Diabetics are less likely to develop thoracic aortic dissection: a 10-year single-center analysis

Diabetes and aortic dissection: unraveling the role of 3-hydroxybutyrate through mendelian randomization

BACKGROUND

In observational and experimental studies, diabetes has been reported as a protective factor for aortic dissection. 3-Hydroxybutyrate, a key constituent of ketone bodies, has been found to favor improvements in cardiovascular disease. However, whether the protective effect of diabetes on aortic dissection is mediated by 3-hydroxybutyrate is unclear. We aimed to investigate the causal effects of diabetes on the risk of aortic dissection and the mediating role of 3-hydroxybutyrate in them through two-step Mendelian randomization.

MATERIALS AND METHODS

We performed a two-step Mendelian randomization to investigate the causal connections between diabetes, 3-hydroxybutyrate, and aortic dissection and calculate the mediating effect of 3-hydroxybutyrate. Publicly accessible data for Type 1 diabetes, Type 2 diabetes, dissection of aorta and 3-hydroxybutyrate were obtained from genome-wide association studies. The association between Type 1 diabetes and dissection of aorta, the association between Type 2 diabetes and dissection of aorta, and mediation effect of 3-hydroxybutyrate were carried out separately.

RESULTS

The IVW method showed that Type 1 diabetes was negatively associated with the risk of aortic dissection (OR 0.912, 95% CI 0.836-0.995), The weighted median, simple mode and weighted mode method showed consistent results. The mediated proportion of 3-hydroxybutyrate on the relationship between Type 1 diabetes and dissection of aorta was 24.80% (95% CI 5.12-44.47%). The IVW method showed that Type 2 diabetes was negatively associated with the risk of aortic dissection (OR 0.763, 95% CI 0.607-0.960), The weighted median, simple mode and weighted mode method showed consistent results. 3-Hydroxybutyrate does not have causal mediation effect on the relationship between Type 2 diabetes and dissection of aorta.

CONCLUSION

Mendelian randomization study revealed diabetes as a protective factor for dissection of aorta. The protective effect of type 1 diabetes on aortic dissection was partially mediated by 3-hydroxybutyrate, but type 2 diabetes was not 3-hydroxybutyrate mediated.

Diabetes Mellitus Lowers the Risk of Aortic Dissection: a Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aimed to investigate the association between diabetes mellitus and aortic dissection.

METHODS

The PubMed and Embase databases were searched until December 2019 to identify all articles reporting diabetes mellitus and aortic dissection. The pooled odds ratio and 95% confidence interval were calculated using random-effects model.

RESULTS

A total of 14 articles with 15,794 participants, of which 2133 diabetes mellitus patients, were eligible and included in this meta-analysis. The data suggested that diabetes mellitus decreased the risk of aortic dissection. In the subgroup analysis, this association was significant in worldwide studies except for the Chinese cohort and in studies adjusted for confounding factors. The results were stable after sensitivity analysis and no evidence of publication bias was found among studies.

CONCLUSIONS

The result of this meta-analysis indicated that diabetes mellitus was associated with a lower risk of aortic dissection.

Effect of Glycation on Interlamellar Bonding of Arterial Elastin

BACKGROUND

Interlamellar bonding in the arterial wall is often compromised by cardiovascular diseases. However, several recent nationwide and hospital-based studies have uniformly reported reduced risk of thoracic aortic dissection in patients with diabetes. As one of the primary structural constituents in the arterial wall, elastin plays an important role in providing its interlamellar structural integrity.

OBJECTIVE

The purpose of this study is to examine the effects of glycation on the interlamellar bonding properties of arterial elastin.

METHODS

Purified elastin network was isolated from porcine descending thoracic aorta and incubated in 2 M glucose solution for 7, 14 or 21 days at 37 °C. Peeling and direct tension tests were performed to provide complimentary information on understanding the interlamellar layer separation properties of elastin network with glycation effect. Peeling tests were simulated using a cohesive zone model (CZM). Multiphoton imaging was used to visualize the interlamellar elastin fibers in samples subjected to peeling and direct tension.

