Can statins suppress the development of abdominal aortic aneurysms? A review of the current evidence

The effects of statin therapy on aneurysm size, growth rate, and matrix metalloproteinases-9 levels in patients with aortic aneurysm: a systematic review and meta-analysis

BACKGROUND

Aortic aneurysm enlargement over time causes rupture, which frequently results in death. The family of proteases known as matrix metalloproteinases (MMP) is assumed to be proteolytic activity involved in the growth of aortic aneurysms. Statins are pleiotropic lipid-lowering medications with anti-inflammatory action. Statins can lower aneurysmal enlargement and MMP secretion, according to a number of studies, however the evidence is still up for debate. The purpose of this study is to assess how statins affect aortic aneurysm patient's aneurysm diameter size, growth rate, and MMP-9 levels.

METHODS

From January 2000 to December 2022, electronic journal searches in PubMed, ScienceDirect, and Cochrane were conducted to discover papers evaluating the effects of statin treatment in patients with aortic aneurysm. Aneurysm diameter size, growth rate, and MMP-9 levels were the outcomes we were looking for. Meta-analyses were run on the included studies, and mean differences (MD) and 95% CIs were calculated with Review Manager v5.4.

RESULTS

Our analysis includes a total of ten research. Statin medication substantially reduced aneurysm diameter size by 0.30 mm (P = 0.04; MD - 0.30; 95% CI - 0.58 to - 0.01) and growth rate by 0.34 mm/year (P < 0.00001; MD - 0.34; 95% CI - 0.40 to - 0.29) compared to placebo. There was no significant change in MMP-9 concentrations between individuals with aortic aneurysm who took a statin and those who did not.

CONCLUSION

Overall, this meta-analysis demonstrates that statin medication is considerably helpful in reducing aneurysm diameter size and aneurysmal growth rate in individuals with aortic aneurysm.

Research advances in drug therapy for abdominal aortic aneurysms over the past five years: An updated narrative review

BACKGROUND

Abdominal aortic aneurysms (AAA) rupture can lead to patient death. Surgical treatment is currently the optimal treatment for AAA with large diameter (≥50 mm). For AAA with small diameter (30-50 mm), how to administer effective pharmacological treatment to reduce aneurysm expansion rate and rupture risk is the current focus in the field of vascular surgery. There is still no effective drug for the treatment of asymptomatic AAA.

METHODS

This article searches the PubMed, Web of Science, Embase, and Cochrane databases for clinical studies on the drug treatment of abdominal aortic aneurysms in the past 5 years. The latest progress in the drug treatment of AAA was reviewed, including antibiotics, antihypertensive drugs, antiplatelet drugs, hypoglycemic drugs, hypolipidemic drugs, mast cell inhibitors and corticosteroids.

RESULTS

25 studies were included in this narrative review. Among them, metformin revealed therapeutic effect in 2 prospective cohort study and 3 retrospective cohort study. The therapeutic effect of statins was controversial in 3 retrospective cohort study. However, the definite therapeutic effects of antihypertensive agents, antibiotics, mast cell inhibitors, antiplatelet agents and corticosteroids on abdominal aortic aneurysms have not been verified in prospective studies.

CONCLUSION

Metformin provided a positive effect in reducing expansion rate, rupture risk, and perioperative mortality. The therapeutic effect of statins was controversial, which warrant further validation in prospective cohorts. However, there is still a lack of effective agents for the treatment of AAA based on recent studies.

Effect of Acupuncture on the p38 Signaling Pathway in Several Nervous System Diseases: A Systematic Review

Acupuncture is clinically used to treat various diseases and exerts positive local and systemic effects in several nervous system diseases. Advanced molecular and clinical studies have continually attempted to decipher the mechanisms underlying these effects of acupuncture. While a growing understanding of the pathophysiology underlying several nervous system diseases shows it to be related to inflammation and impair cell regeneration after ischemic events, the relationship between the therapeutic mechanism of acupuncture and the p38 MAPK signal pathway has yet to be elucidated. This review discusses the latest advancements in the identification of the effect of acupuncture on the p38 signaling pathway in several nervous system diseases. We electronically searched databases including PubMed, Embase, and the Cochrane Library from their inception to April 2020, using the following keywords alone or in various combinations: "acupuncture", "p38 MAPK pathway", "signaling", "stress response", "inflammation", "immune", "pain", "analgesic", "cerebral ischemic injury", "epilepsy", "Alzheimer's disease", "Parkinson's disease", "dementia", "degenerative", and "homeostasis". Manual acupuncture and electroacupuncture confer positive therapeutic effects by regulating proinflammatory cytokines, ion channels, scaffold proteins, and transcription factors including TRPV1/4, Nav, BDNF, and NADMR1; consequently, p38 regulates various phenomena including cell communication, remodeling, regeneration, and gene expression. In this review article, we found the most common acupoints for the relief of nervous system disorders including GV20, GV14, ST36, ST37, and LI4. Acupuncture exhibits dual regulatory functions of activating or inhibiting different p38 MAPK pathways, contributing to an overall improvement of clinical symptoms and function in several nervous system diseases.

