Relationship between biofilm-forming microorganisms (BFM: Staphylococcus aureus and Pseudomonas aeruginosa) and DEFB1 gene variants on ß-defensin levels in periprosthetic joint infection (PJI).

BACKGROUND: The purpose of this study was to investigate the relationship between biofilm-forming microorganisms (BFM) and DEFB1 gene variants on ß-defensin levels in patients with periprosthetic joint infection (PJI) of Mexican origin. METHODS AND RESULTS: One hundred and five clinical aspirates were obtained from patients with suspected PJI. After microbiologic culture, samples were classified as non-septic and septic; of the latter, only those positive for Staphylococcus aureus and Pseudomonas aeruginosa were selected. ß-Defensin levels were quantified by ELISA, DNA was extracted from total leukocytes of the samples, and - 20G > A (rs11362) and - 44 C > G (rs1800972) variants were genotyped using TaqMan probes. Forty-one clinical aspirates were non-septic, 18 were positive for S. aureus and 18 were positive for P. aeruginosa. It was observed that ß-defensin levels were higher in the P. aeruginosa group compared to S. aureus group (2339.0 pg/mL IQR = 1809.2 vs. 1821.3 pg/mL IQR = 1536.4) and non-septic group (2339.0 pg/mL IQR = 1809.2 vs. 1099.7 pg/mL IQR = 1744.5, P < 0.001). The CG genotype of the rs1800972 variant was associated with higher ß-defensin levels compared to the CC genotype for both P. aeruginosa and S. aureus (1905.8 vs. 421.7 pg/mL, P = 0.004; and 1878.2 vs. 256.4 pg/mL, P = 0.006, respectively). CONCLUSIONS: Our results show that ß-defensin levels are significantly elevated in patients with BFM-associated PJI compared to those without infection. Furthermore, carriers of the CG genotype of the rs1800972 variant have an increased risk of PJI. Further research is needed to replicate these findings in a larger population.

Relationship between rs4349859 and rs116488202 polymorphisms close to MHC-I region and serum urate levels in patients with gout.

BACKGROUND: Gout is the most common inflammatory rheumatic disease and elevated levels of serum urate (SU) are the main cause for its development. Major histocompatibility complex class 1 (MHC-1) plays an important role in the development of multiple inflammatory diseases; however, there is little evidence of its involvement in gout. The present study focused on evaluating the association of the rs4349859 and rs116488202 single nucleotide polymorphisms (SNPs) close to the MHC-1 region in patients with gout. METHODS AND RESULTS: One hundred and seventy-six individuals of Mexican origin were included, of which 81 were patients with primary gout and 95 were healthy controls. The rs4349859 and rs116488202 SNPs were genotyped using TaqMan probes by allelic discrimination by real-time PCR. Serum concentrations of biochemical parameters were measured with enzymatic methods. Descriptive statistics were applied and P-values < 0.05 were considered significant. It was observed that the rs4349859 and rs116488202 SNPs showed significant association with the risk of gout (OR = 146, 95%CI = 44.8-480.2, P < 0.01; OR = 2885, 95%CI = 265-31398, P < 0.01, respectively). Our results also showed significantly higher serum SU levels in gout patients with respect to controls (P < 0.01) in the carriers of the GA genotype compared with the GG genotype of the rs4349859 variant, and in the carriers of the CT genotype compared with the CC genotype of the rs116488202 variant. CONCLUSION: The study revealed that rs4349859 and rs116488202 SNPs close to MHC-I region confers strong susceptibility to gout in Mexican population, and the heterozygous genotypes of both were associated with higher levels of SU.

A modified animal-free serum technique for efficient isolation and proliferation of mesenchymal stem cells from Hoffa fat pad.

