RESUMEN
Endothelium represents a defense barrier and responds and integrates neuro humoral stimulus which describes as a compensatory mechanism. Endothelium formed with endothelial cells (ECs) and their progenitors. Endothelial progenitor cells (EPCs) represent minor subpopulation of mononuclear cells in the blood. During acute hypoxia, larger amount of EPCs mobilize into the peripheral blood and they directly contribute revascularization process. One of the subtypes of EPC is termed endothelial colony forming cells (ECFCs) which they possess de novo vessel-forming ability. The present study aims to investigate the role of hypoxia in EPCs functional and vessel-forming ability. Furthermore, it was investigated whether fetal exposure to a diabetic intrauterine environment influence EPCs adaptation ability. Human umbilical cord blood (HUCB) derived ECFCs were selected in all experimental procedures obtained from normal and gestational diabetes mellitus (GDM) subjects via in vitro cell culture methods. Early passage (<5) HUCB ECFCs obtain from GDM (n; 5) and control (n; 5) subjects were cultured with plates pre-coated with collagen in vitro 72 h hypoxic as well as normoxic condition. Endothelial, angiogenic and hypoxia associated gene specific primers designed to perform Real-time PCR. Senescenes assay conducted onto HUCB ECFCs to investigate their functional clonogenic ability. To quantify their vessel forming ability matrigel assay was applied. These data demonstrates that moderate hypoxia results increased vessel-forming ability and VEGFA expression in HUCB ECFCs obtained from control subjects. However, GDM caused to impede compensatory defense reaction against hypoxia which observed in control subjects. Thus, it illuminates beneficial information related future therapeutic modalities.
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Gestational diabetes mellitus (GDM) has long-term health consequences, and fetal exposure to a diabetic intrauterine environment increases cardiovascular risk for her adult offspring. Some part of this could be related to their endothelial progenitor cells (EPCs). Understanding the vessel-forming ability of human umbilical cord blood (HUCB)-derived endothelial colony-forming cells (ECFCs) against pathological stress such as GDM response to hypoxia could generate new therapeutic strategies. This study aims to investigate the role of chronic hypoxia in EPCs functional and vessel-forming ability in GDM subjects. Each ECFC was expressed in endothelial and pro-angiogenic specific markers, namely endothelial nitric oxide synthase (eNOS), platelet (PECAM-1) endothelial cell adhesion molecule 1, vascular endothelial-cadherin CdH5 (Ca-dependent cell adhesion molecule), vascular endothelial growth factor A, (VEGFA) and insulin-like growth factor 1 (IGF1). Chronic hypoxia did not affect CdH5, but PECAM1 MRNA expressions were increased in control and GDM subjects. Control hypoxic and GDM normoxic VEGFA MRNA expressions and hypoxia-inducible factor 1-alpha (HIF1α) protein expressions were significantly increased in HUCB ECFCs. GDM resulted in most failure of HUCB ECFC adaptation and eNOS protein expressions against chronic hypoxia. Chronic hypoxia resulted in an overall decline in HUCB ECFCs' proliferative ability due to reduction of clonogenic capacity and diminished vessel formation. Furthermore, GDM also resulted in most failure of cord blood ECFC adaptation against chronic hypoxic environment.
RESUMEN
Metabolic syndrome is characterized by a combination of obesity, hypertension, insulin resistance, dyslipidemia, and impaired glucose tolerance. This multifaceted syndrome is often accompanied by a hyperdynamic circulatory state characterized by increased blood pressure, total blood volume, cardiac output, and metabolic tissue demand. Experimental, epidemiological, and clinical studies have demonstrated that patients with metabolic syndrome have significantly elevated cardiovascular morbidity and mortality rates. One of the main and frequent complications seen in metabolic syndrome is cardiovascular disease. The primary endpoints of cardiometabolic risk are coronary and peripheral arterial disease, myocardial infarction, congestive heart failure, arrhythmia, and stroke. Alterations in expression and/or functioning of several key proteins involved in regulating and maintaining ionic homeostasis can cause cardiac disturbances. One such group of proteins is known as ryanodine receptors (intracellular calcium release channels), which are the major channels through which Ca(2+) ions leave the sarcoplasmic reticulum, leading to cardiac muscle contraction. The economic cost of metabolic syndrome and its associated complications has a significant effect on health care budgets. Improvements in body weight, blood lipid profile, and hyperglycemia can reduce cardiometabolic risk. However, constant hyperadrenergic stimulation still contributes to the burden of disease. Normalization of the hyperdynamic circulatory state with conventional therapies is the most reasonable therapeutic strategy to date. JTV519 (K201) is a newly developed 1,4-benzothiazepine drug with antiarrhythmic and cardioprotective properties. It appears to be very effective in not only preventing but also in reversing the characteristic myocardial changes and preventing lethal arrhythmias. It is also a unique candidate to improve diastolic heart failure in metabolic syndrome.
