69 research outputs found
Twin studies of cardiorespiratory disease, daily cardiovascular activity and imaging
No full textTwin studies have helped gain insight into the role of heritability in disease and disease processes. Given the large burden cardiorespiratory diseases place on society, these diseases have featured largely in twin studies. In part A of this chapter, a brief overview of the outcomes of such studies is provided for a wide variety of cardiovascular and respiratory diseases. A moderate to high influence of genes is seen for the vast majority of these diseases. This highlights the importance of screening high-risk individuals, as well as studying gene-by-environment interactions. While studying the disease itself is important, insight into the processes leading up to the disease may increase our understanding of disease development. By studying cardiovascular function for prolonged periods of time in nonpatient populations, valuable insights can be obtained in normal day cardiovascular functioning. In part B of this chapter, we review twin studies in which indices of cardiovascular function were recorded throughout the day and night using ambulatory monitoring. Here too, it is evident that heritability influences the variation of everyday blood pressure and heart action. Another way of gaining insight into the physiological processes underlying disease development is through imaging studies. In part C of this chapter, we discuss the inclusion of twins in imaging studies. Twin studies of imaging data are still sparse and cover a wide variety of traits. Studies including both monozygotic and dizygotic twins generally point to a role for genetic factors, though the degree differs across the traits. Within imaging studies, the twin discordant design is also often applied, demonstrating the occurrence of gene-by-environment interaction. Overall, twin studies have shown that genetic factors play an important role in individual variation in many physiological diseases and disease processes. Future studies are expected to provide more insight into the interplay of genetic and environmental factors with respect to physiological function and risk. Of particular interest are studies looking into epigenetic mechanisms, which are gradually emerging and may further help the development of more personalized medicine, based on genetic vulnerability as well as lifestyle and environment.</p
Association between personality profile and subclinical atherosclerosis: the role of genes and environment
No full textBackground. The mechanism underlying the association between personality profile and
subclinical atherosclerosis is poorly understood. This study explores the association between
personality, carotid atherosclerosis and arterial stiffness, and the contribution of genes and
environment to this association.
Methods. Early atherosclerotic traits, including carotid intima-media thickness (CCA-IMT),
aortic pulse wave velocity (PWVao) and heart rate, were assessed in 318 adult twins, who
also completed a Big Five personality questionnaire. Using the co-twin control approach, the
association between intra-pair differences in clinical and personality scores was assessed in
dizygotic (DZ) and monozygotic (MZ) twins separately.
Results. An association between CCA-IMT and extroverted personality, as well as between
PWVao and openness to experience was detected. The inverse association between CCAIMT
and extraversion was persistent in DZ and disappeared in MZ twins, suggesting genetic
confounding. In contrast, the association between PWVao and openness to experience was of
the same magnitude in DZ and MZ twins, thus surviving the adjustment for genetic and
shared environmental factors.
Conclusions. This study highlights that the association between some psychological factors
and cardiovascular traits may be partly explained by genetic factors. This result may provide
support for the feasibility of prevention programs based on assessing familiarity for
personality disorders to detect genetic risk for subclinical cardiovascular disease
Twin studies of cardiorespiratory disease, daily cardiovascular activity and imaging
No full textTwin studies have helped gain insight into the role of heritability in disease and disease processes. Given the large burden cardiorespiratory diseases place on society, these diseases have featured largely in twin studies. In part A of this chapter, a brief overview of the outcomes of such studies is provided for a wide variety of cardiovascular and respiratory diseases. A moderate to high influence of genes is seen for the vast majority of these diseases. This highlights the importance of screening high-risk individuals, as well as studying gene-by-environment interactions. While studying the disease itself is important, insight into the processes leading up to the disease may increase our understanding of disease development. By studying cardiovascular function for prolonged periods of time in nonpatient populations, valuable insights can be obtained in normal day cardiovascular functioning. In part B of this chapter, we review twin studies in which indices of cardiovascular function were recorded throughout the day and night using ambulatory monitoring. Here too, it is evident that heritability influences the variation of everyday blood pressure and heart action. Another way of gaining insight into the physiological processes underlying disease development is through imaging studies. In part C of this chapter, we discuss the inclusion of twins in imaging studies. Twin studies of imaging data are still sparse and cover a wide variety of traits. Studies including both monozygotic and dizygotic twins generally point to a role for genetic factors, though the degree differs across the traits. Within imaging studies, the twin discordant design is also often applied, demonstrating the occurrence of gene-by-environment interaction. Overall, twin studies have shown that genetic factors play an important role in individual variation in many physiological diseases and disease processes. Future studies are expected to provide more insight into the interplay of genetic and environmental factors with respect to physiological function and risk. Of particular interest are studies looking into epigenetic mechanisms, which are gradually emerging and may further help the development of more personalized medicine, based on genetic vulnerability as well as lifestyle and environment