We focus on this study in designing an alternative technique for obtaining mesenchymal stem cells (MSCs) from residual tissue, Hoffa fat, in arthroscopic procedures. Two males and two females were included, and underwent knee arthroscopy; a sample of infrapatellar adipose tissue was obtained with basket forceps. The primary culture was made using the explant method and the culture media: DMEM-high glucose, supplemented with 10% of inactivated human allogeneic serum. All the cellular cultures remained under culture conditions for three weeks, after that by flow cytometry the cells were characterized by MSCs antibody panel: CD105, CD73 and CD90. Subsequently, in the first pass, the MSCs were cultured in commercial human chondrogenic, osteogenic and adipogenic mediums, respectively. After primary culture, we obtained on average 95,600.00 ± 7,233.26 cells/cm2, and the duplication time of MSCs isolate from Hoffa fat pad was established in 39 hours. By flow cytometry, we found that surface markers percentage for expanded MSCs (CD105, CD73, CD90) in primary culture significantly increased and its morphology was fibroblastic-like. After differentiation culture which was made in the first pass, by immunofluorescence, we obtained positive cell markers for three lineages of differentiation, adipocytes: LPL protein, osteocytes: RUNX2, Osteopontin, chondrocytes: SOX9, Aggrecan and COL2A1. We managed to isolate a significant number of MSCs from this source using an easy method to implement and minimal nutrient supplementation, with high potential for differentiation to mature mesenchymal tissues and potential use in basic experimental, preclinical and even clinical research.

HLA-B27 may modulate the interaction between ERAP1 polymorphisms and smoking in ankylosing spondylitis patients.

BACKGROUND: Ankylosing spondylitis (AS) is an autoimmune disease that affects the enthesis and synovial membrane of the spine, the sacroiliac vertebrae and peripheral joints. Genetic susceptibility to AS is mainly due to the presence of the HLA-B*27 (B27) allele, and endoplasmic reticulum aminopeptidase-1 (ERAP-1) plays a key role in antigen processing and presentation to HLA class I molecules. Tobacco consumption is one of the main environmental factors involved in the pathogenesis of various diseases, including AS. The objective of the present study was to evaluate the association and the interactive effects of variants of the ERAP1 gene with smoking in modulating the risk of AS. METHODS AND RESULTS: A case-control study in the Mexican population. The association of two functional variants of the ERAP1 gene (rs30187 and rs27044) in patients with AS was analyzed by the allelic discrimination method using TaqMan probes. B27 was typified by PCR-SSP. The interaction between the variants of ERAP1 and B27 and smoking was assessed using the multifactorial dimensionality reduction (MDR) method. There was no significant association of the two variants of ERAP1 in the cases compared with the controls (P > 0.05); however, a strong interaction between the variants and smoking could be demonstrated, with entropy values of 4.97% for rs30187 and 5.13% for rs27044. In addition, these interaction effects were increased in patients carrying the B27 allele. CONCLUSIONS: The rs30187 and rs27044 variants of the ERAP1 gene appear to potentiate the effect of smoking in patients with AS carrying the B27 allele.

The interplay between HLA-B and NLRP3 polymorphisms may be associated with the genetic susceptibility of gout.

BACKGROUND: HLA and NLRP3 play an important role in the development of various autoimmune and autoinflammatory diseases. Gout is an autoinflammatory disease associated with multiple genetic and environmental factors. The objective of the present study was to evaluate the interaction and association between genetic polymorphisms of HLA-B and the NLRP3 gene in Mexican patients with gout. METHODS AND RESULTS: Eighty-one patients with gout were included and compared with 95 healthy subjects. The polymorphisms rs4349859, rs116488202, rs2734583 and rs3099844 (within the HLA-B region) and rs3806268 and rs10754558 of the NLRP3 gene were genotyped using TaqMan probes in a Rotor-Gene device. The interactions were determined using the multifactorial dimensionality reduction (MDR) method, while the associations were determined through logistic regression models. The MDR analysis revealed significant interactions between the rs116488202 and rs10754558 polymorphisms with an entropy value of 4.31% (p < 0.0001). Significant risk associations were observed with rs4349859 and rs116488202 polymorphisms (p < 0.01); however, no significant associations were observed with the polymorphisms of the NLRP3 gene. CONCLUSIONS: The results suggest that HLA-B polymorphisms and their interaction with NLRP3 may contribute to the genetic susceptibility of gout.

