Inès Zidi

Endocrine Disrupting Chemicals and Human Health Risk Assessment: A Critical Review

Concerns over the threats posed by a large number of molecules, collectively termed as endocrine disrupting compounds (EDCs) and generally known to alter and disrupt hormone systems and physiological functions, have often been expressed in academic and scholarly debates. From the perspective of classical toxicology, EDCs have genomic mechanisms of actions and exert agonistic or antagonistic effects on steroid receptors. They are also able to alter reproductive function by binding to estrogen or androgen receptors, and the neuroendocrine system by binding to the thyroid receptor. Recently, EDCs have been shown to have equally complex nongenomic mechanisms, altering steroid synthesis or steroid metabolism. As environmental contaminants, these molecules proved disruptively harmful for many wildlife species, particularly those from or depending on the aquatic ecosystem. An increasingly growing body of research has voiced further concerns that human populations are not immune from the dangers of EDCs. Studies from this line of research caution that EDCs can alter hormonal balance and that a whole range of breast and prostate cancers, endometriosis, cryptorchidism, and hypospadias have been linked to exposure to EDCs. This particular area has raised a lot of controversy and the literature on this subject often presents opposing, and sometimes conflicting, perceptions and perspectives. Accordingly, the authors aimed to contribute to the committed academic search for better appreciation of the topic. They first discuss the major natural and synthetic chemicals with endocrine disrupting properties to which humans and wildlife may be exposed. They then describe the key endocrine mechanisms of action and conclude by addressing the main observed effects in human and wildlife populations.

Golimumab and malignancies: true or false association?

Malignancy is one of the comorbidities linked to golimumab, a biological TNF-α blocker. In this systematic review and meta-analysis, we searched different databases and analyzed original publications to elucidate the remaining open question about the real association of malignancies with golimumab therapy. The most frequent cancer in patients treated with golimumab, in association or not with methotrexate, is the lung adenocarcinoma. However, lymphoma is not very commonly represented in these patients. We show that there is no major and evident risk of malignancies associated with golimumab in current scientific literature. An increased risk of malignancies may be associated with golimumab, but this warrants further clinical confirmation. Also, this risk mentioned in different studies must be taken with caution because of number of limits and biases.

Association of an HLA-G 14-bp Insertion/Deletion polymorphism with high HBV replication in chronic hepatitis.

Identification of an HLA‐G 14‐bp Insertion/Deletion (Ins/Del) polymorphism at the 3′ untranslated region of HLA‐G revealed its importance in HLA‐G mRNA stability and HLA‐G protein level variation. We evaluated the association between the HLA‐G 14‐bp Ins/Del polymorphism in patients with chronic Hepatitis B virus (HBV) infection in a case–control study. Genomic DNA was extracted from 263 patients with chronic HBV hepatitis and 246 control subjects and was examined for the HLA‐G 14‐bp Ins/Del polymorphism by PCR. The polymorphic variants were genotyped in chronic HBV seropositive cases stratified according to HBV DNA levels, fibrosis stages and in a control population. There was no statistical significant association between the 14‐bp Ins/Del polymorphism and increased susceptibility to HBV infection neither for alleles (P = 0.09) nor for genotypes (P = 0.18). The stratification of HBV patients based on HBV DNA levels revealed an association between the 14‐bp Ins/Del polymorphism and an enhanced HBV activity with high HBV DNA levels. In particular, the Ins allele was significantly associated with high HBV DNA levels (P = 0.0024, OR = 1.71, 95% CI 1.2–2.4). The genotype Ins/Ins was associated with a 2.5‐fold (95% CI, 1.29–4.88) increased risk of susceptibility to high HBV replication compared with the Del/Del and Ins/Del genotypes. This susceptibility is linked to the presence of two Ins alleles. No association was observed between the 14‐bp Ins/Del polymorphism and fibrosis stage of HBV infection. We observed an association between the 14‐bp Ins/Del polymorphism and high HBV replication characterized by high HBV DNA levels in chronic HBV patients. These results suggest a potential prognostic value for disease outcome evaluation.

Association between sHLA-G and HLA-G 14-bp deletion/insertion polymorphism in Crohn’s disease

The aim of this study was to evaluate the association between the HLA-G 14-bp deletion/insertion (Del/Ins) polymorphism and soluble (s) HLA-G production in patients with Crohns disease (CD). We analyzed also the sHLA-G molecules by ELISA and western blot in plasma samples. Among unselected patients, the 14-bp Del/Ins polymorphism was not significantly associated with increased CD risk neither for alleles (P = 0.371) nor for genotypes (P = 0.625). However, a significant association was reported between the 14-bp Del/Ins polymorphism and CD, in particular in young-onset CD patients for alleles [P = 0.020, odds ratio (OR) = 2.438, 95% confidence interval (CI): 1.13-5.25] but not with adult-onset CD patients. A significant association was reported concerning the genotype Ins/Ins for young-onset CD patients (P = 0.029, OR = 3.257, 95% CI: 1.08-9.77). We observed also a significant increase in sHLA-G measured by ELISA in CD patients compared to controls (P = 0.002). The 14-bp Del/Del and 14-bp Del/Ins genotypes are the high HLA-G producers. Among sHLA-G(positive) patients, 43% of subjects present dimers of HLA-G. The presence of dimers seems to be related to the advanced stages of the disease. The 14-bp Del/Ins polymorphism is associated with an increased risk of CD particularly in young-onset CD patients and controls sHLA-G plasma levels. Dimers of sHLA-G are frequent in advanced disease stages. The above findings indicate that the genetic 14-bp Del/Ins polymorphism in exon 8 of the HLA-G gene is associated with the risk of CD and suggest a role for sHLA-G as a prognostic marker for progressive disease.

