Roberta Pastorino

Strong association of the APOA5-1131T>C gene variant and early-onset acute myocardial infarction

BACKGROUND Epidemiological studies support the role for a strong genetic component in the occurrence of early-onset myocardial infarction (MI), although the specific genetic variants responsible for familial clustering remain largely unknown. METHODS The Italian study of early-onset MI is a nationwide case-control study involving 1864 case patients <45 years old who were hospitalized for a first MI, and age/sex/place of origin-matched controls (n = 1864). We investigated the association between early-onset MI, lipid levels and 20 single nucleotide polymorphisms (SNPs) in the candidate genes ADIPOQ, APOA5, ALOX5AP, CYBA, IL6, LPL, PECAM1, PLA2G2A and PLA2G7, chosen because of previously reported associations with Coronary Heart Disease (CHD) or with CHD risk factors. RESULTS Of all the SNPs investigated, APOA5-1131T>C [(rs662799), minor allele frequency 0.084 (95% confidence interval (CI) 0.07-0.09)] alone showed a statistically significant association with risk of early-onset MI (p = 6.7 × 10(-5)), after Bonferroni correction, with a per C allele odds ratio of 1.44 (95% CI 1.23-1.69). In controls, APOA5-1131T>C was significantly associated with raised plasma triglyceride levels (p = 0.001), compared with non-carriers, the per C allele increase being 11.4% (95% CI 4-19%), equivalent to 0.15 mmol/L (95% CI 0.11-0.20 mmol/L). In cases, the association with early MI risk remained statistically significant after adjustment for triglycerides (p = 0.006). CONCLUSIONS The APOA5-1131C allele, associated with higher fasting triglyceride levels, strongly affects the risk for early-onset MI, even after adjusting for triglycerides. This raises the possibility that APOA5-1131T>C may affect the risk of early MI over and above effects mediated by triglycerides.

Association between the ACCN1 gene and multiple sclerosis in central east sardinia

Multiple genome screens have been performed to identify regions in linkage or association with Multiple Sclerosis (MS, OMIM 126200), but little overlap has been found among them. This may be, in part, due to a low statistical power to detect small genetic effects and to genetic heterogeneity within and among the studied populations. Motivated by these considerations, we studied a very special population, namely that of Nuoro, Sardinia, Italy. This is an isolated, old, and genetically homogeneous population with high prevalence of MS. Our study sample includes both nuclear families and unrelated cases and controls. A multi-stage study design was adopted. In the first stage, microsatellites were typed in the 17q11.2 region, previously independently found to be in linkage with MS. One significant association was found at microsatellite D17S798. Next, a bioinformatic screening of the region surrounding this marker highlighted an interesting candidate MS susceptibility gene: the Amiloride-sensitive Cation Channel Neuronal 1 (ACCN1) gene. In the second stage of the study, we resequenced the exons and the 3′ untranslated (UTR) region of ACCN1, and investigated the MS association of Single Nucleotide Polymorphisms (SNPs) identified in that region. For this purpose, we developed a method of analysis where complete, phase-solved, posterior-weighted haplotype assignments are imputed for each study individual from incomplete, multi-locus, genotyping data. The imputed assignments provide an input to a number of proposed procedures for testing association at a microsatellite level or of a sequence of SNPs. These include a Mantel-Haenszel type test based on expected frequencies of pseudocase/pseudocontrol haplotypes, as well as permutation based tests, including a combination of permutation and weighted logistic regression analysis. Application of these methods allowed us to find a significant association between MS and the SNP rs28936 located in the 3′ UTR segment of ACCN1 with p = 0.0004 (p = 0.002, after adjusting for multiple testing). This result is in tune with several recent experimental findings which suggest that ACCN1 may play an important role in the pathogenesis of MS.

Prognostic relevance of aberrant DNA methylation in g1 and g2 pancreatic neuroendocrine tumors.

