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OBJECTIVE: To evaluate the 104-week safety of dapagliflozin in older patients with type 2 diabetes mellitus. METHODS: Pooled analysis assessing general safety (nine phase III studies ≤104 weeks) and cardiovascular safety (21 phase IIb/III studies ≤208 weeks) by age (<65; ≥65; ≥75 years). Patients with type 2 diabetes mellitus (±background glucose-lowering therapy) received: dapagliflozin 10 mg (n = 2026) vs. placebo (n = 1956) (nine-study pool); or dapagliflozin (2.5-50 mg; n = 5936) vs. control (placebo/comparator) (n = 3403) (21-study pool). RESULTS: Adverse events (AEs) and discontinuations owing to AEs were more common in older vs. younger patients, and were more frequent with dapagliflozin than placebo (AEs: <65 years: 73.1 vs. 70.7 %; ≥65 years: 77.4 vs. 73.1 %; ≥75 years: 80.4 vs. 75.3 %, respectively; discontinuations: <65 years: 5.9 vs. 5.0 %; ≥65 years: 14.4 vs. 12.2 %; ≥75 years: 26.8 vs. 22.1 %, respectively); serious AE (SAE) frequency was similar (<65 years: 11.0 vs. 11.8 %; ≥65 years: 20.0 vs. 20.2 %; ≥75 years: 19.6 vs. 18.2 %, respectively). Hypoglycaemia frequency was similar across age groups and was higher with dapagliflozin than placebo (<65 years: 18.0 vs. 13.4 %; ≥65 years: 20.2 vs. 17.7 %; ≥75 years: 17.5 vs. 16.9 %, respectively); major episodes were rare. Urinary tract infection frequency was similar between treatment groups in older patients, with no increase vs. younger patients (<65 years: 8.8 vs. 5.5 %; ≥65 years: 8.1 vs. 7.6 %; ≥75 years: 8.2 vs. 9.1 %, respectively); urinary tract infection SAEs were rare. Genital infection AEs were more common with dapagliflozin, with no increase in older patients (<65 years: 8.2 vs. 1.0 %; ≥65 years: 6.6 vs. 0.9 %; ≥75 years: 7.2 vs. 0.0 %, respectively) and no SAEs. Volume reduction AEs were uncommon, with a higher frequency with dapagliflozin vs. placebo and in patients ≥75 years (<65 years: 1.7 vs. 1.2 %; ≥65 years: 2.3 vs. 1.7 %; ≥75 years: 3.1 vs. 2.6 %, respectively). Dapagliflozin did not increase the risk of fractures (<65 years: 1.1 vs. 1.1 %; ≥65 years: 1.1 vs. 2.7 %; ≥75 years: 1.0 vs. 2.6 %, respectively) or falls (<65 years: 0.7 vs. 0.7 %; ≥65 years: 0.6 vs. 2.1 %; ≥75 years: 0.0 vs. 1.3 %, respectively), regardless of age. AEs of renal function were more common with dapagliflozin than placebo and increased with age (<65 years: 3.5 vs. 2.3 %; ≥65 years: 14.0 vs. 7.9 %; ≥75 years: 29.9 vs. 20.8 %, respectively). Most were non-serious small transient increases in serum creatinine. Dapagliflozin did not increase cardiovascular risk regardless of age [hazard ratio (95 % confidence interval) vs. CONTROL: <65 years: 0.726 (0.473, 1.114); ≥65 years: 0.879 (0.565, 1.366); ≥75 years: 0.950 (0.345, 2.617), respectively]. CONCLUSION: Dapagliflozin treatment up to 104 weeks was well tolerated in older patients. Older dapagliflozin-treated patients had more renal AEs than placebo-treated patients; the majority of which were non-serious small transient changes in serum creatinine.
