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1.
J Med Chem ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38960379

RESUMO

Amylin, a member of the calcitonin family, acts via amylin receptors in the hindbrain and hypothalamus to suppress appetite. Native ligands of these receptors are peptides with short half-lives. Conjugating fatty acids to these peptides can increase their half-lives. The long-acting human amylin analog, NN1213, was generated from structure-activity efforts optimizing solubility, stability, receptor affinity, and selectivity, as well as in vivo potency and clearance. In both rats and dogs, a single dose of NN1213 reduced appetite in a dose-dependent manner and with a long duration of action. Consistent with the effect on appetite, studies in obese rats demonstrated that daily NN1213 dosing resulted in a dose-dependent reduction in body weight over a 21-day period. Magnetic resonance imaging indicated that this was primarily driven by loss of fat mass. Based on these data, NN1213 could be considered an attractive option for weight management in the clinical setting.

2.
Drug Metab Dispos ; 2022 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-35680133

RESUMO

NN1177 is a glucagon/glucagon-like peptide 1 receptor co-agonist investigated for chronic weight management and treatment of non-alcoholic steatohepatitis. Here, we show concentration-dependent down-regulation of cytochrome P450 enzymes using freshly isolated human hepatocytes treated with this linear 29-amino acid peptide. Notably, reductions in CYP3A4 mRNA expression (57.2-71.7%) and activity (18.5-51.5%) were observed with a clinically-relevant concentration of 100 nM NN1177. CYP1A2 and CYP2B6 were also affected, but to a lesser extent. Physiological-based pharmacokinetic modelling simulated effects on CYP3A4 and CYP1A2 probe substrates (midazolam and caffeine, respectively) and revealed potential safety concerns related to drug-drug interactions (DDIs). To investigate the clinical relevance of observed in vitro CYP down-regulation, a phase 1 clinical cocktail study was initiated to assess the DDI potential. The study enrolled 45 study participants (BMI 23.0-29.9 kg/m2) to receive a Cooperstown 5+1 cocktail (midazolam, caffeine, omeprazole, dextromethorphan, and S-warfarin/vitamin K) alone and following steady state NN1177 exposure. The analysis of pharmacokinetic profiles for the cocktail drugs showed no significant effect from the co-administration of NN1177 on AUC0-inf for midazolam or S-warfarin. Omeprazole, caffeine, and dextromethorphan generally displayed decreases in AUC0-inf and Cmax following NN1177 co-administration. Thus, the in vitro observations were not reflected in the clinic. These findings highlight remaining challenges associated with standard in vitro systems used to predict DDIs for peptide-based drugs as well as the complexity of DDI trial design for these modalities. Overall, there is an urgent need for better pre-clinical models to assess potential drug-drug interaction risks associated with therapeutic peptides during drug development. Significance Statement This study highlights significant challenges associated with assessing drug-drug interaction risks for therapeutic peptides using in vitro systems, since potential concerns identified by standard assays did not translate to the clinical setting. Further research is required to guide investigators involved in peptide-based drug development towards better non-clinical models in order to more accurately evaluate potential drug-drug interactions.

4.
J Med Chem ; 64(15): 11183-11194, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34288673

RESUMO

A hallmark of the pancreatic hormone amylin is its high propensity toward the formation of amyloid fibrils, which makes it a challenging drug design effort. The amylin analogue pramlintide is commercially available for diabetes treatment as an adjunct to insulin therapy but requires three daily injections due to its short half-life. We report here the development of the stable, lipidated long-acting amylin analogue cagrilintide (23) and some of the structure-activity efforts that led to the selection of this analogue for clinical development with obesity as an indication. Cagrilintide is currently in clinical trial and has induced significant weight loss when dosed alone or in combination with the GLP-1 analogue semaglutide.


