Abstract-Thyrotropin-releasing hormone (TRH) plays an important role in central cardiovascular regulation. Recently, we described that the TRH precursor gene overexpression induces hypertension in the normal rat. In addition, we published that spontaneously hypertensive rats (SHR) have central extrahypothalamic TRH hyperactivity with increased TRH synthesis and release and an elevated TRH receptor number. In the present study, we report that intracerebroventricular antisense (AS) treatment with a phosphorothioate oligonucleotide against the TRH precursor gene significantly diminished up to 72 hours and in a dose-dependent manner the increased diencephalic TRH content, whereas normalized systolic blood pressure (SABP) was present in the SHR compared with Wistar-Kyoto (WKY) rats. Although basal thyrotropin was higher in SHR compared with WKY rats and this difference disappeared after antisense treatment, no differences were observed in plasma T4 or T3 between strains with or without AS treatment, indicating that the effect of the AS on SABP was independent of the thyroid status. Because the encephalic renin-angiotensin system seems to be crucial in the development and/or maintenance of hypertension in SHR, we investigated the effect of antisense inhibition of TRH on that system and found that TRH antisense treatment significantly diminished the elevated diencephalic angiotensin II (Ang II) content in the SHR without any effect in control animals, suggesting that the Ang II system is involved in the TRH cardiovascular effects. To summarize, the central TRH system seems to be involved in the etiopathogenesis of hypertension in this model of essential hypertension. Key Words: angiotensin II Ⅲ antisense Ⅲ blood pressure Ⅲ hypertension Ⅲ SHR Ⅲ thyroid hormones Ⅲ TRH Ⅲ TSH I n addition to its endocrine function, thyrotropin-releasing hormone (TRH; pyro-Glu-His-Pro-amide) also serves as a neurotransmitter in the central nervous system. 1 TRH immunoreactivity is widely distributed throughout the central nervous system, including the brain and spinal cord. 2 Although the lack of antagonists to the TRH receptor has made difficult to determine the physiological role for the extrahypothalamic TRH system, its presence in brain nuclei involved in cardiovascular regulation, such as the periventricular region and the preoptic area, suggests that this tripeptide may modulate the cardiovascular function. 3 In fact, many groups have described that brain microinjections of TRH produce dose-dependent pressor effects. 4 Recently, we have reported that the overexpression of the TRH precursor in the third ventricle of the central nervous system of normal rats induces a long-lasting elevation of arterial blood pressure along with an increase in the diencephalic TRH content in a dose-dependent manner. These effects were specifically reversed by an antisense treatment, indicating that the extrahypothalamic TRH system effectively participates in cardiovascular regulation in the rat. 5 Spontaneously hypertensive rats (SHR) have been extensive...

In addition to the angiotensin-converting enzyme (ACE) and angiotensinogen (AGT) gene variants, gene-gene interactions may be important causative factors in a complex disease such as young-onset essential hypertension.

Extrahypothalamic TRH participates in cardiovascular regulation and spontaneous hypertension of the rat. To investigate whether an increase in central TRH activity produces hypertension we studied the effect of the preTRH overproduction induced by ICV transfection with a naked eukaryotic expression plasmid vector which encodes preTRH (pCMV-TRH). Northern blot analysis and RT-PCR showed that pCMV-TRH was transcribed in vitro and in vivo. At 24, 48, and 72 hours, pCMV-TRH (100 μg) in a significant and dose-dependent manner increased 37%, 84%, and 49%, respectively, the diencephalic TRH content and SABP (42±3, 50±2, and 22±2 mm Hg, respectively) with respect to the vector without the preTRH cDNA insert (V TRH(− ) ) as measured by RIA and the plethysmographic method, respectively, in awake animals. In addition, using immunohistochemistry we found that the increase of TRH was produced in circumventricular areas where the tripeptide is normally located. To further analyze the specificity of these effects we studied the actions of 23-mer sense (S), antisense (AS), and 3’self-stabilized sense (Ss) and antisense (ASs) phosphorothioate oligonucleotides against the initiation codon region. Only ASs inhibited the increase of TRH content and SABP induced by pCMV-TRH treatment. In addition, pCMV-TRH-induced hypertension seems not to be mediated by central Ang II or serum TSH. To summarize, central TRH overproduction in periventricular areas induced by ICV transfection pro-duces hypertension in rats which is reversed by specific antisense treatment. This model may help in testing effective antisense oligodeoxynucleotides against other candidate genes.

