Promoting early neovascularization by allotransplanted adipose-derived Muse cells in an ovine model of acute myocardial infarction.

BACKGROUND: Recent preclinical studies have demonstrated that bone marrow (BM)-derived Muse cells have a homing mechanism to reach damaged cardiac tissue while also being able to reduce myocardial infarct size and improve cardiac function; however, the potential of BM-Muse cells to foster new blood-vessel formation has not been fully assessed. Up to date, adipose tissue (AT)-derived Muse cells remain to be studied in acute myocardial infarction (AMI). The aim of the present study was to analyze in vitro and in vivo the neovascularization capacity of AT-Muse cells while exploring their biodistribution and differentiation potential in a translational ovine model of AMI. METHODS AND RESULTS: AT-Muse cells were successfully isolated from ovine adipose tissue. In adult sheep, one or more diagonal branches of the left anterior descending coronary artery were permanently ligated for thirty minutes. Sheep were randomized in two groups and treated with intramyocardial injections: Vehicle (PBS, n = 4) and AT-Muse (2x107 AT-Muse cells labeled with PKH26 Red Fluorescent Dye, n = 4). Molecular characterization showed higher expression of angiogenic genes (VEGF, PGF and ANG) and increased number of tube formation in AT-Muse cells group compared to Adipose-derived mesenchymal stromal cells (ASCs) group. At 7 days post-IAM, the AT-Muse group showed significantly more arterioles and capillaries than the Vehicle group. Co-localization of PKH26+ cells with desmin, sarcomeric actin and troponin T implied the differentiation of Muse cells to a cardiac fate; moreover, PKH26+ cells also co-localized with a lectin marker, suggesting a possible differentiation to a vascular lineage. CONCLUSION: Intramyocardially administered AT-Muse cells displayed a significant neovascularization activity and survival capacity in an ovine model of AMI.

In silico performance analysis of web tools for CRISPRa sgRNA design in human genes.

Angiogenic gene overexpression has been the main strategy in numerous vascular regenerative gene therapy projects. However, most have failed in clinical trials. CRISPRa technology enhances gene overexpression levels based on the identification of sgRNAs with maximum efficiency and safety. CRISPick and CHOP CHOP are the most widely used web tools for the prediction of sgRNAs. The objective of our study was to analyze the performance of both platforms for the sgRNA design to angiogenic genes (VEGFA, KDR, EPO, HIF-1A, HGF, FGF, PGF, FGF1) involving different human reference genomes (GRCH 37 and GRCH 38). The top 20 ranked sgRNAs proposed by the two tools were analyzed in different aspects. No significant differences were found on the DNA curvature associated with the sgRNA binding sites but the sgRNA predicted on-target efficiency was significantly greater when CRISPick was used. Moreover, the mean ranking variation was greater for the same platform in EPO, EGF, HIF-1A, PGF and HGF, whereas it did not reach statistical significance in KDR, FGF-1 and VEGFA. The rearrangement analysis of the ranking positions was also different between platforms. CRISPick proved to be more accurate in establishing the best sgRNAs in relation to a more complete genome, whereas CHOP CHOP showed a narrower classification reordering.

Effect of intramuscular baculovirus encoding mutant hypoxia-inducible factor 1-alpha on neovasculogenesis and ischemic muscle protection in rabbits with peripheral arterial disease.

BACKGROUND AIMS: Peripheral arterial disease (PAD) is a progressive, disabling ailment for which no effective treatment exists. Gene therapy-mediated neovascularization has emerged as a potentially useful strategy. We tested the angiogenic and arteriogenic efficacy and safety of a baculovirus (BV) encoding mutant, oxygen-resistant hypoxia-inducible factor 1-alpha (mHIF-1α), in rabbits with PAD. METHODS: After assessing the transfection efficiency of the BV.mHIF-1α vector and its tubulogenesis potential in vitro, we randomized rabbits with experimental PAD to receive 1 × 109 copies of BV.mHIF-1α or BV.null (n = 6 per group) 7 days after surgery. Two weeks post-treatment, collateralization (digital angiography) and capillary and arteriolar densities (immunohistochemistry) were measured in the posterior limbs. Ischemic damage was evaluated in adductor and gastrocnemius muscle samples. Tracking of viral DNA in injected zones and remote tissues at different time points was performed in additional rabbits using a BV encoding GFP. RESULTS: Angiographically visible collaterals were more numerous in BV.mHIF-1α-treated rabbits (8.12 ± 0.42 vs 6.13 ± 1.15 collaterals/cm2, P < 0.05). The same occurred with arteriolar (27.9 ± 7.0 vs 15.3 ± 4.0 arterioles/mm2) and capillary (341.8 ± 109.9 vs 208.8 ± 87.7 capillaries/mm2, P < 0.05) densities. BV.mHIF-1α-treated rabbits displayed less ischemic muscle damage than BV.null-treated animals. Viral DNA and GFP mRNA were detectable only at 3 and 7 days after injection in hind limbs. Neither the virus nor GFP mRNA was detected in remote tissues. CONCLUSIONS: In rabbits with PAD, BV.mHIF-1α induced neovascularization and reduced ischemic damage, exhibiting a good safety profile at 14 days post-treatment. Complementary studies to evaluate its potential usefulness in the clinic are needed.