Assuntos
Desenvolvimento de Medicamentos , Hipoglicemiantes/farmacologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/antagonistas & inibidores , Relação Dose-Resposta a Droga , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/síntese química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacologia , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade
5.
Diabetes Obes Metab ; 23(7): 1594-1603, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33710717

RESUMO

AIM: To assess the effects of oral semaglutide on postprandial glucose and lipid metabolism, and gastric emptying, in subjects with type 2 diabetes (T2D). MATERIALS AND METHODS: In this randomized, double-blind, single-centre, crossover trial, subjects with T2D received once-daily oral semaglutide (escalated to 14 mg) followed by placebo, or vice versa, over two consecutive 12-week periods. Glucose and lipid metabolism, and gastric emptying (paracetamol absorption) were assessed before and after two types of standardized meals (standard and/or fat-rich) at the end of each treatment period. The primary endpoint was area under the glucose 0-5-h curve (AUC0-5h ) after the standard breakfast. RESULTS: Fifteen subjects were enrolled (mean age 58.2 years, HbA1c 6.9%, body weight 93.9 kg, diabetes duration 3.1 years; 13 [86.7%] males). Fasting concentrations of glucose were significantly lower, and C-peptide significantly greater, with oral semaglutide versus placebo. Postprandial glucose (AUC0-5h ) was significantly lower with oral semaglutide versus placebo (estimated treatment ratio, 0.71; 95% CI, 0.63, 0.81; p < .0001); glucose incremental AUC (iAUC0-5h/5h ) and glucagon AUC0-5h were also significantly reduced, with similar results after the fat-rich breakfast. Fasting concentrations of triglycerides, very low-density lipoprotein (VLDL) and apolipoprotein B48 (ApoB48) were significantly lower with oral semaglutide versus placebo. AUC0-8h for triglycerides, VLDL and ApoB48, and triglycerides iAUC0-8h/8h , were significantly reduced after oral semaglutide versus placebo. During the first postprandial hour, gastric emptying was delayed (a 31% decrease in paracetamol AUC0-1h ) with oral semaglutide versus placebo. One serious adverse event (acute myocardial infarction) occurred during oral semaglutide treatment. CONCLUSION: Oral semaglutide significantly improved fasting and postprandial glucose and lipid metabolism, and delayed gastric emptying.


Assuntos
Diabetes Mellitus Tipo 2 , Glicemia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Método Duplo-Cego , Esvaziamento Gástrico , Peptídeos Semelhantes ao Glucagon , Glucose , Humanos , Hipoglicemiantes , Metabolismo dos Lipídeos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial
6.
Diabetes Obes Metab ; 23(2): 581-588, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33184979

RESUMO

AIM: To evaluate the effect of oral semaglutide on energy intake and appetite in subjects with type 2 diabetes (T2D). MATERIALS AND METHODS: In this randomized, double-blind, placebo-controlled, two-period cross-over trial, 15 subjects with T2D received 12 weeks of treatment with once-daily oral semaglutide (4-week dose escalation from 3 to 7 to 14 mg) followed by placebo, or vice versa. Energy intake was measured during an ad libitum lunch, evening meal and snack box after a standard breakfast. Appetite ratings were measured using a visual analogue scale after standard and fat-rich breakfasts. Other assessments included eating and craving control (using the Control of Eating Questionnaire), and changes in body weight and composition. RESULTS: Following a standard breakfast, total daily ad libitum energy intake was significantly lower (38.9%) with oral semaglutide versus placebo in 13 evaluable subjects (estimated treatment difference, -5096.0 kJ; 95% CI -7000.0, -3192.1; P = .0001). After a fat-rich breakfast, there were significant differences in favour of oral semaglutide versus placebo for measures of satiety, hunger and for overall appetite score, with no significant differences following a standard breakfast. Fewer food cravings and better eating control were seen with oral semaglutide versus placebo. Overall, mean body weight decreased by 2.7 kg with oral semaglutide and 0.1 kg with placebo, mostly attributable to body fat mass loss. CONCLUSION: After 12 weeks of treatment, ad libitum energy intake was lower with oral semaglutide versus placebo, resulting in reduced body fat mass, and was associated with increased satiety and fullness after a fat-rich breakfast, and improved eating control. TRIAL REGISTRATION NUMBER: NCT02773381.