RESULTS

Peeling and direct tension tests show that interlamellar energy release rate and strength both increases with the duration of glucose treatment. The traction at damage initiation estimated for the CZM agrees well with the interlamellar strength measurements from direct tension tests. Glycation was also found to increase the interlamellar failure strain of arterial elastin. Multiphoton imaging confirmed the contribution of radially running elastin fibers to resisting dissection.

CONCLUSIONS

Nonenzymatic glycation reduces the propensity of arterial elastin to dissection. This study also suggests that the CZM effectively describes the interlamellar bonding properties of arterial elastin.

Effect of diabetes mellitus on the dissection properties of the rabbit descending thoracic aortas

Effect of diabetes mellitus (DM) on the dissection properties of thoracic aortas remains largely unclear and relevant biomechanical analysis is lacking. In the present study forty adult rabbits (1.6-2.2 kg) were collected and type 1 diabetic rabbit model was induced by injection of alloxan. A total of 10 control and 30 diabetic (with different time exposure to diabetic condition) rabbit descending thoracic aortas were harvested. Peeling tests were performed to quantitatively determine force/width values and dissection energy in the control and diabetic aortas. Histological and mass fraction analyses were performed to characterize the dissected morphology and to quantify dry weight percentages of elastin and collagen. The resisting force/width values were significantly higher for the diabetic thoracic aortas (in 8 weeks) than those of the control thoracic aortas (axial: 26.1 ± 4.0 vs. 20.5 ± 3.1 mN/mm, p = 0.04; circ: 19.7 ± 2.8 vs. 15.3 ± 1.9 mN/mm, p = 0.03). There was a higher resistance to the dissection in both axial and circumferential directions for the diabetic aortas. The dissection energy generated by axial and circumferential peeling of the diabetic aortas (in 6 and 8 weeks) was statistically significantly higher than that of the control aortas (axial: 5.6 ± 0.7 vs. 4.3 ± 0.5 mJ/cm², p = 0.02; circ: 3.9 ± 0.3 vs. 3.2 ± 0.3 mJ/cm², p = 0.02). Histology showed that dissection mainly occurred in the aortic media and the dissected surfaces were close to external elastic lamina for some specimens. The mass fractions of collagen within the diabetic aortas increased significantly as compared to the control aortas, whereas no significant change was found for that of elastin. Our data suggest that the experimentally induced DM may lead to a lower propensity of dissection for the rabbit thoracic aortas. The dissection properties of the rabbit thoracic aortas vary with time exposed to diabetic condition.

Risk Factors Associated With Reintervention After Thoracic Endovascular Aortic Repair for Descending Aortic Pathologies

BACKGROUND:

Thoracic endovascular aortic repair (TEVAR) is associated with several short-term benefits, including reduced morbidity and mortality; however, the long-term durability of TEVAR and the need for secondary aortic reintervention remain unclear. We aimed to determine the adverse outcomes, including aortic reintervention, after TEVAR for thoracic aortic aneurysms and dissection.

METHODS:

Between October 2009 and July 2016, 130 patients underwent TEVAR at Kyungpook National University Hospital. We excluded 35 patients with traumatic injury and included the remaining 95 patients in our study after TEVAR. The patients included in this study were categorized into 2 groups (reintervention [R] and nonintervention [N] groups) according to the need for reintervention. The mean follow-up period for all 95 patients was 22.4 (20.6) months.

RESULTS:

The overall actuarial survival rates were 83.7% (4.1%) and 63.6% (8.8%) at 1 and 5 years, respectively. The rates of freedom from aortic reintervention after TEVAR were 94.0% (3.5%), 72.8% (8.2%), and 48.9% (10.5%) at 2, 3, and 5 years, respectively. The independent risk factors for aortic reintervention were endoleaks after TEVAR (odds ratio [OR] 6.13, P = .017), increase in aortic size by over 5% per year (OR 20.40, P = .001), and peripheral vascular occlusive disease (PVOD; OR 13.62, P = .007). Patients with preoperative hemoptysis tended to show a greater need for aortic reintervention ( P = .059). Increase in aortic size by over 5% per year and PVOD were the primary risk factors for endoleaks (OR 3.82, P = .013 and OR 4.37, P = .021, respectively).