Novel insights into cardiac regeneration based on differential fetal and adult ovine heart transcriptomic analysis.

The adult mammalian cardiomyocyte has a very limited capacity to reenter the cell cycle and advance into mitosis. Therefore, diseases characterized by lost contractile tissue usually evolve into myocardial remodeling and heart failure. Analyzing the cardiac transcriptome at different developmental stages in a large mammal closer to the human than laboratory rodents may serve to disclose positive and negative cardiomyocyte cell cycle regulators potentially targetable to induce cardiac regeneration in the clinical setting. Thus we aimed at characterizing the transcriptomic profiles of the early fetal, late fetal, and adult sheep heart by employing RNA-seq technique and bioinformatic analysis to detect protein-encoding genes that in some of the stages were turned off, turned on, or differentially expressed. Genes earlier proposed as positive cell cycle regulators such as cyclin A, cdk2, meis2, meis3, and PCNA showed higher expression in fetal hearts and lower in AH, as expected. In contrast, genes previously proposed as cell cycle inhibitors, such as meis1, p16, and sav1, tended to be higher in fetal than in adult hearts, suggesting that these genes are involved in cell processes other than cell cycle regulation. Additionally, we described Gene Ontology (GO) enrichment of different sets of genes. GO analysis revealed that differentially expressed gene sets were mainly associated with metabolic and cellular processes. The cell cycle-related genes fam64a, cdc20, and cdk1, and the metabolism-related genes pitx and adipoq showed strong differential expression between fetal and adult hearts, thus being potent candidates to be targeted in human cardiac regeneration strategies.NEW & NOTEWORTHY We characterized the transcriptomic profiles of the fetal and adult sheep hearts employing RNAseq technique and bioinformatic analyses to provide sets of transcripts whose variation in expression level may link them to a specific role in cell cycle regulation. It is important to remark that this study was performed in a large mammal closer to humans than laboratory rodents. In consequence, the results can be used for further translational studies in cardiac regeneration.

Biomarcadores de aterosclerosis e indicadores de resistencia insulínica en pacientes acromegálicos no diabéticos / Biomarkers of Atherosclerosis and Indicators of Insulin Resistance in Non-Diabetic Acromegalic Patients

Introducción En la acromegalia, las comorbilidades cardiovasculares, respiratorias y metabólicas contribuyen a un aumento significativo de la mortalidad de los pacientes afectados. Asimismo, una proporción elevada de estos pacientes presentan diabetes mellitus. Pese a que el hallazgo de un perfil lipídico y lipoproteico anormal en pacientes acromegálicos suele ser habitual, cuando se intenta identificar y/o establecer el grado de modificaciones de parámetros específicos, los resultados son controversiales. Objetivos Evaluar la presencia de biomarcadores de aterosclerosis en pacientes con acromegalia activa no diabéticos y su asociación con la hormona del crecimiento (GH) y el factor de crecimiento similar a la insulina tipo 1 (IGF-1). Material y métodos Se estudiaron 14 pacientes y 14 controles sanos pareados por sexo y edad. Se midieron las concentraciones de GH e IGF-1 por inmunoensayos. Se evaluaron indicadores de resistencia insulínica (glucosa, insulina y HOMA), perfil lipoproteico, niveles plasmáticos de lipoproteínas de baja densidad oxidadas (LDLox), moléculas de adhesión celular vascular 1 (VCAM-1), endotelina-1 y actividad de fosfolipasa A2 asociada con lipoproteínas (LpPLA2). Resultados En comparación con los controles, los pacientes presentaron aumentos de GH (p < 0,05) e IGF-1 (p < 0,001), de los indicadores de resistencia insulínica (insulina p < 0,001; HOMA p < 0,001), triglicéridos (p < 0,05), apo B (p < 0,001), LDLox (117 ± 20 versus 89 ± 23 U/ L; p < 0,05) y endotelina-1 (0,9 ± 0,2 versus 0,7 ± 0,2 pg/ml; p < 0,05). Más aún, la GH y el IGF-1 se asociaron positivamente con (r; p <) insulina (0,40; 0,05 y 0,73; 0,001), HOMA (0,39; 0,05 y 0,74; 0,001), triglicéridos (0,57; 0,05 y 0,64; 0,001), colesterol de lipoproteínas de muy baja densidad (C-VLDL) (0,54; 0,05 y 0,47; 0,05), apo B (0,40; 0,05 y 0,54; 0,05), LDLox (0,59; 0,05 y 0,66; 0,05) y endotelina-1 (0,55; 0,05 y 0,51; 0,05). Conclusiones Los pacientes con acromegalia activa no diabéticos presentaron un estado de resistencia insulínica, así como modificaciones sutiles en el perfil lipoproteico y concentraciones elevadas de LDLox y endotelina-1. Las alteraciones descriptas podrían contribuir a un estado de mayor propensión al desarrollo de enfermedad cardiovascular aterosclerótica, la cual se sumaría a la miocardiopatía específica de la acromegalia.

