Identification of SARS-CoV-2 in urban rodents from Southern Mexico City at the beginning of the COVID-19 pandemic.

Currently, there are some concerns about the situation and, in particular, about the future of the COVID-19 pandemic and the new emerging variants of SARS-CoV-2. Rodents are an example of synanthropic animals in urban environments that harbor important zoonoses. Although the molecular identification of SARS-CoV-2 in Rattus norvegicus from New York City had been reported, in other studies, urban wild rodents infected with this virus have not been found. This study aimed to molecularly identify the presence of SARS-CoV-2 in urban wild rodents from Mexico City, trapped along a water channel of a public park as part of a pest control program, at the beginning of the COVID-19 pandemic, during the fall and winter of 2020. Up to 33 Mus musculus and 52 R. norvegicus were captured and euthanized, large intestine samples with feces from the animals were obtained. RNAs were obtained and subjected to qRT-PCR for SARS-CoV-2 identification and threshold cycle (Ct) values were obtained. Four mice (12.1%) and three rats (5.8%) were positive, three rodents exhibited Ct<30. Our results on the frequency of SARS-CoV-2 in urban rats are in line with other previous reports. Thus, similar to other authors, we suggest that surveillance for the detection of SARS-CoV-2 in urban wild rodents, as sentinel animals, should be maintained.

Identification of SARS-CoV-2 in urban rodents from Southern Mexico City at the beginning of the COVID-19 pandemic

ABSTRACT Currently, there are some concerns about the situation and, in particular, about the future of the COVID-19 pandemic and the new emerging variants of SARS-CoV-2. Rodents are an example of synanthropic animals in urban environments that harbor important zoonoses. Although the molecular identification of SARS-CoV-2 in Rattus norvegicus from New York City had been reported, in other studies, urban wild rodents infected with this virus have not been found. This study aimed to molecularly identify the presence of SARS-CoV-2 in urban wild rodents from Mexico City, trapped along a water channel of a public park as part of a pest control program, at the beginning of the COVID-19 pandemic, during the fall and winter of 2020. Up to 33 Mus musculus and 52 R. norvegicus were captured and euthanized, large intestine samples with feces from the animals were obtained. RNAs were obtained and subjected to qRT-PCR for SARS-CoV-2 identification and threshold cycle (Ct) values were obtained. Four mice (12.1%) and three rats (5.8%) were positive, three rodents exhibited Ct<30. Our results on the frequency of SARS-CoV-2 in urban rats are in line with other previous reports. Thus, similar to other authors, we suggest that surveillance for the detection of SARS-CoV-2 in urban wild rodents, as sentinel animals, should be maintained.

Presence of human adenovirus 36 in visceral fat tissue, viral load, and analysis of its genetic variability.

It has been proposed that infection by adipogenic viruses constitutes a "low risk" factor for obesity. Here, we report the presence of adenovirus 36 (Ad36) and its viral load copy number in fat tissue of participants with obesity and normal weight; phylogenetic analysis was performed to describe their relationship and genetic variability among viral haplotypes. Adipose tissue obtained from 105 adult patients with obesity (cases) and 26 normal-weight adult participants as controls were analyzed by quantitative polymerase chain reaction (qPCR) amplifying the partial Ad36 E1a gene. The amplicons were examined by melting curves and submitted to sequencing. Then, genetic diversity and phylogenetic inferences were performed. Ad36 was identified at rates of 82% and 46% in the case and control groups, respectively (p = 1.1 × 10-4 , odds ratio = 5.28); viral load copies were also significantly different between both groups, being 25% higher in the case group. Melting curve analysis showed clear amplification among positive samples. Phylogenetic inferences and genetic diversity analyses showed that the Ad36 E1a gene exhibits low genetic variability and differentiation with strong gene flow due to an expanding process. Our results suggest that the phenomenon of infectobesity by Ad36 might not be a low-risk factor, as has been previously argued by other authors.

Identification of Blastocystis sp. in school children from a rural Mexican village: subtypes and risk factors analysis.