sHLA-G1 and HLA-G5 levels are decreased in Tunisian women with multiple abortion

Pregnancy is associated with increased levels of soluble (s) human leukocyte antigen (HLA)-G molecules, while during abortion these molecules are decreased. To date, little is known about the role of sHLA-G isoforms during abortion. In this study, we investigated the levels of total sHLA-G and its isoforms: HLA-G1 (membrane shedded isoform) and alternative spliced HLA-G5 in plasma samples obtained from 55 women who had experienced spontaneous abortion, 108 pregnant healthy women and 56 non pregnant healthy women. We found that pregnant women exhibited higher amounts of sHLA-G compared to either non pregnant women or women with abortion. Among women who had experienced spontaneous abortion, women with recurrent abortions (RSA) had lower sHLA-G than women with only one abortion. In particular, RSA women were characterized by the absence of sHLA-G1 isoform, suggesting a possible implication in abortion event.

HLA-E polymorphism and soluble HLA-E plasma levels in chronic hepatitis B patients

Chronic hepatitis B virus (HBV) infection occurs in association to a deregulation of immune system. Human leukocyte antigen E (HLA‐E) is an immune‐tolerant nonclassical HLA class I molecule that could be involved in HBV progression. To measure soluble (s) HLA‐E in patients with chronic HBV hepatitis (CHB). We tested the potential association of HLA‐E*01:01/01:03 A > G gene polymorphism to CHB. Our cohort consisted of 93 Tunisian CHB patients (stratified in CHB with high HBV DNA levels and CHB with low HBV DNA levels) and 245 healthy donors. Plasma sHLA‐E was determined using enzyme‐linked immunosorbent assay (ELISA). Genotyping was performed using polymerase chain reaction sequence‐specific primer. No association between HLA‐E*01:01/01:03 A > G polymorphism and HBV DNA levels in CHB patients was found. G/G genotype is less frequent in CHB patients without significance. sHLA‐E is significantly enhanced in CHB patients compared with healthy controls (P = 0.0017). Stratification according to HBV DNA levels showed that CHB patients with low HBV DNA levels have higher sHLA‐E levels compared with CHB patients with high HBV DNA levels. CHB patients with G/G genotype have enhanced sHLA‐E levels compared with other genotypes (P = 0.037). This significant difference is maintained only for CHB women concerning G/G genotypes (P = 0.042). Finally, we reported enhanced sHLA‐E in CHB patients with advanced stages of fibrosis (P = 0.032). We demonstrate, for the first time, the association of sHLA‐E to CHB. Owing to the positive correlation of HLA‐E*01:01/01:03 A > G polymorphism and the association of sHLA‐E to advanced fibrosis stages, HLA‐E could be a powerful predictor for CHB progression. Further investigations will be required to substantiate HLA‐E role as a putative clinical biomarker of CHB.

Nonclassical human leukocyte antigen (HLA-G, HLA-E, and HLA-F) in coronary artery disease

AIMS Several evidences suggest the association between the evolution of coronary artery disease (CAD) and the development of coronary syndrome that is often associated with disrupted plaque and partial or complete thrombosis of the related artery. Because of the inflammatory nature of CAD, we investigated the human leukocyte antigen (HLA)-G, HLA-E, and HLA-F genetic polymorphisms within CAD patients and evaluated their potential association with this disease in Tunisian population. METHODS Different polymorphisms in HLA-G (14-bp Insertion/Deletion, +3142C/G), HLA-E (HLA-E*01:01/01:03 A/G), HLA-F (HLA-F*01:02 T/C, 01:03 C/T, 01:04 A/C) genes were typed using different laboratory techniques in a cohort of 89 CAD patients and 84 controls. RESULTS A significant association was reported between the HLA-G +3142 G allele (OR=1.64, 95% CI=1.05-2.56, p=0.02) and increased risk of CAD. No association was found for the other studied polymorphisms. When we considered the haplotypes, we found TDELCA and TDELGG haplotypes associated to CAD with p=0.008 and p=0.030, respectively, suggesting the potential interaction between HLA-G and HLA-E genes. CONCLUSIONS Our findings indicated that the HLA-G +3142C/G polymorphism and TDELCA and TDELGG haplotypes can harbour a reliable diagnosis value for the risk of CAD development suggesting that HLA-G, -E and -F molecules might be involved in the pathogenesis of the disease. However, further studies are necessary to confirm our results.