Background Cardiovascular, respiratory and metabolic comorbidities associated with acromegaly contribute to a significant increase in the mortality of this disease. Many of these patients are also diabetic. Although it is frequent to find abnormal lipid and lipoprotein profiles in patients with acromegaly, controversial outcomes arise in an attempt to identify and/or establish the degree of the modifications of specific parameters. Objectives To assess the presence of biomarkers of atherosclerosis in non-diabetic patients with active acromegaly and its association with growth hormone (GH) and with insulin-like growth factor type 1 (IGF-1). Material and Methods The study included 14 patients and 14 healthy controls, pared by sex and age. Serum concentration of GH and IGF- 1 were determined by immunoassays. Indicators of insulin resistance (glucose, insulin and HOMA) were measured, as well as lipoprotein profile, plasmatic levels of oxidized LDL (oxLDL), vascular cell adhesion molecule 1 (VCAM-1), endothelin-1 and lipoprotein-associated phospholipase A2 activity (LpPLA2). Results Compared to controls, non-diabetic acromegalic patients had increased levels of GH (p<0.05) and IGF-1 (p<0.001), of indicators of insulin resistance (insulin p<0.001; HOMA p<0.001), triglycerides (p<0.05), apo B (p<0.001), oxLDL (117±20 versus 89±23 U/L; p<0.05) and endothelin-1 (0.9±0.2 versus 0.7±0.2 pg/ml; p<0.05). In addition, GH and IGF-1 were positively associated with (r; p <) insulin (0.40; 0.05 and 0.73; 0.001), HOMA (0.39; 0.05 and 0.74; 0.001), triglycerides (0.57; 0.05 and 0.64; 0.001), very low density lipoprotein-cholesterol (VLDL-C) (0.54; 0.05 and 0.47; 0.05), apo B (0.40; 0.05 and 0.54; 0.05), oxLDL (0.59; 0.05 and 0.66; 0.05) and endothelin-1 (0.55; 0.05 and 0.51; 0.05). Conclusions Non-diabetic patients with active acromegaly presented an insulin-resistant status, as well as subtle modifications of lipid profile and increased levels of oxLDL and endothelin- 1. These alterations could explain why these patients are more likely to develop atherosclerotic cardiovascular disease in addition to acromegalic cardiomyopathy.

Expression of the MDR-1 gene-encoded P-glycoprotein in cardiomyocytes of conscious sheep undergoing acute myocardial ischemia followed by reperfusion.

We have recently reported that in chronic myocardial ischemia, adult mammalian cardiomyocytes express P-glycoprotein (P-gp). We now investigate if P-gp is also expressed in acute regional ischemia followed by reperfusion. Adult conscious sheep underwent 12-min occlusion of the mid-left anterior descending artery (inflatable cuff). Successful ischemia-reperfusion was confirmed by monitoring percent systolic left ventricular anterior wall thickening (sonomicrometry) during the whole ischemic period and every 10 min over 2 hr following cuff deflation. At 3, 24, and 48 hr after reperfusion, P-gp expression was investigated by immunohistochemistry and Western blot and MDR-1 mRNA by RT-PCR. Cardiomyocytes in the occluded artery territory (but not those in remote areas) consistently expressed P-gp at their sarcolemma. Whereas at 3 and 24 hr P-gp was mainly observed in the T tubules, at 48 hr it predominated in intercalated discs and gap junctions. RT-PCR and Western blot revealed higher expression in ischemic than in control myocardium. We conclude that in adult sheep with acute myocardial ischemia, the MDR-1 gene-encoded P-gp is expressed at the sarcolemma of the cardiomyocytes from 3 hr up to at least 48 hr after reperfusion.

