinous xanthomatosis (CTX) is a lack of a hepatic mitochondrial C27-steroid 26-hydroxylase, involved in the normal biosynthesis of bile acids (1980. J. Clin. Invest. 65: 1418-1430; 1981. J. Lipid Res. 22: 191-200; 22: 632-640). In the present work, this hypothesis was tested in vivo. One patient with CTX and two control subjects received intravenously a mixture of [4-14C]7 alpha-hydroxy-4-cholesten-3-one and [6 beta-3H]7 alpha,26-dihydroxy-4-cholesten-3-one, steroids believed to be important precursors of chenodeoxycholic acid. The ratio between 14C and 3H in cholic acid and chenodeoxycholic acid isolated from bile of the CTX-patient was approximately 1/40 and 1/60 of those of the control subjects, respectively. Another patient with CTX and one control subject received a mixture of [4-14C]5 beta-cholestane-3 alpha,7 alpha-diol and [1,2-3H]5 beta-cholestane-3 alpha,7 alpha,26-triol, both possible precursors to chenodeoxycholic acid. In this case the 14C/3H ratio in cholic acid and chenodeoxycholic acid from the patient with CTX was 1/10 and 1/15, respectively, compared with that of the control subject. The most likely explanation for these findings is that very little of the 14C-precursors, i.e. without a 26-hydroxyl group, can be converted into cholic acid and chenodeoxycholic acid because of a defect of the 26-hydroxylase step. The results obtained are in accord with our previous findings in vitro. The results further underline the importance of the 26-hydroxylase pathway in the normal biosynthesis of cholic acid and chenodeoxycholic acid in man.
Assuntos
Ácidos e Sais Biliares/biossíntese , Erros Inatos do Metabolismo Lipídico/enzimologia , Esteroide Hidroxilases/deficiência , Adulto , Ácido Quenodesoxicólico/biossíntese , Feminino , Humanos , Fígado/enzimologiaRESUMO
Oxidation of side chain of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol was studied in a patient with cerebrotendinous xanthomatosis (CTX) and in control subjects, using various subcellular fractions of liver homogenate and a method based on isotope dilution-mass spectrometry. In the control, 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol was converted into 5 beta-cholestane-3 alpha,7 alpha,12 alpha,26-tetrol and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid by the mitochondrial fraction, and into 5 beta-cholestane-3 alpha,7 alpha,12 alpha,-25-tetrol by the microsomal fraction. In the CTX patient, liver mitochondria were completely devoid of 26-hydroxylase activity. The same mitochondrial fraction catalyzed 25-hydroxylation of vitamin D3. The microsomal fraction of liver of the subject with CTX contained more than 50-fold the normal amount of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol. The basic metabolid defect in CTX appears to be a lack of the mitochondrial 26-hydroxylase. The excretion in the bile of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25-tetrol and 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24 alpha,25-pentol observed in CTX patients may be secondary to the accumulation of the major substrate for the 26-hydroxylase, i. e., 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, and exposure of this substrate to the normally less active microsomal 25-and 24-hydroxylases. It is concluded that the major pathway in the biosynthesis of cholic acid in human liver involves a mitochondrial C27-steroid 26-hydroxylation.
Assuntos
Ácidos Cólicos/biossíntese , Mitocôndrias Hepáticas/enzimologia , Esteroide Hidroxilases/metabolismo , Xantomatose/enzimologia , Colestanóis , Humanos , Microssomos Hepáticos/metabolismo , Esteroide Hidroxilases/deficiênciaRESUMO
26-Hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol and other C27-steroids was demonstrated in cultured skin fibroblasts from healthy individuals. Activities in skin fibroblasts were approximately 5-10% of those previously found in human liver homogenates, and were inhibited by CO. The apparent Km was lowest for 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol (1.3 mumol/liter) and highest for 5-cholestene-3 beta, 7 alpha-diol (12 mumol/liter). The rate of 26-hydroxylation was highest with 7 alpha-hydroxy-4-cholesten-3-one. These characteristics are similar to those of hepatic mitochondrial C27-steroid 26-hydroxylase. In skin fibroblasts from three patients with cerebrotendinous xanthomatosis (CTX), 26-hydroxylation of C27-steroids proceeded at a rate of only 0.2-2.5% of healthy controls. No accumulation of endogenous 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol could be demonstrated in these cells, and the lowered formation of radioactive, 26-hydroxylated products could not be explained by dilution of the labeled exogenous substrate. The present results add strong evidence to the concept that the primary metabolic defect in CTX is a deficiency of C27-steroid 26-hydroxylase.