Synovial membrane mesenchymal stem cells for cartilaginous tissues repair.

BACKGROUND: The present review is focused on general aspects of the synovial membrane as well as specialized aspects of its cellular constituents, particularly the composition and location of synovial membrane mesenchymal stem cells (S-MSCs). S-MSC multipotency properties are currently at the center of translational medicine for the repair of multiple joint tissues, such as articular cartilage and meniscus lesions. METHODS AND RESULTS: We reviewed the results of in vitro and in vivo research on the current clinical applications of S-MSCs, surface markers, cell culture techniques, regenerative properties, and immunomodulatory mechanisms of S-MSCs as well as the practical limitations of the last twenty-five years (1996 to 2021). CONCLUSIONS: Despite the poor interest in the development of new clinical trials for the application of S-MSCs in joint tissue repair, we found evidence to support the clinical use of S-MSCs for cartilage repair. S-MSCs can be considered a valuable therapy for the treatment of repairing joint lesions.

Rheumatoid Arthritis and Oxidative Stress.

Rheumatoid arthritis (RA) is an autoimmune disease that affects approximately 1% of the worldwide population. In recent decades, oxidative stress (OS) has been shown to be involved in the progression of this disease through DNA, lipid and protein damage, resulting in synovial inflammation. There are many causes of OS; metabolism is involved in the production of reactive oxygen species (ROS) but pollution, diet and microbiota imbalances could lead to the overproduction of these ROS. A decade of research focused on understanding how OS is promoted by known RA risk factors is described herein. The use of antioxidants represents an integrative treatment for patients with rheumatoid arthritis, given the evidence of the damage caused by oxidative stress in this disease. Understanding the different factors that contribute to the development and progression of RA, such as OS, will pave the way not only for better pharmacological treatments but also for recommendations for dietary and health behaviours that will benefit patients with this disease.

Osteogenic Potential of Monosodium Urate Crystals in Synovial Mesenchymal Stem Cells.

Background and Objectives: Deposits of monosodium urate (MSU) crystals due to increased levels of uric acid (UA) have been associated with bone formation and erosion, mainly in patients with chronic gout. The synovial membrane (SM) comprises several types of cells, including mesenchymal stem cells (SM-MSCs); however, it is unknown whether UA and MSU induce osteogenesis through SM-MSCs. Materials and Methods: Cultures of SM were immunotyped with CD44, CD69, CD90, CD166, CD105, CD34, and CD45 to identify MSCs. CD90+ cells were isolated by immunomagnetic separation (MACS), colony-forming units (CFU) were identified, and the cells were exposed to UA (3, 6.8, and 9 mg/dL) and MSU crystals (1, 5, and 10 µg/mL) for 3 weeks, and cellular morphological changes were evaluated. IL-1ß and IL-6 were determined by ELISA, mineralization was assessed by alizarin red, and the expression of Runx2 was assessed by Western blot. Results: Cells derived from SM and after immunomagnetic separation were positive for CD90 (53 ± 8%) and CD105 (52 ± 18%) antigens, with 53 ± 5 CFU identified. Long-term exposure to SM-MSCs by UA and MSU crystals did not cause morphological damage or affect cell viability, nor were indicators of inflammation detected. Mineralization was observed at doses of 6.8 mg/dL UA and 5 µg/mL MSU crystals; however, the differences were not significant with respect to the control. The highest dose of MSU crystals (10 µg/mL) induced significant Runx2 expression with respect to the control (1.4 times greater) and SM-MSCs cultured in the osteogenic medium. Conclusions: MSU crystals may modulate osteogenic differentiation of SM-MSCs through an increase in Runx2.