Obesity and hypertension are increasing medical problems in adolescents. We evaluated the association between being overweight-particularly abdominal fat-and having hypertension and assessed the contribution of the Trp64Arg ␤ 3 -adrenergic receptor gene variant. In a population-based study, we determined family history, anthropometric variables, and arterial blood pressure of 934 high school students, out of whom we selected 121 normotensive and 54 hypertensive students. Biochemical measurements included circulating renin and angiotensin-converting enzyme activities, leptin, glucose, insulin and lipid levels, and ␤ 3 -adrenergic receptor genotypes. We used Mann-Whitney U test, 2 -test, and Spearman rank-order correlation. In the total population, hypertension prevalence increased across the entire range of body mass index (BMI) percentiles. In the sample, hypertensive students showed higher BMI, waist-tohip ratio, triglycerides, and insulin resistance and lower HDLcholesterol than normotensive students did. Age-and sexadjusted systolic arterial blood pressure was correlated with BMI, waist-to-hip ratio, insulin resistance, and leptin. Leptin was correlated with BMI and homeostasis model assessment method.We found no association among hypertension, BMI, and leptin levels with ␤ 3 -adrenergic receptor genotypes. Especially in girls, the waist-to-hip ratio was, however, suggestively higher in Arg64 variant carriers than in noncarriers, independent of hypertension. In fact, there was a significantly (p Ͻ 0.01) higher frequency of carriers of the Arg64 variant across the waist-to-hip ratio quartiles. In adolescents of European origin, hypertension is associated with an increased degree of obesity among other characteristics of the metabolic syndrome; the Trp64Arg variant of the ␤ 3 -adrenergic receptor gene may favor the central adiposity gain. In many countries, last century's developments have led to lifestyle alterations characterized by increased caloric and fat intakes and reduction in physical activity along with a dramatic increase in metabolic syndrome-related diseases such as diabetes, dyslipidemias, hypertension, and obesity. Accordingly, obesity has become an important health problem in children and adolescents. Many of the above-mentioned outcomes associated with obesity-hypertension, type 2 diabetes mellitus, dyslipidemia, left ventricular hypertrophy, nonalcoholic steatohepatitis, obstructive sleep apnea, and orthopedic problems that were previously thought of as adults' diseases-are now affecting children as well (1). Although prevention would be an optimum strategy, it may be difficult to identify children at risk of obesity and its comorbidities before they become overweight. Obesity is a complex disorder determined by an interplay of both environmental and genetic factors (2). The ␤ 3 AR is expressed in adipose tissue as an important lipolysis regulator, and a variant in this gene resulting from a substitution of arginine for tryptophan at codon 64 (Trp64Arg) has been identified (3-5). This allele s...

Our objective was to search for differences in genotypes of peroxisome proliferator-activated receptor gamma (PPAR ) (Pro12 Ala) and its coactivator PGC-1 (Gly482 Ser) in adolescents harboring features of metabolic syndrome. In a population-based study, we determined medical history, anthropometric variables, biochemical measurements and arterial blood pressures of 934 high-school students of Caucasian origin. We selected 220 adolescents who had systolic or diastolic blood pressures more than the 80th or less than the 20th percentiles based on the previous single set of measurements. One hundred and seventy-five adolescents completed the study and underwent two additional blood pressure measurements on different days, as well as biochemical analysis and genotyping. We found no association between insulin resistance, body mass index (BMI) and leptin levels and PPAR and PGC-1 genotypes. The 12 Ala PPAR allele was associated with increased waist-to-hip ratio (WHR) and carriers seemed to have higher diastolic blood pressure and lower pulse pressure than non-carriers, particularly in the hypertensive and overweight group. Although Ser482 Ser PGC-1 homozygotes had lower WHRs than other PGC-1 genotypes, they were more frequent in the hypertensive group than in the normotensive (44·4 vs 24·5%, P,0·03), so the 482 Ser PGC-1 allele was in our population a risk factor for hypertension independently of WHR, homeostasis model assessment of insulin resistance, BMI and Pro12 Ala PPAR variant (odds ratio=4·0, 95% confidence interval 1·5-10·6, P,0·01). Multiple regression analysis showed that age-and sex-adjusted systolic blood pressure correlated with the 482 Ser PGC-1 allele regardless of those covariates. In conclusion, the Gly482 Ser variant of the PGC-1 gene may be an independent genetic risk factor for young-onset hypertension.