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Compostos Benzidrílicos/efeitos adversos , Compostos Benzidrílicos/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glucosídeos/efeitos adversos , Glucosídeos/uso terapêutico , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/uso terapêutico , Adulto , Idoso , Compostos Benzidrílicos/administração & dosagem , Doenças Cardiovasculares/epidemiologia , Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Feminino , Fraturas Ósseas/induzido quimicamente , Fraturas Ósseas/epidemiologia , Glucosídeos/administração & dosagem , Humanos , Hipoglicemia/induzido quimicamente , Hipoglicemia/epidemiologia , Hipoglicemiantes/administração & dosagem , Rim/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Segurança , Infecções Urinárias/induzido quimicamente , Infecções Urinárias/epidemiologiaRESUMO
OBJECTIVE: Dapagliflozin reduces hyperglycemia in type 2 diabetes mellitus (T2DM) and lowers blood pressure, at least in part, secondary to mild diuresis consequent to dapagliflozin-induced glucosuria. While blood-pressure lowering may contribute to cardiovascular risk reduction, dapagliflozin-induced diuresis may potentially contribute to adverse events (AEs) of volume reduction. The present analysis compared the frequency of AEs of volume reduction between dapagliflozin and placebo. METHODS: Pooled data were assessed from 13 placebo-controlled dapagliflozin clinical trials ≤24 weeks in patients with T2DM, overall, and in those at risk (aged ≥65y, estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m(2), or on antihypertensive therapy). Longer-term (≤104 weeks) data were available for 9 of these trials. RESULTS: The frequency of patients experiencing ≥1 AE of volume reduction over 24 weeks was low overall; 27/2360 (1.1%) with dapagliflozin 10 mg and 17/2295 (0.7%) with placebo; and slightly more frequent in patients ≥65 years (11/665 [1.7%] and 6/711 [0.8%], respectively) and in patients receiving loop diuretics (6/236 [2.5%] and 4/267 [1.5%], respectively). Over 104 weeks, AEs of volume reduction occurred in 38/2026 (1.9%) with dapagliflozin 10 mg and in 27/1956 (1.4%) with placebo; serious AEs of volume reduction in 4/2026 (0.2%) and 6/1956 (0.3%), respectively; and 2 patients in each group discontinued therapy due to these AEs. Dapagliflozin versus placebo incidence rate ratios did not suggest any meaningful increase in frequency of these AEs with dapagliflozin 10 mg, either overall or in those at risk. Although mean eGFR declined by 4.2 ml/min/1.73 m(2) within the first week of dapagliflozin therapy, thereafter eGFR gradually recovered to baseline levels by 104 weeks (mean change from baseline +0.02 mL/min/1.73 m(2); 95%CI: -0.9, 1.0). CONCLUSION: No meaningful increase in frequency of AEs of volume reduction occurred with dapagliflozin 10 mg in patients with T2DM, either overall, or in those at increased risk of these events. However, caution should nevertheless be exercised when prescribing dapagliflozin to elderly patients, those with reduced eGFR, and those receiving antihypertensive medication.
Assuntos
Compostos Benzidrílicos/efeitos adversos , Glucosídeos/efeitos adversos , Hipoglicemiantes/efeitos adversos , Hipovolemia/epidemiologia , Inibidores do Transportador 2 de Sódio-Glicose , Fatores Etários , Idoso , Compostos Benzidrílicos/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Nitrogênio da Ureia Sanguínea , Diurese/efeitos dos fármacos , Feminino , Fraturas Ósseas/induzido quimicamente , Fraturas Ósseas/epidemiologia , Taxa de Filtração Glomerular/efeitos dos fármacos , Glucosídeos/farmacologia , Humanos , Hipoglicemiantes/farmacologia , Hipotensão Ortostática/epidemiologia , Hipovolemia/induzido quimicamente , Incidência , Masculino , Pessoa de Meia-Idade , Osmose/efeitos dos fármacos , Placebos/efeitos adversos , Poliúria/induzido quimicamente , Poliúria/epidemiologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Inibidores de Simportadores de Cloreto de Sódio e Potássio/efeitos adversos , Transportador 2 de Glucose-SódioRESUMO
INTRODUCTION: Hyperkalemia risk is increased in diabetes, particularly in patients with renal impairment or those receiving angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) or potassium-sparing diuretics. Conversely, other diuretics can increase hypokalemia risk. We assessed the effects of the sodium glucose co-transporter 2 (SGLT2) inhibitor dapagliflozin on serum potassium levels in a pooled analysis of clinical trials in patients with type 2 diabetes mellitus (T2DM). METHODS: Fourteen randomized, placebo-controlled, double-blind T2DM studies were analyzed: pooled data from 13 studies of ≤24 weeks' duration (dapagliflozin 10 mg, N = 2360; placebo, N = 2295); and one 52-week moderate renal impairment study in patients with baseline