High homocysteine and low folate concentrations in acute aortic dissection

A Comprehensive Exploration of Novel Biomarkers for the Early Diagnosis of Aortic Dissection

Aortic dissection (AD) is a catastrophic life-threatening cardiovascular emergency with a 1-2% per hour mortality rate post-diagnosis, characterized physiologically by the separation of aortic wall layers. AD initially presents as intense pain that can then radiate to the back, arms, neck or jaw along with neurological deficits like difficulty in speaking, and unilateral weakness in some patients. This spectrum of clinical features associated with AD is often confused with acute myocardial infarction, hence leading to a delay in AD diagnosis. Cardiac and vascular biomarkers are structural proteins and microRNAs circulating in the bloodstream that correlate to tissue damage and their levels become detectable even before symptom onset. Timely diagnosis of AD using biomarkers, in combination with advanced imaging diagnostics, will significantly improve prognosis by allowing earlier vascular interventions. This comprehensive review aims to investigate emerging biomarkers in the diagnosis of AD, as well as provide future directives for creating advanced diagnostic tools and imaging techniques.

New Directions in Diagnostics for Aortic Aneurysms: Biomarkers and Machine Learning

This review article presents an appraisal of pioneering technologies poised to revolutionize the diagnosis and management of aortic aneurysm disease, with a primary focus on the thoracic aorta while encompassing insights into abdominal manifestations. Our comprehensive analysis is rooted in an exhaustive survey of contemporary and historical research, delving into the realms of machine learning (ML) and computer-assisted diagnostics. This overview draws heavily upon relevant studies, including Siemens' published field report and many peer-reviewed publications. At the core of our survey lies an in-depth examination of ML-driven diagnostic advancements, dissecting an array of algorithmic suites to unveil the foundational concepts anchoring computer-assisted diagnostics and medical image processing. Our review extends to a discussion of circulating biomarkers, synthesizing insights gleaned from our prior research endeavors alongside contemporary studies gathered from the PubMed Central database. We elucidate the prevalent challenges and envisage the potential fusion of AI-guided aortic measurements and sophisticated ML frameworks with the computational analyses of pertinent biomarkers. By framing current scientific insights, we contemplate the transformative prospect of translating fundamental research into practical diagnostic tools. This narrative not only illuminates present strides, but also forecasts promising trajectories in the clinical evaluation and therapeutic management of aortic aneurysm disease.

Tracking an Elusive Killer: State of the Art of Molecular-Genetic Knowledge and Laboratory Role in Diagnosis and Risk Stratification of Thoracic Aortic Aneurysm and Dissection

The main challenge in diagnosing and managing thoracic aortic aneurysm and dissection (TAA/D) is represented by the early detection of a disease that is both deadly and “elusive”, as it generally grows asymptomatically prior to rupture, leading to death in the majority of cases. Gender differences exist in aortic dissection in terms of incidence and treatment options. Efforts have been made to identify biomarkers that may help in early diagnosis and in detecting those patients at a higher risk of developing life-threatening complications. As soon as the hereditability of the TAA/D was demonstrated, several genetic factors were found to be associated with both the syndromic and non-syndromic forms of the disease, and they currently play a role in patient diagnosis/prognosis and management-guidance purposes. Likewise, circulating biomarker could represent a valuable resource in assisting the diagnosis, and several studies have attempted to identify specific molecules that may help with risk stratification outside the emergency department. Even if promising, those data lack specificity/sensitivity, and, in most cases, they need more testing before entering the “clinical arena”. This review summarizes the state of the art of the laboratory in TAA/D diagnostics, with particular reference to the current and future role of molecular-genetic testing.

