Presence of Borrelia burgdorferi sensu lato antibodies in the serum of patients with abdominal aortic aneurysms

Status of diagnosis and therapy of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are characterized by localized dilation of the abdominal aorta. They are associated with several serious consequences, including compression of adjacent abdominal organs, pain, treatment-related financial expenditure. The main complication of AAA is aortic rupture, which is responsible for about 200,000 deaths per year worldwide. An increasing number of researchers are dedicating their efforts to study AAA, resulting in significant progress in this field. Despite the commendable progress made thus far, there remains a lack of established methods to effectively decelerate the dilation of aneurysms. Therefore, further studies are imperative to expand our understanding and enhance our knowledge concerning AAAs. Although numerous factors are known to be associated with the occurrence and progression of AAA, the exact pathway of development remains unclear. While asymptomatic at most times, AAA features a highly unpredictable disease course, which could culminate in the highly deadly rupture of the aneurysmal aorta. Current guidelines recommend watchful waiting and lifestyle adjustment for smaller, slow-growing aneurysms, while elective/prophylactic surgical repairs including open repair and endovascular aneurysm repair are recommended for larger aneurysms that have grown beyond certain thresholds (55 mm for males and 50 mm for females). The latter is a minimally invasive procedure and is widely believed to be suited for patients with a poor general condition. However, several concerns have recently been raised regarding the postoperative complications and possible loss of associated survival benefits on it. In this review, we aimed to highlight the current status of diagnosis and treatment of AAA by an in-depth analysis of the findings from literatures.

Abdominal Aortic Aneurysms (Etiology, Epidemiology, and Natural History)

Abdominal aortic aneurysm is a potentially lethal condition that is decreasing in frequency as tobacco use declines. The exact etiology remains unknown, but smoking and other perturbations seem to trigger an inflammatory state in the tunica media. Male sex and advanced age are clear demographic risk factors for the development of abdominal aortic aneurysms. The natural history of this disease varies, but screening remains vital as it is rarely diagnosed on physical examination, and elective repair (most commonly done endovascularly) offers significant morbidity and mortality advantages over emergent intervention for aortic rupture.

Mycotic abdominal aortic aneurysm caused by Borrelia afzelii: a case report

Background

Inflammatory aneurysms and mycotic aneurysms make up a minority of abdominal aortic aneurysms. Mainly autoimmune mechanisms are proposed in the pathogenesis of inflammatory aneurysms, and it is not routine to check for infectious agents as disease culprits.

Case presentation

A 58-year-old European male with complaints of abdominal and back pain for 8 weeks was admitted after a semi-urgent computed tomography scan revealed an 85 mm inflammatory abdominal aortic aneurysm. The patient had normal vital signs, slightly elevated inflammatory markers, and mild anemia on admission. Clinical examination revealed a tender pulsating mass in his abdomen. His clinical condition was interpreted as impending rupture and urgent repair of the aneurysm was deemed necessary. Due to the patient’s relatively young age and aneurysm neck morphology, open aortic repair was preferred. Preoperatively, the aneurysm appeared inflamed, with fibrous wall thickening and perianeurysmal adhesions. Aneurysm wall biopsies were sent to histopathological and microbiological diagnostics. Routine cultures were negative, but 16S rRNA gene real-time polymerase chain reaction was positive and Borrelia afzelii was identified by DNA sequencing of the polymerase chain reaction product. B. afzelii was also identified by sequencing the polymerase chain reaction product of a Borrelia-specific groEL target. Immunoglobulin G and M anti-Borrelia antibodies were present on serological analysis. Histopathological analysis displayed loss of normal aortic wall structure and diffuse infiltration of lymphocytes and plasma cells. The patient had an uneventful recovery and was discharged after 1 week to a regional rehabilitation facility. Though the patient fares clinically well and inflammatory markers had normalized, antimicrobial treatment with doxycycline continues at 3 months follow-up due to remaining radiologic signs of inflammation.

Conclusions

Borrelia infection in the setting of acute aortic pathology is a rare entity. To our knowledge, this is the first case report to demonstrate a mycotic abdominal aortic aneurysm as a rare manifestation of Lyme disease. Aortic wall biopsies and real-time polymerase chain reaction analysis of the specimen were essential for accurate diagnosis. This finding may contribute to the understanding of the etiology of inflammatory aneurysmal disease and abdominal aneurysms in general.

Fluoroquinolones and the Risk of Aortic Aneurysm or Aortic Dissection: A Systematic Review and Meta-Analysis

OBJECTIVES

We performed a systematic review and meta-analysis to explore the risk of an aortic aneurysm or aortic dissection following fluoroquinolone administration.

METHODS

PubMed, Cochrane library, ClinicalTrials.gov, Embase and Google Scholar were systematically reviewed for controlled studies including adult patients exposed to fluoroquinolones with a primary outcome of aortic aneurysm or aortic dissection.