Development of mild aortic valve stenosis in a rabbit model of hypertension.

OBJECTIVES: This study was designed to investigate the association between hypertension and aortic valve stenosis (AVS) in a rabbit model. BACKGROUND: Degenerative AVS is a prevalent disease in elderly persons. Its molecular mechanisms remain unclear, in part because of the absence of experimental models. Epidemiologic data suggest a link between hypertension and AVS. However, there has been no evidence of a cause-effect relationship. METHODS: New Zealand White rabbits were divided into two groups: 1) animals (n = 20) instrumented according to one-kidney/one-clip hypertensive model; and 2) control animals (n = 10) sham operated. Echocardiography (S12 MHz) was used to assess aortic valve (AV) morphology and function as well as left ventricular mass at baseline and after two and four months of hypertension. RESULTS: Blood pressure and left ventricular mass increase were highly significant in the animal model but not in controls at two months, without noticeable AV function abnormalities. After 4 months, however, 14 hypertensive survived animals showed a 14.6% reduction of AV area (0.240 +/- 0.063 cm2 vs. 0.205 +/- 0.060 cm2, p < 0.05), a 19.6% increase of AV thickness (0.056 +/- 0.011 cm vs. 0.067 +/- 0.010 cm, p < 0.001), a 40.4% increase of transvalvular mean gradient (5.35 +/- 2.26 mm Hg vs. 7.51 +/- 3.73 mm Hg, p < 0.05) and a 63.6% increase of transvalvular maximal gradient (10.56 +/- 3.68 mm Hg vs. 17.28 +/- 10.95 mm Hg, p < 0.05). Control animals did not show significant changes. CONCLUSIONS: We report a novel experimental model of AVS in rabbits that may prove useful in studying the progression of the disease and the efficacy of new treatments. The present findings support the hypothesis of a causal link between hypertension and AVS.

Six novel mutations of the LDL receptor gene in FH kindred of Sicilian and Paraguayan descent.

Familial hypercholesterolemia (FH) is an autosomal dominant inherited disease caused by mutations in the gene coding for the low density lipoprotein receptor (LDL-R). It is characterized by a high concentration of low density lipoprotein (LDL), which frequently gives rise to premature coronary artery disease. We studied the probands of five FH Sicilian families with 'definite' FH and one proband of Paraguayan descent with homozygous FH who has been treated with an effective living-donor liver transplantation. In order to seek the molecular defect in these six families, we used direct sequencing to define the molecular defects of the LDL-R gene responsible for the disease. We described three novel missense mutations (C100Y, C183Y and G440C), two frameshift mutations (g.1162delC in exon 8 and g.2051delC in exon 14) and one mutation (g.2390-1Gright curved arrow A) at splicing acceptor consensus sequences located in intron 16 of the LDL-R gene; the analysis of cDNA of this splicing mutation showed the activation of a cryptic splice site in intron 16 and the binding studies showed a reduction in internalisation of LDL-DIL in the proband's cultured fibroblasts. Moreover, a g.2051delC in exon 14 was identified in the proband of Paraguayan ancestry with clinical features of homozygous FH. The mutation identified in the South American patient represents the first description of a variant in South American patients other than Brazilian FH patients. The 5 mutations identified in the Sicilian patients confirm the heterogeneity of LDL-R gene mutations in Sicily.

Sialic acid as a protective barrier against neointima development.

