Self-rated health scores predict mortality among people with type 2 diabetes differently across three different country groupings: findings from the ADVANCE and ADVANCE-ON trials.

AIMS: To explore whether there is a different strength of association between self-rated health and all-cause mortality in people with type 2 diabetes across three country groupings: nine countries grouped together as 'established market economies'; Asia; and Eastern Europe. METHODS: The ADVANCE trial and its post-trial follow-up were used in this study, which included 11 140 people with type 2 diabetes from 20 countries, with a median follow-up of 9.9 years. Self-rated health was reported on a 0-100 visual analogue scale. Cox proportional hazard models were fitted to estimate the relationship between the visual analogue scale score and all-cause mortality, controlling for a range of demographic and clinical risk factors. Interaction terms were used to assess whether the association between the visual analogue scale score and mortality varied across country groupings. RESULTS: The visual analogue scale score had different strengths of association with mortality in the three country groupings. A 10-point increase in visual analogue scale score was associated with a 15% (95% CI 12-18) lower mortality hazard in the established market economies, a 25% (95% CI 21-28) lower hazard in Asia, and an 8% (95% CI 3-13) lower hazard in Eastern Europe. CONCLUSIONS: Self-rated health appears to predict 10-year all-cause mortality for people with type 2 diabetes worldwide, but this relationship varies across groups of countries.

Involvement of human monogenic cardiomyopathy genes in experimental polygenic cardiac hypertrophy.

Hypertrophic cardiomyopathy thickens heart muscles, reducing functionality and increasing risk of cardiac disease and morbidity. Genetic factors are involved, but their contribution is poorly understood. We used the hypertrophic heart rat (HHR), a unique normotensive polygenic model of cardiac hypertrophy and heart failure, to investigate the role of genes associated with monogenic human cardiomyopathy. We selected 42 genes involved in monogenic human cardiomyopathies to study: 1) DNA variants, by sequencing the whole genome of 13-wk-old HHR and age-matched normal heart rat (NHR), its genetic control strain; 2) mRNA expression, by targeted RNA-sequencing in left ventricles of HHR and NHR at 5 ages (2 days old and 4, 13, 33, and 50 wk old) compared with human idiopathic dilated cardiomyopathy data; and 3) microRNA expression, with rat microRNA microarrays in left ventricles of 2-day-old HHR and age-matched NHR. We also investigated experimentally validated microRNA-mRNA interactions. Whole-genome sequencing revealed unique variants mostly located in noncoding regions of HHR and NHR. We found 29 genes differentially expressed in at least 1 age. Genes encoding desmoglein 2 ( Dsg2) and transthyretin ( Ttr) were significantly differentially expressed at all ages in the HHR, but only Ttr was also differentially expressed in human idiopathic cardiomyopathy. Lastly, only two microRNAs differentially expressed in the HHR were present in our comparison of validated microRNA-mRNA interactions. These two microRNAs interact with five of the genes studied. Our study shows that genes involved in monogenic forms of human cardiomyopathies may also influence polygenic forms of the disease.

The influence of physical activity on vascular complications and mortality in patients with type 2 diabetes mellitus.

AIMS: There is limited evidence regarding the association between physical activity and vascular complications, particularly microvascular disease, in patients with type 2 diabetes. METHODS: From the 11 140 patients in the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron modified release Controlled Evaluation) trial, the effect of physical activity, categorized as none, mild, moderate or vigorous, and the number of sessions within a week, was examined in multivariable regression models adjusted for potential confounders. The study end-points were major cardiovascular events, microvascular complications and all-cause mortality. RESULTS: Forty-six percent of participants reported undertaking moderate to vigorous physical activity for >15 min at least once in the previous week. During a median of 5 years of follow-up, 1031 patients died, 1147 experienced a major cardiovascular event and 1136 a microvascular event. Compared to patients who undertook no or mild physical activity, those reporting moderate to vigorous activity had a decreased risk of cardiovascular events (HR: 0.78, 95% CI: 0.69-0.88, p < 0.0001), microvascular events (HR: 0.85, 95% CI: 0.76-0.96, p = 0.010) and all-cause mortality (HR: 0.83, 95% CI: 0.73-0.94, p = 0.0044). CONCLUSIONS: Moderate to vigorous, but not mild, physical activity is associated with a reduced incidence of cardiovascular events, microvascular complications and all-cause mortality in patients with type 2 diabetes.

