Elastin degradation in the superficial temporal arteries of patients with intracranial aneurysms reflects changes in plasma elastase

Correlation of periodontal diseases with intracranial aneurysm formation: novel predictive indicators

Background

We investigated whether periodontal diseases, specifically, periodontitis and gingivitis, could be risk factors of the incidence of intracranial aneurysms (IAs).

Methods

We performed a case–control study to compare the differences in the periodontal disease parameters of 281 cases that were divided into the IAs group and non-IAs group. All cases underwent complete radiographic examination for IAs and examination for periodontal health.

Results

Comparing with those in the non-IAs group, the cases in the IAs group were older (53.95 ± 8.56 vs 47.79 ± 12.33, p < 0.001) and had a higher incidence of hypertension (76 vs 34, p = 0.006). Univariate logistic regression analysis revealed that age (> 50 years) and hypertension were predictive risk factors of aneurysm formation (odds ratio [OR] 1.047, 95% confidence interval [95% CI] 1.022–1.073, p < 0.001 and OR 2.047, 95% CI 1.232–3.401, p = 0.006). In addition, univariate and multivariate logistic regression analyses showed that the parameters of periodontal diseases, including gingival index, plaque index, clinical attachment loss, and alveolar bone loss, were significantly associated with the occurrence of IAs (all p < 0.05). For further statistical investigation, the parameters of periodontal diseases were divided into four layers based on the quartered data. Poorer periodontal health condition (especially gingival index > 1.1 and plaque index > 1.5) had the correlation with IAs formation (p = 0.007 and p < 0.001).

Conclusion

Severe gingivitis or periodontitis, combining with hypertension, is significantly associated with the incidence of IAs.

Neutrophil Extracellular Traps Promote the Development of Intracranial Aneurysm Rupture

[Figure: see text].

Intracranial Aneurysm Biomarker Candidates Identified by a Proteome-Wide Study

The scientific basis of intracranial aneurysm (IA) formation, its rupture and further development of cerebral vasospasm is incompletely understood. Aberrant protein expression may drive structural alterations of vasculature found in IA. Deciphering the molecular mechanisms underlying these events will lead to identification of early detection biomarkers and in turn, improved treatment outcomes. To unravel differential protein expression in three clinical subgroups of IA patients: (1) unruptured aneurysm, (2) ruptured aneurysm without vasospasm, (3) ruptured aneurysm who developed vasospasm, we performed untargeted quantitative proteomic analysis of aneurysm tissue and serum samples from three subgroups of IA patients and control subjects. Candidate molecules were then validated in a larger cohort of patients using enzyme-linked immunosorbent assay. A total of 937 and 294 proteins were identified from aneurysm tissue and serum samples, respectively. Several proteins that are known to maintain structural integrity of vasculature were found to be dysregulated in the context of aneurysm. ORM1, a glycoprotein, was significantly upregulated in both tissue and serum samples of unruptured aneurysm patients. We employed a larger cohort of subjects (n = 26) and validated ORM1 as a potential biomarker for screening of unruptured aneurysms. Samples from ruptured aneurysms with vasospasm showed significant upregulation of MMP9, a protease, compared with ruptured aneurysms without vasospasm. We validated MMP9 as a potential biomarker for vasospasm in a larger cohort (n = 52). This study reports the first global proteomic analysis of the entire clinical spectrum of IA. Furthermore, this study suggests ORM1 and MMP9 as potential biomarkers for unruptured aneurysm and cerebral vasospasm, respectively.

Role of oral pathogens in the pathogenesis of intracranial aneurysm: review of existing evidence and potential mechanisms

Degeneration of intracranial aneurysm wall is under active research and recent studies indicate an increased risk of rupture of intracranial aneurysm among patients with periodontal diseases. In addition, oral bacterial DNA has been identified from wall samples of ruptured and unruptured aneurysms. These novel findings led us to evaluate if oral diseases could predispose to pathological changes seen on intracranial aneurysm walls eventually leading to subarachnoid hemorrhage. The aim of this review is to consider mechanisms on the relationship between periodontitis and aneurysm rupture, focusing on recent evidence.