Arterial sialic acid (SA) has been shown to attenuate the binding of fibrinogen and low-density lipoproteins (LDL) to the vessel wall, presumably protecting against atherosclerosis. This study was aimed to assess the effect of changes in SA content in intimal thickening, an early step in the development of atherosclerosis. New Zealand white rabbits were subjected to bilateral carotid periarterial collaring, followed by in situ-perfusion with neuroaminidase (random artery) and with vehicle (contralateral control artery). The efficiency of SA removal was evaluated in perfusates and arterial homogenates, and arterial tissue samples were obtained 7 and 14 days after the intervention to assess morphological changes. Neuraminidase significantly reduced SA by 16.7%. Arterial desialylation was associated with a significantly increased neointimal formation. Proliferation of smooth muscle cells (SMCs), assessed by incorporation of bromo-2'-deoxyuridine into replicating DNA was also significantly increased in desialylated arteries. In addition, immunohistochemical studies showed a slightly stronger oxidized-LDL (ox-LDL) immunostaining in neointima of desialylated arteries than in control vessels. A mild reduction of SA increases intimal thickening, at least partly due to an enhanced proliferation of SMCs, and may facilitate the accretion of atherogenic lipoproteins, providing evidence for the potential role of SA in the protection against neointimal development.

Cardiomyocytes of chronically ischemic pig hearts express the MDR-1 gene-encoded P-glycoprotein.

The multidrug-resistant (MDR)-1 gene-encoded P-glycoprotein (Pgp-170) is not normally present in the cardiomyocyte. Given that in other tissues Pgp-170 is not found under normoxic conditions but is expressed during hypoxia, we searched for Pgp-170 in chronically ischemic porcine cardiomyocytes. Pgp-170 was detected and localized via immunohistochemistry in ischemic and nonischemic cardiomyocytes of eight adult pigs 8 weeks after placement of an Ameroid constrictor at the origin of the left circumflex artery (Cx). Regional myocardial ischemia in the Cx bed was documented with nuclear perfusion scans. Pgp-170 mass was quantified using Western blot analysis. In all pigs, Pgp-170 was consistently present in the sarcolemma and T invaginations of the cardiomyocytes of the ischemic zone. Pgp-170 expression decreased toward the border of the ischemic zone and was negative in nonischemic regions as well as in the myocardium of sham-operated animals. Western blot analysis yielded significantly higher Pgp-170 mass in ischemic than in nonischemic areas. We conclude that Pgp-170 is consistently expressed in the cardiomyocytes of chronically ischemic porcine myocardium. Its role in the ischemic heart as well as in conditions such as myocardial hibernation, stunning, and preconditioning may have potentially relevant clinical implications and merits further investigation.

Reducción del tamaño del infarto de miocardio mediante la transferencia génica de VEGF en ovejas / Myocardial infarct size reduction after VEGF gene transfer in sheep

La transferencia génica de plásmido codificante para VEGF (pVEGF) induce angiogénesis, incremento del índice mitótico e hiperplasia miocítica en cerdos con isquemia miocárdica crónica. El presente trabajo se realizó con el objetivo de estudiar el efecto del pVEGF sobre el tamaño del infarto de miocardio. Una hora después de la ligadura de la descendente anterior, 28 ovejas de 23 ± 0,5 kg se agruparon al azar para recibir 10 inyecciones intramiocárdicas de 3,8 mg de pVEGF (n = 14) o placebo (n= 14) distribuídas en la periferia del infarto. La función miocárdica se estudió con SPECT gatillado y los animales se sacrificaron 7, 10 y 15 días después del tratamiento. El tamaño del infarto fue el 34 por ciento menor en el grupo tratado que en el placebo (placebo: 17,1 ± 2,1 por ciento, VEGF: 11,2 ± 1,5 por ciento, p < 0,05) a los 15 pero no a los 10 días. Aunque hubo una leve tendencia a favor del grupo tratado, la mejoría de la función miocárdica no fue diferente entre grupos (placebo: 3,3 ± 1,4; VEGF: 3,8 ± 2,4; p = NS). El estudio histológico mostró que los mecanismos involucrados fueron la respuesta angiogénica a los 7 días (placebo: 676 ± 31 capilares / mm²: VEGF: 1925 ± 262; p <0,05), la menor fibrosis periinfarto a los 10 días (contenido de colágeno; placebo: 70, 1 ± 1,7 por ciento; VEGF: 43,5 ± 4,4 por ciento; p < 0,05); la proliferación de mioblastos a los 7 y 10 días. La expresión del pVEGF fue positiva a los 3 (ARNm), 7 y 10 días. La expresión del pVEGF fue positiva a los 3 (ARNm), 7 y 10 días (proteína) posadministración. Conclusión: A los 15 días la transferencia génica de VEGF humano reduce el tamaño de infarto en ovejas mediante angiogénesis, disminución de la fibrosis e inducción de proliferación de mioblastos (miocardiogénesis). (AU)

Reducción del tamaño del infarto de miocardio mediante la transferencia génica de VEGF en ovejas / Myocardial infarct size reduction after VEGF gene transfer in sheep