Association of biomarkers related to preoperative inflammatory and coagulation with postoperative in-hospital deaths in patients with type A acute aortic dissection

The aim of this study was to analyze the role of blood biomarkers regarding preoperative inflammation and coagulation in predicting the postoperative in-hospital mortality of patients with type A acute aortic dissection (AAD). A total of 206 patients with type A AAD who had received surgical treatment were enrolled in this study. Patients were divided into two groups: the death group (28 patients who died during hospitalization) and the survival group (178 patients). Peripheral blood samples were collected before anesthesia induction. Preoperative levels of D-dimer, fibrinogen (FIB), platelet (PLT), white blood cells (WBC) and neutrophil (NEU) were compared between the two groups. Univariable and multivariable logistic regression analysis were utilized to identify the independent risk factors for postoperative in-hospital deaths of patients with type A AAD. Receiver operating characteristic (ROC) curve were used to analyze the predictive value of these indices in the postoperative in-hospital mortality of the patients. Univariable logistic regression analysis showed that the P values of the five parameters including D-dimer, FIB, PLT, WBC and NEU were all less than 0.1, which may be risk factors for postoperative in-hospital deaths of patients with type A AAD. Further multivariable logistic regression analysis indicated that higher preoperative D-dimer and WBC levels were independent risk factors for postoperative in-hospital mortality of patients with type A AAD. ROC curve analysis indicated that application of combining FIB and PLT could improve accuracy in prediction of postoperative in-hospital mortality in patients with type A AAD. Both preoperative D-dimer and WBC in patients with type A AAD may be used as independent risk factors for the postoperative in-hospital mortality of such patients. The combination of FIB and PLT may improve the accuracy of clinical prognostic assessment.

Current progress on the mechanisms of hyperhomocysteinemia-induced vascular injury and use of natural polyphenol compounds

Cardiovascular disease is one of the most common diseases in the elderly population, and its incidence has rapidly increased with the prolongation of life expectancy. Hyperhomocysteinemia is an independent risk factor for various cardiovascular diseases, including atherosclerosis, and damage to vascular function plays an initial role in its pathogenesis. This review presents the latest knowledge on the mechanisms of vascular injury caused by hyperhomocysteinemia, including oxidative stress, endoplasmic reticulum stress, protein N-homocysteinization, and epigenetic modification, and discusses the therapeutic targets of natural polyphenols. Studies have shown that natural polyphenols in plants can reduce homocysteine levels and regulate DNA methylation by acting on oxidative stress and endoplasmic reticulum stress-related signaling pathways, thus improving hyperhomocysteinemia-induced vascular injury. Natural polyphenols obtained via daily diet are safer and have more practical significance in the prevention and treatment of chronic diseases than traditional drugs.

The analysis of the levels of plasma inflammation-related cytokines and endotoxins in patients with acute aortic dissection

OBJECTIVE

To investigate the changes in the levels of plasm interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), matrix metalloproteinase-9 (MMP-9) and endotoxins in patients with acute aortic dissection (AAD).

METHODS

55 AAD patients who were admitted and scheduled to undergo emergency surgery in our hospital from January 2017 to July 2017 were selected and retrospectively analyzed. They were divided into the survival group (n = 40) and the death group (n = 15). The levels of plasma IL-6, TNF-α, CRP, MMP-9 and endotoxins at admission and at 6 h, 12 h and 24 h after admission (T0, T1, T2 and T3) were measured, and the correlations of inflammatory cytokines with endotoxins were analyzed.

RESULTS

At T1, T2 and T3, the levels of inflammatory cytokines and endotoxins were increased. The levels of plasma IL-6, TNF-α, CRP, MMP-9 and endotoxins in the death group were significantly higher than those in the survival group at each time point (p < 0.05 in all comparisons). Neutrophil and platelet counts in the death group were higher than those in the survival group (p < 0.05). Correlation analyses indicated that the levels of IL-6, TNF-α, CRP and MMP-9 were positively correlated with the level of endotoxin.

CONCLUSION

Patients with AAD are often accompanied by systemic inflammatory responses, with inflammation-related cytokines (IL-6, TNF-α, CRP and MMP-9) and endotoxins levels significantly elevated. Combined monitoring of dynamic changes in inflammatory cytokines and endotoxins, as well as early interventions, has important clinical implications for evaluating the prognosis of AAD and reducing mortality.

Relationship between total plasma homocysteine and the risk of aneurysms - a meta-analysis

Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

Platelet to lymphocyte ratio in acute aortic dissection

BACKGROUND

Inflammation plays an important role in the initiation and progression of acute aortic dissection (AAD). New inflammatory indices derived from full cell blood count and its differential may be associated with increased risk. We evaluated platelet-lymphocyte (PLR), red cell distribution width (RDW) and RDW/PLT's (platelets) (RPR) in AAD.