Assuntos
Apetite , Diabetes Mellitus Tipo 2 , Peso Corporal , Desjejum , Estudos Cross-Over , Diabetes Mellitus Tipo 2/tratamento farmacológico , Ingestão de Alimentos , Ingestão de Energia , Preferências Alimentares , Peptídeos Semelhantes ao Glucagon , Humanos
7.
Diabetologia ; 60(8): 1390-1399, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28526920

RESUMO

AIMS/HYPOTHESIS: Semaglutide is a glucagon-like peptide-1 analogue in development for the treatment of type 2 diabetes. Its effects on first- and second-phase insulin secretion and other measures of beta cell function and glycaemic control were assessed. METHODS: In this single-centre, double-blind, placebo-controlled, parallel-group trial, conducted at the Profil Institut für Stoffwechselforschung, Germany, 75 adult (aged 18-64 years) participants with type 2 diabetes (eligibility: HbA1c of 6.5-9.0% (47.5-74.9 mmol/mol); BMI 20.0-35.0 kg/m2; and treatment with diet and exercise and/or metformin monotherapy with a dose unchanged in the 30 days prior to screening) were randomised (1:1) to once-weekly s.c. semaglutide 1.0 mg (0.25, 0.5, 1.0 mg escalated) or placebo for 12 weeks. Co-primary endpoints were changes from baseline to end of treatment in the first (AUC0-10 min) and second (AUC10-120 min) insulin secretion phases, as measured by the IVGTT. An arginine stimulation test (AST) and a 24 h meal stimulation test were also conducted. A graded glucose infusion test (GGIT) assessed insulin secretion rate (ISR) in treated participants and a group of untreated healthy participants. Safety endpoints were also assessed. RESULTS: In total, 37 participants received semaglutide and 38 received placebo. Following IVGTT, for insulin, both AUC0-10min and AUC10-120min were significantly increased with semaglutide (estimated treatment ratio [95% CI] 3.02 [2.53, 3.60] and 2.10 [1.86, 2.37], respectively; p < 0.0001). The 24 h meal test showed reduced fasting, postprandial and overall (AUC0-24h) glucose and glucagon responses with semaglutide (p < 0.0001). The AST showed that maximal insulin capacity increased following semaglutide treatment. During GGIT, semaglutide significantly increased ISR to levels similar to those in healthy participants. Semaglutide was well tolerated. CONCLUSIONS/INTERPRETATION: Twelve weeks of once-weekly treatment with semaglutide significantly improved beta cell function and glycaemic control in participants with type 2 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT02212067 FUNDING: The study was funded by Novo Nordisk A/S.


Assuntos
Glicemia/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Peptídeos Semelhantes ao Glucagon/uso terapêutico , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Adolescente , Adulto , Diabetes Mellitus Tipo 2/sangue , Método Duplo-Cego , Feminino , Peptídeos Semelhantes ao Glucagon/administração & dosagem , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/uso terapêutico , Metformina/administração & dosagem , Metformina/uso terapêutico , Pessoa de Meia-Idade , Gravidez , Adulto Jovem
8.
Eur J Neurosci ; 40(7): 3055-66, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25040689

RESUMO

Amylin reduces meal size by activating noradrenergic neurons in the area postrema (AP). Neurons in the AP also mediate the eating-inhibitory effects of salmon calcitonin (sCT), a potent amylin agonist, but the phenotypes of the neurons mediating its effect are unknown. Here we investigated whether sCT activates similar neuronal populations to amylin, and if its anorectic properties also depend on AP function. Male rats underwent AP lesion (APX) or sham surgery. Meal patterns were analysed under ad libitum and post-deprivation conditions. The importance of the AP in mediating the anorectic action of sCT was examined in feeding experiments of dose-response effects of sCT in APX vs. sham rats. The effect of sCT to induce Fos expression was compared between surgery groups, and relative to amylin. The phenotype of Fos-expressing neurons in the brainstem was examined by testing for the co-expression of dopamine beta hydroxylase (DBH) or tryptophan hydroxylase (TPH). By measuring the apposition of vesicular glutamate transporter-2 (VGLUT2)-positive boutons, potential glutamatergic input to amylin- and sCT-activated AP neurons was compared. Similar to amylin, an intact AP was necessary for sCT to reduce eating. Further, co-expression between Fos activation and DBH after amylin or sCT did not differ markedly, while co-localization of Fos and TPH was minor. Approximately 95% of neurons expressing Fos and DBH after amylin or sCT treatment were closely apposed to VGLUT2-positive boutons. Our study suggests that the hindbrain pathways engaged by amylin and sCT share many similarities, including the mediation by AP neurons.