RESULTS

The meta-analysis was conducted by pooling the effect estimates of four controlled observational studies (one case-control, one case-crossover and two cohort studies). Fluoroquinolone administration more than doubled the risk to develop aortic aneurysm or aortic dissection within 60 days following fluoroquinolone exposure (adjusted Relative Risk [RR] (95% confidence interval [CI]) = 2.14 (1.93 - 2.36); I2 = 15.8%). The quality of the finding was rated as moderate. The risk increase for aortic aneurysm alone was found to be significant (adjusted RR (95% CI) = 2.23 (2.01 - 2.45); I2 = 0%) while the risk increase for aortic dissection alone was not found to be significant (adjusted RR = 1.88 (0.11 - 3.65); I2 = 74%). In subgroup analysis, the risk increase for aortic aneurysm or aortic dissection appeared to be higher in females compared to males (RR = 1.87 (1.24 - 2.51); I2 = 0% versus RR = 1.58 (1.25 - 1.92); I2 = 0%, respectively) and higher in older patients compared to younger patients (RR = 1.72 (1.37 - 2.07); I2 = 0% versus RR = 1.47 (0.91 - 2.04); I2 = 0%, respectively). Subgroup analysis of two studies which measured the duration-response analysis found that as the duration of fluoroquinolone therapy increased from 3 to 14 days to greater than 14 days, there was an increased risk of aortic aneurysm or dissection.

CONCLUSION

The findings of this meta-analysis confirm the positive association between fluoroquinolones and the development of aortic aneurysm or dissection. The data tend to show that this association may be majorly driven by aortic aneurysm. Additionally, some risk factors appear to prevail including prolonged fluoroquinolone treatment and older age.

Cerebral vasculitis and intracranial multiple aneurysms in a child with Lyme neuroborreliosis

Introduction. Lyme borreliosis is a multisystem tick-borne disease caused by Borrelia burgdorferi. Neurological manifestations are reported in up to 15 % of adult patients with Lyme disease, while the frequency among children is higher. The most common manifestations are painful radiculopathy, facial nerve paresis and lymphocytic meningitis. Epileptic seizures and cerebral vasculitis with stroke or aneurysms are very rare complications.

Case presentation. We describe a paediatric patient with sensorineural auditory dysfunction, headache, fatigue and epileptic seizures as sequelae of meningoencephalitis/Lyme neuroborreliosis (LNB) caused by B. burgdorferi. Brain magnetic resonance imaging revealed widespread enhancement of the leptomeninges, cranial nerves and artery walls compatible with vasculitis and disturbances in cerebrospinal fluid (CSF) circulation. The patient was treated with ceftriaxone for 2 weeks. Two years later, the patient had an ischemic stroke. Brain magnetic resonance angiography revealed multiple aneurysms, which were not present previously. The largest aneurysm was operated rapidly. The patient was treated with another course of intravenous ceftriaxone for 4 weeks and pulse therapy with corticosteroids. He recovered well.

Cerebrovascular Manifestations of Lyme Neuroborreliosis-A Systematic Review of Published Cases

BACKGROUND

Lyme neuroborreliosis (LNB) is a disease caused by spirochete Borrelia burgdorferi, involving the nervous system. It usually manifests as lymphocytic meningoradiculitis, but in rare cases, it can also lead to cerebrovascular complications. We aimed to perform a systematic review of all reported cases of LNB complicated by central nervous system vasculitis and stroke or transient ischemic attack (TIA).

MATERIALS AND METHODS

We conducted a systematic review of literature between May 1987 and December 2016 with patients who presented with cerebrovascular course of LNB.

RESULTS

This study included 88 patients with a median age of 46 years. The median interval from onset of symptoms suggesting Lyme disease to first symptoms of cerebrovascular manifestations of LNB was 3.5 months. The most common cerebrovascular manifestation of LNB was ischemic stroke (76.1%), followed by TIA (11.4%). The posterior circulation was affected alone in 37.8% of patients, the anterior circulation in 24.4% of patients, and in 37.8% of cases, posterior and anterior circulations were affected simultaneously. The most common affected vessels were middle cerebral artery-in 19 cases, basilar artery-in 17 cases, and anterior cerebral artery-in 16 cases. A good response to antibiotic treatment was achieved in the vast number of patients (75.3%). The overall mortality rate was 4.7%.

CONCLUSION

Cerebral vasculitis and stroke due to LNB should be considered, especially in patients who live in or have come from areas with high prevalence of tick-borne diseases, as well as in those without cardiovascular risk factors, but with stroke-like symptoms of unknown cause.