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We tested the hypothesis that adrenergic and nonadrenergic receptor responsiveness and protein expression would be altered with advancing age. Young (n = 6; 22 ± 1 mo; mean ± SE) and old (n = 6; 118 ± 9 mo) beagles were instrumented with flow probes and an indwelling catheter for continuous measurement of external iliac blood flow and arterial blood pressure. Vascular conductance (VC) was calculated as hindlimb blood flow/mean arterial pressure. Selective agonists for α-1, α-2, neuropeptide-Y (NPY), and purinergic (P2X) receptors were infused at rest and during treadmill running at moderate (2.5 mph) and heavy (4 mph with 2.5% grade) exercise intensities. Feed arteries were dissected from gracilis muscles, and α-1D, α-1B, α-2A, P2X-4, P2X-1, and NPY-Y1 receptor protein expression was determined. Phenylephrine produced similar decreases (P > 0.05) in VC in young and old beagles at rest (young: -62 ± 5%; old: -59 ± 5%) and during moderate (young: -67 ± 5%; old: -62 ± 4%) and heavy (young: -54 ± 4%; old: -49 ± 3%) exercise. Clonidine caused similar (P > 0.05) decreases in VC in old compared with young dogs at rest (young: -59 ± 8%; old: -70 ± 6%) and during moderate (young: -52 ± 6%; old: -47 ± 5%)- and heavy (young: -42 ± 5%; old: -43 ± 5%)-intensity exercise. NPY infusion resulted in a similar decline in VC in young and old beagles at rest (young: -40 ± 7%; old: -39 ± 9%) and during moderate (young: -47 ± 6%; old: -40 ± 6%)- and heavy (young: -40 ± 3%; old: -38 ± 4%)-intensity exercise. α-ß-Methylene-ATP also produced similar decreases in VC in young and old beagles at rest (young: -36 ± 6%; old: -40 ± 8%) and during exercise at moderate (young: -42 ± 5%; old: -40 ± 9%) and heavy (young: -47 ± 5%; old: -42 ± 8%) intensities. α-1B receptor protein expression was elevated (P < 0.05) in old compared with young dogs, whereas there were no age-related differences in α-1D or α-2A receptor expression and nonadrenergic P2X-4, P2X-1, and NPY-Y1 receptor expression. The present findings indicate that postsynaptic adrenergic and nonadrenergic receptor responsiveness was not altered by advancing age. Moreover, the expression of adrenergic and nonadrenergic receptors in skeletal-muscle feed arteries was largely unaffected by aging.
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Envejecimiento/fisiología , Músculo Esquelético/fisiología , Receptores Adrenérgicos alfa 1/biosíntesis , Receptores Adrenérgicos alfa 2/biosíntesis , Receptores de Neuropéptido Y/metabolismo , Receptores Purinérgicos P2X/biosíntesis , Agonistas de Receptores Adrenérgicos alfa 1/farmacología , Agonistas de Receptores Adrenérgicos alfa 2/farmacología , Envejecimiento/metabolismo , Animales , Arterias/efectos de los fármacos , Arterias/metabolismo , Arterias/fisiología , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Clonidina/farmacología , Perros , Hemodinámica/efectos de los fármacos , Hemodinámica/fisiología , Miembro Posterior/irrigación sanguínea , Miembro Posterior/efectos de los fármacos , Miembro Posterior/metabolismo , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Norepinefrina/farmacología , Fenilefrina/farmacología , Condicionamiento Físico Animal/fisiología , Agonistas del Receptor Purinérgico P2X/farmacología , Receptores Adrenérgicos alfa 1/genética , Receptores Adrenérgicos alfa 1/metabolismo , Receptores Adrenérgicos alfa 2/genética , Receptores Adrenérgicos alfa 2/metabolismo , Receptores de Neuropéptido Y/agonistas , Receptores de Neuropéptido Y/genética , Receptores Purinérgicos P2X/genética , Receptores Purinérgicos P2X/metabolismo , Flujo Sanguíneo Regional/efectos de los fármacos , Flujo Sanguíneo Regional/fisiología , Descanso/fisiologíaRESUMEN
Ossabaw swine have a "thrifty genotype" and consumption of excess calories induces many classical components of the metabolic syndrome, including obesity, insulin resistance, impaired glucose tolerance, dyslipidemia, hyperleptinemia, and hypertension. Earlier studies indicate that the metabolic syndrome is associated with diminished cardiac function; however, to what degree this impairment is associated with alterations in myocardial ß(1)- and ß(2)-adrenoceptor (AR) expression has not been fully elucidated. Accordingly, the present study was designed to investigate the effects of the metabolic syndrome on cardiac ß(1)- and ß(2)-AR expression. Studies were conducted on left ventricular tissue samples obtained from control lean and chronically (50 weeks) high-fat-fed obese animals. Chronic feeding significantly increased fasting plasma insulin, total cholesterol, triglycerides, blood glucose, systolic and diastolic blood pressure, and heart rate. Real-time polymerase chain reaction revealed no significant alterations in cardiac ß(1)- and ß(2)-AR mRNA expression. In contrast, Western blot analysis revealed a significant decrease in ventricular ß(1)- and ß(2)-AR protein expression. This is the first report in a novel large animal model that induction of metabolic syndrome is accompanied by a significant reduction in cardiac ß(1)- and ß(2)-AR protein expression that could contribute to impaired cardiac function.