Assuntos
Área Postrema/fisiologia , Calcitonina/fisiologia , Ingestão de Alimentos/fisiologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/fisiologia , Neurônios/metabolismo , Animais , Área Postrema/efeitos dos fármacos , Área Postrema/metabolismo , Calcitonina/farmacologia , Dopamina beta-Hidroxilase/análise , Ingestão de Alimentos/efeitos dos fármacos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacologia , Masculino , Neurônios/efeitos dos fármacos , Fenótipo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Wistar , Triptofano Hidroxilase/análise , Proteína Vesicular 2 de Transporte de Glutamato/análise
9.
J Endocrinol ; 220(2): 97-107, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24204009

RESUMO

Obesity is a major burden to people and to health care systems around the world. The aim of the study was to characterize the effect of a novel selective α-MSH analog on obesity and insulin sensitivity. The subchronic effects of the selective MC4-R peptide agonist MC4-NN1-0182 were investigated in diet-induced obese (DIO) rats and DIO minipigs by assessing the effects on food intake, energy consumption, and body weight. The acute effect of MC4-NN1-0182 on insulin sensitivity was assessed by a euglycemic-hyperinsulinemic clamp study in normal rats. Three weeks of treatment of DIO rats with MC4-NN1-0182 caused a decrease in food intake and a significant decrease in body weight 7±1%, P<0.05 compared with 3±1% increase with the vehicle control. In DIO minipigs, 8 weeks of treatment with MC4-NN1-0182 resulted in a body weight loss of 13.3±2.5 kg (13±3%), whereas the vehicle control group had gained 3.7±1.4 kg (4±1%). Finally, clamp studies in normal rats showed that acute treatment with MC4-NN1-0182 caused a significant increase in glucose disposal (Rd) compared with vehicle control (Rd, mg/kg per min, 17.0±0.7 vs 13.9±0.6, P<0.01). We demonstrate that treatment of DIO rats or minipigs with a selective MC4-R peptide agonist causes weight loss. Moreover, we have demonstrated weight-independent effects on insulin sensitivity. Our observations identify MC4 agonism as a viable target for the treatment of obesity and insulin resistance.


Assuntos
Fármacos Antiobesidade/farmacologia , Resistência à Insulina , Obesidade/metabolismo , Redução de Peso/efeitos dos fármacos , alfa-MSH/análogos & derivados , alfa-MSH/farmacologia , Animais , Dieta , Avaliação Pré-Clínica de Medicamentos , Feminino , Resistência à Insulina/fisiologia , Masculino , Obesidade/tratamento farmacológico , Obesidade/etiologia , Ratos , Ratos Sprague-Dawley , Suínos , Porco Miniatura , alfa-MSH/uso terapêutico
10.
Br J Nurs ; 21(22): 1312-5, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23249795

RESUMO

Peristomal skin complications (PSCs) are common and troublesome and the consequences are substantial both for the patient and from a health-economic viewpoint. The purpose of this article is to demonstrate that early detection and treatment of PSCs, combined with the use of a correctly fitted and appropriate pouching system, can reduce treatment costs-in the UK, it is estimated to save £28.1m annually. A model for cost estimation of PSCs and a real-life global data set of people with stomas are used for the calculations. A high priority should be given to ensuring resources are available to provide education, guidance and assistance to people with a stoma. This would support increased awareness of the first signs of PSCs and enable self-management at an early stage.