Blastocystis sp. is a common eukaryotic microorganism that colonizes the intestinal tract of several animals, including humans, although its role as a pathogen is still unclear. In the present study, we report the prevalence and risk factors associated with Blastocystis infection in scholars from a rural community in Mexico. A cross-sectional observational study was carried out on schoolchildren aged 3 to 15 years old; fecal samples were analyzed by culture, Faust technique, and molecular analysis. In addition, a structured questionnaire was applied to identify possible risk factors. Of the 177 samples obtained, Blastocystis sp. was the microorganism that presented the highest frequency (n=78, 44%), and included the following subtypes (STs): ST1 (n=43, 56.5%), ST2 (n=18, 23.6%), and ST3 (n=15, 19.7%); Blastocystis STs were not identified in two cases. No associating factors were found between Blastocystis infection or among STs vs. symptoms. During bivariate analysis, no statistically significant risk factors were found, except for the variable of "eating sweets, snacks, and handmade food on the way home" (p=0.04). Therefore, it is plausible to conclude that schoolchildren become infected with Blastocystis sp. mainly outside their homes, perhaps by eating contaminated handmade food on their way to or from school; however, this variable should be evaluated in detail in future studies.

Long-term infection passaging of Human Adenovirus 36 in monkey kidney cells.

Human Adenovirus 36 (HAdV-36) has been related to diverse effects on metabolism and may attenuate the lipid accumulation in kidneys with increased adiposity. Some of these effects would be related to viral persistence. However, until now, a model of persistent in vitro infection by HAdV-36 is unknown. In this study, we examined the cells of the Vero lineage to explore their permissiveness to long-term HAdV-36 infection. HAdV-36 was productively replicated in Vero cells and maintained long-term infection for up to 35 cell passages. A subculture was obtained from the cells that survived the primary infection at a low MOI (0.5). The production of the extracellular infectious virus with titers ranging from 104 to 106 TCID50/mL and DNA-bearing cells was detected. In long-term infected cells, the intracellular distribution of viral antigen was demonstrated by performing immunolocalization (IFI) and expression of cell-viral antigen in 50% of cells by flow cytometry, using anti-HAdV-36 hyperimmune rabbit serum. Furthermore, E1a and E4orf1 genes in long-term infected passages showed a decreasing trend. Our preliminary results reveal that renal epithelial monkey cells are permissive for the productive infection of HAdV-36. Vero cell culture long-term infection might be a promising model for addressing the fundamental aspects of the HAdV-36 biology that cannot reveal broadly-used cultures, which do not maintain long-term infection in primary or transformed cells.

Identification of α-L-fucosidase (ALFuc) of Blastocystis sp. subtypes ST1, ST2 and ST3.

Blastocystis sp. is a common intestinal microorganism. The α-L-fucosidase (ALFuc) is an enzyme long associated with the colonization of the gut microbiota. However, this enzyme has not been experimentally identified in Blastocystis cultures. The objective of the present study was to identify ALFuc in supernatants of axenic cultures of Blastocystis subtype (ST)1 ATCC-50177 and ATCC-50610 and to compare predicted ALFuc proteins of alfuc genes in sequenced STs1-3 isolates in human Blastocystis carriers. Excretion/secretion (Es/p) and cell lysate proteins were obtained by processing Blastocystis ATCC cultures and submitting them to SDS-PAGE and immunoblotting. In addition, 18 fecal samples from symptomatic Blastocystis human carriers were analyzed by sequencing of amplification products for subtyping. A complete identification of the alfuc gene and phylogenetic analysis were performed. Immunoblotting showed that the amplified band corresponding to ALFuc (~51 kDa) was recognized only in the ES/p. Furthermore, prediction analysis of ALFuc 3D structures revealed that the domain α-L-fucosidase and the GH29 family's catalytic sites were conserved; interestingly, the galactose-binding domain was recognized only in ST1 and ST2. The phylogenetic inferences of ALFuc showed that STs1-3 were clearly identifiable and grouped into specific clusters. Our results show, for the first time through experimental data that ALFuc is a secretion product of Blastocystis sp., which could have a relevant role during intestinal colonization; however, further studies are required to clarify this condition. Furthermore, the alfuc gene is a promising candidate for a phylogenetic marker, as it shows a conserved classification with the SSU-rDNA gene.