Genetic and environmental factors on the relation of lung function and arterial stiffness
No full textSummaryBackgroundAn association between reduced lung function and increased cardiovascular risk has been reported, but the underlying mechanisms are unknown. The aim of this study was to assess the heritability of lung function and to estimate its genetic association with arterial stiffness.Methods150 monozygotic and 42 dizygotic healthy Hungarian and American Caucasian twin pairs (age 43 ± 17 years) underwent spirometry (forced vital capacity/FVC/, forced expiratory volume in 1 s/FEV1/; MIR Minispir, USA); and their brachial and central augmentation indices (AIx), and aortic pulse wave velocity (PWV) were measured by oscillometric Arteriograph (TensioMed Ltd, Budapest, Hungary). Phenotypic correlations and bivariate Cholesky decomposition models were applied.ResultsAge-, sex-, country- and smoking-adjusted heritability of FEV1, percent predicted FEV1, FVC and percent predicted FVC were 73% (95% confidence interval /CI/: 45–85%), 28% (95% CI: 0–67%), 68% (95% CI: 20–81%) and 45% (95% CI: 0–66%), respectively. Measured and percent predicted FVC and FEV1 values showed no significant phenotypic correlations with AIx or aortic PWV, except for phenotypic twin correlations between measured FEV1, FVC with brachial or aortic augmentation indices which ranged between −0.12 and −0.17. No genetic covariance between lung function and arterial stiffness was found.ConclusionsLung function is heritable and the measured FVC and FEV are phenotypically, but not genetically, associated with augmentation index, a measure of wave reflection. This relationship may in turn reveal further associations leading to a better mechanistic understanding of vascular changes in various airway diseases
The Role of Soluble Low-Density Lipoprotein Receptor-Related Protein-1 in Obstructive Sleep Apnoea
No full textIntermittent hypoxia in obstructive sleep apnoea (OSA) is related to inflammation and metabolic abnormalities. Soluble low-density lipoprotein receptor-related protein-1 (sLRP-1) is involved in anti-inflammatory and metabolic processes. However, its ligand, calreticulin (CALR) promotes pro-inflammatory responses and apoptosis. Our aim was to analyse the levels of these biomarkers in OSA. We recruited 46 patients with OSA and 30 control subjects. Inpatient sleep study was performed and fasting plasma samples were collected. Triglyceride glucose index (TyG) and atherogenic index of plasma (AIP) were calculated. Plasma sLRP-1 levels were significantly lower in the OSA group compared to the controls (1.67 (0.90–2.11) mg/L vs. 1.99 (1.53–3.51) mg/L; p = 0.04) after adjustment for age, gender, BMI and lipid profile. Plasma sLRP-1 concentrations were inversely related to age (r = −0.29), BMI (r = −0.35), cigarette pack years (r = −0.31), LDL-C (r = −0.34) and triglyceride levels (r = −0.27), TyG (r = −0.37) and AIP (r = −0.27) as well as to the oxygen desaturation index (ODI, r = −0.24; all p < 0.05). BMI (p = 0.01) and ODI (p = 0.04) were independent predictors for low sLRP-1 levels. CALR did not differ significantly between the two groups (0.23 (0.17–0.34) ng/mL vs. 0.24 (0.20–0.36) ng/mL p = 0.76). We detected lower sLRP-1 levels in subjects with OSA which could contribute to metabolic abnormalities associated with this disease
Heritability of central blood pressure and arterial stiffness: a twin study
No full textOBJECTIVE:: Central blood pressure and aortic stiffness have been consistently reported as strong cardiovascular risk factors. Twin studies by comparing identical with nonidentical twins produce information on the relative contribution of genes and environment. METHODS:: One hundred and fifty-four monozygotic (MZ) and 42 dizygotic (DZ) twin pairs (age 43 +/- 17 years) from Hungary and the United States underwent brachial and central augmentation index (AIx), brachial and central pressure, and aortic pulse wave velocity (PWV) measurements with the invasively validated Arteriograph device. Bivariate Cholesky decomposition models were applied. RESULTS:: Age-adjusted, sex-adjusted and country-adjusted heritability was 60.0% for central SBP [95% confidence interval (CI), 44.8-69.6%], 50.1% for aortic PWV (95%CI, 26.0-66.8%), 48.7% for aortic AIx (95%CI, 1.7-74.0%), 46.8% for brachial AIx (95%CI, 1.1-73.8%), 46.7% for central pulse pressure (PP) (95%CI, 12.4-61.4%), and 30.0% for brachial PP (95%CI, 0.0-53.4%). Central SBP and PP had strong bivariate correlations with brachial (r = 0.461 and 0.425) and central AIx (r = 0.457 and 0.419), as well as with aortic PWV (r = 0.341 and 0.292, all P < 0.001). Brachial PP had a weak correlation with brachial AIx (r = -0.118, P < 0.05), central AIx (r = -0.122, P < 0.05), and none with aortic PWV (r = 0.08, P = n.s.). Genetic factors explained a moderate phenotypic correlation between central PP, SBP, brachial SBP and aortic PWV. CONCLUSIONS:: Central systolic and PPs, brachial PP, AIx, aortic PWV are moderately heritable. A moderate genetic covariance among aortic PWV and central PP, central SBP and brachial SBP was found