RESUMEN
BACKGROUND: Ankle foot orthoses (AFO) are commonly used orthotic device in order to restore the ankle foot function and to improve the balance and gait in post-stroke hemiparetic patients. However, there remain some discussions about their effectiveness on long term hemiparetic patients who had mild to moderate spasticity. AIM: To investigate the relative effect of prefabricated thermoplastic posterior leaf spring AFO (PLS-AFO) on balance and fall risk. DESIGN: A cross-over interventional study SETTING: The Department of PMR of a tertiary hospital. POPULATION: Twenty-five chronic post-stroke long duration hemiparetic patients who had Ashworth grade 1-2 spasticity at affected calf muscles and lower limb Brunnstrom stage 2-3 and also able to walk independently without an assistive device. METHODS: Berg Balance Scale (BERG), and the postural stability test (PST) and the fall risk test (FRT) of Biodex balance systems were used for the assessments. All of the patients were assessed with AFO and without AFO. All assessments were made with footwear. RESULTS: The mean post-stroke duration was 20,32±7,46 months. The BERG scores were 42,12±9,05 without AFO and 47,52±7,77 with AFO; the overall stability scores of FRT were 3,35±1,97 without AFO and 2,69±1,65 with AFO (P<0,001). CONCLUSION: It was found that the prefabricated thermoplastic PLS-AFO improve balance and provide fall risk reduction in chronic post-stroke ambulatory hemiparetic patients who had mild to moderate spasticity on their affected lower limb. CLINICAL REHABILITATION IMPACT: These results encourage the usage of AFO on long duration hemiparetic patients in order to provide better balance and lesser fall risk.
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Accidentes por Caídas/prevención & control , Hemiplejía/rehabilitación , Espasticidad Muscular/rehabilitación , Aparatos Ortopédicos , Equilibrio Postural , Rehabilitación de Accidente Cerebrovascular , Adulto , Anciano , Anciano de 80 o más Años , Articulación del Tobillo/fisiología , Articulación del Tobillo/fisiopatología , Enfermedad Crónica , Estudios Cruzados , Diseño de Equipo , Femenino , Pie/fisiología , Pie/fisiopatología , Marcha/fisiología , Hemiplejía/etiología , Humanos , Masculino , Persona de Mediana Edad , Espasticidad Muscular/etiología , Índice de Severidad de la Enfermedad , Accidente Cerebrovascular/complicacionesRESUMEN
AIM: The objective of this study was to determine whether regular combined exercise program, which consists strength, stretching and aerobic exercises and additional jumping training, improve balance, fall risk, quality of life and depression status of older people living in a residential care. METHODS: A total of 168 residents who live in a long term care facility were screened. The trial began with 78 eligible participants and they were randomly grouped as combined exercises program (COM) group that includes stretching, strength and aerobic exercises, and COM plus jumping (COMpJ) group. 66 of the participants finished the trial. The groups were convened three times a week for six weeks. Each group had a warm-up, effective training and a cooling down periods. The total exercising time was no longer than 45 minutes in each group. Berg balance test and Biodex Balance System for the assessment of the dynamic balance and fall risk, short form 36 (SF 36) for the health related quality of life and Geriatric Depression Scale (GDS) for evaluation of the depression status were used. RESULTS: The balance improvement and fall risk reduction were observed in both of the groups at the end of the trial; however, the improvements were statistically better in jumping combined group. Also health related quality of life improved in both groups. CONCLUSION: Regular group exercise in a long term care facility have several beneficial effects on the elderly residents in regard to balance improvement, fall risk reduction and quality of life. The addition of jumping to strength, stretching and aerobic exercises provides important contributions to balance improvement and fall risk reduction.
Asunto(s)
Accidentes por Caídas/prevención & control , Terapia por Ejercicio , Cuidados a Largo Plazo , Actividad Motora , Calidad de Vida , Anciano , Anciano de 80 o más Años , Depresión/prevención & control , Femenino , Humanos , Masculino , Resultado del TratamientoRESUMEN
The role of large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels in regulation of coronary microvascular function is widely appreciated, but molecular and functional changes underlying the deleterious influence of metabolic syndrome (MetS) have not been determined. Male Ossabaw miniature swine consumed for 3-6 mo a normal diet (11% kcal from fat) or an excess-calorie atherogenic diet that induces MetS (45% kcal from fat, 2% cholesterol, 20% kcal from fructose). MetS significantly impaired coronary vasodilation to the BK(Ca) opener NS-1619 in vivo (30-100 microg) and reduced the contribution of these channels to adenosine-induced microvascular vasodilation in vitro (1-100 microM). MetS reduced whole cell penitrem A (1 microM)-sensitive K(+) current and NS-1619-activated (10 microM) current in isolated coronary vascular smooth muscle cells. MetS increased the concentration of free intracellular Ca(2+) and augmented coronary vasoconstriction to the L-type Ca(2+) channel agonist BAY K 8644 (10 pM-10 nM). BK(Ca) channel alpha and beta(1) protein expression was increased in coronary arteries from MetS swine. Coronary vascular dysfunction in MetS is related to impaired BK(Ca) channel function and is accompanied by significant increases in L-type Ca(2+) channel-mediated coronary vasoconstriction.