Long-term infection passaging of Human Adenovirus 36 in monkey kidney cells

ABSTRACT Human Adenovirus 36 (HAdV-36) has been related to diverse effects on metabolism and may attenuate the lipid accumulation in kidneys with increased adiposity. Some of these effects would be related to viral persistence. However, until now, a model of persistent in vitro infection by HAdV-36 is unknown. In this study, we examined the cells of the Vero lineage to explore their permissiveness to long-term HAdV-36 infection. HAdV-36 was productively replicated in Vero cells and maintained long-term infection for up to 35 cell passages. A subculture was obtained from the cells that survived the primary infection at a low MOI (0.5). The production of the extracellular infectious virus with titers ranging from 104 to 106 TCID50/mL and DNA-bearing cells was detected. In long-term infected cells, the intracellular distribution of viral antigen was demonstrated by performing immunolocalization (IFI) and expression of cell-viral antigen in 50% of cells by flow cytometry, using anti-HAdV-36 hyperimmune rabbit serum. Furthermore, E1a and E4orf1 genes in long-term infected passages showed a decreasing trend. Our preliminary results reveal that renal epithelial monkey cells are permissive for the productive infection of HAdV-36. Vero cell culture long-term infection might be a promising model for addressing the fundamental aspects of the HAdV-36 biology that cannot reveal broadly-used cultures, which do not maintain long-term infection in primary or transformed cells.

Identification of α-L-fucosidase (ALFuc) of Blastocystis sp. subtypes ST1, ST2 and ST3

ABSTRACT Blastocystis sp. is a common intestinal microorganism. The α-L-fucosidase (ALFuc) is an enzyme long associated with the colonization of the gut microbiota. However, this enzyme has not been experimentally identified in Blastocystis cultures. The objective of the present study was to identify ALFuc in supernatants of axenic cultures of Blastocystis subtype (ST)1 ATCC-50177 and ATCC-50610 and to compare predicted ALFuc proteins of alfuc genes in sequenced STs1-3 isolates in human Blastocystis carriers. Excretion/secretion (Es/p) and cell lysate proteins were obtained by processing Blastocystis ATCC cultures and submitting them to SDS-PAGE and immunoblotting. In addition, 18 fecal samples from symptomatic Blastocystis human carriers were analyzed by sequencing of amplification products for subtyping. A complete identification of the alfuc gene and phylogenetic analysis were performed. Immunoblotting showed that the amplified band corresponding to ALFuc (~51 kDa) was recognized only in the ES/p. Furthermore, prediction analysis of ALFuc 3D structures revealed that the domain α-L-fucosidase and the GH29 family's catalytic sites were conserved; interestingly, the galactose-binding domain was recognized only in ST1 and ST2. The phylogenetic inferences of ALFuc showed that STs1-3 were clearly identifiable and grouped into specific clusters. Our results show, for the first time through experimental data that ALFuc is a secretion product of Blastocystis sp., which could have a relevant role during intestinal colonization; however, further studies are required to clarify this condition. Furthermore, the alfuc gene is a promising candidate for a phylogenetic marker, as it shows a conserved classification with the SSU-rDNA gene.

Human Leukocyte Antigens -DQA1 and -DQB1 Alleles in Patients With Common Warts.

Introduction The human papillomavirus induces the formation of lesions in different epithelia. Several studies describe an association of class II human leukocyte antigen with genital lesions, implying that they could also be related to the presence of common warts. The goal of this work was to determine the frequency of human leukocyte antigens (HLA)-DQA1 and HLA-DQB1 in Mexicans with common warts. Methods Thirty-two patients with a diagnosis of common warts, without any other systemic disease, and 100 healthy subjects from the same geographic area were recruited. The second exon of the HLA-DQA1 and HLA-DQB1 loci was typed by dot-blot and chemiluminescence. Results Alleles DQA1*03:01:01 (P = 0.021) and DQB1*03:02 (P = 0.036) were associated with the presence of skin warts. DQA1*04:01-DQB1*04:02 (P = 0.009) and DQA1*03:01:01-DQB1*03:02 (P = 0.044) were the most frequent haplotypes in patients. Conclusion In conclusion, the results of our study showed that the alleles DQA1 *03:01:01, DQB1*03:02, DQA1 *04:01, and DQB1*04:02 were associated with susceptibility to common warts, while DQA1*05:01 was significantly diminished in them. Consequently, the haplotypes DQA1*04:01-DQB1*04: 02 and DQA1*03:01:01-DQB1*03:02 were found to be associated with susceptibility, and DQA1*05:01-DQB1*03:01 increased significantly in controls. Therefore, the alleles of the DQA1 and DQB1 genes that are associated with susceptibility could be presenting human papillomavirus (HPV) peptides to T lymphocytes that activate a Th2-type response (anti-inflammatory cytokines), which allows the development of skin warts in this population.