La transferencia génica de plásmido codificante para VEGF (pVEGF) induce angiogénesis, incremento del índice mitótico e hiperplasia miocítica en cerdos con isquemia miocárdica crónica. El presente trabajo se realizó con el objetivo de estudiar el efecto del pVEGF sobre el tamaño del infarto de miocardio. Una hora después de la ligadura de la descendente anterior, 28 ovejas de 23 ± 0,5 kg se agruparon al azar para recibir 10 inyecciones intramiocárdicas de 3,8 mg de pVEGF (n = 14) o placebo (n= 14) distribuídas en la periferia del infarto. La función miocárdica se estudió con SPECT gatillado y los animales se sacrificaron 7, 10 y 15 días después del tratamiento. El tamaño del infarto fue el 34 por ciento menor en el grupo tratado que en el placebo (placebo: 17,1 ± 2,1 por ciento, VEGF: 11,2 ± 1,5 por ciento, p < 0,05) a los 15 pero no a los 10 días. Aunque hubo una leve tendencia a favor del grupo tratado, la mejoría de la función miocárdica no fue diferente entre grupos (placebo: 3,3 ± 1,4; VEGF: 3,8 ± 2,4; p = NS). El estudio histológico mostró que los mecanismos involucrados fueron la respuesta angiogénica a los 7 días (placebo: 676 ± 31 capilares / mm²: VEGF: 1925 ± 262; p <0,05), la menor fibrosis periinfarto a los 10 días (contenido de colágeno; placebo: 70, 1 ± 1,7 por ciento; VEGF: 43,5 ± 4,4 por ciento; p < 0,05); la proliferación de mioblastos a los 7 y 10 días. La expresión del pVEGF fue positiva a los 3 (ARNm), 7 y 10 días. La expresión del pVEGF fue positiva a los 3 (ARNm), 7 y 10 días (proteína) posadministración. Conclusión: A los 15 días la transferencia génica de VEGF humano reduce el tamaño de infarto en ovejas mediante angiogénesis, disminución de la fibrosis e inducción de proliferación de mioblastos (miocardiogénesis).

Hyperhomocysteinemia induces renal hemodynamic dysfunction: is nitric oxide involved?

Hyperhomocysteinemia is associated with endothelial dysfunction, although the underlying mechanism is unknown. Previous studies have shown that nitric oxide (NO) plays an important role in the regulation of systemic and renal hemodynamics. This study investigated whether hyperhomocysteinemia induces renal oxidative stress and promotes renal dysfunction involving disturbances of the NO-pathway in Wistar rats. During 8 wk, control (C) and hyperhomocysteinemic (HYC) groups had free access to tap water and homocysteine-thiolactone (HTL, 50 mg/kg per d), respectively. At 8 wk, plasma homocysteine concentration, renal superoxide anion (O(2)), nitrotyrosine, and nitrite+nitrate levels, and renal function were measured. To assess NO involvement, the responses to L-Arginine (L-Arg, 300 mg/kg) and N(G)-nitro-L-arginine-methyl-ester (L-NAME, 20 microg/kg per min for 60 min) were analyzed. The HYC group showed higher homocysteine concentration (7.6 +/- 1.7 versus 4.9 +/- 1.0 micromol/L; P < 0.001), (O(2) production (157.92 +/- 74.46 versus 91.17 +/- 29.03 cpm. 10(3)/mg protein), and nitrite+nitrate levels (33.4 +/- 5.1 versus 11.7 +/- 4.3 micro mol/mg protein; P < 0.001) than the control group. Western blot analyses showed a nitrotyrosine mass 46% higher in the HYC group than in the controls. Furthermore, the HYC group showed lower GFR, renal plasma flow (RPF), and higher renal vascular resistance (RVR) than the controls. After L-Arg administration, the responses of GFR, RPF, and RVR were attenuated by 36%, 40%, and 50%, respectively; after L-NAME, the responses of RPF and RVR were exaggerated by 79% and 112%, respectively. This suggests a reduced NO bioavailability to produce vasodilation and an enhanced sensitivity to NO inhibition. In conclusion, hyperhomocysteinemia induces oxidative stress, NO inactivation, and renal dysfunction involving disturbances on the NO-pathway.