Association of HbA1c levels with vascular complications and death in patients with type 2 diabetes: evidence of glycaemic thresholds.

AIMS/HYPOTHESIS: There is conflicting evidence regarding appropriate glycaemic targets for patients with type 2 diabetes. Here, we investigate the relationship between HbA(1c) and the risks of vascular complications and death in such patients. METHODS: Eleven thousand one hundred and forty patients were randomised to intensive or standard glucose control in the Action in Diabetes and Vascular disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. Glycaemic exposure was assessed as the mean of HbA(1c) measurements during follow-up and prior to the first event. Adjusted risks for each HbA(1c) decile were estimated using Cox models. Possible differences in the association between HbA(1c) and risks at different levels of HbA(1c) were explored using linear spline models. RESULTS: There was a non-linear relationship between mean HbA(1c) during follow-up and the risks of macrovascular events, microvascular events and death. Within the range of HbA(1c) studied (5.5-10.5%), there was evidence of 'thresholds', such that below HbA(1c) levels of 7.0% for macrovascular events and death, and 6.5% for microvascular events, there was no significant change in risks (all p > 0.8). Above these thresholds, the risks increased significantly: every 1% higher HbA(1c) level was associated with a 38% higher risk of a macrovascular event, a 40% higher risk of a microvascular event and a 38% higher risk of death (all p < 0.0001). CONCLUSIONS/INTERPRETATION: In patients with type 2 diabetes, HbA(1c) levels were associated with lower risks of macrovascular events and death down to a threshold of 7.0% and microvascular events down to a threshold of 6.5%. There was no evidence of lower risks below these levels but neither was there clear evidence of harm.

Susceptibility variants on chromosome 7p21.1 suggest HDAC9 as a new candidate gene for male-pattern baldness.

BACKGROUND: Male-pattern baldness (androgenetic alopecia, AGA) is the most common form of hair loss among humans. Research has shown that it is caused by genetic factors. Numerous studies have unequivocally identified two major genetic risk loci for AGA: the X-chromosomal AR/EDA2R locus, and the PAX1/FOXA2 locus on chromosome 20. OBJECTIVES: To identify further candidate genes for AGA, and thus gain further insights into this phenotype. METHODS: A German sample of 581 severely affected cases and 617 controls was used to perform a genome-wide association study. The identified associated locus was further analysed by fine-mapping, and then independently replicated in an Australian sample. Expression and pathway analyses were performed to characterize the susceptibility gene identified. RESULTS: The most significant association signal was obtained for rs756853 (P = 1·64 × 10(-7) ), which is located intronically in the histone deacetylase 9 (HDAC9) gene. Fine-mapping and a family-based analysis revealed that rs756853 and the 6-kb distal rs2249817 were the most highly associated single nucleotide polymorphisms. The association finding was replicated in an independent Australian sample, when the analysis was restricted to severely affected cases and unaffected controls (P = 0·026). Analysis of rs2249817 in a combined sample of severely affected German and Australian cases and unaffected controls revealed a strong association signal (P = 9·09 × 10(-8) ). Tissue expression studies demonstrated HDAC9 expression in various tissues, including tissues of relevance to AGA. No strong genotypic effects were observed in genotype-specific expression or splice studies. Pathway analyses supported the hypothesis that HDAC9 plays a functional role in AGA via interaction with the AR gene. CONCLUSIONS: The present study suggests that HDAC9 is the third AGA susceptibility gene.

Association between alcohol consumption and diabetic retinopathy and visual acuity-the AdRem Study.