CONCLUSION:

Survival after TEVAR for thoracic aortic pathologies was satisfactory in most of the patients chosen as candidates for the procedure. However, the occurrence of endoleaks, increase in aortic size by over 5% per year, and PVOD were the primary causes of aortic reintervention.

Reduced Long-Term Risk of Aortic Aneurysm and Aortic Dissection Among Individuals With Type 2 Diabetes Mellitus: A Nationwide Observational Study

BACKGROUND

No studies have examined long-term risks for aortic aneurysm (AA) and aortic dissection (AD) or mortality after AA or AD hospitalization among patients with type 2 diabetes mellitus (T2DM).

METHODS AND RESULTS

In this observational cohort study, we linked data for patients with T2DM in the Swedish National Diabetes Register, and 5 individually matched population-based control subjects (CSs) without diabetes mellitus (on the basis of sex, age, and county), to other national databases to capture hospitalizations and death. We examined the risk of hospitalization for AA and AD, as well as mortality risk after AA and AD using Kaplan-Meier curves and Cox regression hazards models. Data on 448 319 patients with T2DM and 2 251 015 CSs were obtained between 1998 and 2015. Mean follow-up time was 7.0 years for the T2DM group and 7.2 years for the CS group. Patients with T2DM had a relative risk reduction of 28% (hazard ratio, 0.72; 95% confidence interval, 0.68-0.76; P<0.0001) for AA and a 47% relative risk reduction (hazard ratio, 0.53; 95% confidence interval, 0.42-0.65; P<0.0001) for AD compared with CSs. Patients with T2DM had a relative risk reduction of 12% (hazard ratio, 0.88; 95% confidence interval, 0.82-0.94; P<0.0001) for mortality after hospitalization for AA, and unaltered risk (hazard ratio, 1.07; 95% confidence interval, 0.85-1.34; P=0.5859) for mortality after AD, up to 2 years compared with CSs.

CONCLUSIONS

Patients with T2DM had significantly reduced risks of AA and AD as well as reduced risk of mortality after hospitalization for AA, compared to CS. Data suggest that glycated cross-links in aortic tissue may play a protective role in the progression of aortic diseases among patients with T2DM.

Therapeutics Targeting Drivers of Thoracic Aortic Aneurysms and Acute Aortic Dissections: Insights from Predisposing Genes and Mouse Models

Thoracic aortic diseases, including aneurysms and dissections of the thoracic aorta, are a major cause of morbidity and mortality. Risk factors for thoracic aortic disease include increased hemodynamic forces on the ascending aorta, typically due to poorly controlled hypertension, and heritable genetic variants. The altered genes predisposing to thoracic aortic disease either disrupt smooth muscle cell (SMC) contraction or adherence to an impaired extracellular matrix, or decrease canonical transforming growth factor beta (TGF-β) signaling. Paradoxically, TGF-β hyperactivity has been postulated to be the primary driver for the disease. More recently, it has been proposed that the response of aortic SMCs to the hemodynamic load on a structurally defective aorta is the primary driver of thoracic aortic disease, and that TGF-β overactivity in diseased aortas is a secondary, unproductive response to restore tissue function. The engineering of mouse models of inherited aortopathies has identified potential therapeutic agents to prevent thoracic aortic disease.

Autonomic remodeling may be responsible for decreased incidence of aortic dissection in STZ-induced diabetic rats via down-regulation of matrix metalloprotease 2

Background

Epidemiological studies reported that diabetic patients had a lower incidence of aortic dissection (AD), but the definite mechanism is unknown. We aim to investigate the possible protective effect of diabetes mellitus (DM) on AD formation with an emphasis on autonomic remodeling.

