Investigating the inverse association between glycaemia and abdominal aortic dilatation in a large Chinese hypertensive population: a cross-sectional study.

Background: There is epidemiological evidence that diabetes has a protective effect on the occurrence and development of abdominal aortic aneurysms (AAAs). However, information on the role of glucose level on abdominal aortic diameter is limited. This study sought to assess the relationship between fasting plasma glucose (FPG) and infra-renal aortic diameter in a Chinese hypertensive population. Methods: The prospective participants comprised candidates from 2 large population-based studies on the clinical presentation and management of hypertension in China. In total, 18,034 hypertensive participants (6,942 male and 11,092 females, with a mean age of 64.72±7.41 years) were included in the study. The maximal diameter of the infra-renal aorta was measured by ultrasound scanning. Multivariate linear regression analyses were conducted to assess the specific association between FPG and abdominal aortic diameter. The interaction terms between the baseline covariables and the aortic diameter were used to determine if a variable affected the association between FPG and abdominal aortic diameter. Results: Of these, 22 cases of AAA were identified, and the prevalence of diabetes was lower in those with AAA than those without. A significant negative association was also found between FPG and aortic diameter in both sexes. A dose-dependent decrease in the prevalence of diabetes across quartiles of aortic diameter was also observed, with an estimated odds ratio (OR) of 0.60 (95% CI: 0.50-0.72) for men and 0.72 (95% CI: 0.63-0.82) for women for the top quartiles compared to the bottom quartiles. Cigarette smoking only interacted with the association between FPG level and aortic diameter in women. The association did not differ with other subgroups. Conclusions: Our findings indicate that glycaemia may plays a protective role in the early stage of aortic dilatation in both sexes in a Chinese hypertensive population. Prospective studies need to be conducted to confirm our findings and explore the mechanism underlying this association in different populations.

Small infrarenal aortic diameter associated with lower-extremity peripheral artery disease in Chinese hypertensive adults.

Several studies suggest that infrarenal aortic diameter is associated with lower-extremity peripheral artery disease (LE-PAD). However, data regarding the associations between infrarenal aortic diameter and LE-PAD are limited, especially in large sample populations and Asian or Chinese populations. Our analysis included 17279 Chinese hypertensive adults comprising 6590 men and 10689 women with a mean age of 64.74 ± 7.41 years. Participants were selected from 22693 candidates from two large population-based cohort-studies. The primary noninvasive test for diagnosis of LE-PAD is the ankle-brachial index (ABI) at rest and typically an ABI ≤ 0.90 is used to define LE-PAD. The prevalence of LE-PAD was found to significantly decrease as the aortic diameter increased according to the tertile of the aortic diameter. LE-PAD was significantly more prevalent in the lowest tertile (OR = 1.58, 95% CI = 1.29-1.94, p < 0.001) and similarly prevalent in the highest tertile (OR = 0.92, 95% CI = 0.73-1.16, p = 0.49) when compared with the median tertile. No significant interactions between the aortic diameter and any of the stratified variables were found (all p > 0.05). In conclusion, Small aortic diameter (as opposed to large aortic diameter) is significantly associated with LE-PAD in Chinese hypertensive adults.

[Ultrasonographic screening for the infrarenal aorta diameter and common iliac artery diameter of young males in a Chinese school].

OBJECTIVE: To establish the ultrasonographic criteria for normal size of infrarenal aorta (IRA) and common iliac arteries (CIA) of young males in a Chinese school and to determine the associations between IRA diameter (IRAD) and CIA diameter (CIAD) and body habitus as well as traditional cardiovascular risk factors. METHODS: Cross-sectional study was done of 203 Chinese young males enrolled from a technical school in Beijing Changping district from May to June 2013. The IRA and CIA scans were carried out using ultrasonography. Longitudinal scans were used to assess aortic morphology and tortuosity. The maximum internal anteroposterior IRAD and CIAD in any area of the arteries were measured during the cardiac cycle. Participants information on demographic, medical history, smoking history and alcohol consumption was obtained through unified questionnaire. Univariate and multivariate linear regression was used to determine the associations between arterial diameter and body habitus as well as other risk factors. RESULTS: The median participants age was 21.5 (ranging from 18 to 28) years. The IRAD was (13.4±1.9) mm, and the CIAD was (9.4±1.6) mm. There was no significant difference between the left and right CIAD. Waist circumference was significantly associated with increasing IRAD (P=0.03), while alcohol had an inverse correlation (P=0.04). Age, hip circumference were significantly associated with increasing CIAD (P=0.00, 0.04), while the systolic pressure and alcohol had inverse correlations (P=0.01, 0.00). By dividing the entire group into equal four groups using quartile values for both age and waist/hip circumference, the older group and the larger waist/hip circumference had greater arterial diameter. CONCLUSIONS: The enrolled Chinese young males have smaller IRAD and CIAD compared with foreign older population. Age, waist circumference, hip circumference, alcohol and systolic pressure have statistically significance but small effects on arterial diameter.

[A matched case-control study of risk factors in abdominal aortic aneurysm].