AIMS: We investigated the association between alcohol consumption and diabetic retinopathy and deterioration of visual acuity in individuals with Type 2 diabetes. METHODS: We conducted a cohort analysis of 1239 participants with Type 2 diabetes aged 55-81 years enrolled in the AdRem study, a sub-study of the Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE) trial. Current and past consumption of wine, spirits and beer was measured by self-report. Moderate and heavy alcohol consumption was defined as 1-14 and >14 drinks/week, respectively. Diabetic retinopathy, measured by mydriatic stereoscopic seven-field retinal photography, was defined by a 2-step progression in the Early Treatment of Diabetic Retinopathy Study (ETDRS) score or the presence of any retinal vascular lesions. Deterioration of visual acuity was defined by a decrease of two lines in best vision in either eye, measured corrected, or through a pinhole using a Snellen chart. RESULTS: In a mean follow-up of 5.5 years, we identified 182 participants with a 2-step progression in the ETDRS score, 640 participants with the presence of any retinal vascular lesions and 693 participants with a deterioration of visual acuity. Current moderate consumption of alcohol, compared with no current consumption, was not associated with presence or progression of diabetic retinopathy; however, it was associated with higher risk of deterioration of visual acuity (multivariable-adjusted OR 1.83; 95% CI 1.34-2.48; P<0.001). CONCLUSIONS: Alcohol consumption is associated with increased risk of deterioration of visual acuity, but not with retinopathy in individuals with Type 2 diabetes.

Gene-wide association study between the aromatase gene (CYP19A1) and female pattern hair loss.

BACKGROUND: Female pattern hair loss (FPHL) is a common trait in which androgens and oestrogens may have a pathogenic role. The aromatase enzyme converts androgens to oestrogens in scalp hair follicles and is differentially expressed in balding and nonbalding scalps of women. Sequence variation in the gene encoding aromatase, CYP19A1, might influence the risk of developing FPHL. OBJECTIVES: To examine the role of CYP19A1 genetic variation in the heritability of FPHL. METHODS: We investigated associations between FPHL and 61 tag single nucleotide polymorphisms (SNPs) representing variation in and around CYP19A1 in 484 caucasian women with grades 3-5 FPHL on the Sinclair scale, and 471 caucasian women with no evidence of hair loss. RESULTS: For the tag SNP rs4646 (overall genotype frequencies: CC, 53.6%; AC, 39.3%; AA, 7.1%), the genotype CC was more frequent in women with FPHL (58.1%) than controls (48.9%) (P = 0.006). Although this result did not achieve experiment-wide significance (P < 0.001 by permutation testing), subanalyses according to sources of recruitment and ages at presentation revealed consistent patterns of association. In particular, young cases (< 40 years) had the highest frequency of the CC genotype (68.2%) among all subgroups. CONCLUSIONS: These findings suggest that the common rs4646 C allele, which has been associated previously with higher circulating oestrogen levels, might be associated with predisposition to FPHL.

Effects of a fixed combination of perindopril and indapamide on macrovascular and microvascular outcomes in patients with type 2 diabetes mellitus (the ADVANCE trial): a randomised controlled trial.

