Chiara Boiocchi

Inflammation and Atherosclerosis: The Role of TNF and TNF Receptors Polymorphisms in Coronary Artery Disease

Inflammation plays an important role in the pathogenesis of atherosclerosis and coronary syndromes; moreover, various lines of evidence suggest that genetic factors contribute significantly to the risk of coronary artery disease (CAD). Through its effects on endothelial function, coagulation, insulin resistance and lipid metabolism, the proinflammatory cytokine TNF could be involved in cardiovascular pathophysiology. The aim of our study is to analyze whether TNF gene promoter (-308 G/A; −857 G/A) and TNF receptor polymorphisms (TNFR1 MspA1 I exon 1 and TNFR2 Nla III exon 6) show involvement in CAD predisposition in a group of Italian patients compared with healthy controls. Genotyping was performed by PCR-RFLP. Consecutive Italian patients with angiographically proven CAD (n= 248) were compared with controls (n=241), matched for age, sex and geographical origins. CAD patients showed a higher frequency of the TNF −308 A allele than healthy controls (p=0.046). After stratification according to risk factors for CAD, our analysis revealed that CAD patients with diabetes (p=0.042) and CAD patients without hypertension (p=0.0495) displayed a higher frequency of the TNF −308 AA genotype compared with healthy controls. Our data stress the inflammatory nature of CAD and show a possible involvement of TNF −308G/A promoter polymorphisms in the predisposition to the development of this disease. The less frequent A allele seems to be a predisposing factor for development of CAD in particular pathological settings associated with the disease itself, such as diabetes.

The 374T/A RAGE Polymorphism Protects Against Future Cardiac Events in Nondiabetic Patients with Coronary Artery Disease

BACKGROUND The -374T/A polymorphism of the Receptor for Advanced Glycation End products (RAGE) may exert a protective effect toward the development of atherosclerosis. No data are currently available on the potential prognostic role of this polymorphism in patients with angiographically proven coronary artery disease (CAD). Hereto we sought to address this issue in a large consecutive cohort of patients undergoing coronary revascularization. METHODS A total of 643 CAD patients who underwent myocardial revascularization were followed for 4.2 years (interquartile range: 2.2-8.1 years). The rates of major cardiac adverse events (death, nonfatal myocardial infarction, and unstable angina) were compared according to the -374T/A RAGE polymorphism. RESULTS During a median follow-up period of 4.2 years, the study endpoint was reached by 126/643 patients (19.6%). We observed adverse cardiac events in 13.4% of patients with AA, 17.5% of those with AT, and 24.2% of those with TT genotype (p <0.05). In univariate Cox proportional hazard analysis, the AA genotype was significantly related to a better outcome in nondiabetic patients (hazard ratio: 0.47, 95% CI: 0.20-0.96; p <0.05). No association was found with adverse events in diabetic subjects. After allowance for potential confounders, the AA genotype remained a significant prognostic factor in the nondiabetic group (adjusted HR: 0.41, 95% CI: 0.17-0.94, p <0.05). CONCLUSIONS The -374T/A RAGE polymorphism is an independent protective factor for cardiac events in nondiabetic patients with CAD. The effect of this genetic variant seems to be attenuated in diabetics, who have chronic RAGE upregulation.

Age of Onset of Myocardial Infarction: Is Promoter Polymorphism of the RAGE Gene Implicated?

Receptor for advanced glycation endproducts (RAGE) is a cell-surface molecule member of the immunoglobulin superfamily and engages differing ligands relevant to distinct processes. A growing body of evidence has suggested that RAGE may promote vascular inflammation through several mechanisms. The objective of this study was to identify the possible relationship between the -374 T/A polymorphism of the RAGE gene, myocardial infarction (MI), and its age of onset. A total of 691 MI patients and 234 matched controls were investigated. In this study, the frequency of the A allele and AA genotype of the -374 T/A promoter polymorphism is significantly lower in patients with MI respect to the control group (p < 0.01). Our results showed a significant role of the AA genotype on age of onset of MI. In particular, the mean age of the first MI was higher in patients with the AA genotype as compared to those that were AT or TT genotype carriers (p = 0.002). The relationship between -374 T/A RAGE polymorphism and age for the appearance of MI was independently related to common risk factors of disease (p < 0.01). Kaplan-Meier curves confirmed that subjects with the AA genotype have a later development of MI (p = 0.0022). This study is the first to investigate the role of RAGE polymorphisms on the susceptibility to develop the acute coronary events in the Italian population and identified this polymorphism as an age-related factor for MI development. The homozygous AA genotype may exert a protective role against the early development of MI.