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Circulación Coronaria , Canales de Potasio de Gran Conductancia Activados por el Calcio/metabolismo , Síndrome Metabólico/metabolismo , Microcirculación , Músculo Liso Vascular/metabolismo , Vasoconstricción , Vasodilatación , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacología , 2-Cloroadenosina/farmacología , Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico/farmacología , Animales , Arteriolas/metabolismo , Arteriolas/fisiopatología , Bencimidazoles/farmacología , Agonistas de los Canales de Calcio/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo L/efectos de los fármacos , Canales de Calcio Tipo L/metabolismo , Señalización del Calcio , Circulación Coronaria/efectos de los fármacos , Vasos Coronarios/metabolismo , Vasos Coronarios/fisiopatología , Dieta Aterogénica , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Subunidades alfa de los Canales de Potasio de Gran Conductancia Activados por Calcio/metabolismo , Subunidades beta de los Canales de Potasio de Gran Conductancia Activados por el Calcio/metabolismo , Canales de Potasio de Gran Conductancia Activados por el Calcio/efectos de los fármacos , Masculino , Potenciales de la Membrana , Síndrome Metabólico/etiología , Síndrome Metabólico/fisiopatología , Microcirculación/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiopatología , Micotoxinas/farmacología , Nicardipino/farmacología , Péptidos/farmacología , Fenotipo , Bloqueadores de los Canales de Potasio/farmacología , Porcinos , Porcinos Enanos , Vasoconstricción/efectos de los fármacos , Vasoconstrictores/farmacología , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacologíaRESUMEN
Endogenous periadventitial adipose-derived factors have been shown to contribute to coronary vascular regulation by impairing endothelial function through a direct inhibition of endothelial nitric oxide synthase (eNOS). However, our understanding of the underlying mechanisms remains uncertain. Accordingly, this study was designed to test the hypothesis that periadventitial adipose tissue releases agents that attenuate coronary endothelial nitric oxide production via a protein kinase C (PKC)-beta-dependent mechanism. Isometric tension studies were conducted on isolated canine circumflex coronary arteries with and without natural amounts of periadventitial adipose tissue. Adipose tissue significantly diminished coronary endothelial-dependent vasodilation and nitric oxide production in response to bradykinin and acetylcholine. The selective inhibition of endothelial PKC-beta with ruboxistaurin (1 microM) abolished the adipose-induced impairment of bradykinin-mediated coronary vasodilation and the endothelial production of nitric oxide. Western blot analysis revealed a significant increase in eNOS phosphorylation at the inhibitory residue Thr(495) in arteries exposed to periadventitial adipose tissue. This site-specific phosphorylation of eNOS was prevented by the inhibition of PKC-beta. These data demonstrate that periadventitial adipose-derived factors impair coronary endothelial nitric oxide production via a PKC-beta-dependent, site-specific phosphorylation of eNOS at Thr(495).
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Tejido Adiposo/fisiología , Vasos Coronarios/fisiología , Endotelio Vascular/fisiología , Óxido Nítrico Sintasa de Tipo III/metabolismo , Proteína Quinasa C/fisiología , Animales , Western Blotting , Bradiquinina/farmacología , Perros , Inhibidores Enzimáticos/farmacología , Indoles/farmacología , Maleimidas/farmacología , Contracción Muscular/efectos de los fármacos , Contracción Muscular/fisiología , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiología , Óxido Nítrico/biosíntesis , Pericardio/fisiología , Fosforilación , Proteína Quinasa C/antagonistas & inhibidores , Proteína Quinasa C betaRESUMEN
BACKGROUND: This study was designed to elucidate the in vivo efficacy of epidermal growth factor (EGF) on wound healing in non diabetic and diabetic rats. METHODS: Ninety-six male Wistar-Albino rats were randomly divided into six groups. Saline-moistened gauze, pure gelatin or EGF in gelatin-microsphere dressings were used in a dermal excision model in both normal and streptomycin-induced diabetic rats. Wound healing was evaluated on day 7 and 14. Reduction in wound area, hydroxypyroline content and tensile strength of the wound were evaluated in each rat. Tissue samples taken from the wounds were examined histopathologically for reepithelialisation, cellular infiltration, number of fibroblasts, granulation and neovascularisation. RESULTS: On day 7, the use of EGF-containing dressing was observed to reduce the wound area better when compared with the other dressings tested. This effect was significant in normal rats rather than diabetic rats. The difference in reduction of wound area did not persist on day 14. No significant effect on hydroxyproline content of the wound was found with EGF-containing dressing in either normal or diabetic rats. There was a statistically significant increase in tensile strength values of EGF-applied non diabetic rats over the 14 day period. An increase in tensile strength was prominent in also EGF-applied diabetic rats on day 14. Histological examination revealed higher histopathologic scores in EGF-applied diabetic and non diabetic rats. CONCLUSION: These findings implicate that use of EGF in gelatin-microsphere dressings improves wound healing both in normal and diabetic rats.
