Summary

• The practical implication of screening candidate patients is feasible by examining the GNB3 C1594T allele before the onset of high blood pressures.

• We suspect that the GNB3 gene could form or contribute to the arterial network.

Objectives (I)

• To evaluate whether genetic factors contribute to essential hypertension.

• To investigate the association between G-protein beta3 polymorphism, an average of five retinal arterial bifurcation angles, and essential hypertension.

Objectives (II)

• To examine the relationship between the GNB3 C1594T allele and blood pressure among gender and age group in the Korean population.

• The practical implication of screening candidate patients before the onset of high blood pressure is examined in the study.

Background (I)

• The narrowing angles of retinal arterial bifurcation are associated with increased circulatory energy cast.

• It may be related to lower than normal micro-vascular density. Abnormalities of cardiovascular structure are frequently seen in hypertension and that abnormality may precede the onset of high blood pressure.

Background (II)

• A C1594T polymorphism of the gene encoding G protein beta3 sub-unit contributes to the genesis of essential hypertension.

• The link between the gene and blood pressure is not consistently found in different populations.

Method (I)

• The C1594T polymorphism was diagnosed by restriction of the PCR amplicon by Bse DI (MBI Fermentas), with oligonucleotide primers 5'-TGATCCCTGACCCACTTGCCACCCGTGC-3' (sense) & 5'-GAGGAAGCAGCAGCCAGGGCTGGCCC-3' (antisense),

resulting in 2 fragments of 192 and 107 bp for the C allele and in an unrestricted fragment of 299 bp for the T allele.

Method (II)

• An Analysis of Variance model was adopted to find the relationship between blood pressures and a candidate gene GNB3 genotypes (CC,CT,TT).

• An Analysis of Variance model was fitted to average retinal bifurcation angle with GNB3 in a sample of 245 Korean individuals.

Method (III)

• The retinal vascular geometry was tested using F statistics in the GNB3.

• The retinal vascular geometry was tested to systolic and diastolic blood pressures with GNB3 as Analysis of Covariance model.

Method (IV)

• Other characteristics (age, gender, BMI, total cholesterol level, TG) were consider as covariates in ANOVA and ANCOVA models.

Proportion of GNB3 in Korean Population

24%

56%

20%

CC

CT

TT

Relationship between Blood Pressure and GNB3

134.1150.6 151.4

84.494.5 94.7

0

40

80

120

160

CC CT TT

GNB3

Blo

od P

ress

ure

SBPDBP

Relationship between Average of Retinal Arterial Bifurcation Angles and GNB3

74.2

65.967.8

60

70

80

CC CT TT

GNB3

Ang

le

Primer Locations of Human Guanine Nucleotide-Binding Protein (GNB3) for PCR

GNB3c (Sense) 5’-TGATCCCTGACCCACTTGCCACCCGTGC-3’GNB3d (Antisense) 5’-GAGGAAGCAGCAGCCAGGGCTGGCCC-3’

Exon 10

GNB3c GNB3d

Resulting BseD I fragments for C1594T SNP of GNB3 from the PCR products using primers GNB3c and GNB3d

CC CT TT

299192

107

(bp)

Example of Result from Restriction Enzyme Treatment

Restriction Enzyme : BseDI, 37°C for 1 hour

300Kb200Kb

52 3 41 6 7 8 9 10 1211 13 14M

Pictures of Retinal Arterial Bifurcation Measurement

Conclusion (I)

• CT and TT of gene G-protein beta 3-C1594T genotypes have significant higher blood pressures than CC of genotype.

• A larger retinal arterial bifurcation angles in CC of GNB3 genotype.

• The retinal vascular network asymmetry was detected in CT and TT of GNB 3 genotypes.

Conclusion (II)

• No relationship was found between blood pressures and average of five retinal arterial bifurcation angles.

• The demographic and biological characteristics of Korean individuals were not significantly related with blood pressures and GNB3 gene.