Taxonomic variations in the gut microbiome of gout patients with and without tophi might have a functional impact on urate metabolism.

OBJECTIVE: To evaluate the taxonomic composition of the gut microbiome in gout patients with and without tophi formation, and predict bacterial functions that might have an impact on urate metabolism. METHODS: Hypervariable V3-V4 regions of the bacterial 16S rRNA gene from fecal samples of gout patients with and without tophi (n = 33 and n = 25, respectively) were sequenced and compared to fecal samples from 53 healthy controls. We explored predictive functional profiles using bioinformatics in order to identify differences in taxonomy and metabolic pathways. RESULTS: We identified a microbiome characterized by the lowest richness and a higher abundance of Phascolarctobacterium, Bacteroides, Akkermansia, and Ruminococcus_gnavus_group genera in patients with gout without tophi when compared to controls. The Proteobacteria phylum and the Escherichia-Shigella genus were more abundant in patients with tophaceous gout than in controls. Fold change analysis detected nine genera enriched in healthy controls compared to gout groups (Bifidobacterium, Butyricicoccus, Oscillobacter, Ruminococcaceae_UCG_010, Lachnospiraceae_ND2007_group, Haemophilus, Ruminococcus_1, Clostridium_sensu_stricto_1, and Ruminococcaceae_UGC_013). We found that the core microbiota of both gout groups shared Bacteroides caccae, Bacteroides stercoris ATCC 43183, and Bacteroides coprocola DSM 17136. These bacteria might perform functions linked to one-carbon metabolism, nucleotide binding, amino acid biosynthesis, and purine biosynthesis. Finally, we observed differences in key bacterial enzymes involved in urate synthesis, degradation, and elimination. CONCLUSION: Our findings revealed that taxonomic variations in the gut microbiome of gout patients with and without tophi might have a functional impact on urate metabolism.

A proposed HLA-B*27 screening method for ankylosing spondylitis detection based on tag-single nucleotide polymorphisms: a preliminary study.

BACKGROUND: Ankylosing spondylitis (AS) is a type of inflammatory arthritis that affects primarily the spine. There is a strong association of the HLA-B*27 allele with AS pathogenesis, but recent studies have demonstrated the participation of ERAP1 gene in the genetic susceptibility. The aim of this study was to determine whether HLA-B tag-single nucleotide polymorphisms (SNPs) and ERAP1-related genetic variations associated with AS have equal or similarly performance in patients´ screening compared to HLA-B*27 standard genotyping in Mexican population. METHODS AND RESULTS: Genomic DNA from patients with AS and population-based controls from Mexico City was analyzed for five single nucleotide polymorphisms (SNPs): rs4349859, rs13202464, rs116488202, tagging HLA-B*27; and rs30187 and rs27044 in ERAP1 gene. TaqMan genotype assay method was used for SNPs genotyping. We found a significant association between AS and the heterozygote genotypes and minor alleles of the HLA-B*27 tag-SNPs, as well as for their haplotypes. With respect to ERAP1 polymorphisms, no significant associations were observed (p > 0.05). The sensitivity and specificity analysis showed values of 0.96 and 1.00 for the rs4349859 SNP, and 0.96 and 0.94 for the rs116488202 SNP, respectively, in detecting HLA-B*27 compared to the B27 test as the gold standard. CONCLUSIONS: HLA-B*27 tag-SNPs are associated with AS susceptibility; furthermore, the rs4349859 SNP by its own have an outstanding performance in detecting HLA-B*27 and therefore can be proposed as screening marker in the identification of HLA-B*27 in our population.

Multifactor dimensionality reduction reveals a strong gene-gene interaction between STC1 and COL11A1 genes as a possible risk factor of knee osteoarthritis.