High Serum Level of Matrix Metalloproteinase-7 Is Associated With Increased Risk of Spontaneous Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Increased degradation of the extracellular matrix in the arterial wall by matrix metalloproteinases (MMPs) may be an important mechanism in the pathogenesis of intracranial aneurysms and subarachnoid hemorrhage (SAH). MMP-2 and MMP-9 have been suggested to be involved in matrix degradation preceding SAH. We studied serum levels of MMP-1, -2, -3, -7, -9, -10, and -12 and the risk of incident SAH.

METHODS

A nested case-control study within the population-based cohort, Malmö Diet and Cancer study, was performed including incident cases of spontaneous SAH (n=79) and controls matched by age, sex, and follow-up time (n=232). MMPs were measured in serum from the baseline examination in 1991 to 1996. MMPs were compared between cases and controls, using conditional logistic regression adjusting for risk factors.

RESULTS

Baseline levels of MMP-7, MMP-10, and MMP-12 were significantly higher in incident SAH cases compared with controls. Odds ratios (95% confidence interval) for SAH per 1 SD increase of MMP-7, MMP-10, and MMP-12 were 1.78 (1.31-2.41), 1.45 (1.11-1.91), and 1.53 (1.17-2.01), respectively. After adjustment for SAH risk factors, MMP-7 was still significantly associated with SAH (odds ratio: 1.64; 95% confidence interval: 1.19-2.27; P=0.0026), whereas associations for MMP-10 and MMP-12 were attenuated and nonsignificant. We did not find any association between high serum levels of MMP-2 or MMP-9 and SAH risk.

CONCLUSIONS

High serum level of MMP-7 was associated with increased risk of incident spontaneous SAH, independently of the main risk factors for SAH. High serum levels of MMP-2 and MMP-9 did not predict SAH risk.

Pulmonary artery rupture during Swan-Ganz catheterisation: a case report

Catheter-induced pulmonary artery rupture is an infrequent complication that may occur during invasive cardiopulmonary monitoring. Fatal cases are uncommon and result from hemoptysis and flooding of the opposite lung with resulting hypoyxia. Alpha-1-antitrypsin deficiency is a rare genetic disorder characterised by low serum levels of alpha-1-antitrypsin, critical in maintaining connective tissue integrity. Besides pulmonary emphysema, recent observations suggest that alpha-1-antitrypsin deficiency may also be involved in vascular wall weakening, thereby predisposing arteries to dissection and aneurysm formation. In this article, we describe an autopsy case of pulmonary artery iatrogenic rupture due to insertion of a Swan-Ganz catheter in an 82-year-old woman suffering from pulmonary hypertension and alpha-1-antitrypsin deficiency. The exact source of bleeding could not be precisely identified during autopsy due to the extent of tissue hemorrhage, though postmortem angiography revealed a contrast medium extravasation from a branch of the left pulmonary lower lobar artery. The case herein emphasises the importance of postmortem angiography in facilitating the detection of vascular injuries, the importance of familiarity with intensive care techniques and procedures on behalf of forensic pathologists as well as in-depth knowledge of all possible contributing conditions and predisposing disorders in the pathogenesis of death.

Molecular Genetics of Human Intracranial Aneurysms

Intracranial aneurysms (IAs) are the dilatations of blood vessels in the brain and pose potential risk of rupture leading to subarachnoid hemorrhage. Although the genetic basis of IAs is poorly understood, it is well-known that genetic factors play an important part in the pathogenesis of IAs. Therefore, the identifying susceptible genetic variants might lead to the understanding of the mechanism of formation and rupture of IAs and might also lead to the development of a pharmacological therapy. To elucidate the molecular pathogenesis of diseases has become a crucial step in the development of new treatment strategies. Although extensive genetic research and its potential implications for future prevention of this often fatal condition are urgently needed, efforts to elucidate the susceptibility loci of IAs are hindered by the issues bewildering the most common and complex genetic disorders, such as low penetrance, late onset, and uncertain modes of inheritance. These efforts are further complicated by the fact that many IA lesions remain asymptomatic or go undiagnosed. In this review, we present and discuss the current status of genetic studies of IAs and we recommend comprehensive genome-wide association studies to identify genetic loci that underlie this complex disease.