BACKGROUND: Blood pressure is an important determinant of the risks of macrovascular and microvascular complications of type 2 diabetes, and guidelines recommend intensive lowering of blood pressure for diabetic patients with hypertension. We assessed the effects of the routine administration of an angiotensin converting enzyme (ACE) inhibitor-diuretic combination on serious vascular events in patients with diabetes, irrespective of initial blood pressure levels or the use of other blood pressure lowering drugs. METHODS: The trial was done by 215 collaborating centres in 20 countries. After a 6-week active run-in period, 11 140 patients with type 2 diabetes were randomised to treatment with a fixed combination of perindopril and indapamide or matching placebo, in addition to current therapy. The primary endpoints were composites of major macrovascular and microvascular events, defined as death from cardiovascular disease, non-fatal stroke or non-fatal myocardial infarction, and new or worsening renal or diabetic eye disease, and analysis was by intention-to-treat. The macrovascular and microvascular composites were analysed jointly and separately. This trial is registered with ClinicalTrials.gov, number NCT00145925. FINDINGS: After a mean of 4.3 years of follow-up, 73% of those assigned active treatment and 74% of those assigned control remained on randomised treatment. Compared with patients assigned placebo, those assigned active therapy had a mean reduction in systolic blood pressure of 5.6 mm Hg and diastolic blood pressure of 2.2 mm Hg. The relative risk of a major macrovascular or microvascular event was reduced by 9% (861 [15.5%] active vs 938 [16.8%] placebo; hazard ratio 0.91, 95% CI 0.83-1.00, p=0.04). The separate reductions in macrovascular and microvascular events were similar but were not independently significant (macrovascular 0.92; 0.81-1.04, p=0.16; microvascular 0.91; 0.80-1.04, p=0.16). The relative risk of death from cardiovascular disease was reduced by 18% (211 [3.8%] active vs 257 [4.6%] placebo; 0.82, 0.68-0.98, p=0.03) and death from any cause was reduced by 14% (408 [7.3%] active vs 471 [8.5%] placebo; 0.86, 0.75-0.98, p=0.03). There was no evidence that the effects of the study treatment differed by initial blood pressure level or concomitant use of other treatments at baseline. INTERPRETATION: Routine administration of a fixed combination of perindopril and indapamide to patients with type 2 diabetes was well tolerated and reduced the risks of major vascular events, including death. Although the confidence limits were wide, the results suggest that over 5 years, one death due to any cause would be averted among every 79 patients assigned active therapy.

The impact of level of education on vascular events and mortality in patients with type 2 diabetes mellitus: Results from the ADVANCE study.

AIMS: The relationship between educational level and the risk of all-cause mortality is well established, whereas the association with vascular events in individuals with type 2 diabetes is not well described. Any association may reflect a link with common cardiovascular or lifestyle-based risk factors. METHODS: The relationships between the highest level of educational attainment and major cardiovascular events, microvascular complications and all-cause mortality were explored in a cohort of 11,140 individuals with type 2 diabetes. Completion of formal education before the age of 16 was categorized as a low level of education. Regional differences between Asia, East Europe and Established Market Economies were also assessed. RESULTS: During a median of 5years of follow up, 1031 (9%) patients died, 1147 (10%) experienced a major cardiovascular event and 1136 (10%) a microvascular event. After adjustment for baseline characteristics and risk factors, individuals with lower education had an increased risk of cardiovascular events (hazard ratio (HR) 1.31, 95% CI 1.16-1.48, p<0.0001), microvascular events (HR 1.23, 95% CI 1.08-1.39, p=0.0013) and all-cause mortality (HR 1.34, 95% CI 1.18-1.52, p<0.0001). In regional analyses the increased risk of studied outcomes associated with lower education was weakest in Established Market Economies and strongest in East Europe. CONCLUSIONS: A low level of education is associated with an increased risk of vascular events and death in patients with type 2 diabetes, independently of common lifestyle associated cardiovascular risk factors. The effect size varies between geographical regions.

Polymorphism of the androgen receptor gene is associated with male pattern baldness.

The common heritable loss of scalp hair known as male pattern baldness or androgenetic alopecia affects up to 80% of males by age 80. A balding scalp is characterized by high levels of the potent androgen dihydrotestosterone and increased expression of the androgen receptor gene. To determine if the androgen receptor gene is associated with male pattern baldness, we compared allele frequencies of the androgen receptor gene polymorphisms (StuI restriction fragment length polymorphism and two triplet repeat polymorphisms) in cases with cosmetically significant baldness (54 young and 392 older men) and controls (107 older men) with no indication of baldness. The androgen receptor gene StuI restriction site was found in all but one (98.1%) of the 54 young bald men (p = 0.0005) and in 92.3% of older balding men (p = 0.000004) but in only 76.6% of nonbald men. The combination of shorter CAG and GGC triplet repeat lengths was also more prevalent in bald men (p = 0.03). The ubiquity of the androgen receptor gene StuI restriction site, and higher incidence of shorter triplet repeat haplotypes in bald men suggests that these markers are very close to a functional variant that is a necessary component of the polygenic determination of male pattern baldness. Functional mutation in or near the androgen receptor gene may explain the reported high levels of expression of this gene in the balding scalp.