Articular cartilage is an avascular tissue with a structure that allows it to support and cushion the overload of the surfaces in contact. It maintains its metabolic functions due to the contribution of different signaling pathways. However, several factors play a role in its deterioration, allowing to the development of osteoarthritis (OA), and one of the major factors is genetic. Our goal was to identify gene-gene interactions (epistasis) between five signaling pathways involved in the articular cartilage metabolism as possible indicators of OA risk. We applied the Multifactor-Dimensionality Reduction (MDR) method to identify and characterize the epistasis between 115 SNPs located in 73 genes related to HIF-1α, Wnt/ß-catenin, cartilage extracellular matrix metabolism, oxidative stress, and uric acid transporters. Ninety three patients diagnosed with primary knee OA and 150 healthy controls were included in the study. Genotyping was performed with the OpenArray system, the statistical analysis was carried out with the STATA software v14, and epistasis was analyzed with the MDR software v3.0.2. The MDR analysis revealed that the best interaction model was between polymorphisms rs17786744 of the STC1 gene and rs2615977 of the COL11A1 gene, with an entropy value of 4.44%, CVC 8/10, OR 5.60, 95% CI 3.27-9.59, p < 0.0001. Under this interaction model, we identified high and low risk genotypes involved in OA development. Our results suggest complex interactions between STC1 and COL11A1 genes that might have an impact on genetic susceptibility to develop OA. Further studies are required to confirm it.

Epistasis of polymorphisms related to the articular cartilage extracellular matrix in knee osteoarthritis: Analysis-based multifactor dimensionality reduction.

Osteoarthritis (OA) is a complex disease with a multifactorial etiology. The genetic component is one of the main associated factors, resulting from interactions between genes and environmental factors. The aim of this study was to identify gene-gene interactions (epistasis) of the articular cartilage extracellular matrix (ECM) in knee OA. Ninety-two knee OA patients and 147 healthy individuals were included. Participants were genotyped in order to evaluate nine variants of eight genes associated with ECM metabolism using the OpenArray technology. Epistasis was analyzed using the multifactor dimensionality reduction (MDR) method. The MDR analysis showed significant gene-gene interactions between MMP3 (rs679620) and COL3A1 (rs1800255), and between COL3A1 (rs1800255) and VEGFA (rs699947) polymorphisms, with information gain values of 3.21% and 2.34%, respectively. Furthermore, in our study we found interactions in high-risk genotypes of the HIF1AN, MMP3 and COL3A1 genes; the most representative were [AA+CC+GA], [AA+CT+GA] and [AA+CT+GG], respectively; and low-risk genotypes [AA+CC+GG], [GG+TT+GA] and [AA+TT+GA], respectively. Knowing the interactions of these polymorphisms involved in articular cartilage ECM metabolism could provide a new tool to identify individuals at high risk of developing knee OA.

Common gene variants interactions related to uric acid transport are associated with knee osteoarthritis susceptibility.

BACKGROUND: The presence of genetic variants in uric acid (UA) transporters can be associated with hyperuricemia, and therefore with an increased risk of monosodium urate (MSU) crystal precipitation. The inflammatory process triggered by these crystals leads to cartilage damage, which, in turn, could promote knee osteoarthritis (KOA). OBJECTIVE: To determine whether genetic polymorphisms of the UA transporters and their interactions are associated with KOA. MATERIALS AND METHODS: Two hundred forty-three unrelated Mexican-mestizo individuals were recruited for this case-control study. Ninety-three of them were KOA patients but without gout, and one hundred and fifty healthy individuals with no symptoms or signs of KOA were recruited as controls. Forty-one single-nucleotide polymorphisms (SNPs) involved in the UA transporters were genotyped with OpenArray technology in a QuantStudio 12K flex-System with both cases and controls. RESULTS: After adjusting by age, gender, BMI, and ancestry, significant associations were found for eight SNPs: rs1260326 (GCKR), rs780093 (GCKR), rs17050272 (INHBB), rs1471633 (PDZK1), rs12129861 (PDZK1), rs7193778 (IGF1R), rs17786744 (STC1), and rs1106766 (R3HDM2). With respect to gene-gene interactions, the pairwise interactions of rs112129861 (PDZK1) and rs7193778 (IGF1R); rs17050272 (INHBB) and rs1106766 (R3HDM2); rs1106766 (R3HDM2) and rs780093 (GCKR); rs1260326 (GCKR) and rs17786744 (STC1); and rs17786744 (STC1) and rs1106766 (R3HDM2) make it possible to visualize the synergistic or antagonistic effect of their genotypes or alleles on KOA development. CONCLUSIONS: Our preliminary results show that the common gene variants related to UA transport are associated with KOA in the Mexican population. Further studies must be carried out to corroborate it.