Aterosclerosis subclínica: un índice objetivo de susceptibilidad y riesgo vascular / Subclinic atherosclerosis: an objective index of susceptibility and vascular risk

La observación clínica indica que la susceptibilidad de cada sujeto a desarrollar aterosclerosis no depende exclusivamente de su exposición a los FRV clásicos o "emergentes". Aunque recientes investigaciones con animales transgénicos sugieren la existencia de condicionantes genéticos adicionales, la situación en el humano es menos conocida. Si bien es posible que el proyecto genoma humano permita identificar marcadores específicos, hasta el presente el presente la única manera concreta y precoz de distinguir al sujeto susceptible es la detección no invasiva de aterosclerosis. La exploración de vasos superficiales por ecotomografía de alta resolución acoplada a métodos apropriados de procesamiento de imágenes permite realizar una evaluación cuali y cuantitativa altamente reproducible de las lesiones arteriales, desde sus etapas más tempranas. El método adquiere singular relevada clínica por el valor adicional de la detección de aterosclerosis silente para la predicción del riesgo vascular global, un índice que influye significativamente en la toma de decisiones médicas. Es presumible que la inclusión de los resultados de este tipo de estudios en la recategorización del riesgo vascular de sujetos asintomáticos permita dirigir las intervenciones de prevención primaria de una manera más racional y reducir su relación costo/beneficio. (AU)

Aterosclerosis subclínica: un índice objetivo de susceptibilidad y riesgo vascular / Subclinic atherosclerosis: an objective index of susceptibility and vascular risk

La observación clínica indica que la susceptibilidad de cada sujeto a desarrollar aterosclerosis no depende exclusivamente de su exposición a los FRV clásicos o "emergentes". Aunque recientes investigaciones con animales transgénicos sugieren la existencia de condicionantes genéticos adicionales, la situación en el humano es menos conocida. Si bien es posible que el proyecto genoma humano permita identificar marcadores específicos, hasta el presente el presente la única manera concreta y precoz de distinguir al sujeto susceptible es la detección no invasiva de aterosclerosis. La exploración de vasos superficiales por ecotomografía de alta resolución acoplada a métodos apropriados de procesamiento de imágenes permite realizar una evaluación cuali y cuantitativa altamente reproducible de las lesiones arteriales, desde sus etapas más tempranas. El método adquiere singular relevada clínica por el valor adicional de la detección de aterosclerosis silente para la predicción del riesgo vascular global, un índice que influye significativamente en la toma de decisiones médicas. Es presumible que la inclusión de los resultados de este tipo de estudios en la recategorización del riesgo vascular de sujetos asintomáticos permita dirigir las intervenciones de prevención primaria de una manera más racional y reducir su relación costo/beneficio.

Lipoproteína (a) y riesgo de enfermedad coronaria en hombres hipercolesterolémicos / Lipoprotein (a) as a risk factor for coronary heart disease in hypercholesterolemic men

La Lp(a) es una partícula con capacidad aterogénica que ha sido indicada, con resultados contradictorios, como factor de riesgo coronario. En el presente estudio fueron incluídos 121 hombres con hiperlipidemia severa (valores de colesterol > 30 mg/dl), de los cuales 66 tuvieron evidencias de enfermedad coronaria, y un grupo control de 55 hombres. Se realizó un análisis multivariado con regresión logística, incluyendo las siguientes variables: edad, colesterol, HDL-colesterol, triglicéridos, Lp(a). Los resultados del presente estudio sugieren que la Lp(a) es un parámetro de riesgo independiente en hombres con hiperlipidemia severa, por lo cual su determinación permitiría seleccionar entre los sujetos hiperlipidémicos un subgrupo con mayor riesgo de enfermedad coronaria (AU)

Lipoproteína (a) y riesgo de enfermedad coronaria en hombres hipercolesterolémicos / Lipoprotein (a) as a risk factor for coronary heart disease in hypercholesterolemic men

La Lp(a) es una partícula con capacidad aterogénica que ha sido indicada, con resultados contradictorios, como factor de riesgo coronario. En el presente estudio fueron incluídos 121 hombres con hiperlipidemia severa (valores de colesterol > 30 mg/dl), de los cuales 66 tuvieron evidencias de enfermedad coronaria, y un grupo control de 55 hombres. Se realizó un análisis multivariado con regresión logística, incluyendo las siguientes variables: edad, colesterol, HDL-colesterol, triglicéridos, Lp(a). Los resultados del presente estudio sugieren que la Lp(a) es un parámetro de riesgo independiente en hombres con hiperlipidemia severa, por lo cual su determinación permitiría seleccionar entre los sujetos hiperlipidémicos un subgrupo con mayor riesgo de enfermedad coronaria