Methods

Streptozotocin (STZ) intraperitoneal injection was applied to induce diabetes, unilateral renal artery stenosis (URAS) together with β-amino propionitrile (BAPN) oral treatment was used to induce AD. Sixty SD rats were equally and randomly divided into four groups (normal group, DM group, URAS + BAPN oral treatment group, DM + URAS + BAPN oral treatment group). Rats were fed for 6 weeks, the number of AD was recorded and remained rats were sacrificed. Thoracic aorta were harvested, morphological changes were assessed. Expression of tyrosine hydroxylase (TH), choline acetylase (ChAT), matrix metalloprotease 2 (MMP2) and matrix metalloprotease 9 (MMP9) were evaluated.

Results

A total of 7 AD was noted in S + B group, DM rats did not develop AD. Diabetic rats had a lower incidence of AD (P < 0.01). In dissected aorta, collagen deposition increased while elastic fiber became fragmented. These pathological changes diminished in diabetic rats. Diabetic rats had a lower expression of ChAT (P < 0.01). URAS + BAPN treatment elevated expression of TH in normal rat and ChAT in diabetic rats (P < 0.001). Expression of MMP2 and MMP9 elevated in all the rats after URAS + BAPN, but the elevation range of MMP2 in diabetic rats was smaller (P < 0.001).

Conclusions

STZ-induced diabetic rats have a lower incidence of AD after URAS and BAPN treatment, this protective effect could be possibly attributed to autonomic innervation modification and possible related down-regulation of MMP2.

Negative Association of Diabetes With Thoracic Aortic Dissection and Aneurysm

We performed a meta-analysis to assess the association of diabetes mellitus (DM) with the presence of thoracic aortic dissection (TAD) and/or thoracic aortic aneurysm (TAA). MEDLINE and EMBASE were searched through December 2015 using PubMed and OVID. For each study, data regarding DM prevalence in both the TAD/TAA and control groups were used to generate unadjusted odds ratios (ORs) for DM and 95% confidence intervals (CIs). Alternatively, an unadjusted and/or adjusted OR was directly abstracted from each individual study. Eleven eligible studies enrolling a total of 47 827 participants were included. A primary pooled analysis of all the 11 studies demonstrated that TAD/TAA was associated with significantly lower DM prevalence than controls (OR, 0.43; 95% CI, 0.31-0.59; P < .00001). Separate pooled analyses of 6 TAD case studies and 4 TAA case studies demonstrated TAD (OR, 0.34; 95% CI, 0.19-0.61; P = .0003) and TAA (OR, 0.65; 95% CI, 0.45-0.94; P = .02) were associated with significantly lower DM prevalence than controls. In conclusion, DM may be negatively associated with the presence of TAD/TAA.

Association between Diabetes and Risk of Aortic Dissection: A Case-Control Study in a Chinese Population

Background

It is well-recognized that diabetes represents a powerful independent risk factor for cardiovascular diseases. However, very few studies have investigated the relationship between diabetes and risk of aortic dissection (AD).

Aim

The aim of this case-control study was to evaluate the association between diabetes and risk of AD in Chinese population.

Methods

A hospital-based case-control study, consisting of 2160 AD patients and 4320 controls, was conducted in a Chinese population. Demographic, clinical characteristics and risk factors were collected. Diabetes rate of patients with overall AD, Stanford type A AD and type B AD group was compared with that of corresponding matched control groups. Logistic regression analysis was used to estimate the odds ratios (OR) and 95% confidence intervals (95% CI) for relationship between diabetes and AD risk.

Results

The prevalence of diabetes was lower in AD cases than that of control subjects, whether it is the overall AD, type A AD or type B AD group (4.7% vs. 10.0%, 2.9% vs. 8.8%, 5.9% vs. 10.9%, all P<0.001). Furthermore, in multivariate model, diabetes was found to be associated with lower AD risk, which not only applies to the overall AD (OR = 0.2, 95%CI: 0.15–0.26), but also type A AD (OR = 0.12, 95% CI: 0.07–0.20) and type B AD (OR = 0.25, 95%CI: 0.18–0.33).

Conclusions

We observed the paradoxical inverse relationship between DM and risk of AD in the Chinese population. These results suggest diabetes may play a protective role in the development of AD. However, further studies are needed to enrich related evidence, especially with regard to underlying mechanisms for these trends.