A Pilot Study of Protein Microarray for Simultaneous Analysis of 274 Cytokines Between Abdominal Aortic Aneurysm and Normal Aorta

Cytokines play an important role in the pathogenesis of abdominal aortic aneurysm (AAA). We evaluated the cytokine expression profile of large AAA walls using a 274-cytokine protein array. We hypothesized that AAAs are characterized by an inflammatory, chemotactic cytokine profile. We investigated the cytokine expression profile of 12 patients with AAA and 6 nonaneurysmal controls using an antibody-based protein array. The array generated antibodies against homogenized human aortic tissues to validate the cytokines differentially expressed in AAAs and normal aortas. Data were quantified using fluorescent signal intensities and statistically analyzed by the t test. Fifty-nine cytokines were differentially expressed between the AAA and control samples. Of the 35 selected cytokines that had relative expression >1000, 29 were significantly higher and 6 were lower in AAA samples than in controls. They respectively belonged to CC chemokines, CXC chemokines, pro-inflammatory cytokines, growth factors, proteolytic proteins and inhibitors, and cell adhesion cytokines. Our results show that distinct cytokines are involved in AAAs and suggest that the pathways involving these cytokines may be associated with the pathogenesis and development of AAAs. These findings, if confirmed by larger studies, may suggest treatment targets.

C-reactive protein polymorphism rs3091244 is associated with abdominal aortic aneurysm

BACKGROUND

Abdominal aortic aneurysm (AAA) formation involves an inflammatory process with a strong genetic background. C-reactive protein (CRP) regulates inflammation and is elevated in patients with AAA. The aim of this study was to investigate the association of the triallelic (C, A, and T alleles) rs3091244 functional CRP single nucleotide polymorphism (SNP) with AAA.

METHODS

This was a case-control study involving two independent populations: 351 AAA patients (mean aortic diameter, 6.25 ± 1.47 cm) and 391 controls (mean diameter, 2.4 ± 0.2 cm) were recruited from Greece (the main cohort); and 371 patients (mean diameter, 5.4 ± 1.0 cm) and 362 controls (mean diameter, 2.4 ± 0.6 cm) were recruited from the United Kingdom (replication cohort). The frequency of the functional triallelic (C, T, and A alleles) rs3091244 polymorphism was analyzed in univariate and adjusted (for cardiovascular risk factors) analyses, assuming that the rare T and A alleles have similar functional properties (pooled analysis for T and A). Three groups were constructed: group A included those with the rare T and A alleles (genotypes TT, AA, and TA), group B included heterozygotes for the C allele (CT, CA), and group C included C allele homozygotes (CC, reference genotype). Finally, meta-analysis of the two populations was performed together with previously reported results.

RESULTS

Genotype distributions differed significantly between cases and controls in both cohorts (P < .001 and P = .001). Adjusted analysis (for all aneurysm-related risk-factors) showed an estimated odds ratio of 4.88 (95% confidence interval [CI], 2.96-8.04) for SNP group A and 2.38 (95% CI, 1.69-3.36) for SNP group B (P < .001 in both cases) in the initial cohort and 2.07 (95% CI, 1.33-3.21) for SNP group A and 1.70 (95% CI, 1.21-2.39) for SNP group B (P = .001 and .002) in the replication cohort. The SNP group A patients among the main cohort also had higher CRP levels (median, 26; interquartile range, 17-52 mg/L vs median, 4; interquartile range, 4-12 mg/L; P < .001). Aneurysms >5.5 cm were significantly more frequent among the SNP groups A and B compared with C allele homozygotes both in the main and the replication cohorts (P < .001 and P = .001, respectively). Meta-analysis of the two populations with previously reported results showed a positive association between minor-allele and aneurysm presence with an odds ratio of 1.47 (95% CI, 1.01-2.14; I(2) = 83.1%; P = .04).

CONCLUSIONS

The rare T and A alleles were significantly related with AAA presence in both populations and correlated with higher CRP levels and AAA diameter.

Statins and noncardiac vascular disease

PURPOSE OF REVIEW

To discuss the beneficial effects of statin treatment in patients with peripheral arterial disease (PAD), abdominal aortic aneurysms (AAAs), atherosclerotic renal artery stenosis (ARAS) and carotid artery disease.

RECENT FINDINGS

Evidence suggests that statins may reduce the progression (or even reverse the development) of carotid artery stenosis and AAAs. Statins also improve several indices (e.g. serum creatinine) and preserve renal function in ARAS. In patients with PAD, statins are associated with improved claudication distance and time, reduced cardiovascular events, and improved graft patency rates should these patients undergo surgery. Finally, statins are associated with improved perioperative and long-term morbidity and mortality rates in all vascular patients whether they undergo surgery or endovascular procedures.

SUMMARY

Routine statin treatment should be implemented for all vascular patients to ensure a reduced progression of their disease, as well as a reduction in cardiovascular events.

Statin therapy reduces growth of abdominal aortic aneurysms

BACKGROUND

The aim of this study was to evaluate the influence of statins on the growth of small abdominal aortic aneurysms (AAAs).

METHODS

We retrospectively examined AAA diameter in 211 patients who had undergone serial imaging surveillance.