Epistasis between ADIPOQ rs1501299 and PON1 rs662 polymorphisms is potentially associated with the development of knee osteoarthritis.

Overweight produces oxidative stress (OS) on the articular cartilage, with the subsequent risk of developing knee osteoarthritis (OA). Associations between genetic polymorphisms related to OS and OA have been reported, but it is currently unknown whether there exist interactions among them that affect OA development. To identify and evaluate interactions between multiple SNPs related to OS in Mexican knee OA patients. Ninety-two knee OA patients were included in the study, which were compared to 147 healthy controls. Nine variants of six genes (PEPD, AGER, IL6, ADIPOQ, PON1, and CA6) related to OS were genotyped in both study groups through the OpenArray system. Epistasis was analyzed with the multifactor dimensionality reduction (MDR) method. The MDR analysis revealed a significant interaction (p = 0.0107) between polymorphisms rs1501299 (ADIPOQ) and rs662 (PON1), with an entropy value of 9.84%; in addition, high and low risk genotypes were identified between these two polymorphisms. The effect of the interaction between rs1501299 (ADIPOQ) and rs662 (PON1) polymorphisms seems to play an important role in OA pathogenesis; so the epistasis analysis may provide an excellent tool for identifying individuals at high risk for developing OA.

Gene-gene interactions of the Wnt/ß-catenin signaling pathway in knee osteoarthritis.

This study was designed to investigate whether genetic polymorphisms of the Wnt/ß-catenin signaling pathway and its interactions are involved in the development of knee osteoarthritis (KOA). Patients with KOA (n = 131) and healthy individuals (n = 190) with different ancestry from two Mexican populations (Mexico City and Guadalajara City) were analyzed. Twenty-five SNPs from thirteen genes (WISP1, DKK1, SOST, FRZB, LRP1, LRP4, LRP5, LRP6, GSKB, ADAMTS5, GDF5, FMN2 and COL11A1) involved in the Wnt/ß-catenin signaling pathway were genotyped. Genetic and allelic frequencies and gene-gene interactions were performed for this study. After adjusting for age, sex, BMI and admixture, significant associations were found for five SNPs in Mexico City: LRP6 rs12314259 (G/G genotype OR 0.22, P = 0.029; and G allele OR 0.48, P = 0.022), SOST rs851054 (C/T genotype OR 0.42, P = 0.027; and T allele OR 0.62, P = 0.026), FMN2 rs986690 (G/A genotype OR 0.42, P = 0.034; and A allele OR 0.50, P = 0.015), FRZB rs409238 (A/G genotype, OR 2.41, P = 0.022), and COL11A1 rs2615977 (A/C genotype OR 2.39, P = 0.024); no associations for Guadalajara City were found. With respect to gene-gene interactions, the pairwise interactions of WISP1-COL11A1, COL11A1-FRZB, FRZB-SOST and WISP1-FMN2 make it possible to visualize the synergistic or antagonistic effect of their genotypes or alleles in both populations. These results suggest that gene-gene interactions in the Wnt/ß-catenin signaling pathway play a role in the etiology of KOA.

The association of AKNA gene polymorphisms with knee osteoarthritis suggests the relevance of this immune response regulator in the disease genetic susceptibility.