Background/Aims: The occurrence and clinical relevance of DNA hypermethylation and global hypomethylation in pancreatic neuroendocrine tumours (PanNETs) are still unknown. We evaluated the frequency of both epigenetic alterations in PanNETs to assess the relationship between methylation profiles and chromosomal instability, tumour phenotypes and prognosis. Methods: In a well-characterized series of 56 sporadic G1 and G2 PanNETs, methylation-sensitive multiple ligation-dependent probe amplification was performed to assess hypermethylayion of 33 genes and copy number alterations (CNAs) of 53 chromosomal regions. Long interspersed nucleotide element-1 (LINE-1) hypomethylation was quantified by pyrosequencing. Results: Unsupervised hierarchical clustering allowed to identify a subset of 22 PanNETs (39%) exhibiting high frequency of gene-specific methylation and low CNA percentages. This tumour cluster was significantly associated with stage IV (p = 0.04) and with poor prognosis in univariable analysis (p = 0.004). LINE-1 methylation levels in PanNETs were significantly lower than in normal samples (p < 0.01) and were approximately normally distributed. 12 tumours (21%) were highly hypomethylated, showing variable levels of CNA. Interestingly, only 5 PanNETs (9%) were observed to show simultaneously LINE-1 hypomethylation and high frequency of gene-specific methylation. LINE-1 hypomethylation was strongly correlated with advanced stage (p = 0.002) and with poor prognosis (p < 0.0001). In the multivariable analysis, low LINE-1 methylation status and methylation clusters were the only independent significant predictors of outcome (p = 0.034 and p = 0.029, respectively). Conclusion: The combination of global DNA hypomethylation and gene hypermethylation analyses may be useful to define distinct subsets of PanNETs. Both alterations are common in PanNETs and could be directly correlated with tumour progression.

Hierarchical clustering analysis of pathologic and molecular data identifies prognostically and biologically distinct groups of colorectal carcinomas

This work has evaluated the potential superiority of a morphomolecular classification based on the combination of clinicopathologic and molecular features of colorectal cancers. A cohort of 126 colorectal carcinomas was investigated by unsupervised hierarchical clustering analysis to combine 13 routinely assessed clinicopathologic features and all five molecular markers recently suggested by Jass’ classification to distinguish four molecular subtypes of sporadic colorectal carcinomas. Survival analysis was assessed by a Cox proportional hazards model. A clear separation into three prognostically significant groups was identified: cluster A and cluster C were associated with good prognosis and cluster B with poor prognosis (P=0.006). Clinicopathologic and molecular features of cluster A and cluster B tumors were strongly concordant with colorectal cancer profiles characterized by microsatellite instability or by chromosomal instability, respectively. The clinicopathologic features of cluster C tumors were suggestive of a less aggressive disease than cluster B tumors. Genetically, they appeared intermediate between cluster A and cluster B tumors, as they were mainly microsatellite stable tumors showing high levels of both MGMT methylation and loss of heterozygosity. Chromosomal instability was significantly lower in cluster C than in cluster B tumors. A more accurate tumor classification should combine the prognostic power of clinicopathologic parameters with molecular biomarkers that provide information regarding the natural history of the cancer. Hierarchical clustering seems to be a useful, promising and powerful tool for further translational studies and should lead us to define a diagnostic and prognostic signature for different carcinomas.