Assuntos
Dermatite/economia , Custos de Cuidados de Saúde/estatística & dados numéricos , Estomia/economia , Higiene da Pele/economia , Especialidades de Enfermagem/economia , Idoso , Redução de Custos , Dermatite/enfermagem , Dermatite/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estomia/efeitos adversos , Estomia/enfermagem , Higiene da Pele/métodos , Higiene da Pele/enfermagem , Reino Unido
11.
PLoS One ; 7(10): e44270, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23049674

RESUMO

AIMS/HYPOTHESIS: Several studies have shown that adiponectin can lower blood glucose in diabetic mice. The aim of this study was to establish an effective adiponectin production process and to evaluate the anti-diabetic potential of the different adiponectin forms in diabetic mice and sand rats. METHODS: Human high molecular weight, mouse low molecular weight and mouse plus human globular adiponectin forms were expressed and purified from mammalian cells or yeast. The purified protein was administered at 10-30 mg/kg i.p. b.i.d. to diabetic db/db mice for 2 weeks. Furthermore, high molecular weight human and globular mouse adiponectin batches were administered at 5-15 mg/kg i.p. b.i.d. to diabetic sand rats for 12 days. RESULTS: Surprisingly, none of our batches had any effect on blood glucose, HbA1c, plasma lipids or body weight in diabetic db/db mice or sand rats. In vitro biological, biochemical and biophysical data suggest that the protein was correctly folded and biologically active. CONCLUSIONS/INTERPRETATION: Recombinant adiponectin is ineffective at lowering blood glucose in diabetic db/db mice or sand rats.


Assuntos
Adiponectina/farmacologia , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Proteínas Recombinantes/farmacologia , Adiponectina/genética , Adiponectina/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Cromatografia em Gel , Clonagem Molecular , Primers do DNA/genética , Eletroforese em Gel de Poliacrilamida , Gerbillinae , Hemoglobinas Glicadas/metabolismo , Células HEK293 , Humanos , Lipídeos/sangue , Camundongos , Camundongos Obesos , Mutagênese Sítio-Dirigida , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae , Especificidade da Espécie
12.
J Med Chem ; 55(5): 1969-77, 2012 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-22335602

RESUMO

We report in vitro and in vivo data of new α-melanocyte-stimulating hormone (α-MSH) analogues which are N-terminal modified with a long chain fatty acid derivative. While keeping the pharmacophoric motif (d-Phe-Arg-Trp) fixed, we tried to improve selectivity and physicochemical parameters like solubility and stability of these analogues by replacing amino acids further away from the motif. Receptor specific changes in binding affinity to the melanocortin receptors were observed between the acetyl derivatives and the fatty acid analogues. Furthermore, amino acids at the N-terminal of α-MSH (Ser-Tyr-Ser) not considered to be part of the pharmacophore were found to have an influence on the MC4/MC1 receptor selectivity. While the acetyl analogues have an in vivo effect for around 7 h, the long chain fatty acid analogues have an effect up to 48 h in an acute feeding study in male Sprague-Dawley rats after a single subcutaneous administration.


Assuntos
Fármacos Antiobesidade/síntese química , Receptor Tipo 4 de Melanocortina/agonistas , alfa-MSH/análogos & derivados , alfa-MSH/síntese química , Animais , Fármacos Antiobesidade/farmacocinética , Fármacos Antiobesidade/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Ácidos Graxos/síntese química , Ácidos Graxos/farmacocinética , Ácidos Graxos/farmacologia , Injeções Subcutâneas , Masculino , Ratos , Ratos Sprague-Dawley , Solubilidade , Relação Estrutura-Atividade , alfa-MSH/farmacocinética , alfa-MSH/farmacologia
13.
Amyloid ; 18(4): 222-8, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22047620