eGFR ≥30 to <60 mL/min/1.73 m(2) (dapagliflozin 10 mg, N = 85; placebo, N = 84). Central laboratory serum potassium levels were determined at each study visit. RESULTS: No clinically relevant mean changes from baseline in serum potassium ≤24 weeks were reported for dapagliflozin 10 mg [-0.05 mmol/L; 95% confidence interval (CI) -0.07, -0.03] versus placebo (-0.02 mmol/L; 95% CI -0.04, 0.00) in the pooled population or in the renal impairment study (-0.03 mmol/L; 95% CI -0.14, 0.08 vs. -0.02 mmol/L; 95% CI -0.13, 0.09, respectively). The incidence rate ratio for serum potassium ≥5.5 mmol/L over 24 weeks for dapagliflozin 10 mg versus placebo was 0.90 (95% CI 0.74, 1.10) in the pooled population; with no increased risk in patients receiving ARBs/ACE inhibitors, or potassium-sparing diuretics, or in those with moderate renal impairment. Slightly more patients receiving dapagliflozin 10 mg had serum potassium ≤3.5 mmol/L versus placebo (5.2% vs. 3.6%); however, no instances of serum potassium ≤2.5 mmol/L were reported. CONCLUSION: Dapagliflozin is not associated with an increased risk of hyperkalemia or severe hypokalemia in patients with T2DM. FUNDING: Bristol-Myers Squibb and AstraZeneca.
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BACKGROUND: Hypertension is a common comorbidity in patients with type 2 diabetes mellitus and a major risk factor for microvascular and macrovascular disease. Although the blood pressure-lowering effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors are already established, guidance is needed on how to use these drugs in patients already receiving antihypertensive therapy. We aimed to compare blood pressure and glycaemic effects of the SGLT2 inhibitor dapagliflozin with placebo in patients with inadequately controlled type 2 diabetes mellitus and hypertension. METHODS: In this double-blind, placebo-controlled, phase 3 study we enrolled patients from 311 centres in 16 countries across five continents. Patients had uncontrolled type 2 diabetes (HbA1c 7·0%-10·5%; 53-91 mmol/mol) and hypertension (systolic 140-165 mm Hg and diastolic 85-105 mm Hg at both enrolment and randomisation, and a mean 24 h blood pressure of ≥130/80 mm Hg by ambulatory monitoring within 1 week of randomisation) and were receiving oral antihyperglycaemic drugs, insulin, or both, plus a renin-angiotensin system blocker and an additional antihypertensive drug. Using an interactive voice-response system, we randomly assigned (1:1) patients to dapagliflozin 10 mg once a day or to placebo, with randomisation stratified by additional antihypertensive drug use and insulin use at baseline, in a block size of two. The co-primary endpoints were changes in seated systolic blood pressure and HbA1c measured in the full analysis set, which included all patients who received at least one dose of study drug and had both a baseline and at least one post-baseline measurement of efficacy. This trial is registered with ClinicalTrials.gov, number NCT01195662. FINDINGS: Between Oct 29, 2010, and Oct 4, 2012, we randomly assigned 225 patients to dapagliflozin and 224 to placebo. Seated systolic blood pressure was significantly reduced in the group assigned to dapagliflozin (adjusted mean change from baseline -11·90 mm Hg [95% CI -13·97 to -9·82]) compared with those assigned to placebo (-7·62 mm Hg [-9·72 to -5·51]; placebo-adjusted difference for dapagliflozin -4·28 mm Hg [-6·54 to -2·02]; p=0·0002). Reductions in HbA1c concentrations were also significantly greater in patients assigned to dapagliflozin (adjusted mean change from baseline -0·63% [95% CI -0·76 to -0·50]) than in those assigned to placebo (-0·02% [-0·15 to 0·12]; placebo-adjusted difference -0·61% [-0·76 to -0·46,]; p<0·0001). In a post-hoc analysis, we found difference in blood pressure versus placebo was greater in patients receiving a ß blocker (-5·76 mm Hg [95% CI -10·28 to -1·23]) or a calcium-channel blocker (-5·13 mm Hg, [-9·47 to -0·79]) as their additional antihypertensive drug than in those receiving a thiazide diuretic (-2·38 mm Hg [-6·16 to 1·40]). Adverse events were similar in the dapagliflozin and placebo groups (98 [44%] patients vs 93 [42%], respectively, had at least one adverse event), with few adverse events related to renal function (1% vs <1%) or volume depletion (<1% vs 0%). INTERPRETATION: Dapagliflozin 10 mg significantly improved blood pressure and HbA1c and was tolerated similarly to placebo. Its blood pressure-lowering properties were particularly favourable in patients already receiving a ß blocker or calcium-channel blocker. Dapagliflozin could benefit patients with type 2 diabetes who need a diuretic-like effect to optimise control of blood pressure, adding meaningful efficacy to antihypertensive drug regimens. FUNDING: Bristol-Myers Squibb, AstraZeneca.