Genetics Of Intracranial Aneurysms

Despite advances in the treatment of intracranial aneurysms (IA) in recent years, the overall outcome of patients with aneurysmal subarachnoid hemorrhage has shown only modest improvement. Given this poor prognosis, diagnosis of IA before rupture is of paramount importance. Currently, there are no reliable methods other than screening imaging studies of high-risk individuals to diagnose asymptomatic patients. Multiple levels of evidence suggest that environmental factors acting in concert with genetic susceptibilities lead to the formation, growth, and rupture of aneurysms in these patients. Epidemiological studies have already identified aneurysm-specific risk factors such as size and location, as well as patient-specific risk factors, such as age, sex, and presence of medical comorbidities, such as hypertension. In addition, exposure to certain environmental factors such as smoking have been shown to be important in the formation of IA. Furthermore, substantial evidence proves that certain loci contribute genetically to IA pathogenesis. Genome-wide linkage studies using relative pairs or rare families that are affected with the Mendelian forms of IA have already shown genetic heterogeneity of IA, suggesting that multiple genes, alone or in combination, are important in the disease pathophysiology. The linkage results, along with association studies, will ultimately lead to the identification of IA susceptibility genes. Identification of the genes important in IA pathogenesis will not only provide novel insights into the primary determinants of IA, but will also result in new opportunities for early diagnosis in the preclinical setting. Ultimately, novel therapeutic strategies based on biology will be developed, which will target these newly elucidated genetic susceptibilities.

Differential gene expression in human abdominal aorta: aneurysmal versus occlusive disease

OBJECTIVE

Inflammation and atherosclerosis are present in both abdominal aortic aneurysm (AAA) and arterial occlusive disease (AOD). Changes in gene expression that underlie the development of AAA versus AOD are poorly defined. This study evaluated differences in gene expression in AAA, AOD, and control aortic tissue with human gene array technology.

METHODS

RNA was isolated from human aortic specimens (seven AAA, five AOD, and five control), and complementary DNA (cDNA) probes were generated. The cDNA probes were hybridized to a human cell interaction array of 265 genes and quantitated with phosphorimaging. The data were corrected for background and were standardized to housekeeping genes. Statistical differences in individual gene expression were determined with the Kruskal-Wallis test.

RESULTS

Of 265 genes studied, 11 showed statistically different expression in diseased aorta as compared with control. The following three genes were downregulated in AAA: collagen VI alpha1 (P <.037), glycoprotein IIIA (P <.006), and alpha2-macroglobulin (P <.020). The following two genes were upregulated in AOD: laminin alpha4 (P <.034) and insulin-like growth factor 2 receptor (P <.049). The following three genes were upregulated in both AAA and AOD: matrix metalloproteinase-9 (MMP-9; P <.005), intercellular adhesion molecule-1 (P <.012), and tumor necrosis factor--beta receptor (P <.022). The following three genes were downregulated in both AAA and AOD: integrin alpha5 (P <.012), ephrin A5 (P <.037), and rho/rac guanine nucleotide exchange factor (P <.028). Of 16 MMPs evaluated, only MMP-9 was significantly (P <.005) upregulated in both AAA and AOD. Evaluation results of four tissue inhibitors of metalloproteinases showed no significant difference in expression for all tissue types, although tissue inhibitor of metalloproteinase-1 trended toward upregulation in AAA (P =.053). Eight of the fifteen most highly expressed genes in all the groups were extracellular matrix or secreted proteins. Of these, only collagen VI alpha1 (P <.037) showed a significant change, although biglycan trended toward downregulation in AAA (P =.076).

CONCLUSION

This study used cDNA array technology in the comparison of human control and pathologic aortic tissue. Six genes had similar differential expression in both AAA and AOD as compared with control. Even more interesting were differences between AAA and AOD in the expression of five genes. These data suggest a similarity in genetic expression for both AAA and AOD, with altered expression of several genes playing a role in disease differentiation.

Alpha-1 antitrypsin deficiency and splenic artery aneurysm rupture: an association?