Are the Morphological Indices of the Vertebrobasilar System Heritable? A Twin Study Based on 3D Reconstructed Models
No full textBackground and Objectives: The asymmetrical vertebral artery (VA) flow and diameter are common findings, which can result in an asymmetrical blood flow in the basilar artery (BA), leading to bending of the artery over time. This study investigated whether the variation of the different vertebrobasilar morphological indices that influence flow characteristics might be inherited. Materials and Methods: We analyzed 200 cerebral magnetic resonance imaging (MRI) scans of healthy Caucasian twins (100 pairs) who underwent time-of-flight MRI. From the scans, we reconstructed the 3D mesh of the posterior circulation from the start of the V4 segment to the basilar tip and subsequently analyzed the morphology of the vertebrobasilar system. The phenotypic covariances of the different morphological parameters were decomposed into heritability (A), shared (C), and unshared (E) environmental effects. Results: 39% of the twins had left dominant VA, while 32.5% had right dominant. In addition, 28.5% were classified as equal. The vertebral artery V4 segment diameter, curvature, and tortuosity were mainly influenced by shared (C) and unshared (E) environmental factors. A moderate heritability was found for the BA length (A: 63%; 95% CI: 45.7–75.2%; E: 37%; 95% CI: 24.8–54.3%) and volume (A: 60.1%; 95% CI: 42.4–73.2%; E: 39.9%; 95% CI: 26.8–57.6%), while the torsion of both arteries showed no heritability and were only influenced by the unshared environment. Conclusions: The length and volume of the BA show a moderate genetical influence. However, most of the measured morphological indices were influenced by shared and unshared factors, which highlight the role of the ever-changing hemodynamic influences shaping the geometry of the vertebrobasilar system
Lobular Difference in Heritability of Brain Atrophy among Elderly Japanese: A Twin Study
No full textBackground and Objectives: Brain atrophy is related to cognitive decline. However, the heritability of brain atrophy has not been fully investigated in the Eastern Asian population. Materials and Methods: Brain imaging of 74 Japanese twins registered in the Osaka University Twin Registry was conducted with voxel-based morphometry SPM12 and was processed by individual voxel-based morphometry adjusting covariates (iVAC) toolbox. The atrophy of the measured lobes was obtained by comparing the focal volume to the average of healthy subjects. Classical twin analysis was used to measure the heritability of its z-scores. Results: The heritability of brain atrophy ranged from 0.23 to 0.97, depending upon the lobes. When adjusted to age, high heritability was reported in the frontal, frontal-temporal, and parietal lobes, but the heritability in other lobes was lower than 0.70. Conclusions: This study revealed a relatively lower heritability in brain atrophy compared to other ethnicities. This result suggests a significant environmental impact on the susceptibility of brain atrophy the Japanese. Therefore, environmental factors may have more influence on the Japanese than in other populations
Genetic and environmental variance of renal parenchymal thickness: a twin study
No full textAim To estimate heritability and environmental effects on
renal parenchymal thickness.
Methods In this twin study, renal parenchymal thickness
of 98 Hungarian healthy adult twin pairs (68 monozygotic,
30 dizygotic) without kidney disease was measured bilaterally
using renal ultrasound with Esaote MyLab 70X ultrasound
machine with low-frequency curved transducers
(1-8 MHz).
Results In both monozygotic and dizygotic group there
were more women (76.5%). Mean right and left renal parenchymal
thickness was 1.32 ± 0.33 cm and 1.62 ± 0.31
cm, respectively. Age- and sex-adjusted heritability of renal
parenchymal thickness was 0.0% (95% confidence interval,
0.0 to 50.2%), shared and unshared environmental
factor was 30.2% (4.1 to 55.9%) and 69.8% (45.8 to 89.5%),
respectively.
Conclusion This study shows a negligible role of heritability
and an important role of environmental effects in developing
renal parenchymal thickness, emphasizing the importance
of lifestyle for primary prevention
Genetic influence on femoral plaque and its relationship with carotid plaque: an international twin study.
No full textTo disentangle genetic and environmental influences on the development of femoral plaques using a population of adult twins. To evaluate the potential role of shared genetic and environmental factors in the co-occurrence of femoral and carotid plaques. The sample included 566 twins belonging to 164 monozygotic (MZ) and 119 dizygotic (DZ) twin pairs, who underwent peripheral arterial assessment by B-mode ultrasound in different centers. The variance in femoral plaques onset was due to genetic factors and the remaining 50% was explained by common (15%) and unique (35%) environmental factors. Findings on sidedness and number of femoral plaques indicated that also these traits were mainly under genetic control. No effect of common environment was found on plaques composition, and variability of this trait was explained by genetics (64%) and unique environment (36%). Covariation between the liabilities to carotid and femoral plaques was mainly attributed to shared genes (77%), with the remaining 23% explained by individual-specific environmental factors shared by the two districts. Inter-individual differences in plaque onset as well as in their number, sidedness and composition are mainly genetic in origin. The results on the cooccurrence of carotid and femoral plaque underline the genetic role in atherogenesis
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