METHODS

We studied 120 consecutive patients with AAD type I admitted for emergency surgery (group I), 121 consecutive patients with aortic aneurysms of the ascending aorta prior to elective repair (group II) and 121 controls (group III), age and sex matched.

RESULTS

PLR was significantly higher in group I vs both groups II and III (P < .001). There was an excellent correlation of PLR with neutrophil/lymphocyte ratio (NLR) in all three groups (P < .001 for all). After adjustment for hemoglobin, RDW did not differ but RPR remained significantly higher in group I compared to groups II and III (P < .001). The best cutoff value of PLR to predict dissection was 159 with 53% sensitivity and 86% specificity. No association between PLR, RDW, and RPR and mortality in group I was found.

CONCLUSIONS

Indices derived from full cell blood count may provide diagnostic information in patients with AAD; whether these indices may contribute to prognosis assessment should be further investigated.

Clinical Parameters and Gut Microbiome Changes Before and After Surgery in Thoracic Aortic Dissection in Patients with Gastrointestinal Complications

Thoracic aortic dissection (TAAD) is one of the most common types of aortic diseases. Although surgery remains the main method of treatment, the high rate of postoperative gastrointestinal complications significantly influences the effects of surgery and the recovery process. Moreover, the mechanisms underlying this disease remain unclear. To address these problems, we examined changes in the gut microbiota in 40 thoracic aortic dissection patients with abdominal complications after surgery. Levels of white blood cells (WBC), neutrophile granulocytes (NE), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were higher in all patients after surgery. Levels of inflammatory cytokines, including interleukin (IL)-2, IL-6, IL-8, and IL-10, were also higher after surgery. A metagenome analysis revealed that levels of Oscillibacter, Anaerotruncus, Alistipes, and Clostridium difficile were higher after the operation. The abundance of functional genes, such as the spermidine/putrescine transport system permease protein, the flagellar motor switch protein, and branched-chain amino acid transport system proteins, was also higher post-surgery. These changes likely contribute to diarrhea, bloating, gastrointestinal bleeding, and other abdominal complications after surgery, and our research opens up new treatment possibilities for patients suffering from abdominal complications after surgical treatment.

Is there a role for biomarkers in thoracic aortic aneurysm disease?

Thoracic aortic aneurysm (TAA) represents a major cause of mortality and morbidity in Western countries. The natural history of TAA is indolent, with patients usually being asymptomatic until a catastrophic event such as rupture or dissection ensues. As such, early diagnosis is crucial and the search is ongoing for a biomarker that can indicate the presence of TAA with sufficient accuracy to act as a screening tool. To date, no such marker has been developed for the diagnosis of non-familial or 'sporadic' TAA. However, our increased understanding of the pathogenesis of both familial and sporadic TAA has suggested potential candidates for diagnostic biomarkers. Many markers/pathways have been shown to have differential activity levels or expression in the aortic tissue of TAA. However, priority is given to markers that have shown differential levels in blood plasma, as blood tests represent the easiest route for mass screening for TAA. This review aims to evaluate the efficacy of clinical tests already in use in diagnosing TAA, explore novel proposed biomarkers and identify key areas of future interest.

Moderately Elevated Homocysteine Does Not Contribute to Thoracic Aortic Aneurysm in Mice