Assuntos
Encefalopatias/enzimologia , Fibroblastos/enzimologia , Esteroide Hidroxilases/deficiência , Xantomatose/enzimologia , Células Cultivadas , Colestanotriol 26-Mono-Oxigenase , Colestanóis/metabolismo , Feminino , Humanos , Hidroxicolesteróis/metabolismo , Hidroxilação , Cinética , Masculino , Pessoa de Meia-Idade , Especificidade por SubstratoRESUMO
Whole-saliva IgA appears like an attractive noninvasive readout for intestinal immune induction after enteric infection or vaccination, but has failed to show consistent correlation with established invasive markers and IgA in feces or intestinal lavage. For reference, we measured antibodies in samples from 30 healthy volunteers who were orally infected with wild-type enterotoxigenic Escherichia coli. The response against these bacteria in serum, lavage, and lymphocyte supernatants (antibody-in-lymphocyte-supernatant, ALS) was compared with that in targeted parotid and sublingual/submandibular secretions. Strong correlation occurred between IgA antibody levels against the challenge bacteria in sublingual/submandibular secretions and in lavage (r=0.69, P<0.0001) and ALS (r=0.70, P<0.0001). In sublingual/submandibular secretions, 93% responded with more than a twofold increase in IgA antibodies against the challenge strain, whereas the corresponding response in parotid secretions was only 67% (P=0.039). With >twofold ALS as a reference, the sensitivity of a >twofold response for IgA in sublingual/submandibular secretion was 96%, whereas it was only 67% in the parotid fluid. To exclude that flow rate variations influenced the results, we used albumin as a marker. Our data suggested that IgA in sublingual/submandibular secretions, rather than whole saliva with its variable content of parotid fluid, is a preferential noninvasive proxy for intestinal immune induction.
Assuntos
Anticorpos Antibacterianos/metabolismo , Escherichia coli Enterotoxigênica/imunologia , Infecções por Escherichia coli/imunologia , Imunoglobulina A/metabolismo , Intestinos/imunologia , Glândula Parótida/metabolismo , Saliva/metabolismo , Biomarcadores/metabolismo , Células Cultivadas , Meios de Cultivo Condicionados/metabolismo , Infecções por Escherichia coli/diagnóstico , Fezes , Humanos , Imunidade nas Mucosas , Linfócitos/imunologia , Sensibilidade e EspecificidadeRESUMO
Sexual abuse contributes to the development of multiple forms of psychopathology, including anxiety and depression, but the extent to which genetics contributes to these disorders among sexual abuse victims remains unclear. In this translational study, we first examined gene expression in the brains of rodents exposed to different early-life conditions (long, brief or no maternal separation). Hypothesizing that genes revealing changes in expression may have relevance for psychiatric symptoms later in life, we examined possible association of those genes with symptoms of anxiety and depression in a human sample of sexual abuse victims. Changes in rodent brain gene expression were evaluated by means of correspondence and significance analyses of microarrays by comparing brains of rodents exposed to different early-life conditions. Tag single-nucleotide polymorphisms (SNPs) of resulting candidate genes were genotyped and tested for their association with symptoms of anxiety and depression (Hospital Anxiety and Depression Scale) in a sample of 361 sexual abuse victims, using multinomial logistic regression. False discovery rate was applied to account for multiple testing in the genetic association study, with q-value of 0.05 accepted as significant. We identified four genes showing differential expression among animals subjected to different early-life conditions as well as having potential relevance to neural development or disorders: Notch1, Gabrr1, Plk5 and Zfp644. In the human sample, significant associations were observed for two NOTCH1 tag SNPs: rs11145770 (OR=2.21, q=0.043) and rs3013302 (OR=2.15, q=0.043). Our overall findings provide preliminary evidence that NOTCH1 may be implicated in the susceptibility to anxiety and depression among sexual abuse victims. The study also underscores the potential importance of animal models for future studies on the health consequences of early-life stress and the mechanisms underlying increased risk for psychiatric disorders.
Assuntos
Transtornos de Ansiedade/genética , Transtorno Depressivo/genética , Expressão Gênica/genética , Predisposição Genética para Doença/genética , Receptor Notch1/genética , Delitos Sexuais/psicologia , Alelos , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Acontecimentos que Mudam a Vida , Masculino , Transtornos do Neurodesenvolvimento/genética , Polimorfismo de Nucleotídeo Único/genética , Ratos Wistar , Pesquisa Translacional BiomédicaRESUMO
In livers of rats fed a single morning dose of 100 mg tetradecylthioacetic acid (TTA) total long-chain acyl-CoA increased significantly to 3 times control levels within 6 h, then the level declined almost to control value within the next morning. Hepatic malonyl-CoA was reduced 75% 6 h after TTA treatment. From 6 to 24 h malonyl-CoA increased about 10-fold to about 3 times that of controls. Paradoxically there was nearly a 2-fold higher oxidation of both [1-14C]palmitic acid (0.5 mM) and [1-14C]oleic acid (0.5 mM) in hepatocytes isolated from rats 24 h after TTA treatment compared to controls. After 6 h, when malonyl-CoA was at a minimum in vivo, fatty acid oxidation in cells was not increased. Acylcarnitine formation in digitonin permeabilized hepatocytes isolated 24 h after administration of TTA was increased both in the absence and in the presence of malonyl-CoA. At 24 h peroxisomal palmitoyl-CoA oxidase activity was not increased. The results suggest that an increased CPT activity and increased acylcarnitine formation in the presence of malonyl-CoA is a delayed response to increased acyl-CoA levels. Furthermore, in hepatocytes isolated after 24 h incorporation of [1-14C]oleic acid into triacylglycerols was significantly reduced. The data show that in hepatocytes isolated from rats 24 h after administration of a single dose of TTA, there is a diversion of hepatic acyl-CoA from synthesis of triacylglycerols into beta-oxidation in the mitochondria.