RESUMO

Diabetes in the domestic ferret (Mustela putorius furo) has previously been described and the purpose of this study was to evaluate if the ferret could serve as a model for the study of ß-cell degeneration associated with formation of islet amyloid. The nucleotide and amino acid sequence of ferret islet amyloid polypeptide (IAPP) 1-37 was identified and the synthesized peptide was studied with regards to in vitro amyloidogenicity and potential cellular toxicity in a comparative approach to human, cat and the nonamyloidogenic rat IAPP. Ferret IAPP forms amyloid-like fibrils, but with a longer lag phase than human and cat IAPP and the aggregation process was shown to reduce cell viability of cultured ß-cells, but with less potency than these two amyloidogenic counterparts. Immunohistochemistry of ferret pancreas confirmed IAPP expression in the islets of Langerhans, but no islet amyloid was found in a very limited sample size of one diabetic and five healthy ferrets. Islet amyloid has never been described in ferrets, and it is not possible to determine if it is due to lack of studies/material or to the fact that the ferret's life span is too short to present with such pathology.


Assuntos
Amiloidose/veterinária , Diabetes Mellitus Tipo 2/veterinária , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Sequência de Aminoácidos , Amiloide/química , Amiloide/metabolismo , Amiloide/ultraestrutura , Amiloidose/etiologia , Amiloidose/patologia , Animais , Gatos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Diabetes Mellitus Tipo 2/complicações , Modelos Animais de Doenças , Furões , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacologia , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Dados de Sequência Molecular , Pâncreas/metabolismo , Pâncreas/patologia , Fragmentos de Peptídeos/farmacologia , Multimerização Proteica , Homologia de Sequência de Aminoácidos
14.
Psychoanal Study Child ; 65: 313-31, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-26027150

RESUMO

An important area for psychoanalytic study is the significance for intrapsychic life of important events taking place in the community of which analyst and analysand are a part. September 11, 2001 provides a vantage point for examination of questions that arise from looking at the interrelationship between current environment and intrapsychic life. Two cases are presented as a focus for discussing the interaction of the memorialized past and occurrences in present reality, the significance for an analysis of analyst and patient sharing the same experience, instigations to progress that a current event may provide and the ways in which communal experience influences intrapsychic life. As a part of the discussion, we ask as well in what ways a common experience may be shared, and the significance of radically different meanings that the same event may have for analyst and analysand. We also pose the question whether the differences and similarities, each in their own way, may serve as progressive forces in the analysis.


Assuntos
Relações Profissional-Paciente , Psicanálise/métodos , Ataques Terroristas de 11 de Setembro/psicologia , Adulto , Humanos , Masculino , Pessoa de Meia-Idade
15.
Lab Anim ; 42(1): 34-44, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18348765

RESUMO

The Galalpha1-3Galbeta1-4GlcNAc epitope is the key antigen in the hyperacute rejection of pig-to-man xenotransplantation. In the alpha-1,3-galactosyltransferase knockout (alpha-1,3GT-KO) mouse - a model for xenograft donor pigs - a targeted mutation of the alpha-1,3 galactosyltransferase gene (Ggta1) has been constructed. These mice are depleted of the carbohydrate antigen and besides the mice are also known to develop cortical cataracts. The present study aimed at evaluating the morphology and the degree of the cataract in a population of alpha-GT KO mice, its age of onset, its progression and the impact the cataract may have on aggression, anxiety and perception of light. The alpha-gal epitope could be shown in the lenses with lectin GS1 B4 in all wild-type and none of the alpha-GT KO mice. Histology showed apparent cataract in all alpha-GT KO mice from six weeks of age. Apart from a single wild-type mouse with a small degree of microscopically visible cataract without epithelial involvement at the age of 30 weeks none of the wild-type mice showed signs of cataract. Behavioural testing demonstrated significantly more mounting behaviour and a longer duration of attacking in the alpha-GT KO mice. Apart from this, the agonistic behaviour was not influenced by genotype. Neither did the genotype affect anxiety or perception of light.