Brain-Derived Neurotrophic Factor Gene Variants and Alzheimer Disease: An Association Study in an Alzheimer Disease Italian Population

Brain-derived neurotrophic factor (BDNF) promotes neuronal survival during development and protects neurons from insults of various kinds. Changes in production of BDNF have been reported in differing neurodegenerative pathologies and, in particular, in Alzheimer disease (AD). We studied 200 AD patients and 408 healthy controls for BDNF Val66Met(G196A) polymorphism, 200AD and 384 healthy controls for BDNF 270 C/T polymorphism, and 200AD and 393 healthy controls for BDNF 11757 G/C polymorphism by restriction fragment length polymorphism (RFLP) and real-time PCR. Our results indicated that the 11757 G/C BDNF polymorphism was significantly associated with AD. A statistically significant increase of GG genotype frequency in AD versus healthy subjects (p=0.0331) was observed, whereas the CG genotype demonstrates a statistically significant decrease of frequency in AD patients versus controls (p=0.0194). We focused our attention on haplotype reconstruction: A statistically significant decrease of the TAC haplotype frequency in AD patients versus healthy controls group (p=0.005) and a statistically significant increase of the CAC haplotype frequency in patients versus control (p=0.019) was demonstrated. We then studied the haplotype frequencies dividing patients according to gender. A statistically significant increase of the CAC haplotype in the male AD group compared with male healthy controls (p=0.041) was found, whereas a statistically significant decrease of TAC haplotype frequency in AD females versus healthy females (p=0.005) and a statistically significant increase of CAC haplotype frequency in female patients versus healthy females (p=0.019) was noticed. We propose that these haplotypes could be a further effective marker for AD.

The -374T/A variant of the rage gene promoter is associated with clinical restenosis after coronary stent placement.

Upregulation of the receptor for advanced glycation end products (RAGE) may play a crucial role in neointimal formation upon vessel injury. The −374T/A variant of the RAGE gene promoter, which has been associated with an altered expression of the cell-surface receptor, could exert a protective effect toward the development of vascular disease. The aim of this study is to determine the impact of this common genetic variant in the occurrence of clinical in-stent restenosis after coronary stent implantation. The −374T/A polymorphism of the RAGE gene promoter was evaluated by PCR-RFLPs in 267 patients with coronary artery disease who underwent coronary stent implantation and a subsequent coronary angiography 6–9 months later for suspected restenosis. In-stent restenosis was assessed by means of quantitative angiography. Carriers of the-374AA genotype showed a significantly reduced risk of developing restenosis after percutaneous transluminal intervention than non-carriers. To determine whether the protective effect of the homozygous AA genotype toward clinical restenosis was independent of potential confounders, we performed multivariable logistic regression analysis. After allowance for clinical and biochemical risk factors and stent length, the AA genotype remained significantly associated with a reduced prevalence of in-stent restenosis. No relation was evident between the RAGE genotype and established cardiovascular risk factors. In conclusion, the −374AA genotype of the RAGE gene promoter could be associated with a reduced risk of in-stent restenosis after coronary stent implantation.

APJ polymorphisms in coronary artery disease patients with and without hypertension

Apelin is an endogenous peptide that increases cardiac inotropism through its APJ receptor. Certain findings indicate that the apelinergic system may have a pathophysiological role in cardiovascular disease and there is evidence showing the role of the apelinergic system in blood pressure regulation in vitro and in animal models. The role of the apelin-APJ system in cardiovascular physiology and its interaction with other neuroendocrine pathways has not been fully elucidated. However, the small number of reported studies indicates that apelin signaling may be involved in the regulation of blood pressure, cardiac contractile function, fluid balance, angiogenesis and inhibition of apoptosis. We evaluated the possible relationship between the G212A and A445C APJ polymorphisms and coronary artery disease (CAD) in Italian patients and in healthy controls by RFLP-PCR. We analyzed the allelic and genotypic frequencies of APJ polymorphisms in 664 patients (378 with hypertension) and 143 controls. There were no differences between allelic and genotypic frequencies in patients in respect to the controls for both polymorphisms analyzed. In the CAD population, there was an increased frequency of the G212 allele in patients with hypertension in respect to patients without hypertension. No differences were present in the two subgroups for the A445C polymorphism. Although the functional role of the G212A polymorphism has not yet been identified, it is possible to hypothesize that the presence of the A allele may cause a gain in function of the apelin/APJ system associated with a lower risk of hypertension.