Increased plasmatic soluble HLA-G levels in endometrial cancer

HIGHLIGHTSsHLA‐G is significantly increased in patients with EC.sHLA‐G is highly increased in early stages and in high grade EC.HLA‐G5 are more represented than sHLA‐G1 molecules in patients with EC.sHLA‐G are represented majorly in monomeric forms.sHLA‐G dimeric forms are specifically associated to early stages of EC. ABSTRACT Human Leukocyte Antigen‐G (HLA‐G) is known as an immune suppressive molecule; it interacts with several immune cells and inhibits their functions. HLA‐G molecule is highly represented in pathological conditions including malignant transformation. To the best of our knowledge this is the first study that focuses on the expression of soluble HLA‐G (sHLA‐G) in endometrial cancer (EC). We aimed at exploring sHLA‐G plasma levels and its prognostic value in EC. We examined total sHLA‐G expression as well as the sHLA‐G1 and HLA‐G5 isoforms expression in plasma samples from 40 patients with EC and 45 healthy controls by a specific sandwich ELISA. Immunoprecipitation and Coomassie blue staining were performed to explore the presence of plasmatic sHLA‐G monomers and dimers. sHLA‐G plasma level was significantly enhanced in patients with EC compared to healthy controls (p=0.028). Additionally, HLA‐G5 molecules were highly represented than sHLA‐G1 molecules in EC, at the borderline of significance (p=0.061). Interestingly, sHLA‐G has been shown to be increased in early stages (Stages I and II) as well as in high grade EC (Grade 3) that is associated with rapid spread of the disease (p=0.057). sHLA‐G positive EC plasma were majorly in monomeric form (75%). Clinically, all the HLA‐G dimers were detected in early stages and in high grade of EC. Our data strengthen the implication of HLA‐G molecules in EC etiology and especially in progression.

High-resolution melting-curve (HRM) analysis for C. meleagridis identification in stool samples

BACKGROUND Cryptosporidiosis represents a major public health problem. This infection, caused by a protozoan parasite of the genus Cryptosporidium, has been reported worldwide as a frequent cause of diarrhoea. In the immunocompetent host, the typical watery diarrhea can be self-limiting. However, it is severe and chronic, in the immunocompromised host and may cause death. Cryptosporidium spp. are coccidians, which complete their life cycle in both humans and animals. The two species C. hominis and C. parvum are the major cause of human infection. Compared to studies on C. hominis and C. parvum, only a few studies have developed methods to identify C. meleagridis. AIM To develop a new real time PCR-coupled High resolution melting assay allowing the detection for C. meleagridis, in addition of the other dominant species (C. hominis and C. parvum). METHODS The polymorphic sequence on the dihydrofolate reductase gene (DHFR) of three species was sequenced to design primers pair and establish a sensitive real-time PCR coupled to a high-resolution melting-curve (HRM) analysis method, allowing the detection of Cryptosporidium sp. and discrimination between three prevalent species in Tunisia. We analyzed a collection of 42 archived human isolates of the three studied species. RESULTS Real-time PCR coupled to HRM assay allowed detection of Cryptosporidium, using the new designed primers, and basing on melting profile, we can distinguish C. meleagridis species in addition to C. parvum and C. hominis. CONCLUSION We developed a qPCR-HRM assay that allows Cryptosporidium genotyping. This method is sensitive and able to distinguish three Cryptosporidium species.

Increased levels of soluble HLA-G molecules in Tunisian patients with chronic hepatitis B infection

Hepatitis B virus (HBV) infection is a global health problem. The mechanisms of immune tolerance in HBV infection are still unclear. The host immune response plays a critical role in determining the outcome of HBV infection. Human leucocyte antigen‐G (HLA‐G) is involved in immunotolerogenic process and infectious diseases. This study aimed to explore the implication of soluble HLA‐G (sHLA‐G) and its isoforms in HBV infection. Total sHLA‐G (including shedding HLA‐G1 and HLA‐G5) was analysed by ELISA in 95 chronic HBV patients, 83 spontaneously resolvers and 100 healthy controls (HC). To explore the presence of sHLA‐G dimers, we performed an immunoprecipitation and a Western blot analysis on positive samples for sHLA‐G in ELISA. The serum levels of sHLA‐G were significantly increased in patients with chronic HBV patients compared to spontaneously resolvers and HC (P<.0001). Interestingly, we found an increased level of sHLA‐G1 in chronic HBV patients than in spontaneously resolvers and HC (P<.001). In addition, the expression of HLA‐G5 seems to be higher in the sera of chronic HBV patients than spontaneously resolvers (P=.026). The analysis of HLA‐G dimers showed the presence of homodimers in 93% of chronic HBV patients, 67% in spontaneously resolvers and 60% in HC. These results provide evidence that sHLA‐G may have a crucial role in the outcome of HBV infection and could be proposed as a biomarker for infection outcome. Based on its tolerogenic function, HLA‐G might be considered as a new promising immunotherapeutic approach to treat the chronic infection with HBV.