Association between cycle threshold (Ct ) values and clinical and laboratory data in inpatients with COVID-19 and asymptomatic health workers.

In-house assays for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), are feasible alternatives, particularly in developing countries. Cycle threshold (Ct ) values obtained by qRT-PCR were compared with clinical and laboratory data from saliva of inpatients with COVID-19 and asymptomatic health workers (AHW) were studied. Saliva specimens from 58 inpatients confirmed by qRT-PCR for SARS-CoV-2 using nasopharyngeal specimens, and 105 AHW were studied by qRT-PCR using three sets of primers for the N (N1, N2, and N3) gene of SARS-CoV-2, according to the CDC Diagnostic Panel protocol, showing a positivity of 88% for inpatients and 8% for AHW. Bivariate analysis revealed an association between Ct < 38.0 values for N2 and mechanical ventilation assistance among patients (p = .013). In addition, values of aspartate-transaminase, lactate dehydrogenase, and ferritin showed significant correlations with Ct values of N1 and N3 genes in inpatients. Therefore, our results show that Ct values correlate with some relevant clinical data for inpatients with COVID-19.

Cervical lymph node tuberculosis and TNF, IL8, IL10, IL12B and IFNG polymorphisms.

Cervical lymph node tuberculosis (LNTB) is the most common manifestation of extrapulmonary tuberculosis, resulting from the interaction of environmental and genetic factors. The immune response against TB is regulated by several cytokines, which have single nucleotide polymorphisms (SNPs), leading to different levels of expression. The aim of this study was to evaluate the association of LNTB with the TNF, IL8, IL10, IL12B and IFNG gene polymorphisms in Mexican patients. We investigated the association of ten SNPs in 14 patients with LNTB and 138 healthy controls. Significant differences were found for the allele TNF-238A (P=0.03) and the genotypes TNF-238GA (P=0.03), IL8+396GG (P=0.01) and IL12B+1188CC (P=0.04). Allele IL8+781C showed some association trend (P=0.08). Haplotypes TNF-AA and IL10-GTA were of susceptibility, whereas haplotype IL8-ATT was of protection. No association was found with IFNG. The association of these polymorphisms with extrapulmonary TB was compared in different populations. Our results suggest that these cytokine SNPs may influence the manifestation of LNTB in Mexican patients; however, we are aware of the limitations of our study, so it is necessary to make a replica using a larger sample of patients, as well as an increased number of cytokines with SNPs.

Interaction between human mucins and parasite glycoproteins: the role of lectins and glycosidases in colonization by intestinal protozoa.

Intestinal mucins are the first line of defense against microorganisms. Although knowledge about the mechanisms involved in the establishment of intestinal protozoa is limited, there is evidence that these parasites produce lectin-like molecules and glycosidases, that exert both, constitutive and secretory functions, promoting the establishment of these microorganisms. In the present review, we analyse the main interactions between mucins of the host intestine and the four main protozoan parasites in humans and their implications in intestinal colonization. There are lectin-like molecules that contain complex oligosaccharide structures and N-acetylglucosamine (GlcNAc), mannose and sialic acid as main components, which are excreted/secreted by Giardia intestinalis, and recognized by the host using mannose-binding lectins (MBL). Entamoeba histolytica and Cryptosporidium spp. express the lectin galactose/N-acetyl-D-galactosamine, which facilitates their adhesion to cells. In Cryptosporidium, the glycoproteins gp30, gp40/15 and gp900 and the glycoprotein lectin CpClec are involved in protozoan adhesion to intestinal cells, forming an adhesion-attack complex. G. intestinalis and E. histolytica can also produce glycosidases such as ß-N-acetyl-D-glucosaminidase, α-d-glucosidase, ß-d-galactosidase, ß-l-fucosidase, α-N-acetyl-d-galactosaminidase and ß-mannosidase. In Blastocystis, α-D-mannose, α-D-glucose, GlcNAc, α-D-fucose, chitin and sialic acid that have been identified on their surface. Fucosidases, hexosaminidases and polygalacturonases, which may be involved in the mucin degradation process, have also been described in the Blastocystis secretoma. Similarly, symbiotic coexistence with the intestinal microbiota promotes the survival of parasites facilitating cell invasion and nutrients obtention. Furthermore, it is necessary to identify and characterize more glycosidases, which have been only partially described by in silico analyses of the parasite genome.

