6 research outputs found
Heritability of the dimensions, compliance and distensibility of the human internal jugular vein wall
AIMS: The elasticity of the internal jugular vein (IJV) is a major determinant of cerebral venous drainage and right atrium venous return. However, the level of genetic determination of IJV dimensions, compliance and distensibility has not been studied yet. METHODS: 170 adult Caucasian twins (43 monozygotic [MZ] and 42 dizygotic [DZ] pairs) were involved from the Italian twin registry. Anteroposterior and mediolateral diameters of the IJV were measured bilaterally by ultrasonography. Measurements were made both in the sitting and supine positions, with or without Valsalva maneuver. Univariate quantitative genetic modeling was performed. RESULTS: Genetic factors are responsible for 30-70% of the measured properties of IJV at higher venous pressure even after adjustment for age and gender. The highest level of inheritance was found in the supine position regarding compliance (62%) and venous diameter during Valsalva (69%). Environmental and measurement-related factors instead are more important in the sitting position, when the venous pressure is low and the venous lumen is almost collapsed. The range of capacity changes between the lowest and highest intraluminal venous pressure (full distension range) are mainly determined by genetic factors (58%). CONCLUSIONS: Our study has shown substantial heritability of IJV biomechanics at higher venous pressures even after adjustment for age and gender. These findings yield an important insight to what degree the geometric and elastic properties of the vascular wall are formed by genetic and by environmental factors in humans
Intertwin correlation of average diameter, compliance and distensibility for monozygotic and ditzygotic twins in the sitting and in the supine positions without and with a 60 mmHg controlled Valsalva attempt.
<p>At right the significance levels of the correlation coefficients are shown (valid for monozygotes, n = 40, but almost identical for dizygotes, n = 42). Note higher correlation values for monozygotic twins (hinting for genetic factors). Note limited correlation of values sitting (measured at lower initial pressure).</p
Baseline characteristics of study subjects.
<p>Baseline characteristics of study subjects.</p
Age and sex adjusted parameter estimates for additive hereditary (A), common environment (C) and unique environmental influences (E) of compliance, distensibility and full distension range (values averaged for both sides) by structural equation modeling.
<p>Age and sex adjusted parameter estimates for additive hereditary (A), common environment (C) and unique environmental influences (E) of compliance, distensibility and full distension range (values averaged for both sides) by structural equation modeling.</p
Age and sex adjusted parameter estimates for additive hereditary (A), common environment (C) and unique environmental influences (E) of mean internal jugular vein diameter by structural equation modeling.
<p>Age and sex adjusted parameter estimates for additive hereditary (A), common environment (C) and unique environmental influences (E) of mean internal jugular vein diameter by structural equation modeling.</p
Heritability of the dimensions, compliance and distensibility of the human internal jugular vein wall - Fig 1
<p>Inner jugular vein diameters measured ultrasonographically in monozygotic (a) and dizygotic (b) A and B twins, in the sitting and in the supine body position, without and with a controlled 60 mmHg Valsalva. Antero-posterior and lateral diameters were averaged for the left and right sides for each person. Note very close mean values for two members of the twin pairs in both groups. Distensibilities computed for monozygotic (c) and dizygotic (d) A and B twins. Distensibilities for the left and right inner jugular veins measured between 0–60 mmHg Valsalva were averaged for each person.</p