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Diabetes Mellitus Experimental , Factor de Crecimiento Epidérmico/administración & dosificación , Esponja de Gelatina Absorbible/administración & dosificación , Cicatrización de Heridas/efectos de los fármacos , Administración Tópica , Animales , Esponja de Gelatina Absorbible/química , Masculino , Microesferas , Ratas , Ratas Wistar , Estreptozocina , Cicatrización de Heridas/fisiología , Heridas Penetrantes/tratamiento farmacológicoRESUMEN
The presence of anti-gliadin antibodies (AGA) and their relationship with intestinal permeability and prevalence of undiagnosed coeliac disease (CD) in ankylosing spondylitis (AS) were investigated. Blood samples from 30 AS patients and 19 age- and sex-matched controls were analysed for human leucocyte antigen (HLA)-B27, AGA and endomysial antibodies (EMA). Immunoglobulin (Ig) A-type AGA and IgG-type EMA were determined by enzyme-linked immunosorbent assay. AGA-positive patients were examined by gastroduodenoscope and proximal small bowel mucosa biopsies were performed. Eleven (36.7%) AS patients were AGA positive (compared with none of the control subjects) and three (10.0%) of these AS patients were also EMA-positive. The presence of AGA was not associated with more severe AS. Mild-to-severe villous atrophy and hyperplasia of crypts with increased chronic inflammatory cells in the lamina propria, which is typical of CD, was only observed in one AGA/EMA positive AS patient; CD was subsequently diagnosed by histology. Although AGA positivity might contribute to the pathogenesis of AS by increasing intestinal permeability to micro-organisms or by modifying intestinal immune mechanisms, further work is required to clarify its role in AS.
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Anticuerpos/inmunología , Enfermedad Celíaca/complicaciones , Enfermedad Celíaca/inmunología , Espondilitis Anquilosante/complicaciones , Espondilitis Anquilosante/inmunología , Adulto , Anticuerpos/sangre , Estudios de Casos y Controles , Enfermedad Celíaca/sangre , Enfermedad Celíaca/patología , Femenino , Gliadina/inmunología , Humanos , Masculino , Espondilitis Anquilosante/sangre , Espondilitis Anquilosante/patologíaRESUMEN
We previously demonstrated a role for voltage-dependent K(+) (K(V)) channels in coronary vasodilation elicited by myocardial metabolism and exogenous H(2)O(2), as responses were attenuated by the K(V) channel blocker 4-aminopyridine (4-AP). Here we tested the hypothesis that K(V) channels participate in coronary reactive hyperemia and examined the role of K(V) channels in responses to nitric oxide (NO) and adenosine, two putative mediators. Reactive hyperemia (30-s occlusion) was measured in open-chest dogs before and during 4-AP treatment [intracoronary (ic), plasma concentration 0.3 mM]. 4-AP reduced baseline flow 34 +/- 5% and inhibited hyperemic volume 32 +/- 5%. Administration of 8-phenyltheophylline (8-PT; 0.3 mM ic or 5 mg/kg iv) or N(G)-nitro-L-arginine methyl ester (L-NAME; 1 mg/min ic) inhibited early and late portions of hyperemic flow, supporting roles for adenosine and NO. 4-AP further inhibited hyperemia in the presence of 8-PT or L-NAME. Adenosine-induced blood flow responses were attenuated by 4-AP (52 +/- 6% block at 9 microg/min). Dilation of arterioles to adenosine was attenuated by 0.3 mM 4-AP and 1 microM correolide, a selective K(V)1 antagonist (76 +/- 7% and 47 +/- 2% block, respectively, at 1 microM). Dilation in response to sodium nitroprusside, an NO donor, was attenuated by 4-AP in vivo (41 +/- 6% block at 10 microg/min) and by correolide in vitro (29 +/- 4% block at 1 microM). K(V) current in smooth muscle cells was inhibited by 4-AP (IC(50) 1.1 +/- 0.1 mM) and virtually eliminated by correolide. Expression of mRNA for K(V)1 family members was detected in coronary arteries. Our data indicate that K(V) channels play an important role in regulating resting coronary blood flow, determining duration of reactive hyperemia, and mediating adenosine- and NO-induced vasodilation.
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Circulación Coronaria , Vasos Coronarios/metabolismo , Hiperemia/metabolismo , Canales KATP/metabolismo , Canales de Potasio con Entrada de Voltaje/metabolismo , Vasodilatación , 4-Aminopiridina/farmacología , Adenosina/metabolismo , Animales , Circulación Coronaria/efectos de los fármacos , Vasos Coronarios/efectos de los fármacos , Vasos Coronarios/enzimología , Vasos Coronarios/fisiopatología , Perros , Inhibidores Enzimáticos/farmacología , Hiperemia/fisiopatología , Canales KATP/antagonistas & inhibidores , Canales KATP/genética , Masculino , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/metabolismo , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/metabolismo , Nitroprusiato/farmacología , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio con Entrada de Voltaje/antagonistas & inhibidores , Antagonistas de Receptores Purinérgicos P1 , ARN Mensajero/análisis , Receptores Purinérgicos P1/metabolismo , Teofilina/análogos & derivados , Teofilina/farmacología , Factores de Tiempo , Triterpenos/farmacología , Vasodilatación/efectos de los fármacosRESUMEN
Recent studies implicate channels of the transient receptor potential vanilloid family (e.g., TRPV1) in regulating vascular tone; however, little is known about these channels in the coronary circulation. Furthermore, it is unclear whether metabolic syndrome alters the function and/or expression of TRPV1. We tested the hypothesis that TRPV1 mediates coronary vasodilation through endothelium-dependent mechanisms that are impaired by the metabolic syndrome. Studies were conducted on coronary arteries from lean and obese male Ossabaw miniature swine. In lean pigs, capsaicin, a TRPV1 agonist, relaxed arteries in a dose-dependent manner (EC50 = 116 +/- 41 nM). Capsaicin-induced relaxation was blocked by the TRPV1 antagonist capsazepine, endothelial denudation, inhibition of nitric oxide synthase, and K+ channel antagonists. Capsaicin-induced relaxation was impaired in rings from pigs with metabolic syndrome (91 +/- 4% vs. 51 +/- 10% relaxation at 100 microM). TRPV1 immunoreactivity was prominent in coronary endothelial cells. TRPV1 protein expression was decreased 40 +/- 11% in obese pigs. Capsaicin (100 microM) elicited divalent cation influx that was abolished in endothelial cells from obese pigs. These data indicate that TRPV1 channels are functionally expressed in the coronary circulation and mediate endothelium-dependent vasodilation through a mechanism involving nitric oxide and K+ channels. Impaired capsaicin-induced vasodilation in the metabolic syndrome is associated with decreased expression of TRPV1 and cation influx.