Clinical study and some molecular features of Mexican patients with syndromic craniosynostosis.

BACKGROUND: Craniosynostosis is one of the major genetic disorders affecting 1 in 2,100-2,500 live newborn children. Environmental and genetic factors are involved in the manifestation of this disease. The suggested genetic causes of craniosynostosis are pathogenic variants in FGFR1, FGFR2, FGFR3, and TWIST1 genes. METHODS: In order to describe their major clinical characteristics and the presence of pathogenic variants, a sample of 36 Mexican patients with craniosynostosis diagnosed as: Crouzon (OMIM 123,500), Pfeiffer (OMIM 101,600), Apert (OMIM 101,200), Saethre-Chotzen (OMIM 101,400), and Muenke (OMIM 602,849) was analyzed. RESULTS: In addition to craniosynostosis, most of the patients presented hypertelorism, midface hypoplasia, and abnormalities in hands and feet. To detect the pathogenic variants p.Pro252Arg FGFR1 (OMIM 136,350), p.Ser252Trp, p.Pro253Arg FGFR2 (OMIM 176,943), p.Pro250Arg, FGFR3 (OMIM 134,934), and p.Gln119Pro TWIST1 (OMIM 601,622), PCR amplification and restriction enzyme digestion were performed. Four and two patients with Apert presented the pathogenic variants p.Ser252Trp and p.Pro253Arg in FGFR2, respectively (with a frequency of 11.1% and 5.5%). The p.Pro250Arg pathogenic variant of FGFR3 was found in a patient with Muenke (with a frequency of 2.8%). The above percentages were calculated with the total number of patients. CONCLUSION: The contribution of this work is discreet, since only 4 genes were analyzed and sample size is small. However, this strategy could be improved by sequencing the FGFR1, FGFR2, FGFR3, and TWIST1 genes, to determine different pathogenic variants. On the other hand, it would be important to include other genes, such as TCF12 (OMIM 600,480), MSX2 (OMIM 123,101), RAB23 (OMIM 606,144), and EFNB1 (OMIM 300,035), to determine their participation in craniosynostosis in the Mexican population.

Trypanosoma cruzi infection associated with atypical clinical manifestation during the acute phase of the Chagas disease.

BACKGROUND: Chagas disease (CD) is caused by the protozoan parasite Trypanosoma cruzi and is transmitted by triatomine insects. Clinical manifestations vary according to the phase of the disease. Cutaneous manifestations are usually observed in the acute phase (chagoma and Romaña's sign) or after reactivation of the chronic phase by immunosuppression; however, a disseminated infection in the acute phase without immunosuppression has not been reported for CD. Here, we report an unusual case of disseminated cutaneous infection during the acute phase of CD in a Mexican woman. METHODS: Evaluation of the patient included a complete clinical history, a physical exam, and an exhaustive evaluation by laboratory tests, including ELISA, Western blot and PCR. RESULTS: Skin biopsies of a 50-year-old female revealed intracellular parasites affecting the lower extremities with lymphangitic spread in both legs. The PCR tests evaluated biopsy samples obtained from the lesions and blood samples, which showed a positive diagnosis for T. cruzi. Partial sequencing of the small subunit ribosomal DNA correlated with the genetic variant DTU II; however, serological tests were negative. CONCLUSIONS: We present a case of CD with disseminated skin lesions that was detected by PCR and showed negative serological results. In Mexico, an endemic CD area, there are no records of this type of manifestation, which demonstrates the ability of the parasite to initiate and maintain infections in atypical tissues .

Association of Cystathionine ß-Synthase Gene Polymorphisms With Preeclampsia.