Assuntos
Ácidos Graxos/metabolismo , Fígado/efeitos dos fármacos , Sulfetos/farmacologia , Acil Coenzima A/metabolismo , Animais , Carnitina O-Palmitoiltransferase/metabolismo , Células Cultivadas/efeitos dos fármacos , Fígado/metabolismo , Masculino , Malonil Coenzima A/análise , Mitocôndrias Hepáticas/efeitos dos fármacos , Ácido Oleico , Ácidos Oleicos/metabolismo , Oxirredução , Ácido Palmítico , Ácidos Palmíticos/metabolismo , Fosfolipídeos/biossíntese , Ratos , Ratos Wistar , Triglicerídeos/biossínteseRESUMO
The effect of feeding 2% cholestanol or cholesterol on cholesterol-7 alpha-hydroxylase activity and hydroxymethylglutaryl (HMG)-CoA reductase activity was studied in rats. The rate of 7 alpha-hydroxylation of a trace amount of labelled cholesterol increased by about 80% after the cholestanol feeding, whereas the 7 alpha-hydroxylation of endogenous microsomal cholesterol increased by about 40%. The latter conversion was measured with an accurate technique based on isotope dilution-mass spectrometry. After cholesterol feeding, the corresponding figures were about 50 and 60%, respectively. The cholestanol feeding had no significant effect on the HMG-CoA reductase activity, whereas the cholesterol feeding decreased the activity by about 80%. From the results obtained, it is concluded that the increased 7 alpha-hydroxylation observed after cholesterol feeding can not be explained only by a simple expansion of the substrate pool. The similar effect of both cholesterol and cholestanol on the cholesterol 7 alpha-hydroxylase activity and the diverging effect on the HMG-CoA reductase activity show that there is no coupling between cholesterol synthesis and degradation under the conditions employed. The lack of effect of cholestanol on the HMG-CoA reductase activity indicates a high structural specificity of the receptor involved in regulation of the enzyme. If a receptor mechanism is involved in the stimulation of the cholesterol-7 alpha-hydroxylase by cholesterol and cholestanol, these receptor(s) must be different from those involved in the regulation of the HMG-CoA reductase.
Assuntos
Colestanol/farmacologia , Colesterol 7-alfa-Hidroxilase/metabolismo , Colesterol/análogos & derivados , Hidroximetilglutaril-CoA Redutases/metabolismo , Esteroide Hidroxilases/metabolismo , Animais , Colesterol na Dieta/farmacologia , Masculino , Microssomos Hepáticos/análise , Ratos , Ratos Endogâmicos , Relação Estrutura-AtividadeRESUMO
Long-chain alkylthioacetic acids (3-thia fatty acids) inhibit fatty acid synthesis from [1-14C]acetate in isolated hepatocytes, while fatty acid oxidation is nearly unaffected or even stimulated. Desaturation of [1-14C]stearate (delta 9-desaturase) is also unaffected. [1-14C]Dodecylthioacetic acid (a 3-thia fatty acid) is incorporated in triacylglycerol and in phospholipids more efficiently than [1-14C]palmitate in isolated hepatocytes. The metabolism of [1-14C]dodecylthioacetic acid to acid-soluble products (by omega-oxidation) is slow compared to the oxidation of [1-14C]palmitate. In hepatocytes from adapted rats (rats fed tetradecylthioacetic acid for 4 days) the rate of [1-14C]palmitate oxidation is increased and its rate of esterification is decreased. Stearate desaturation is also decreased. The rate of cyanide-insensitive peroxisomal fatty acid beta-oxidation is several-fold increased. The metabolic effects of long-chain 3-thia fatty acids are discussed and it is concluded that they behave essentially like normal fatty acids except for their slow breakdown due to the sulfur atom in the 3 position, which blocks normal beta-oxidation.