Assuntos
Anti-Hipertensivos/uso terapêutico , Compostos Benzidrílicos/uso terapêutico , Diabetes Mellitus Tipo 2/complicações , Glucosídeos/uso terapêutico , Hipertensão/tratamento farmacológico , Inibidores do Transportador 2 de Sódio-Glicose , Idoso , Anti-Hipertensivos/efeitos adversos , Compostos Benzidrílicos/efeitos adversos , Glicemia/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Glucosídeos/efeitos adversos , Hemoglobinas Glicadas/metabolismo , Humanos , Hipertensão/etiologia , Masculino , Pessoa de Meia-Idade , Transportador 2 de Glucose-Sódio , Resultado do TratamentoRESUMO
Hypertension and type 2 diabetes mellitus (T2DM) are risk factors for cardiovascular disease. Dapagliflozin improves glycemic control and systolic blood pressure (SBP) in T2DM patients. This double-blind phase III study evaluated the effects of dapagliflozin on glycemic control and blood pressure in patients with inadequately controlled T2DM and hypertension, despite ongoing therapy with a renin-angiotensin system blocker. Patients were randomized to receive dapagliflozin 10 mg (n = 302) or placebo (n = 311) once daily for 12 weeks. Endpoints were change from baseline to week 12 in seated SBP and glycosylated hemoglobin (HbA1c); longitudinal repeated-measures analysis was performed. Additional endpoints included other hemodynamic measures, serum uric acid, fasting plasma glucose, body weight, blood lipids and heart rate. After 12 weeks, dapagliflozin-treated versus placebo-treated patients showed significant reductions in HbA1c (-0.6% vs -0.1%, p < 0.0001), mean seated SBP (-10.4 vs -7.3 mmHg, p = 0.0010) and mean 24 h ambulatory SBP (-9.6 vs -6.7 mmHg, p = 0.0043). Dapagliflozin also reduced body weight compared with placebo (-1.0 vs -0.3 kg). Dapagliflozin was well tolerated, with adverse events consistent with previous studies. Dapagliflozin improved glycemic control, and reduced SBP as well as body weight in patients with poorly controlled T2DM and hypertension.