Preeclampsia (PE) is a pregnancy disorder that increases maternal and fetal morbidity and mortality worldwide. High plasma levels of homocysteine (Hcy) are a risk factor for several cardiovascular diseases. Cystathionine ß-synthase (CBS) plays an important role in Hcy homeostasis catalyzing the irreversible degradation of Hcy to cystathionine, protecting the endothelium from injury caused by hypoxia. Several mutations and polymorphisms may alter the expression of the CBS gene, resulting in variable levels of Hcy. The purpose of this study was to investigate the association of CBS gene polymorphisms with PE in Mexican women. A case-control study consisting of 129 pregnant women with PE (37 severe and 92 mild) and 173 women with uncomplicated pregnancies was performed. Polymorphisms, such as G797A, C785T, T833C, G919A, T959C, C1105T, and 844ins68 base pair, in the CBS gene were genotyped. The polymorphism G797A was monomorphic in cases with the presence of only G797A-G allele. Allele C785T-T and genotype C785T-C/T were associated with susceptibility in severe and mild PE. Alleles G797A-G and T959C-T were associated with susceptibility only in severe PE. Haplotype TGTWGTC was of susceptibility for severe PE and of protection for mild PE. Haplotypes CGTWGCC and CATWGTC seem to be protective for severe PE, but the latter is related to susceptibility in mild PE. The results suggest that C785T, G797A, and T959C mutations are contributing in different ways in severe and mild PE in our population and could be count as another related factor for this disease.

Is the genetic variability of Cathepsin B important in the pathogenesis of Blastocystis spp.?

The potential role of Blastocystis as a pathogen is controversial because it is found in both symptomatic and asymptomatic carriers. Since Cathepsin B has been identified as a main virulence factor that contributes to the pathogenesis of this parasite, the purpose of this study was to analyze the genetic polymorphisms of cathepsin B from Blastocystis from patients with irritable bowel syndrome and from asymptomatic carriers. DNA from fecal samples of both groups, which were previously genotyped by 18S sequencing, was used to amplify a fragment of the cathepsin B gene. Phylogenetic reconstructions were performed and some genetic population indexes were obtained. Amplicons of 27 samples (15 cases, 10 controls, and two commercial ATCC strains) were obtained and analyzed. Phylogenetic reconstructions using nucleotides or inferred amino acid sequences did not separate between cases or controls or among subtypes. Regarding the values of genetic variability, we found that the haplotype and nucleotide diversity indexes of cathepsin B from cases and controls were similar to the values of 18S from controls. By contrast, 18S from cases showed low variability, suggesting that the genetic variability of cathepsin B was not related to the symptomatology of Blastocystis carriers. However, since no polymorphisms related to cases or controls were found, it is logical to assume that the potential damage caused by Blastocystis in situ may be due to unclear mechanisms of Cathepsin B regulation and expression that should be studied in future studies.

Immunological and Functional Characterization of RhoGDI3 and Its Molecular Targets RhoG and RhoB in Human Pancreatic Cancerous and Normal Cells.

RhoGDI proteins have been implicated in several human cancers; changes in their expression levels have shown pro- or anti-tumorigenic effects. Pancreatic Ductal Adenocarcinoma (PDAC) is a complex pathology, with poor prognosis, and most patients die shortly after diagnosis. Efforts have been focused on understanding the role of RhoGDI's in PDAC, specially, RhoGDI1 and RhoGDI2. However, the role of RhoGDI3 has not been studied in relation to cancer or to PDAC. Here, we characterized the expression and functionality of RhoGDI3 and its target GTPases, RhoG and RhoB in pancreatic cell lines from both normal pancreatic tissue and tissue in late stages of PDAC, and compared them to human biopsies. Through immunofluorescences, pulldown assays and subcellular fractionation, we found a reduction in RhoGDI3 expression in the late stages of PDAC, and this reduction correlates with tumor progression and aggressiveness. Despite the reduction in the expression of RhoGDI3 in PDAC, we found that RhoB was underexpressed while RhoG was overexpressed, suggesting that cancerous cells preserve their capacity to activate this pathway, thus these cells may be more eager to response to the stimuli needed to proliferate and become invasive unlike normal cells. Surprisingly, we found nuclear localization of RhoGDI3 in non-cancerous pancreatic cell line and normal pancreatic tissue biopsies, which could open the possibility of novel nuclear functions for this protein, impacting gene expression regulation and cellular homeostasis.

MSX1 gene polymorphisms in Mexican patients with non-syndromic cleft lip/palate.