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Capsaicina/farmacología , Vasos Coronarios/efectos de los fármacos , Síndrome Metabólico/fisiopatología , Obesidad/fisiopatología , Canales Catiónicos TRPV/agonistas , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacología , Animales , Calcio/metabolismo , Capsaicina/análogos & derivados , Vasos Coronarios/enzimología , Vasos Coronarios/fisiopatología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiopatología , Inhibidores Enzimáticos/farmacología , Masculino , Manganeso/metabolismo , Síndrome Metabólico/metabolismo , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiopatología , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/metabolismo , Obesidad/metabolismo , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio/efectos de los fármacos , Canales de Potasio/metabolismo , Porcinos , Porcinos Enanos , Canales Catiónicos TRPV/metabolismoRESUMEN
The incidence of obesity and the metabolic syndrome has reached epidemic proportions and alterations in coronary microvascular function could contribute to the increased cardiovascular morbidity and mortality observed in these patients. This review highlights key mechanisms of impaired control of coronary blood flow in the metabolic syndrome. Specifically, coronary endothelial dysfunction, altered neurohumoral control, and the potential roles of smooth muscle ion channels are addressed. Recent studies indicate that alterations in endothelial-dependent vasodilation or endothelial-dependent vasoconstriction contribute little to obesity-induced impairments in coronary vascular control. In contrast, augmented vasoconstriction in response to neurohumoral mediators appears to play a significant role in coronary vascular dysfunction. The authors conclude that coronary dysfunction in the metabolic syndrome is characterized by an imbalance between coronary blood flow and myocardial metabolism that may be mediated by sensitization of vasoconstrictor pathways. Further, they suggest that alterations in smooth muscle ion channels, Ca(2+) handling, and cell signaling may be important mechanisms leading to coronary microvascular dysfunction. Importantly, however, more research is needed to clearly delineate specific mechanisms and identify potential therapeutic targets.
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Enfermedad Coronaria/etiología , Resistencia a la Insulina/fisiología , Obesidad/complicaciones , Circulación Coronaria/fisiología , Endotelio Vascular/fisiopatología , Humanos , Síndrome Metabólico/fisiopatología , Transducción de SeñalRESUMEN
OBJECTIVE: The purpose of this study was to examine the effects of simvastatin pretreatment in the setting of acute limb ischemia-reperfusion injury in an experimental diabetes model that is associated with a high risk for limb loss. METHODS: Adult male Sprague-Dawley rats were randomized into two groups. Diabetes was induced in the first group by intravenous streptozotocin injection. The second group served as the nondiabetic group. Eight weeks after the streptozotocin injection, half of the rats in the diabetic and the nondiabetic groups were further randomized to receive either intraperitoneal simvastatin (1 mg/kg per day) or saline treatment for 6 weeks. Bilateral hind-limb ischemia was induced for 4 hours by the tourniquet method. After 24 hours of reperfusion, tissue samples were collected from the gastrocnemius and anterior tibial muscles bilaterally for measurement of muscle edema, percentage of necrosis, and malondialdehyde (MDA), glutathione, and myeloperoxidase (MPO) levels. RESULTS: Ischemic injury was more prominent in diabetic animals. The diabetic animals with limb ischemia exhibited a 7% increase in tissue edema, a 47% increase in muscle necrosis and MPO level, and a 15% reduction in glutathione levels compared with the nondiabetic animals (P < .05). Simvastatin treatment with 1 mg/kg for 6 weeks reduced the ischemic injury. Simvastatin pretreatment led to a 71% reduction in muscle necrosis in diabetic animals (P < .001). The protective effects of simvastatin pretreatment also correlated with a 23% improvement in tissue edema, a 75% reduction in tissue myeloperoxidase content, and a 71% increase in glutathione levels in diabetic animals (P < .01). Furthermore, skeletal muscle injury, characterized by tissue edema and leucosequestration, was significantly less severe with simvastatin pretreatment compared with the nondiabetic animals (P < .01). CONCLUSION: Simvastatin pretreatment reduced limb ischemia-reperfusion injury in diabetic and nondiabetic animals. We conclude that simvastatin pretreatment may be a potential therapeutic intervention for skeletal muscle ischemia-reperfusion injury in the clinical setting.