Assuntos
Antagonistas de Receptores de Angiotensina/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Compostos Benzidrílicos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Glucosídeos/uso terapêutico , Hipertensão/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Sistema Renina-Angiotensina/efeitos dos fármacos , Adulto , Idoso , Glicemia/metabolismo , Determinação da Pressão Arterial , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/fisiopatologia , Método Duplo-Cego , Feminino , Hemoglobinas Glicadas/metabolismo , Frequência Cardíaca/efeitos dos fármacos , Hemorreologia , Humanos , Hipertensão/sangue , Hipertensão/complicações , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Sístole , Ácido Úrico/sangueRESUMO
OBJECTIVE: Dapagliflozin is a highly selective, orally active inhibitor of renal sodium-glucose cotransporter 2 that reduces hyperglycemia by increasing urinary glucose excretion. The goal of this study was to evaluate dapagliflozin as monotherapy in drug-naive Asian patients with type 2 diabetes whose disease was inadequately controlled with diet and exercise. METHODS: In this Phase III, multicenter, parallel-group, double-blind study, drug-naive patients with glycosylated hemoglobin (HbA1c) levels ≥7.0% to ≤10.5% (≥53-≤91 mmol/mol) were randomized (by using an interactive voice response system) to receive placebo (n = 132), dapagliflozin 5 mg (n = 128), or dapagliflozin 10 mg (n = 133). The primary end point was mean change from baseline in HbA1c level at week 24 (last-observation-carried-forward). Secondary end points included changes in fasting plasma glucose, 2-hour postprandial glucose, body weight, and other glycemic parameters. RESULTS: Baseline characteristics were balanced across groups. Most patients (89%) were Chinese, median disease duration was 0.2 year, and mean HbA1c level was 8.26%. Most patients (87%) completed the study. At week 24, mean reductions in HbA1c were -0.29% for placebo versus -1.04% and -1.11% for dapagliflozin 5 and 10 mg, respectively (P < 0.0001 for both doses). Changes in fasting plasma glucose were 2.5, -25.1, and -31.6 mg/dL (0.14, -1.39, and -1.75 mmol/L) for placebo, dapagliflozin 5 mg, and dapagliflozin 10 mg. Changes in 2-hour postprandial glucose were 1.1, -46.8, and -54.9 mg/dL (0.06, -2.60, and -3.05 mmol/L). Reductions in body weight were -0.27, -1.64, and -2.25 kg. Proportions of patients achieving HbA1c levels <7.0% (53 mmol/mol) were 21.3%, 42.6%, and 49.8%. Adverse events (AEs) occurred in 63.6%, 61.7%, and 60.9% of patients, and serious AEs occurred in 1.5%, 3.9%, and 3.0% of patients. No deaths occurred. Hypoglycemia was uncommon (1.5%, 0.8%, and 0.8%); no hypoglycemic event led to discontinuation. Genital infections occurred in 0.8%, 3.1%, and 4.5% of patients and urinary tract infections in 3.0%, 3.9%, and 5.3% of patients. No AEs of renal infection or pyelonephritis were reported. No changes in renal function or AEs of renal failure occurred. CONCLUSIONS: Compared with placebo, dapagliflozin 5 and 10 mg demonstrated clinically and statistically significant improvements in HbA1c levels after 24 weeks of treatment. Dose-dependent, statistically significant reductions in fasting plasma glucose, postprandial glucose, and weight were also observed for both doses compared with placebo. AEs and serious AEs were balanced across groups, with low rates of hypoglycemia and no increase in renal events. Genital infections and urinary tract infections were more common with dapagliflozin. Dapagliflozin as monotherapy in these drug-naive Asian patients was well tolerated, significantly improving glycemic control with the additional benefit of weight loss.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Glucosídeos/administração & dosagem , Glucosídeos/uso terapêutico , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/uso terapêutico , Adulto , Povo Asiático , Compostos Benzidrílicos , Glicemia/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Método Duplo-Cego , Esquema de Medicação , Feminino , Glucosídeos/farmacocinética , Hemoglobinas Glicadas/análise , Humanos , Hipoglicemia/induzido quimicamente , Hipoglicemiantes/farmacocinética , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Infecções do Sistema Genital/induzido quimicamente , Resultado do Tratamento , Infecções Urinárias/induzido quimicamenteRESUMO
BACKGROUND: Management of type 2 diabetes with metformin often does not provide adequate glycemic control, thereby necessitating add-on treatment. In a 24-week clinical trial, dapagliflozin, an investigational sodium glucose cotransporter 2 inhibitor, improved glycemic control in patients inadequately controlled with metformin. The present study is an extension that was undertaken to evaluate dapagliflozin as long-term therapy in this population. METHODS: This was a long-term extension (total 102 weeks) of a 24-week phase 3, multicenter, randomized, placebo-controlled, double-blind, parallel-group trial. Patients were randomly assigned (1:1:1:1) to blinded daily treatment (placebo, or dapagliflozin 2.5 to 5, or 10 mg) plus open-label metformin (≥1,500 mg). The previously published primary endpoint was change from baseline in glycated hemoglobin (HbA1c) at 24 weeks. This