Reproducibilidad de la cuantificacion de la sensibilidad a la accion insulinica con el modelo minimo y comparacion con un test de tolerancia a bajas dosis de insulina / Repeatibility of insulin sensitivity estimation using the Minimal Model and comparison with a modified short low-dose insulin tolerance test

La hiperinsulinemia y la insulino-resistencia son disturbios metabólicos associados a obesidad central, hipertensión arterial, hipertrigliceridemia, sindrome polimetabólico, intolerancia a la glucosa y enfermedad aterosclerótica. La evaluación de los cambios en la sensibilidad a la acción insulínica in vivo (SAI in vivo) inducidos por intervenciones higiénico-dietéticas o farmacológicas requieren una técnica de adecuada reproducibilidad. En el presente estudio fue evaluada la reproducibilidad intra-individual de la SAI in vivo expresada como SI (par metro determinado utilizando el Modelo Mínimo de Bergman modificado con insulina [MMins]), em 11 sujetos con un amplio rango de SAI in vivo. SI (primer estudio) varió entre 0,82 y 8,48 x 10(-4) min(-1)/muU.mL (4,43 + 2,85 x 10(-4) min(-1)/muU.ml; média + DS) y presentó una correlación altamente significativa con SI (segundo estudio) (r = 0,89; p = 0,0002). El coeficiente de variación medio fue del 20,9 + 13,9 por ciento). La SAI in vivo fue também determinada analizando la tasa de caída de los niveles de glucemia luego del suministro IV de 0,025 U/kg de insulina cristalina humana (método de Bonora modificado o BBD), en 11 sujetos. La SAI in vivo determinada por BBD varió entre 21 y 234 mumol/ml/min (134 + 64,8 mumol/ml/min, média + DS). No se observaron hipoglucemias durante los estudios. La correlación entre los valores de SI obtenidos del MMins y los resultados del BBD fue altamente significativa ( r= 0,89, p = 0,0002). Los resultados del presente trabajo sugieren que el MMins tiene una adecuada reproducibilidad intra-sujeto y que el BBD constituye una medida aproximada de la SAI in vivo siendo particularmente aplicable cuando es necesaria la practica de un procedimiento de r pida ejecución y menor complejidad y costo. (AU)

Reproducibilidad de la cuantificacion de la sensibilidad a la accion insulinica con el modelo minimo y comparacion con un test de tolerancia a bajas dosis de insulina / Repeatibility of insulin sensitivity estimation using the Minimal Model and comparison with a modified short low-dose insulin tolerance test

La hiperinsulinemia y la insulino-resistencia son disturbios metabólicos associados a obesidad central, hipertensión arterial, hipertrigliceridemia, sindrome polimetabólico, intolerancia a la glucosa y enfermedad aterosclerótica. La evaluación de los cambios en la sensibilidad a la acción insulínica in vivo (SAI in vivo) inducidos por intervenciones higiénico-dietéticas o farmacológicas requieren una técnica de adecuada reproducibilidad. En el presente estudio fue evaluada la reproducibilidad intra-individual de la SAI in vivo expresada como SI (par metro determinado utilizando el Modelo Mínimo de Bergman modificado con insulina [MMins]), em 11 sujetos con un amplio rango de SAI in vivo. SI (primer estudio) varió entre 0,82 y 8,48 x 10(-4) min(-1)/muU.mL (4,43 + 2,85 x 10(-4) min(-1)/muU.ml; média + DS) y presentó una correlación altamente significativa con SI (segundo estudio) (r = 0,89; p = 0,0002). El coeficiente de variación medio fue del 20,9 + 13,9 por ciento). La SAI in vivo fue também determinada analizando la tasa de caída de los niveles de glucemia luego del suministro IV de 0,025 U/kg de insulina cristalina humana (método de Bonora modificado o BBD), en 11 sujetos. La SAI in vivo determinada por BBD varió entre 21 y 234 mumol/ml/min (134 + 64,8 mumol/ml/min, média + DS). No se observaron hipoglucemias durante los estudios. La correlación entre los valores de SI obtenidos del MMins y los resultados del BBD fue altamente significativa ( r= 0,89, p = 0,0002). Los resultados del presente trabajo sugieren que el MMins tiene una adecuada reproducibilidad intra-sujeto y que el BBD constituye una medida aproximada de la SAI in vivo siendo particularmente aplicable cuando es necesaria la practica de un procedimiento de r pida ejecución y menor complejidad y costo.