Abstract-Leptin, an adipocyte-released hormone, modifies food intake and energy expenditure regulating hypothalamicpituitary-thyroid axis function. We previously reported that thyrotropin-releasing hormone (TRH) precursor gene overexpression induces hypertension in the normal rat and that spontaneously hypertensive rats have central TRH hyperactivity with increased TRH synthesis and release and an elevated TRH receptor number. In both models, intracerebroventricular antisense (AS) treatment against the TRH precursor produced a dose-dependent reduction of the increased diencephalic TRH content while normalizing high arterial blood pressure. In this article, we report that male Wistar rats that were made hypertensive by intracerebroventricular injection of a eucaryotic expression plasmid containing the pre-TRH cDNA showed decreased leptin plasma levels and that pre-TRH AS treatment reversed this phenomenon. In addition, male and female spontaneously hypertensive rats showed lower levels of circulating leptin than did sex-matched Wistar-Kyoto control rats. This difference also was abated by the pre-TRH AS treatment. Conversely, 20 g ICV leptin induced a long-lasting pressor effect (18Ϯ5 mm Hg, nϭ6, PϽ0.01, Ͼ60 minutes) that was not observed in pre-TRH AS pretreated rats (2Ϯ3 mm Hg, nϭ6) but persisted in rats used as controls that were treated with inverted oligonucleotide (20Ϯ6 mm Hg, nϭ4, PϽ0.01). These data suggest that in rats with TRH-induced hypertension, leptin is decreased, inducing compensatory adiposity. We propose that because leptin produces central TRH synthesis and release, obesity may induce hypertension through TRH system activation and that the TRH-leptin interaction may thus contribute to the strong association between hypertension and obesity. Key Words: antisense elements Ⅲ blood pressure Ⅲ hypertension, obesity Ⅲ hormones Ⅲ rats, spontaneously hypertensive O besity is a major risk factor for essential hypertension. Conversely, hypertensive patients tend to be more obese than do normotensive people. 1,2 Weight reduction is an effective way to decrease arterial blood pressure (ABP) in obese hypertensive patients, suggesting an important association between weight and ABP homeostasis. 3 The cumulative body of evidence also suggests that obesity-induced hypertension may be due to an increased sympathetic outflow, among other factors. 4 The mechanisms of this association are poorly understood, however.Leptin is an adipocyte-derived hormone that is involved in the regulation of food intake and body weight, with the hypothalamus being a primary target of its action. 5 In addition, leptin effects include an increase in overall sympathetic activity. 6 As Ahima et al. 7 reported, leptin also counteracts the starvation-induced suppression of thyroid hormone, apparently by upregulating the expression of the thyrotropin-releasing hormone (TRH; pyro-Glu-His-Proamide) precursor gene.Besides its endocrine function, TRH also serves as a neurotransmitter in the central nervous system, and its presence in brain nu...

Abstract-In essential hypertension, a polygenic and multifactorial syndrome, several genes interact with the environment to produce high blood pressure. Thyrotropin-releasing hormone (TRH) plays an important role in central cardiovascular regulation. We have described that TRH overexpression induces hypertension in a normal rat, which was reversed by TRH antisense treatment. This treatment also reduces the central TRH hyperactivity in spontaneously hypertensive rats and normalizes blood pressure. Human TRH receptor (TRHR) belongs to the G protein-coupled seven-transmembrane domain receptor superfamily. Mutations of these receptors may result in constitutive activation. As it has been demonstrated that hypertensive patients have a blunted TSH response to TRH injection, suggesting a defect in the TRHR, we postulate that the TRHR gene is involved in human hypertension. We studied 2 independent populations from different geographic regions of our country: a sample of adult subjects from a referral clinic and a population-based sample of high school students. In search of molecular variants of TRHR, we disclosed that a polymorphic TG dinucleotide repeat (STR) at Ϫ68 bp and a novel single nucleotide polymorphism, a G3 C conversion at Ϫ221 located in the promoter of the TRHR are associated with essential hypertension. As STRs detected in gene promoters are potential Z-DNA-forming sequences and seem to affect gene expression, we studied the potentially different transcriptional activity of these TRHR promoter variants and found that the S/Ϫ221C allele has a higher affinity than does the L/GϪ221 allele to nuclear protein factor(s Key Words: epidemiology Ⅲ genes Ⅲ hypertension, essential Ⅲ hormone Ⅲ thyroliberin Ⅲ receptor T hyrotropin-releasing hormone (TRH), a small neuropeptide (p-Glu-His-Pro-NH 2 ) initially identified in the hypothalamus, which stimulates the synthesis and secretion of thyroid-stimulating hormone (TSH) and prolactin, 1 was shown to be amply distributed in the central nervous system. 2 TRH participates in central cardiovascular regulation, producing dose-dependent pressor effects. 3 We have reported that central overexpression of the TRH precursor in normal rats induces a long-lasting elevation of arterial blood pressure along with an increase in the diencephalic TRH content in a dose-dependent manner. These effects were specifically reversed by an antisense treatment. 4 In addition, spontaneously hypertensive rats (SHR) show a supersensitivity to the hypertensive effects of exogenous TRH 5 and present a pre-and postsynaptic hyperactivity of the extrahypothalamic TRH system. 6 . Accordingly, we also recently reported that a specific intracerebroventricular antisense treatment against the initiation translation codon region of the TRH precursor gene diminished both effects, the augmented TRH content and the increased systolic blood pressure, in a dose-dependent manner, independent of the thyroid status. 7 These results indicated that the central TRH system participates in the development or maintenance...

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