OBJECTIVE

Theoretically, patients with alpha 1-antitrypsin deficiency may be vulnerable to the development of splenic artery aneurysms. alpha-1 antitrypsin deficiency can induce cirrhosis with portal hypertension, and resulting protease-antiprotease imbalances may exaggerate arterial wall weakness due to proteolysis of arterial structural proteins. A splenic artery aneurysm rupture 7 days after liver transplantation provoked a reassessment of the incidence of this phenomenon in a liver transplant population.

METHODS

Case records from three institutions and the results of a survey sent to 126 liver transplantation programs in the United Network for Organ Sharing database were reviewed. The incidence of splenic artery aneurysm rupture in the peritransplantation period, etiology of liver disease associated with this phenomenon, and recommendations regarding management of splenic artery aneurysms was assessed.

RESULTS

Twenty-one cases of splenic artery aneurysm rupture were identified. alpha-1 antitrypsin deficiency was the most common cause of cirrhosis in the majority of identified patients who presented with splenic artery aneurysm rupture, which was associated with a mortality rate of 57%. Respondents to the survey indicated that a preoperative evaluation was warranted if a splenic artery aneurysm was suspected; however, no consensus regarding management exists.

CONCLUSIONS

The presence and risk of rupture of splenic artery aneurysms may be greater in patients with alpha-1 antitrypsin deficiency. If identified before rupture, an aggressive approach to diagnosing and treating these aneurysms should be initiated. At present, no consensus exists regarding the management of splenic artery aneurysms.

Cigarette smoking and the development and rupture of cerebral aneurysms in a mixed race population: implications for population screening and smoking cessation

BACKGROUND

Despite advances in the treatment of aneurysmal subarachnoid hemorhage (aSAH), major additional reductions in morbidity will require the identifications of unruptured aneurysms with a high propensity for bleeding. As screening the entire population is currently not cost-effective, risk factors for the presence of unruptured aneurysms must be identified, and if possible, these risk factors should be modified to reduce disease prevalence.

METHODS

To examine whether cigarette smoking independent of arterial hypertension is a risk factor for the development of cerebral aneurysms rather than just being associated with aSAH and to determine whether smoking cessation decreases this risk, we conducted a case-control study comparing the prevalence and degree of smoking in a consecutive series of patients undergoing surgery for ruptured or unruptured aneurysm with age-, sex-, race-, and geographically matched control subjects culled from the New York Healthy Heart Study.

RESULTS

Hypertension alone carries little additional risk for the development of ruptured or unruptured aneurysms. Smoking is a risk factor for not only aneurysmal subarachnoid hemorrhage (Relative Risk [RR]=2.83) but also aneurysm formation (RR=2.33). Coexistent hypertension increases the risk of smoking only minimally. Younger smokers are at threefold higher risk than middle-aged ones. Smoking cessation appears to reduce risk of aneurysmal rupture. The effect of smoking on aneurysm formation and rupture may be dose-dependent.

CONCLUSIONS

Together these data suggest that smoking, independent of hypertension, plays a critical role in aneurysm development, especially in younger patients, but that physiological mechanisms exist for repair of the damage induced by this toxic insult if cessation is possible.

Actinically degenerate elastic tissue is the likely antigenic basis of actinic granuloma of the skin and of temporal arteritis

Staining technique is paramount for detecting and assessing the severe degeneration that occurs in the elastic tissues of the skin and its arteries in response to prolonged exposure to actinic radiation. With a selective "controlled" hematoxylin-and-eosin stain, actinically damaged ("elastotic") elastic tissue stains blue, as Unna described, and contrasts with normal and simply hyperplastic elastic tissue, which stains red. "Special" elastic stains such as Orcein and Verhoeff do not demonstrate this difference. When resorptive (elastolytic) giant cell reactions develop in relation to actinically degenerate elastic tissue of the skin, the papules that arise tend to form expanding, annular rings. A previously used and appropriate name for these autoimmune lesions in the skin is actinic granuloma because this name highlights the likely actinic origin and pathogenesis of many such lesions. Granulomatous inflammation in connection with actinically degenerate internal elastic lamina appears to be the basis of temporal arteritis. Actinic granulomas may occur in the skin concurrently with temporal arteritis. A recent study of temporal arteritis strongly relates its elastic tissue changes to those of "accelerated" atherosclerosis.