paper reports the follow-up to week 102, with analysis of covariance model performed at 24 weeks with last observation carried forward; a repeated measures analysis was utilized to evaluate changes from baseline in HbA1c, fasting plasma glucose (FPG), and weight. RESULTS: A total of 546 patients were randomized to 1 of the 4 treatments. The completion rate for the 78-week double-blind extension period was lower for the placebo group (63.5%) than for the dapagliflozin groups (68.3% to 79.8%). At week 102, mean changes from baseline HbA1c (8.06%) were +0.02% for placebo compared with -0.48% (P = 0.0008), -0.58% (P <0.0001), and -0.78% (P <0.0001) for dapagliflozin 2.5 to 5, and 10 mg, respectively. In addition, all dapagliflozin groups had sustained reductions from baseline in FPG (-1.07 to -1.47 mmol/l) and body weight (-1.10 to -1.74 kg) at 102 weeks, whereas increases were noted in placebo-treated patients for both of these outcomes. Events of hypoglycemia were rare and were not severe. Evidence suggestive of genital infection was reported in 11.7% to 14.6% of dapagliflozin patients and 5.1% of placebo patients, with one related discontinuation (dapagliflozin 5 mg). Evidence suggestive of urinary tract infection was reported in 8.0% to 13.3% of dapagliflozin patients and 8.0% of placebo patients, with one related discontinuation (dapagliflozin 2.5 mg). CONCLUSIONS: Dapagliflozin added to metformin for 102 weeks enabled sustained reductions in HbA1c, FPG, and weight without increased risk of hypoglycemia in patients with type 2 diabetes who were inadequately controlled on metformin alone. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00528879.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Glucosídeos/administração & dosagem , Hipoglicemiantes/administração & dosagem , Metformina/administração & dosagem , Compostos Benzidrílicos , Glicemia/análise , Método Duplo-Cego , Quimioterapia Combinada/métodos , Hemoglobinas Glicadas/análise , Humanos , Placebos/administração & dosagem , Resultado do TratamentoRESUMO
Farnesoid X receptor (FXR) is a bile acid-activated transcription factor that is a member of the nuclear hormone receptor superfamily. Fxr-null mice exhibit a phenotype similar to Byler disease, an inherited cholestatic liver disorder. In the liver, activation of FXR induces transcription of transporter genes involved in promoting bile acid clearance and represses genes involved in bile acid biosynthesis. We investigated whether the synthetic FXR agonist GW4064 could protect against cholestatic liver damage in rat models of extrahepatic and intrahepatic cholestasis. In the bile duct-ligation and alpha-naphthylisothiocyanate models of cholestasis, GW4064 treatment resulted in significant reductions in serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase, as well as other markers of liver damage. Rats that received GW4064 treatment also had decreased incidence and extent of necrosis, decreased inflammatory cell infiltration, and decreased bile duct proliferation. Analysis of gene expression in livers from GW4064-treated cholestatic rats revealed decreased expression of bile acid biosynthetic genes and increased expression of genes involved in bile acid transport, including the phospholipid flippase MDR2. The hepatoprotection seen in these animal models by the synthetic FXR agonist suggests FXR agonists may be useful in the treatment of cholestatic liver disease.
Assuntos
Colestase/tratamento farmacológico , Citoproteção , Proteínas de Ligação a DNA/fisiologia , Isoxazóis/farmacologia , Proteínas de Membrana Transportadoras , Fatores de Transcrição/fisiologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/fisiologia , Transportadores de Cassetes de Ligação de ATP/fisiologia , Animais , Proteínas de Transporte/genética , Colestase/metabolismo , Colestase/patologia , Proteínas de Ligação a DNA/agonistas , Isocianatos/farmacologia , Masculino , Naftalenos/farmacologia , Transportadores de Ânions Orgânicos Dependentes de Sódio , Transportadores de Ânions Orgânicos Sódio-Independentes/genética , Ratos , Ratos Sprague-Dawley , Receptores Citoplasmáticos e Nucleares , Receptores do Ligante Indutor de Apoptose Relacionado a TNF , Receptores do Fator de Necrose Tumoral/fisiologia , Esteroide 12-alfa-Hidroxilase/genética , Simportadores , Taurina/farmacologia , Fatores de Transcrição/agonistas , Ácido Ursodesoxicólico/farmacologiaRESUMO
The nuclear bile acid receptor FXR has been proposed to play a central role in the feedback repression of the gene encoding cholesterol 7 alpha-hydroxylase (CYP7A1), the first and rate-limiting step in the biosynthesis of bile acids. We demonstrate that FXR directly regulates expression of fibroblast growth factor-19 (FGF-19), a secreted growth factor that signals through the FGFR4 cell-surface receptor tyrosine kinase. In turn, FGF-19 strongly suppresses expression of CYP7A1 in primary cultures of human hepatocytes and mouse liver through a c-Jun N-terminal kinase (JNK)-dependent pathway. This signaling cascade defines a novel mechanism for feedback repression of bile acid biosynthesis and underscores the vital role of FXR in the regulation of multiple pathways of cholesterol catabolism in the liver.