Are Hsp70 protein expression and genetic polymorphism implicated in multiple sclerosis inflammation

Genetic and environmental factors contribute to disease Multiple Sclerosis (MS) susceptibility, the most prevalent neurological pathology affecting young individuals in Western countries. We focused our attention on HSP70-2, an inducible chaperon induced under stress conditions. Genotype analysis of HSP70-2 (+1267 A/G) polymorphism revealed a significant association between the minor allele G and presence of MS (OR:1.31, 95% CI: 1.02-1.69, P = 0.039). In addition, Hsp70-2 protein content in vitro from PBMC was significantly lower in MS patients with GG genotype compared to AA genotype, indicating an implication of the G allele of HSP70-2 gene polymorphism in the development of MS.

Association between two polymorphisms in the HLA-G gene and angiographic coronary artery disease.

Atherosclerosis and related complications still represent the major cause of morbidity and mortality in industrialized countries. Therefore, it is particularly important to investigate the molecules involved in cardiac inflammation. Evidence exists showing that the human leukocyte antigen‑G (HLA-G) gene tissue expression and related protein physiological significance is influenced by two polymorphisms, rs16375 and rs1632933. In this study, allelic, genotypic and haplotypic frequencies of a 14-bp insertion/deletion (Ins/Del) (rs16375) and of rs1632933 polymorphisms of the HLA-G gene were investigated in 664 patients with coronary artery disease (CAD) and 345 matched controls by polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis and real-time PCR. The frequency of the Ins/Ins genotype was significantly higher in patients with CAD compared to the controls (P=0.018). After analysis of confounding variables, the results showed that the homozygous Ins/Ins was significantly and independently associated with the presence of angiographic CAD (odds ratio 2.09, 95% confidence interval 1.10-4.02, P=0.03). Our data demonstrate a new risk factor for this multifactorial inflammatory disease.

Microalbuminuria and sRAGE in High-Risk Hypertensive Patients Treated with Nifedipine/Telmisartan Combination Treatment: A Substudy of TALENT

Some antihypertensive drugs have also renoprotective and anti-inflammatory properties that go beyond their effect on blood pressure. It has been suggested that microalbuminuria and glomerular filtration rate (GFR) are associated with circulating levels of the soluble form of the receptor, sRAGE (soluble receptor for advanced glycation ends-products). In the present analysis, we used data from the TALENT study to evaluate soluble receptor for advanced glycation end-products (sRAGE) plasma levels in patients with hypertension and high-cardiovascular risk-treated nifedipine and telmisartan in combination. Treatment with nifedipine-telmisartan significantly decreased mean systolic and diastolic ambulatory blood pressure and resulted in a significant increase in sRAGE plasma concentrations after 24 weeks of therapy. We concluded that in hypertensive patients with early-stage renal disease, sRAGE concentrations are not influenced by either microalbuminuria or GFR. Long-term treatment with a combination of nifedipine-telmisartan may have a beneficial effect increasing sRAGE plasma levels, thus exerting an atheroprotective and anti-inflammatory activity.

Relationship between sRAGE and eotaxin-3 with CRP in hypertensive patients at high cardiovascular risk.

BACKGROUND Cardiovascular disease (CVD) is the leading cause of death in Western countries and is highly prevalent in patients with kidney disease. Traditional risk factors for CVD often accompany kidney dysfunction, and chronic kidney disease per se is considered an additional risk factor. Risk stratification for CVD remains suboptimal even after the introduction of global risk assessment by various scores. This has prompted the search for novel markers of cardiovascular risk, and several biomarkers have been suggested as candidates, together with C-reactive protein (CRP). The objective of the present study was to investigate the relationship between novel biomarkers of vascular inflammation (soluble form of the receptor for advanced glycation end products [sRAGE] and eotaxin-3) with CRP in a population of hypertensive patients at high cardiovascular risk. METHODS Plasma sRAGE, high-sensitivity CRP (hs-CRP) and eotaxin-3 were measured in 399 hypertensive patients (265 men, mean age 58 ± 8 years)with diabetes mellitus, metabolic syndrome or organ damage. RESULTS Plasma concentrations of sRAGE, eotaxin-3 and hs-CRP were not different between diabetic and nondiabetic subjects. Univariate analysis showed that plasma levels of sRAGE and eotaxin-3 were not associated with hs-CRP in either subgroup. CONCLUSION Our study confirms the robust and widely studied role of CRP as an important marker of vascular inflammation. We also postulate the possible involvement of sRAGE and eotaxin, 2 novel biomarkers, in CVDs. On the basis of our results, we can put forward the hypotheses that hs-CRP, s-RAGE and eotaxin are reliable but unrelated cardiovascular risk markers.