Genetic analysis of male pattern baldness and the 5alpha-reductase genes.

Genetic predisposition and androgen dependence are important characteristics of the common patterned loss of scalp hair known as male pattern baldness. The involvement of the 5alpha-reductase enzyme in male pattern baldness has been postulated due to its role in the metabolism of testosterone to dihydrotestosterone. There are two known isozymes of 5alpha-reductase. Type I has been predominantly localized to the skin and scalp. Type II, also present on the scalp, is the target of finasteride, a promising treatment for male pattern baldness. We conducted genetic association studies of the 5alpha-reductase enzyme genes (SRD5A1 on chromosome 5 and SRD5A2 on chromosome 2) using dimorphic intragenic restriction fragment length polymorphisms. From a population survey of 828 healthy families comprising 3000 individuals, we identified 58 young bald men (aged 18-30 y) and 114 older nonbald men (aged 50-70 y) for a case control comparison. No significant differences were found between cases and controls in allele, genotype, or haplotype frequencies for restriction fragment length polymorphisms of either gene. These findings suggest that the genes encoding the two 5alpha-reductase isoenzymes are not associated with male pattern baldness. Finally, no clear inheritance pattern of male pattern baldness was observed. The relatively strong concordance for baldness between fathers and sons in this study was not consistent with a simple Mendelian autosomal dominant inheritance. A polygenic etiology should be considered.

Genetic analysis of blood pressure and sodium balance in spontaneously hypertensive rats.

Blood pressure and parameters of sodium balance were measured during the first 16 weeks of life in male Okamoto spontaneously hypertensive rats (SHR, n = 22), Wistar-Kyoto rats (WKY, n = 25), and the F1 (n = 27) and F2 (n = 81) hybrids of the SHR and WKY. Genetic analysis revealed that blood pressure in SHR was controlled by approximately four independent genetic loci and the degree of genetic determination was 64.5%. No difference in blood pressure was discernible before 12 weeks of age between those F2 rats that at 16 weeks had blood pressures either higher or lower than one standard deviation from the mean. Exchangeable sodium was measured sequentially in individual rats of all populations by determining their whole-body radioactivity while receiving 37.5 mM 22Na/23NaCl drinking fluid of constant specific activity as their sole source of sodium. The SHR had consistently higher exchangeable sodium levels than WKY and showed evidence of relative sodium retention during the early developmental phase of hypertension. Sodium intake was higher in SHR than WKY from 4 to 16 weeks of age, although saline preference was the same in both strains. None of these parameters of sodium balance were found to correlate with blood pressure in the F2 population. It is concluded that the heritable abnormalities of sodium balance in SHR appear to represent coincidental inbred characteristics controlled by genetic loci that are unrelated to those loci responsible for the expression of hypertension in this model.

Long-term effects of angiotensin-converting enzyme inhibition on renal medullary neutral lipid in spontaneously hypertensive rats.

Short-term treatment of young spontaneously hypertensive rats (SHR) with angiotensin-converting enzyme (ACE) inhibitors reduces systolic blood pressure. Renal medullary neutral lipids (RMNLs) have vasodilator properties that may explain the effects of ACE inhibition. We measured RMNL levels of SHR treated between 6 and 10 weeks of age with (1) vehicle, (2) ramipril 1 mg. kg-1. d-1, (3) the bradykinin B2 receptor antagonist icatibant 0.5 mg. kg-1. d-1, or (4) icatibant 0.5 mg. kg-1. d-1 plus ramipril 1 mg. kg-1. d-1. RMNLs were quantified by oil red O fluorescence at 10 and 20 weeks of age. Systolic blood pressure (BP) was measured by tail-cuff plethysmography. Ramipril reduced BP at 10 weeks of age and increased RMNLs compared with controls (0.99+/-0.07% versus 0.56+/-0. 06%, P<0.01). Icatibant alone had no significant effect on RMNLs (0.55+/-0.04%) but attenuated the increase in RMNLs by ramipril (0. 81+/-0.05%). In control SHR, the increase in BP between 10 and 20 weeks of age was associated with a significant increase in RMNLs (0.79+/-0.09%). SHR that had received ramipril had significantly lower BP than controls at 20 weeks of age, but RMNL was not significantly different (0.92+/-0.10%). Therefore, in young SHR, ACE inhibition increases RMNLs and reduces blood pressure, an effect that appears to depend on bradykinin. The changes in RMNLs at the age of 10 weeks paralleled long-term BP effects and may be involved in setting the BP track in SHR.