Assuntos
Agressão/fisiologia , Comportamento Animal/fisiologia , Catarata/metabolismo , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Animais , Ansiedade , Catarata/patologia , Genótipo , Masculino , Camundongos , Camundongos Knockout , Visão Ocular
16.
APMIS ; 114(11): 805-11, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17078862

RESUMO

Xenotransplantation holds the promise of replacing failing human organs with organs of animal origin. Transplantation of pancreatic islets from pigs to humans might restore glucose homeostasis and offer diabetic patients considerable improvement in their quality of life. The alpha-gal epitope, present in all mammals except humans, apes and Old World monkeys, is a decisive obstruction to successful xenotransplantation of vascularized organs as the reaction of alpha-gal-bearing endothelia with natural alpha-gal antibodies in the human blood mediates hyperacute rejection of the xenograft. Alpha-galactosyl transferase knockout mice (alpha-GT KO) develop cataract, but no other lesions have been established in these mice. Here we report for the first time that alpha-GT KO mice have impaired glucose tolerance (p<0.001) and decreased insulin sensitivity (p<0.0001). Homeostasis model assessment shows impaired beta-cell function (p<0.05). Similar physiological changes have not been examined in the alpha-galactosyl transferase pig. However, an association between alpha-galactosyl transferase knockout and impaired beta-cell function could have critical importance for islet xenotransplantation.


Assuntos
Galactosiltransferases/genética , Intolerância à Glucose/imunologia , Células Secretoras de Insulina/metabolismo , Transplante das Ilhotas Pancreáticas/imunologia , Trissacarídeos/imunologia , Animais , Análise Química do Sangue , Peso Corporal , Intolerância à Glucose/genética , Teste de Tolerância a Glucose , Insulina/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/imunologia , Camundongos , Camundongos Knockout , Modelos Animais , Pâncreas/citologia , Transplante Heterólogo , Trissacarídeos/genética
19.
APMIS ; 111(11): 1019-26, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14629268

RESUMO

Critical to the prevention of xenograft loss is the prevention of delayed xenograft rejection (DXR), due to its resistance to conventional immunosuppression. The role of the carbohydrate galactose-alpha1,3-galactose (alpha1,3Gal) has been a matter of great debate and it has been proposed that the reaction between alpha1,3Gal epitopes on donor endothelial cells and recipient anti-alpha1,3Gal antibodies (Abs) may damage the graft during DXR. Recipient anti-alpha1,3Gal Abs are produced by CD4-dependent B cells. To test the above-mentioned hypothesis, hearts from alpha1,3Gal-free mice (GT-Ko mice), generated by alpha1,3-galacto-syltransferase gene disruption, were transplanted to anti-alpha1,3Gal antibody-free Lew/Mol rats. This model consists of an alpha1,3Gal/alpha1,3Gal-antibody-free environment, eliminating a possible influence of this specific system on DXR. A subgroup of recipients were furthermore CD4 depleted in order to inhibit CD4-dependent B-cell antibody production. Rejected hearts were evaluated by light- and immunofluorescence microscopy. Treatment effects on recipient T-cell subsets and cytokine expression were analyzed by flow cytometry, while antibody production was measured by ELISA. All recipients developed DXR with no differences among the groups. DXR was related to thrombosis with IgG and IgM desposition in vessel walls, as well as macrophage and granulocyte accumulation in the myocardium. No complement C3, CD4 cells or NK cells were found. Flow cytometric analysis confirmed peripheral blood CD4 depletion and IFN-gamma suppression in CD4 Ab-treated recipients. Finally, ELISA showed that specific anti-alpha1,3Gal Ab production was absent. However, Ab(s) against an unidentified Galalpha 1 were found among recipients. In our model, DXR is resistant to alpha1,3-galactosyltransferase gene inactivation and CD4 depletion. However, other Galalpha 1 epitopes and antibodies may play a role during DXR. Further studies are needed to elucidate the precise pathways leading to DXR.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Galactosiltransferases/genética , Galactosiltransferases/imunologia , Rejeição de Enxerto/genética , Rejeição de Enxerto/imunologia , Transplante de Coração/imunologia , Animais , Anticorpos/análise , Linfócitos B/imunologia , Citocinas/sangue , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Galactosiltransferases/deficiência , Rejeição de Enxerto/sangue , Contagem de Linfócitos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia de Fluorescência , Miocárdio/enzimologia , Miocárdio/imunologia , Miocárdio/patologia , Ratos , Linfócitos T/imunologia , Transplante Heterólogo
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