Understanding the pathogenesis of abdominal aortic aneurysms

An aortic aneurysm is a dilatation in which the aortic diameter is ≥3.0 cm. If left untreated, the aortic wall continues to weaken and becomes unable to withstand the forces of the luminal blood pressure resulting in progressive dilatation and rupture, a catastrophic event associated with a mortality of 50-80%. Smoking and positive family history are important risk factors for the development of abdominal aortic aneurysms (AAA). Several genetic risk factors have also been identified. On the histological level, visible hallmarks of AAA pathogenesis include inflammation, smooth muscle cell apoptosis, extracellular matrix degradation and oxidative stress. We expect that large genetic, genomic, epigenetic, proteomic and metabolomic studies will be undertaken by international consortia to identify additional risk factors and biomarkers, and to enhance our understanding of the pathobiology of AAA. Collaboration between different research groups will be important in overcoming the challenges to develop pharmacological treatments for AAA.

The Abdominal Aortic Aneurysm and Intraluminal Thrombus: Current Concepts of Development and Treatment

The pathogenesis of the abdominal aortic aneurysm (AAA) shows several hallmarks of atherosclerotic and atherothrombotic disease, but comprises an additional, predominant feature of proteolysis resulting in the degradation and destabilization of the aortic wall. This review aims to summarize the current knowledge on AAA development, involving the accumulation of neutrophils in the intraluminal thrombus and their central role in creating an oxidative and proteolytic environment. Particular focus is placed on the controversial role of heme oxygenase 1/carbon monoxide and nitric oxide synthase/peroxynitrite, which may exert both protective and damaging effects in the development of the aneurysm. Treatment indications as well as surgical and pharmacological options for AAA therapy are discussed in light of recent reports.

Update on abdominal aortic aneurysm research: from clinical to genetic studies

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta with a diameter of at least 3.0 cm. AAAs are often asymptomatic and are discovered as incidental findings in imaging studies or when the AAA ruptures leading to a medical emergency. AAAs are more common in males than females, in individuals of European ancestry, and in those over 65 years of age. Smoking is the most important environmental risk factor. In addition, a positive family history of AAA increases the person's risk for AAA. Interestingly, diabetes has been shown to be a protective factor for AAA in many large studies. Hallmarks of AAA pathogenesis include inflammation, vascular smooth muscle cell apoptosis, extracellular matrix degradation, and oxidative stress. Autoimmunity may also play a role in AAA development and progression. In this Outlook paper, we summarize our recent studies on AAA including clinical studies related to surgical repair of AAA and genetic risk factor and large-scale gene expression studies. We conclude with a discussion on our research projects using large data sets available through electronic medical records and biobanks.

Opportunities in abdominal aortic aneurysm research: epidemiology, genetics, and pathophysiology

Aortic aneurysms are a complex genetic disorder with known environmental risk factors such as smoking. Along the length of the aorta, significant heterogeneity occurs in the distribution of aneurysmal disease. The prevalence of aneurysm in the abdominal aorta is at least nine times higher than that in the thoracic section of the aorta. A number of studies have shown that aortic aneurysms are frequently familial, even when they are not associated with rare heritable disorders such as Marfan syndrome or Ehlers-Danlos syndrome type IV. The pathobiology of aortic aneurysms is complex and largely unsolved. Unbiased whole-genome approaches are now being used to elucidate the genetic basis of aortic aneurysms to uncover the germline genetic variants that influence the disease risk. The findings will provide critical information about underlying biology of the disease and will help identify potential targets for pharmacological therapies. These studies may lead to therapies that may increase survival rates for individuals with aortic aneurysms and reduce the need for surgical interventions. Abdominal aortic aneurysms were the topic of an international conference "Abdominal Aortic Aneurysm: Epidemiology, Genetics, and Pathophysiology" held recently at the Geisinger Clinic, Danville, Pennsylvania.

Novel pathways in the pathobiology of human abdominal aortic aneurysms

OBJECTIVES

Abdominal aortic aneurysm (AAA), a dilatation of the infrarenal aorta, typically affects males >65 years. The pathobiological mechanisms of human AAA are poorly understood. The goal of this study was to identify novel pathways involved in the development of AAAs.

METHODS

A custom-designed 'AAA-chip' was used to assay 43 of the differentially expressed genes identified in a previously published microarray study between AAA (n = 15) and control (n = 15) infrarenal abdominal aorta. Protein analyses were performed on selected genes.

RESULTS

Altogether 38 of the 43 genes on the 'AAA-chip' showed significantly different expression. Novel validated genes in AAA pathobiology included ADCY7, ARL4C, BLNK, FOSB, GATM, LYZ, MFGE8, PRUNE2, PTPRC, SMTN, TMODI and TPM2. These genes represent a wide range of biological functions, such as calcium signaling, development and differentiation, as well as cell adhesion not previously implicated in AAA pathobiology. Protein analyses for GATM, CD4, CXCR4, BLNK, PLEK, LYZ, FOSB, DUSP6, ITGA5 and PTPRC confirmed the mRNA findings.

CONCLUSION

The results provide new directions for future research into AAA pathogenesis to study the role of novel genes confirmed here. New treatments and diagnostic tools for AAA could potentially be identified by studying these novel pathways.