Significant population variation in adult male height associated with the Y chromosome and the aromatase gene.

The determination of human adult height is dependent on both environmental and genetic factors. Rare causes of abnormal stature have been identified, including mutations in the gene encoding aromatase (CYP19) and regions on the Y chromosome. However, the possible role of these loci in the genetic control of normal adult height is unknown. We have performed an association study using common biallelic polymorphisms within CYP19 and the Y chromosome to determine whether these loci are associated with variation in height in 413 adult males and 335 females drawn at random from a large population sample. An association between CYP19 and height was found (difference, 2.0 cm; 95% confidence interval, 0.16-3.8; P = 0.003), but this was more evident in men (difference, 2.3 cm; 95% confidence interval, 0.38-4.4; P = 0.05) than women (difference, 0.2 cm; 95% confidence interval, -2.1 to 1.6; P = 0.94). An association was also found with the Y chromosome (P = 0.009; difference of 1.9 cm; 95% confidence interval, 0.5-3.4). Additionally, when men were grouped according to haplotypes of the CYP19 and Y chromosome polymorphisms, a difference of 4.2 cm (95% confidence interval, 0.67-7.3) was detected (P = 0.004). These results suggest that in men, genetic variation in CYP19 and on the Y chromosome are involved in determining normal adult height, and that these loci may interact in an additive fashion.

Resetting blood pressure in spontaneously hypertensive rats. The role of bradykinin.

Brief angiotensin-converting enzyme (ACE) inhibition in young spontaneously hypertensive rats (SHR) causes a persistent reduction in blood pressure. Bradykinin accumulation may contribute to these long-term effects, and to test this hypothesis we studied the consequences of bradykinin B2 receptor antagonism during ACE inhibitor treatment in young SHR. Male SHR were treated from 6 to 10 weeks of age with water, ramipril (1 mg/kg per day), Hoe 140 (0.5 mg/kg per day), or both ramipril and Hoe 140. Systolic blood pressure and body weight were measured each week from 6 to 20 weeks of age. During treatment, Hoe 140 treatment resulted in lower blood pressures than in controls. Rampiril caused a larger fall in blood pressure over the same period. The ramipril plus Hoe 140 group had the lowest blood pressures of any group during treatment. After treatment, the blood pressure of Hoe 140-treated SHR was similar to that of untreated SHR. After ramipril, blood pressure rose but plateaued significantly below values in controls. In contrast, withdrawal of combined ramipril and Hoe 140 treatment caused a rapid rise of systolic blood pressure to levels significantly higher than in ramipril-treated SHR but less than in controls. The antihypertensive effects of Hoe 140 during the development of genetic hypertension may represent a direct effect of the drug or some alteration in the normal relation between bradykinin and blood pressure. The antagonism by Hoe 140 of the long-term blood pressure reduction after ramipril withdrawal indicates that the persistent effects of ACE inhibitors may in part be due to the accumulation of bradykinin during a critical stage of development.

Persistent reduction in renal nerve growth factor mRNA after perindopril treatment of young spontaneously hypertensive rats.