OBJECTIVE: To examine the potential influence factors of abdominal aortic aneurysm (AAA). METHODS: A 1:2 pair-matched, case-control study was conducted from July 2011 to December 2012. A pair was composed of one AAA patient recruited from the Vascular Surgery Department, Chinese PLA General Hospital and two gender- and age-matched non-AAA subjects, one from the same hospital and the other from the community in Fangshan District in Beijing. Demographic data, medical history and the lifestyle of each subject were collected. Moreover, all the participants underwent abdominal ultrasound or computed tomography (CT) and peripheral venous blood samples were obtained. RESULTS: There were 155 case/control pairs. The multivariate conditional logistic regression model confirmed that suffering from hypertension conferred a 1.98-fold (95%CI 1.12-3.18) increased likelihood of AAA. Smoking was a strong independent risk factor of AAA, with odds ratios (95% confidence intervals) of 5.23 (2.44-11.23). Dyslipidemia (OR=2.61,95% CI 1.45-4.70), a higher level of serum hsCRP (OR=2.43,95%CI 1.37-4.31) and homocysteine (OR=2.73,95% CI 1.61-4.65) were all associated with AAA. CONCLUSION: Hypertension and smoking are the risk factors of AAA. Dyslipidemia, hsCRP and Hcy are associated with AAA.

Association of polymorphisms on chromosome 9p21.3 region with increased susceptibility of abdominal aortic aneurysm in a Chinese Han population.

OBJECTIVE: Several studies have reported that polymorphisms on chromosome 9p21.3, near the CDKN2A/2B gene, are strongly associated with increased susceptibility to abdominal aortic aneurysm (AAA). However, no convincing data has been reported on a relationship between AAA and these variants in the Chinese Han population. The aim of this study was to evaluate the role of rs10757278 and rs1333049 in determining genetic susceptibility to AAA. METHODS: A total of 155 AAA patients and 310 controls, comparable in age and gender, were enrolled in this study. DNA samples were genotyped for rs10757278 and rs1333049 using the MassArray system. The association between these two single nucleotide polymorphisms and AAAs was tested using multivariate logistic regression. Stratified analysis was also performed by clinical and laboratory features. RESULTS: Single nucleotide polymorphisms rs10757278 and rs1333049 were significantly associated with increased risk of AAA. The frequencies of rs10757278-G and rs1333049-C in AAA patients were significantly higher than in control subjects (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.11-2.11; P = .01, and OR, 1.48; 95% CI, 1.07-2.05; P = .02). Multiple logistic regression analysis indicated that, after adjusting for smoking habits, drinking habits, and histories of other chronic diseases, homozygosity of the risk allele for rs10758278-G and rs1333049-C also increased the likelihood of AAA (OR, 2.31; 95% CI, 1.22-4.36, and OR, 2.14; 95% CI, 1.13-4.05). The frequency of the GC haplotype was significantly higher in AAA patients than in control subjects (OR, 1.44; P = .038). Stratification analysis of clinical and laboratory features revealed no association between polymorphisms and aortic diameters in AAA patients. There was a significantly high frequency of the rs10757278 GG genotype in AAA patients with high serum total homocysteine compared with those control subjects with high serum total homocysteine (OR, 2.71; 95% CI, 1.12-6.58; P = .03) indicating that the genotype GG of rs10757278 might interact with the homocysteine biological pathway to stimulate the presence of AAA. CONCLUSIONS: Present data demonstrate that rs10757278 and rs1333049 on chromosome 9p21.3 are significantly associated with increased risk of AAA in the Chinese population and emphasize the need to further study the role of these markers in AAA.

Elastic fiber regeneration in vitro and in vivo for treatment of experimental abdominal aortic aneurysm.

BACKGROUND: The pathological characteristics of abdominal aortic aneurysm (AAA) involved the regression of extracellular matrix (ECM) in aortic walls, especially elastic structure in medial layer. As the major structural protein of aorta, elastin contributes to the extensibility and elastic recoil of the vessels. We hypothesized that overexpression of elastin in vessel walls might regenerate the elastic structure of ECM, restore the elastic structure of the aneurysmal wall, and eventually lead to a reduction of aortic diameters (ADs) in an experimental model of AAA. METHODS: Tropoelastin (TE) of Sprague Dawley (SD) rat was synthesized by reverse transcription polymerase chain reaction and used to construct adneviral vectors containing elastin precursor protein (AdTE-GFP). Cultured vascular smooth muscle cells (VSMCs) from aortas of male SD rats were transfected with AdTE-GFP, AdGFP, adenoviral vector (AdNull), and phosphate buffered saline (PBS). Immunofluorescence staining was performed to determine the expression of elastin in transfected cells. The expression of elastic fibers in ECM of VSMCs transfected with AdTE-GFP were detected by fluorescence microscopy and transmission electron microscopy (TEM) at 1, 3, and 5 days following gene transfer. The AAA vessel walls were infused with AdTE-GFP or an empty AdNull, or PBS directly into the aneurysmal lumen. ADs of the aneurysms were compared in infused aortas. Formation of new elastic fibers in vivo was assessed by hematoxylin and eosin, and elastic von-Giesson staining. Recombinant elastin-GFP in vivo was identified by immunohistochemical staining. RESULTS: Elastic fibers were increased both in ECM of VSMC and in vessel walls after gene transfer. Histological studies revealed that the AdTE-GFP-transduced aortas had elastic fiber regeneration in the aneurysmal walls. The AdTE-GFP-transduced aortas showed a decreased AD (23.04% ± 14.49%, P < 0.01) in AAA vessel walls. CONCLUSIONS: Elastic fibers have been successfully overexpressed both in vitro and in a rat model of AAA by a technique of gene transfer. The overexpression of elastic fibers within the aneurysmal tissue appeared to reverse the aneurysm dilatation in this model.