Impact of Female Sex on Long-Term Outcomes in Patients With ST-Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention

BACKGROUND Conflicting information exists about whether sex differences affect long-term outcomes in patients undergoing primary percutaneous coronary intervention (PCI). METHODS This retrospective study enrolled consecutive patients with ST-elevation myocardial infarction undergoing primary PCI within 24 hours from symptom onset. Hazard ratios (HRs) of events with 95% confidence interval (CI) were calculated in the overall population and in a propensity score matched cohort of women and men. RESULTS Among 481 patients, median age 66 years old, 138 (28.7%) were women. Women were older than men (72 vs 63 years, P<0.001), had a higher prevalence of hypertension (68% vs 54%, P=0.006), diabetes (27% vs 19%, P=0.04), and Killip class≥3 at admission (19% vs 10%, P=0.007). After a median follow-up of 1041 days women experienced a significant higher incidence of the composite of death, nonfatal myocardial infarction, and hospitalization for heart failure (31.9% vs 18.4%, unadjusted HR 1.86; 95% CI, 1.26-2.74; P=0.002), driven mainly by heart failure (unadjusted HR 2.47; 95% CI, 1.12-5.41; P=0.024), without significant differences in death (unadjusted HR 1.49; 95% CI, 0.88-2.53; P=0.13), or nonfatal myocardial infarction (unadjusted HR 1.59; 95% CI, 0.78-3.27; P=0.19) and no increase in target lesion revascularization (9.4% vs 12.5%, unadjusted HR 0.77; 95% CI, 0.42-1.44; P=0.42). After propensity score matching the hazard of the composite endpoint was largely attenuated (HR 1.32; 95% CI, 0.84-2.06; P=0.23). CONCLUSIONS Women undergoing primary PCI experience worse long-term outcomes than men, but this difference is largely explained by their more adverse baseline cardiovascular profile.

Association between protective and deleterious HLA alleles with multiple sclerosis in Central East Sardinia.

The human leukocyte antigen (HLA) complex on chromosome 6p21 has been unambiguously associated with multiple sclerosis (MS). The complex features of the HLA region, especially its high genic content, extreme polymorphism, and extensive linkage disequilibrium, has prevented to resolve the nature of HLA association in MS. We performed a family based association study on the isolated population of the Nuoro province (Sardinia) to clarify the role of HLA genes in MS. The main stage of our study involved an analysis of the ancestral haplotypes A2Cw7B58DR2DQ1 and A30Cw5B18DR3DQ2. On the basis of a multiplicative model, the effect of the first haplotype is protective with an odds ratio (OR) = 0.27 (95% confidence interval CI 0.13–0.57), while that of the second is deleterious, OR 1.78 (95% CI 1.26–2.50). We found both class I (A, Cw, B) and class II (DR, DQ) loci to have an effect on MS susceptibility, but we saw that they act independently from each other. We also performed an exploratory analysis on a set of 796 SNPs in the same HLA region. Our study supports the claim that Class I and Class II loci act independently on MS susceptibility and this has a biological explanation. Also, the analysis of SNPs suggests that there are other HLA genes involved in MS, but replication is needed. This opens up new perspective on the study of MS.

Radiographic Evaluation of Regenerated Bone Following Poly(Lactic-Co-Glycolic) Acid/Hydroxyapatite and Deproteinized Bovine Bone Graft in Sinus Lifting

AbstractAlthough numerous biomaterials are used for maxillary sinus-lift surgery, the ideal material for such procedures has not yet been identified. Both heterologous and alloplastic bone substitutes have a solely osteoconductive effect and lack the osteoinductive properties of the bone morphogenetic proteins typical of autologous bone. Our group assessed a new alloplastic graft material, poly(lactic-co-glycolic) acid/hydroxyapatite (PLGA/HA), implanted in a human model of maxillary sinus-lift surgery. For this prospective, random, double-blind trial, we used deproteinized bovine bone (DBB) as the comparison material. Radiographic bone vertical height and density were assessed at approximately 28 weeks after grafting using cone-beam computed tomography. The vertical dimension of the regenerated bone was equivalent between the 2 groups. The density of the bone regenerated using PLGA/HA was significantly lower than that obtained with DBB. Despite clinical assessments demonstrating that PLGA/HA has sufficient characteristics for use in sinus-lift surgery, DBB provided greater bone density and an equivalent vertical dimension of grafted bone. Further studies are needed to supplement the radiologic findings with histologic and micromorphometric examinations.