Assuntos
Ácidos Graxos não Esterificados/metabolismo , Fígado/metabolismo , Acetatos/metabolismo , Animais , Células Cultivadas , Ingestão de Alimentos , Ésteres , Jejum , Ácidos Graxos/síntese química , Ácidos Graxos/metabolismo , Iodoacetatos/metabolismo , Ácido Iodoacético , Cinética , Fígado/efeitos dos fármacos , Masculino , Oxirredução , Ácido Palmítico , Ácidos Palmíticos/metabolismo , Ratos , Ratos Endogâmicos , Ácidos Esteáricos/metabolismo , Compostos de Sulfidrila/síntese química , Compostos de Sulfidrila/metabolismoRESUMO
Cerebrotendinous xanthomatosis (CTX) is a lipid storage disease where the basic defect is a lack of the mitochondrial C27-steroid 26-hydroxylase involved in bile acid synthesis (EC 1.14.13.15). Cholestanol and cholesterol accumulate in all tissues. At least part of the accumulation of cholestanol is due to a 7 alpha-dehydroxylation of early bile acid intermediates. Cholesta-4,6-dien-3-one, a proposed intermediate in this pathway, is found in increased concentrations in serum of the patients. This study shows that cholesta-4,6-dien-3-one may be metabolized to 4-cholesten-3-one and cholestanol by liver, adrenals and brain. No conversion was found in intestinal mucosa or in kidneys. The capacity to convert cholesta-4,6-dien-3-one into 4-cholesten-3-one and cholestanol varied in different tissues as well as in different species. The results are discussed in relation to the cholestanol accumulation in CTX.
Assuntos
Colestanóis/biossíntese , Colestenos/metabolismo , Colestenonas/metabolismo , Microssomos/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Feminino , Humanos , Cinética , Microssomos Hepáticos/metabolismo , Especificidade de Órgãos , Ratos , Ratos Endogâmicos , TrítioRESUMO
Liver CoA is markedly higher in hyperthyroid rats as compared to hypothyroid rats, and in fasted rats as compared to fed rats. In hyperthyroid rats the CoA is increased mainly in the cytosol, while in fasted rats the increase is mainly in the mitochondria. Malonyl-CoA is markedly higher in hypothyroid rats than in euthyroid and hyperthyroid rats. With fasting, malonyl-CoA drops 80-85% in all thyroid states. These findings are discussed in relation to the regulation of fatty acid oxidation in the liver.
Assuntos
Acil Coenzima A/metabolismo , Coenzima A/metabolismo , Jejum , Fígado/metabolismo , Malonil Coenzima A/metabolismo , Glândula Tireoide/fisiologia , Animais , Compartimento Celular , Citosol/metabolismo , Ácidos Graxos/metabolismo , Hipertireoidismo/metabolismo , Hipotireoidismo/metabolismo , Fígado/citologia , Masculino , Mitocôndrias Hepáticas/metabolismo , Oxirredução , Ratos , Ratos EndogâmicosRESUMO
Both pivaloylesterified antibiotics and pivalic acid cause pivaloylcarnitine excretion into urine in the rat and human. In the present study, the formation of pivaloylcarnitine, expressed as short-chain acylcarnitines has been observed in rats. The carnitine pool of the rats was radiolabeled by injection of L-[3H]butyrobetaine 24 h prior to exposure to pivalic acid injected i.p. or pivampicillin administered orally. The presence of pivaloylcarnitine in liver, heart, kidney, stomach, small intestine, testis, muscle, brown fat, white fat and serum was determined at zero time, 0.5, 2, 8 and 24 h after exposure to pivalic acid. After injection of pivalic acid, pivaloylcarnitine calculated as percent of free carnitine and short-chain acylcarnitines amounted to (mean +/- SD) 1.1 +/- 0, 15.4 +/- 2.5, 33.4 +/- 0.7 and 37.5 +/- 1.5% in the heart and 1.2 +/- 0.2, 20.6 +/- 9.5, 29.8 +/- 7.6 and 22.5 +/- 1.6% in brown fat after 0, 0.5, 2 and 8 h, respectively. 2 h after administration, pivaloylcarnitine calculated as percent of free carnitine and short-chain acylcarnitines was highest in the heart (20.9 +/- 7.6%) and brown fat (19.0 +/- 8.5%) in the pivalic acid-treated rat, and highest in the kidney (12.4 +/- 3.1%) and brown fat (10.2 +/- 2.8%) in the pivampicillin-treated rat. Pivaloylcarnitine percent in the liver was 2.8 +/- 0.6 in the pivalic acid-treated rat, 3.5 +/- 1.2 in the pivampicillin-treated rat and 1.3 +/- 0.4 in the control group. Pivaloylcarnitine concentration, nmol/g and nmol/organ, was highest in the heart and brown fat in both treatment groups. The present study suggests that the heart and the brown fat, but not the liver, play important roles in pivaloylcarnitine formation in the rat.