Background: Moderate hyperhomocysteinemia is an attractive target for intervention because it is present in 5-7% of the population and can be reversed by diet. This approach presupposes that hyperhomocysteinemia is directly involved in the disease process. Epidemiologic studies have indicated that moderately elevated homocysteine may contribute to thoracic aortic aneurysm (TAA) dilatation and dissection in humans. In vitro, elevated homocysteine disrupts the structure and function of extracellular matrix components, suggesting that moderate hyperhomocysteinemia may contribute to the development and/or progression of TAA.Objective: We investigated moderately elevated homocysteine in the development and progression of TAA in a mouse model of Marfan syndrome (MFS) and in isogenic wild-type mice. The MFS mouse is a well-described model of a systemic connective tissue disorder characterized by thoracic aortic dilatation, dissection, and rupture. We used this model as a sensitized indicator system to examine the impact of homocysteine on the progression of TAA.Methods: Murine fibrillin 1 gene (Fbn1)^C1039G/+ MFS and C57BL/6J wild-type mice were fed a cobalamin-restricted diet to induce moderate hyperhomocysteinemia from weaning until the age of 32 wk. Homocysteine and methylmalonic acid were measured and aortic root diameter assessed with the use of echocardiography in mice aged 3, 7, 15, and 32 wk.Results: Cobalamin-restricted mice exhibited significantly higher homocysteine (P < 0.0001) and methylmalonic acid (P < 0.0001) in the blood. For both strains, no significant difference in thoracic aortic diameter was observed in mice on the cobalamin-restricted diet compared with those on the control diet.Conclusions:Fbn1^C1039G/+ mice are a well-characterized model of progressive aortic root dilation. Hyperhomocysteinemia in the physiologic range did not induce abnormal aortic growth in wild-type mice and did not accelerate or otherwise influence aortic root growth and pathologic progression in mice with an underlying predisposition for aortic dilatation.

Gene polymorphisms as risk factors for predicting the cardiovascular manifestations in Marfan syndrome. Role of folic acid metabolism enzyme gene polymorphisms in Marfan syndrome

Folic acid metabolism enzyme polymorphisms are believed to be responsible for the elevation of homocysteine (HCY) concentration in the blood plasma, correlating with the pathogenesis of aortic aneurysms and aortic dissection. We studied 71 Marfan patients divided into groups based on the severity of cardiovascular involvement: no intervention required (n=27, Group A); mild involvement requiring intervention (n=17, Group B); severe involvement (n=27, Group C) subdivided into aortic dilatation (n=14, Group C1) and aortic dissection (n=13, Group C2), as well as 117 control subjects. We evaluated HCY, folate, vitamin B12 and the polymorphisms of methylenetetrahydrofolate reductase (MTHFR;c.665C>T and c.1286A>C), methionine synthase (MTR;c.2756A>G) and methionine synthase reductase (MTRR;c.66A>G). Multiple comparisons showed significantly higher levels of HCY in Group C2 compared to Groups A, B, C1 and control group (p<0.0001, p<0.0001, p=0.001 and p=0.003, respectively). Folate was lower in Group C2 than in Groups A, B, C1 and control subjects (p<0.0001, p=0.02, p<0.0001 and p<0.0001, respectively). Group C2 had the highest prevalence of homozygotes for all four gene polymorphisms. Multivariate logistic regression analysis revealed that HCY plasma level was an independent risk factor for severe cardiovascular involvement (Group C; odds ratio [OR] 1.85, 95% confidence interval [CI] 1.28-2.67, p=0.001) as well as for aortic dissection (Group C2; OR 2.49, 95%CI 1.30-4.78, p=0.006). In conclusion, severe cardiovascular involvement in Marfan patients, and especially aortic dissection, is associated with higher HCY plasma levels and prevalence of homozygous genotypes of folic acid metabolism enzymes than mild or no cardiovascular involvement. These results suggest that impaired folic acid metabolism has an important role in the development and remodelling of the extracellular matrix of the aorta.

High neutrophil to lymphocyte ratio in type A acute aortic dissection facilitates diagnosis and predicts worse outcome

OBJECTIVE

The authors investigated whether neutrophil to lymphocyte ratio (N/L) can contribute to the diagnosis and risk assessment in patients with type A acute aortic dissection (AAD).

METHODS

The authors studied 120 consecutive patients with type A AAD (group I) and compared them with 121 consecutive patients with chronic aneurysms (group II) and 121 age- and sex-matched healthy subjects (group III).

RESULT

It was found that white blood cell count, N/L, D-dimer and C-reactive protein were significantly higher in group I versus both groups II and III (p < 0.001 for all comparisons). White blood cell count and D-dimer were much higher in patients who died compared to survivors in group I (p = 0.023 and p = 0.033, respectively). A cutoff value of N/L >4.6 was associated with 0.89 sensitivity and 0.91 specificity for AAD.

CONCLUSION

High N/L may contribute to the diagnostic evaluation and prompt immediate therapy in patients with type A AAD.

Biomarkers for the diagnosis of aortic dissection

This review discusses the role of biomarkers for both diagnoses and disease monitoring before, during, and after treatment of aortic dissection.