Direct genetic effects and their estimation from matched case-control data.

In genetic association studies, a single marker is often associated with multiple, correlated phenotypes (e.g., obesity and cardiovascular disease, or nicotine dependence and lung cancer). A pervasive question is then whether that marker exerts independent effects on all phenotypes. In this paper, we address this question by assessing whether there is a genetic effect on one phenotype that is not mediated through the other ones, so called direct genetic effect. Answering such question may represent an important step in the elucidation of the underlying biological mechanism. Under rather restrictive conditions, such direct genetic effects are known to be estimable by standard regression methods. Under more lenient conditions, in a prospective or unmatched case‐control study, these effects can be estimated by using a previously proposed G‐estimation method (Vansteelandt [2009] Epidemiology 20, 851–860). The present paper extends this method to matched case‐control studies, and investigates the conditions under which this extension is valid. We illustrate the method on data from a matched case‐control study, which we use to elucidate the pathway implications of a detected association between myocardial infarction and a genetic locus in the chromosomal region of the FTO gene.

Enrichment for Northern European-derived multiple sclerosis risk alleles in Sardinia

Background: The list of genomic loci associated with multiple sclerosis (MS) susceptibility outside the major histocompatibility complex (MHC) in patients of Northern European (NE) ancestry has increased to 103. Despite the extraordinarily high MS prevalence in the isolated Sardinian population, the contribution of genetic risk factors to MS in Sardinia is largely not understood. Objective: The objective of this paper is to examine the relevance of non-MHC MS susceptibility variants in Sardinia. Methods: We examined a log-additive MS-specific genetic burden score (MSGB) using 110 NE-derived risk alleles in a dataset of 75 Sardinian cases, 346 Sardinian controls and 177 cases and 1967 controls from the United States (US). Results: Sardinian cases demonstrate a heavier non-MHC MSGB load than Sardinian controls and US cases (p = 2E-06, p = 1E-06, respectively). Furthermore, Sardinian controls carry a heavier burden than US controls (p = 2E-14). Our results confirm the limited ability of the 110-SNP MSGB to predict disease status in Sardinia (AUROC = 0.629). Conclusions: Risk alleles discovered in samples of NE ancestry are relevant to MS in Sardinia. Our results suggest a general enrichment of MS susceptibility alleles in Sardinians, encouraging the pursuit of further studies of MS in this population.

Histomorphometric evaluation of two different bone substitutes in sinus augmentation procedures: A randomized controlled trial in humans

PURPOSE The histomorphometric results of sinus floor augmentation with deproteinized bovine bone (DBB) and a new fully synthetic bone substitute, poly(lactic-co-glycolic acid/hydroxyapatite) (PLGA/HA), were compared in humans. MATERIALS AND METHODS Twelve maxillary sinuses of eight patients requiring major maxillary sinus floor augmentation and free of concomitant conditions (ASA scores 1 and 2) were studied. Lateral sinus augmentation was performed using DBB or PLGA/HA grafts; sites were randomly assigned to control or test groups. Patients were reexamined approximately 6 months after grafting using cone beam computed tomography scans, and biopsy samples were harvested from implant sites. Total bone volume, residual graft material volume, and new bone volume were assessed. RESULTS Healing times were similar between groups. Measurable biopsy specimens were available from four of the test sites and six of the control sites. PLGA/HA grafts showed no trace of graft material, whereas DBB grafts had a mean graft area of 16.5% (P < .05). Mean percent newly formed bone tended to be greater for PLGA/HA (44.45%) than for DBB (27.51%). Mean total volume percent did not differ significantly: PLGA/HA = 44.45%, DBB = 44.10%. CONCLUSION DBB and PLGA/HA produced similar total bone volumes. PLGA/HA appeared to be completely resorbed, whereas DBB presented residual graft material. With the limitations due to the small sample size, both materials were suitable for sinus floor augmentation.