Nerve growth factor (NGF) determines sympathetic innervation of target tissues, and NGF levels are increased in young spontaneously hypertensive rats (SHR). Angiotensin can affect NGF levels, and the persistent reduction in blood pressure after brief angiotensin-converting enzyme inhibition in young SHR may involve long-term changes in NGF and sympathetic innervation. We measured the relative abundance of renal NGF mRNA by reverse transcription-polymerase chain reaction in SHR during and after treatment from 6 to 10 weeks of age with vehicle, perindopril (3 mg/kg per day), the bradykinin B2 antagonist Hoe 140 (0.5 mg/kg per day), both perindopril and Hoe 140, or angiotensin II (Ang II; 200 ng/kg per minute). Glomerular filtration rates were estimated at 10 and 20 weeks of age. At 10 weeks of age, Ang II caused a significant (P<.01) increase and perindopril caused a significant (P<.01) decrease in renal NGF mRNA levels. Blockade of the bradykinin B2 receptor during perindopril treatment attenuated (P<.05) the reduction in NGF mRNA levels. Renal NGF mRNA (P=.005) and blood pressure (P<.001) remained significantly lower than control 10 weeks after perindopril treatment was stopped. The partial reduction in blood pressure at 20 weeks of age in rats that had received perindopril and Hoe 140 was not associated with any difference in renal NGF mRNA. Perindopril-induced long-term reduction in renal NGF mRNA levels may decrease sympathetic innervation and thereby contribute to the long-term posttreatment blood pressure reduction.

Cardiac transplantation, perindopril, and left ventricular hypertrophy in spontaneously hypertensive rats.

Angiotensin-converting enzyme inhibitors reduce blood pressure and cardiac mass but may also have a direct effect on myocardial growth. To test this hypothesis, we studied the effects of perindopril on the weight of transplanted hearts in which the left ventricle does not pump blood. Hearts were transplanted between littermate 10-week-old male spontaneously hypertensive rats, and recipients were treated for 2 weeks with vehicle (n = 10), perindopril (3 mg/kg per day) (n = 9), perindopril (3 mg/kg per day) plus the selective bradykinin B2 receptor antagonist Hoe 140 (500 micrograms/kg per day) (n = 13), or angiotensin II (200 ng/kg per minute) (n = 12). Perindopril reduced blood pressure and native left ventricular weight and also caused a significant decrease in the weight of the transplanted left ventricle compared with controls. Hoe 140 did not significantly alter blood pressure or native left ventricular weight of perindopril-treated rats but caused a significant increase in the weight of the transplanted left ventricle compared with rats treated with perindopril alone. Angiotensin treatment resulted in a significant increase in blood pressure and native left ventricular weight but no significant change in the weight of the transplanted left ventricle. Blood pressure and left ventricular weight for native but not for transplanted hearts were positively correlated. Therefore, in the absence of mechanical load, the weight of the left ventricle of spontaneously hypertensive rats responds little to angiotensin II but can be reduced by angiotensin-converting enzyme inhibition. The effect of perindopril on transplanted hearts of spontaneously hypertensive rats appears to depend on bradykinin.

Nerve growth factor gene locus explains elevated renal nerve growth factor mRNA in young spontaneously hypertensive rats.

Nerve growth factor (NGF) controls the growth of sympathetic nerves and is increased in young spontaneously hypertensive rats (SHR). The NGF gene has been linked genetically with hypertension in the SHR strain and may explain high NGF mRNA levels. To test for genetic linkage between the NGF gene and its expression in vivo, we examined renal NGF mRNA levels in male SHR, control Donryu rats (DRY), and F2 rats derived from SHR and DRY at ages 2, 4, 10, and 20 weeks. Tail-cuff blood pressure was measured at 4, 10, and 20 weeks of age. NGF mRNA levels in SHR (NGF genotype: SS) were higher than those in DRY (NGF genotype: DD) at 2, 4, and 10 weeks of age (P<0.0001) but the same at 20 weeks of age. In the F2 generation, the S allele was associated with significantly (P=0.01) higher renal NGF mRNA levels at 2 weeks of age. Mean NGF mRNA levels fell (P=0.01) with age in F2 rats, and the difference between SS and DD genotype F2 rats diminished at older ages and was not significant. In F2 rats there was a positive correlation between the number of NGF S alleles inherited and tail-cuff pressure (P<0.007). Our findings indicate that the NGF locus is an important regulator of NGF mRNA levels. It is likely that mutations in or near the NGF gene explain in part high early NGF gene expression in SHR.