Assuntos
Ácidos e Sais Biliares/biossíntese , Colesterol 7-alfa-Hidroxilase/genética , Proteínas de Ligação a DNA/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Hepatócitos/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Animais , Antracenos/farmacologia , Linhagem Celular , Células Cultivadas , Ácido Quenodesoxicólico/farmacologia , Colesterol 7-alfa-Hidroxilase/metabolismo , Proteínas de Ligação a DNA/agonistas , Proteínas de Ligação a DNA/genética , Repressão Enzimática , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/farmacologia , Regulação da Expressão Gênica , Humanos , Isoxazóis/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno , Camundongos , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-jun/metabolismo , Receptores Citoplasmáticos e Nucleares , Proteínas Recombinantes/farmacologia , Elementos de Resposta , Fatores de Transcrição/agonistas , Fatores de Transcrição/genética , TransfecçãoRESUMO
The application of advanced modern biomedical and chemical research technologies in the pharmaceutical industry has led to a significant increase in the number of potential drug targets and lead candidates. Whereas the drug discovery process is enhanced significantly, the failure rate of new compounds due to toxicity remains very high. The pharmaceutical industry is setting high hopes on the new discipline of toxicogenomics to revolutionize the process of drug toxicity assessment by reducing the bottleneck of new drug candidates and minimizing late-stage developmental failures. Toxicogenomics is expected to facilitate the efficient screening of new compounds at an early stage, resulting in significant savings of time and cost associated with new drug development. In this review, a general description of the new discipline of toxicogenomics and its potential impact on the safety assessment of new drugs in the pharmaceutical industry is provided. An overview of the key issues and questions that are confronting investigators in this field today is also given as well as a prospective view of the future of this new discipline.
Assuntos
Desenho de Fármacos , Farmacogenética , Previsões , Perfilação da Expressão Gênica/instrumentação , Perfilação da Expressão Gênica/métodos , Marcadores GenéticosRESUMO
BACKGROUND: Chediak-Higashi syndrome (CHS) is an inherited immunodeficiency disease characterized by giant lysosomes and impaired leukocyte degranulation. CHS results from mutations in the lysosomal trafficking regulator (LYST) gene, which encodes a 425-kD cytoplasmic protein of unknown function. The goal of this study was to identify proteins that interact with LYST as a first step in understanding how LYST modulates lysosomal exocytosis. MATERIALS AND METHODS: Fourteen cDNA fragments, covering the entire coding domain of LYST, were used as baits to screen five human cDNA libraries by a yeast two-hybrid method, modified to allow screening in the activation and the binding domain, three selectable markers, and more stringent confirmation procedures. Five of the interactions were confirmed by an in vitro binding assay. RESULTS: Twenty-one proteins that interact with LYST were identified in yeast two-hybrid screens. Four interactions, confirmed directly, were with proteins important in vesicular transport and signal transduction (the SNARE-complex protein HRS, 14-3-3, and casein kinase II). CONCLUSIONS: On the basis of protein interactions, LYST appears to function as an adapter protein that may juxtapose proteins that mediate intracellular membrane fusion reactions. The pathologic manifestations observed in CHS patients and in mice with the homologous mutation beige suggest that understanding the role of LYST may be relevant to the treatment of not only CHS but also of diseases such as asthma, urticaria, and lupus, as well as to the molecular dissection of the CHS-associated cancer predisposition.