RESULTS

Patients treated with and without statins were similar regarding age, initial aneurysm size, diagnosis of diabetes and hypertension, and smoking history. Patients receiving statins had a decreased aneurysm growth rate compared with those patients not receiving statins (0.9 mm/y [interquartile range, -1.0 to +1.0] vs 3.2 mm/y [interquartile range, 2.0-4.9], P < 0.0001). This difference in the rate of growth was maintained after adjusting for potential confounding factors.

CONCLUSIONS

To date, this is the one of the largest retrospective studies demonstrating an association between statin use and decreased growth rate of AAA.

Local and systemic alterations in signal transducers and activators of transcription (STAT) associated with human abdominal aortic aneurysms

BACKGROUND

Signal transducers and activators of transcription (STAT) proteins are transcription factors that, when activated by phosphorylation, regulate gene expression and cellular activity. The aim of this study was to evaluate the local and systemic expression and activation of STAT proteins associated with abdominal aortic aneurysms (AAA).

METHODS

Expression and activation of STAT proteins were assessed in aortic wall samples obtained from patients undergoing repair of AAA (n = 9) and from non-aneurysmal (NA) donors (n = 17). Aortic samples were evaluated for mRNA and protein expression for STAT1, 2, 3, 4, 5a, and 5b using RT-PCR and immunoblot (WB) assays and normalized to ß-actin (expressed as arbitrary units). STAT activation was assessed with WB assays using phosphorylated (p)-STAT-specific antibodies. Alterations in STAT activation were calculated by normalizing pSTAT proteins to corresponding total STAT levels. Immunohistochemistry was performed on AAA and NA samples using the total and pSTAT antibodies. Systemic alterations in STAT activation were assessed by evaluating circulating leukocytes for the presence of pSTAT from patients with AAA (AAA, n = 8), repaired aneurysm (RA, n = 8), or age/gender matched controls with no AAA (CT, n = 8). Flow cytometry was performed to assess for circulating levels of STAT1 (pY701), STAT3 (pY705), and STAT5a (pY694) in monocytes, granulocytes, and lymphocytes. Assessments were made at baseline and in response to in vitro stimulation with IFN-γ (50 ng/mL) or IL-6 (100 ng/mL). Results were analyzed using Student's t-test and are expressed as mean ± SEM.

RESULTS

In AAA tissue compared with NA, STAT-1 (1.08 ± 0.09 versus 0.62 ± 0.07), -2 (0.98 ± 0.07 versus 0.55 ± 0.08), and -4 (0.89 ± 0.12 versus 0.35 ± 0.11) mRNA levels were elevated (P < 0.01, all). Corresponding increases in STAT protein were only observed for STAT1 (2.77 ± 0.93 versus 0.93 ± 0.08, P < 0.05). Increases in activation were observed in AAA compared with NA in pSTAT2 (0.77 ± 0.1 versus 0.1 ± 0.02, P < 0.01), pSTAT3 (1.6 ± 0.3 versus 0.2 ± 0.06, P < 0.02) and pSTAT5 (0.57 ± 0.03 versus 0.2 ± 0.03, P < 0.05) levels. Phosphorylated STAT1, 2, 3, and 5 were observed in inflammatory cells invading the AAA adventitia. In addition, STAT3 was observed in the media of AAA and NA, but pSTAT3 was only observed in the media of AAA. There were no differences in baseline levels of pSTAT-positive circulating leukocytes. IFN-γ stimulation decreased STAT-5a (pY694)-positive CT lymphocytes to 40% ± 13% of baseline, but had no effect on AAA or RA lymphocytes (116% ± 35%, 102% ± 19%, respectively; P = 0.01). STAT-5a (pY694)-positive CT granulocytes also decreased to 62% ± 18% of baseline compared with AAA or RA granulocytes (122% ± 25%, 126% ± 17%, respectively; P = 0.01). Alterations in STAT1 (pY701) and STAT3 (pY705) were not observed in leukocytes following cytokine stimulation.

CONCLUSIONS

STAT proteins are important regulators of transcriptional activity and have been linked to cardiovascular disease. The present data suggest that altered levels of phosphorylated STATs are associated with AAA. Understanding their role may provide further insight into the mechanisms of AAA formation and allow for the development of medical treatment options.

Abdominal aortic aneurysm: a review of the genetic basis

BACKGROUND

Abdominal aortic aneurysm (AAA) is a complex disease with a largely unknown pathophysiological background and a strong genetic component. Various studies have tried to link specific genetic variants with AAA.

METHODS

Systematic review of the literature (1947-2009).

RESULTS

A total of 249 studies were identified, 89 of which were eventually deemed relevant to this review. Genetic variants (polymorphisms) in a wide variety of genes, most of which encode proteolytic enzymes and inflammatory molecules, have been associated with AAA development and progression.

CONCLUSION

The genetic basis of AAA remains unknown, and most results from ''candidate-gene'' association studies are contradictory. Further analyses in appropriately powered studies in large, phenotypically well-characterized populations, including genome-wide association studies, are necessary to elucidate the exact genetic contribution to the pathophysiology of AAA.