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Abstract Background Postural orthostatic tachycardia syndrome (POTS) is a variant of cardiovascular (CV) autonomic disorder of unknown etiology characterized by an excessive heart rate increase on standing and orthostatic intolerance. In this study we sought to identify novel CV biomarkers potentially implicated in POTS pathophysiology. Methods We conducted a nested case-control study within the Syncope Study of Unselected Population in Malmö (SYSTEMA) cohort including 396 patients (age range, 15–50 years) with either POTS (n = 113) or normal hemodynamic response during passive head-up-tilt test (n = 283). We used a targeted approach to explore changes in cardiovascular proteomics associated with POTS through a sequential two-stage process including supervised principal component analysis and univariate ANOVA with Bonferroni correction. Results POTS patients were younger (26 vs. 31 years; p

Abstract Background Higher fasting Growth Hormone (GH) has been associated with increased cardiovascular morbidity and mortality. Our objective was to find genetic determinants of fasting GH in order to facilitate future efforts of analyzing the association between fasting growth hormone and cardiovascular disease. A genome-wide association study (GWAS) was performed in a discovery cohort of 4134 persons (58% females; age 46–68 yrs), linking SNPs to fasting hs-GH. Fifteen SNPs were replicated in an independent cohort of 5262 persons (28.9% females; age 56–85 yrs). The best performing SNP was analyzed vs GH-related variables in a third independent cohort (n = 24,047; 61% females; age 44–73 yrs). A candidate gene approach searched for significant SNPs in the genes GH1 and GHR in the discovery cohort and was replicated as previously described. Results In the GWAS, the minor allele of rs7208736 was associated with lower GH in the discovery cohort (p = 5.15*10^-6) and the replication cohort (p = 0.005). The GH reducing allele was associated with lower BMI (P = 0.026) and waist (P = 0.021) in males only. In the candidate gene approach rs13153388 in the GHR-gene was associated with elevated GH-levels (P = 0.003) in the discovery cohort only and reduced height (P = 0.003). Conclusion In the first GWAS ever for GH, we identify a novel locus on chromosome 17 associated with fasting GH levels, suggesting novel biological mechanisms behind GH secretion and GH-related traits. The candidate gene approach identified a genetic variant in the GHR, which was associated with an elevation of fasting hs-GH and lower height suggesting reduced GHR ligand sensitivity. Our findings need further replication.

Abstract Background Growth hormone (GH) has been linked to cardiovascular disease but the exact mechanism of this association is still unclear. We here test if the fasting levels of GH are cross-sectionally associated with carotid intima media thickness (IMT) and whether treatment with fluvastatin affects the fasting level of GH. Methods We examined the association between GH and IMT in 4425 individuals (aged 46–68 years) included in the baseline examination (1991–1994) of the Malmö Diet and Cancer cardiovascular cohort (MDC-CC). From that cohort we then studied 472 individuals (aged 50-70 years) who also participated (1994–1999) in the β-Blocker Cholesterol-Lowering Asymptomatic Plaque Study (BCAPS), a randomized, double blind, placebo-controlled, single-center clinical trial. Using multivariate linear regression models we related the change in GH-levels at 12 months compared with baseline to treatment with 40 mg fluvastatin once daily. Results In MDC-CC fasting values of GH exhibited a positive cross-sectional relation to the IMT at the carotid bulb independent of traditional cardiovascular risk factors (p = 0.002). In a gender-stratified analysis the correlation were significant for males (p = 0.005), but not for females (p = 0.09). Treatment with fluvastatin was associated with a minor reduction in the fasting levels of hs-GH in males (p = 0.05) and a minor rise in the same levels among females (p = 0.05). Conclusions We here demonstrate that higher fasting levels of GH are associated with thicker IMT in the carotid bulb in males. Treatment with fluvastatin for 12 months only had a minor, and probably not clinically relevant, effect on the fasting levels of hs-GH.

BackgroundThe genetic background of Growth Hormone (GH) secretion is not well understood. Mutations giving rise to a stop codon have a high likelihood of affecting protein function.ObjectivesTo analyze likely functional stop codon mutations that are associated with fasting plasma concentration of Growth Hormone.MethodsWe analyzed stop codon mutations in 5451 individuals in the Malmö Diet and Cancer study by genotyping the Illumina Exome Chip. To enrich for stop codon mutations with likely functional effects on protein function, we focused on those disrupting >80% of the predicted amino acid sequence, which were carried by ≥ 10 individuals. Such mutations were related to GH concentration, measured with a high sensitivity assay (hs-GH) and, if nominally significant, to GH related phenotypes, using linear regression analysis.ResultsTwo stop codon mutations were associated with the fasting concentration of hs-GH. rs121909305 (NP_005370.1:p.R93*) [Minor Allele Frequency (MAF) = 0.8%] in the Myosin 1A gene (MYO1A) was associated with a 0.36 (95%CI, 0.04 to 0.54; p=0.02) increment of the standardized value of the natural logarithm of hs-GH per 1 minor allele and rs35699176 (NP_067040.1:p.Q100*) in the Zink Finger protein 77 gene (ZNF77) (MAF = 4.8%) was associated with a 0.12 (95%CI, 0.02 to 0.22; p = 0.02) increase of hs-GH. The mutated high hs-GH associated allele of MYO1A was related to lower BMI (β-coefficient, -0.22; p = 0.05), waist (β-coefficient, -0.22; p = 0.04), body fat percentage (β-coefficient, -0.23; p = 0.03) and with higher HDL (β-coefficient, 0.23; p = 0.04). The ZNF77 stop codon was associated with height (β-coefficient, 0.11; p = 0.02) but not with cardiometabolic risk factors.ConclusionWe here suggest that a stop codon of MYO1A, disrupting 91% of the predicted amino acid sequence, is associated with higher hs-GH and GH-related traits suggesting that MYO1A is involved in GH metabolism and possibly body fat distribution. However, our results are preliminary and need replication in independent populations.