Asunto(s)
Diabetes Mellitus Experimental/tratamiento farmacológico , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/efectos de los fármacos , Daño por Reperfusión/prevención & control , Simvastatina/farmacología , Animales , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Edema/prevención & control , Glutatión/metabolismo , Miembro Posterior , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Isquemia/complicaciones , Masculino , Malondialdehído/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Necrosis/prevención & control , Peroxidasa/metabolismo , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/etiología , Índice de Severidad de la Enfermedad , Simvastatina/uso terapéutico , Factores de Tiempo , TorniquetesRESUMEN
OBJECTIVE: This study tested whether alpha -adrenoceptor-mediated coronary vasoconstriction is augmented in the metabolic syndrome and is accompanied by the alteration of specific alpha(1)- and alpha(2)-coronary adrenoceptors. METHODS: Studies were conducted in control and chronically high-fat-fed (6 weeks of 60% calories from fat) dogs with metabolic syndrome. Alterations in coronary alpha(1B)-, alpha(1D)-, and alpha(2A)-adrenoceptor mRNA and protein expression were examined by real-time PCR and Western analyses, respectively. Coronary blood flow and its response to intracoronary infusion of either the alpha1-adrenoceptor agonist methoxamine (0.1-3 mg) or the alpha(2)-adrenoceptor agonist BHT-933 (0.1-3 mg) were measured in anesthetized dogs. RESULTS: Basal plasma epinephrine and norepinephrine levels were higher in the high-fat-fed dogs compared to controls. Real-time PCR revealed no alterations of coronary artery or arteriole alpha1B-, alpha(1D)-, and alpha(2A)-adrenoceptor mRNA expression. However, Western blot analysis showed a significant decrease in alpha(2A)-adrenoceptor protein density with no change in alpha(1B)- or alpha(1D)-adrenoceptors. Methoxamine and BHT-933 produced dose-dependent decreases in coronary blood flow, but the decrease in coronary flow to methoxamine was significantly greater (approximately 20%) in dogs with the metabolic syndrome. No differences in the coronary flow response to BHT-933 were noted. CONCLUSIONS: These results indicate that the metabolic syndrome is associated with sensitization of alpha1- and alpha2-adrenoceptor signaling that could significantly limit control of coronary blood flow when the sympathetic nervous system is activated.
Asunto(s)
Vasos Coronarios/fisiopatología , Síndrome Metabólico/fisiopatología , Estado Prediabético/fisiopatología , Receptores Adrenérgicos alfa/fisiología , Vasoconstricción/fisiología , Agonistas alfa-Adrenérgicos/farmacología , Animales , Azepinas/farmacología , Secuencia de Bases , Circulación Coronaria/efectos de los fármacos , Circulación Coronaria/fisiología , Vasos Coronarios/efectos de los fármacos , Cartilla de ADN/genética , Grasas de la Dieta/administración & dosificación , Perros , Expresión Génica , Síndrome Metabólico/genética , Metoxamina/farmacología , Estado Prediabético/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores Adrenérgicos alfa/genética , Transducción de Señal , Sistema Nervioso Simpático/fisiopatología , Vasoconstricción/efectos de los fármacosRESUMEN
This study examined the hypothesis that the prediabetic metabolic syndrome alters expression, phosphorylation state and binding affinity of cardiac RyR2. Real-time PCR and Western blot analysis were used to assess mRNA and protein expression in the left ventricle, right ventricle and right atrium from control (n=5) and chronically high-fat-fed (n=5) dogs with the metabolic syndrome. Functional integrity of RyR2 was assessed by RyR2-Ser2809 phosphorylation and the receptor's ability to bind [3H]ryanodine. We found that RyR2 phosphorylation at Ser2809 was significantly elevated in right and left ventricle from high-fat-fed dogs compared to normal control dogs. This hyperphosphorylation was associated with a decrease in RyR2 binding affinity in right and left ventricle (high-fat diet=80.2 and 90.5 fmol/mg protein vs. control=243.6 and 200.9 fmol/mg protein, respectively) and a decrease in cardiac index in exercising dogs. RyR2 phosphorylation at Ser2809 and RyR2 binding affinity were not altered in the right atria of high-fat-fed dogs. In addition, no significant differences in cardiac RyR2 mRNA or protein expression were noted between groups. These data suggest that alterations in RyR2 could be an important mechanism of early cardiac dysfunction in obesity and insulin resistance.