OBJECTIVE: Non-syndromic cleft lip/palate malformation (CL/P) is one of the most common birth defects in humans and has a complex etiology involving genetic and environmental factors. Mutations in the MSX1 gene are critical during craniofacial development. The purpose of this study was to investigate the contribution of MSX1 gene polymorphisms to the risk of developing CL/P in a sample of Mexican patients. METHODS: The sample consisted of 282 subjects (69 cases and 213 relatives). Four single-nucleotide polymorphisms (SNP1, P147Q, SNP5 and P278S) were tested for association with CL/P in triad and case-pseudo-control analyses. Polymorphism typing was performed by restriction fragment length polymorphism and dot-blot techniques. Allele and genotype frequencies were calculated between patients and pseudo-controls and compared using the Chi square test with Yates correction. Odds ratios and 95% confidence intervals were obtained using SPSS software (v19). Triad analysis was also performed using the program HAPLIN (v5.3). RESULTS: In the cases and pseudo-controls, an association was found between CL/P and the SNP1-G allele (P = 0.031) and the SNP1-G/G genotype (P = 0.032), a polymorphism located near MSX1. Triad analysis showed a tendency toward CL/P susceptibility for the genotype SNP1-G/G (P = 0.075) and an association between CL/P and the haplotype GCTC (P = 0.037). No associated haplotype was found in the cases and pseudo-controls. Two partial haplotypes, GT (SNP1-SNP5) (P = 0.032) and GC (SNP1-P278S) (P = 0.033), were associated with susceptibility in the heterozygous and homozygous types, respectively. In contrast, haplotype AT (SNP1-SNP5) was associated with protection (P = 0.012) in the homozygous type. CONCLUSIONS: The results of this study suggest an association between CL/P susceptibility and SNP1, located near the MSX1 gene, in the Mexican population.

Leptin receptor gene polymorphisms and morbid obesity in Mexican patients.

BACKGROUND: Human obesity is due to a complex interaction among environmental, behavioral, developmental and genetic factors, including the interaction of leptin (LEP) and leptin receptor (LEPR). Several LEPR mutations and polymorphisms have been described in patients with early onset severe obesity and hyperphagic eating behavior; however, some contradictory findings have also been reported. In the present study we explored the association of six LEPR gene polymorphisms in patients with morbid obesity. FINDINGS: Twenty eight patients with morbid obesity and 56 non-obese Mexican Mestizo individuals were included. Typing of rs1137100, rs1137101, rs1805134, Ser492Thr, rs1805094 and rs1805096 LEPR polymorphisms was performed by PCR and allele specific hybridization. The LEPR Ser492Thr polymorphism was monomorphic with the presence of only the Ser492Thr-G allele. Allele C and genotype T/C for rs1805134 polymorphism were associated with susceptibility to morbid obesity (p = 0.02 and p = 0.03, respectively). No association was observed with any haplotype. Linkage disequilibrium (LD) showed that five polymorphisms (rs1137100, rs1137101, rs1805134, rs1805094 and rs1805096) were in absolute (D' = 1) but none in perfect (r2 = 1) LD. CONCLUSIONS: Our results suggest that rs1805134 polymorphism could be involved in the development of morbid obesity, whilst none of the alleles of the LEPR gene, rs1137100, rs1137101, rs1805094 and rs1805096 were associated as risk factors. However, more studies are necessary to confirm or reject this hypothesis.

The amniotic band syndrome in the rat is associated with the activation of transforming growth factor-ß.

Amniocentesis in rats is associated with different malformations, such as cleft palate and limb deformation, resembling the human congenital amniotic band syndrome (ABS). Despite many human cases reported in the literature, little is known about the mechanisms involved in ABS. This study addressed if the activation of the transforming growth factor-ß1 (TGF-ß1) pathway is, in part, associated with amniotic band formation and growth restriction induced in rats by amniocentesis, as by a previously published model. For this purpose, quantification of TGF-ß1, α-smooth muscle actin, and collagen type I mRNA and protein levels were determined by quantitative PCR and Western blot analysis, respectively, in the fetus, its amniotic membrane, and the uterus of experimental and control rats. We found that TGF-ß1 mRNA levels are increased in the fetus and the amniotic membrane at 6 hours, whereas α-smooth muscle actin, phosphorylated Smad3, and collagen type I increased at 48 hours, suggesting that a fibrotic response is induced after the amniotic sac puncture. Furthermore, fetuses had hemorrhages, syndactyly, and amputation of limbs, similar to human ABS.