Asunto(s)
Síndrome Metabólico/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Animales , Estructuras de la Membrana Celular/metabolismo , Perros , Femenino , Masculino , Miocardio/metabolismo , Fosforilación , Condicionamiento Físico Animal , Rianodina/metabolismo , Canal Liberador de Calcio Receptor de Rianodina/genética , Serina/metabolismoRESUMEN
OBJECTIVE: The purpose of the present investigation was to test the hypothesis that coronary vasoconstrictor responses to endothelin-1 are augmented in the prediabetic metabolic syndrome. METHODS: ELISA was used to measure plasma endothelin-1 and intracoronary endothelin-1 dose-response experiments were conducted in vivo on normal control and high-fat-fed prediabetic dogs. Additionally, isolated left circumflex (LCX) coronary arteries and arterioles (< 160 microm) were used for in vitro functional studies and molecular analyses (quantitative real-time PCR and Western blotting). RESULTS: Plasma endothelin-1 concentrations were not different between control and prediabetic dogs. Coronary vasoconstriction to endothelin-1 was similar in control and prediabetic dogs, both in vivo and in isolated arterioles. Nonetheless, real-time PCR analysis revealed significant decreases in ET(A) receptor transcript levels in LCX coronary arteries and arterioles. Also, Western blotting revealed a significant decrease in ET(A) receptor protein in LCX coronary arteries. CONCLUSIONS: The findings of the present investigation indicate that although ET(A) receptor-signaling is sensitized by induction of the metabolic syndrome, endothelin-mediated coronary vasoconstriction does not significantly contribute to coronary dysfunction at this early stage of prediabetes.
Asunto(s)
Vasos Coronarios/fisiopatología , Endotelina-1/farmacología , Síndrome Metabólico/fisiopatología , Sistema Vasomotor/efectos de los fármacos , Animales , Arteriolas/fisiopatología , Perros , Estado Prediabético/fisiopatología , Receptor de Endotelina A/análisis , Receptor de Endotelina A/genética , Vasoconstricción/efectos de los fármacosRESUMEN
Hyperleptinemia, associated with prediabetes, is an independent risk factor for coronary artery disease and a mediator of coronary endothelial dysfunction. We previously demonstrated that acutely raising the leptin concentration to levels comparable with those observed in human obesity significantly attenuates coronary dilation/relaxation to acetylcholine (ACh) both in vivo in anesthetized dogs and in vitro in isolated canine coronary rings. Accordingly, the purpose of this investigation was to extend these studies to a model of prediabetes with chronic hyperleptinemia. In the present investigation, experiments were conducted on control and high-fat-fed dogs. High-fat feeding caused a significant increase (131%) in plasma leptin concentration. Furthermore, in high-fat-fed dogs, exogenous leptin did not significantly alter vascular responses to ACh in vivo or in vitro. Coronary vasodilator responses to ACh (0.3-30.0 microg/min) and sodium nitroprusside (1.0-100.0 microg/min) were not significantly different from those observed in control dogs. Also, high-fat feeding did not induce a switch to an endothelium-derived hyperpolarizing factor as a major mediator of muscarinic coronary vasodilation, because dilation to ACh was abolished by combined pretreatment with N(omega)-nitro-l-arginine methyl ester (150 microg/min ic) and indomethacin (10 mg/kg iv). Quantitative, real-time PCR revealed no significant difference in coronary artery leptin receptor gene expression between control and high-fat-fed dogs. In conclusion, high-fat feeding induces resistance to the coronary vascular effects of leptin, and this represents an early protective adaptation against endothelial dysfunction. The resistance is not due to altered endothelium-dependent or -independent coronary dilation, increased endothelium-derived hyperpolarizing factor, or changes in coronary leptin receptor mRNA levels.
Asunto(s)
Circulación Coronaria/fisiología , Endotelio Vascular/fisiología , Leptina/sangre , Estado Prediabético/metabolismo , Estado Prediabético/fisiopatología , Adaptación Fisiológica/fisiología , Anestesia , Animales , Circulación Coronaria/efectos de los fármacos , Vasos Coronarios/patología , Vasos Coronarios/fisiología , Grasas de la Dieta/farmacología , Modelos Animales de Enfermedad , Perros , Leptina/genética , Leptina/farmacología , Masculino , Obesidad/metabolismo , Obesidad/fisiopatología , ARN Mensajero/análisisRESUMEN
Obesity is associated with marked increases in plasma leptin concentration, and hyperleptinemia is an independent risk factor for coronary artery disease. As a result, the purpose of this investigation was to test the following hypotheses: 1) leptin receptors are expressed in coronary endothelial cells; and 2) hyperleptinemia induces coronary endothelial dysfunction. RT-PCR analysis revealed that the leptin receptor gene is expressed in canine coronary arteries and human coronary endothelium. Furthermore, immunocytochemistry demonstrated that the long-form leptin receptor protein (ObRb) is present in human coronary endothelium. The functional effects of leptin were determined using pressurized coronary arterioles (<130 microm) isolated from Wistar rats, Zucker rats, and mongrel dogs. Leptin induced pharmacological vasodilation that was abolished by denudation and the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester and was absent in obese Zucker rats. Intracoronary leptin dose-response experiments were conducted in anesthetized dogs. Normal and obese concentrations of leptin (0.1-3.0 microg/min ic) did not significantly change coronary blood flow or myocardial oxygen consumption; however, obese concentrations of leptin significantly attenuated the dilation to graded intracoronary doses of acetylcholine (0.3-30.0 microg/min). Additional experiments were performed in canine coronary rings, and relaxation to acetylcholine (6.25 nmol/l-6.25 micromol/l) was significantly attenuated by obese concentrations of leptin (625 pmol/l) but not by physiological concentrations of leptin (250 pmol/l). The major findings of this investigation were as follows: 1) the ObRb is present in coronary arteries and coupled to pharmacological, nitric oxide-dependent vasodilation; and 2) hyperleptinemia produces significant coronary endothelial dysfunction.