Recent studies have identified AKNA as a potential susceptibility gene for several inflammatory diseases. Here, we aimed to assess the potential association of AKNA polymorphisms with knee osteoarthritis (KOA) susceptibility in a Mexican population, following STREGA recommendations. From a DNA bank of 181 KOA patients and 140 healthy controls, two AKNA SNPs were genotyped using TaqMan probes. The association between KOA susceptibility and AKNA polymorphisms genotypes was evaluated by multivariated logistic regression analysis. Information regarding patients' inflammatory biomarkers levels was obtained and their association with AKNA polymorphisms genotypes was assessed by lineal regression. We found a positive association with the recessive inheritance model of both AKNA polymorphisms (A/A genotype for both) and KOA susceptibility adjusting by age, body mass index (BMI), gender and place of birth (OR = 2.48, 95% CI 1.09-5.65 for rs10817595 polymorphism; and OR = 4.96; 95% CI 2.421-10.2 for rs3748176 polymorphism). Additionally these associations were also seen after stratifying patients by KOA severity and age. Furthermore the total leukocyte count was positively associated with rs10817595 AKNA polymorphism (ß = 1.39; 95% CI 0.44-2.34) adjusting by age, BMI, gender, place of birth and disease severity. We suggest that regulatory and coding polymorphisms of the inflammatory modulator gene AKNA can influence the development of KOA. Further structural and functional studies might reveal the role of AKNA in OA and other rheumatic diseases.

Anti-inflammatory effects of polyphenols in arthritis.

Polyphenols have been extensively investigated with regard to their antioxidant, anti-inflammatory, and immunomodulant properties in many inflammatory chronic conditions. The aim of this review is to summarise how these compounds can modulate the inflammatory pathways which characterise the most prevalent arthropathies including osteoarthritis, rheumatoid arthritis and crystal-induced arthritis. Among polyphenols, epigallocatechin gallate, carnosol, hydroxytyrosol, curcumin, resveratrol, kaempferol and genistein have been the most widely investigated in arthritis. The most important results of the studies outlined in this article show how polyphenolic compounds are able to inhibit the expression and the release of a number of pro-inflammatory mediators and proteolytic enzymes, the activity of different transcriptional factors and the production of reactive oxygen species in vitro. Studies on animal models of rheumatoid arthritis, osteoarthritis and gout show interesting results in terms of reduced tissue damage, restored cartilage homeostasis, and decreased levels of uric acid, respectively. Despite the multiple protective effects of polyphenols, there are no dietary recommendations for patients affected by rheumatic diseases. Future studies, including intervention trials, should be conducted to determine the relevance of polyphenols consumption or supplementation in arthritis. © 2017 Society of Chemical Industry.

Hyperlipidemic microenvironment conditionates damage mechanisms in human chondrocytes by oxidative stress.

BACKGROUND: Currently, two pathogenic pathways describe the role of obesity in osteoarthritis (OA); one through biomechanical stress, and the other by the contribution of systemic inflammation. The aim of this study was to evaluate the effect of free fatty acids (FFA) in human chondrocytes (HC) expression of proinflammatory factors and reactive oxygen species (ROS). METHODS: HC were exposed to two different concentrations of FFA in order to evaluate the secretion of adipokines through cytokines immunoassays panel, quantify the protein secretion of FFA-treated chondrocytes, and fluorescent cytometry assays were performed to evaluate the reactive oxygen species (ROS) production. RESULTS: HC injury was observed at 48 h of treatment with FFA. In the FFA-treated HC the production of reactive oxygen species such as superoxide radical, hydrogen peroxide, and the reactive nitrogen species increased significantly in a at the two-dose tested (250 and 500 µM). In addition, we found an increase in the cytokine secretion of IL-6 and chemokine IL-8 in FFA-treated HC in comparison to the untreated HC. CONCLUSION: In our in vitro model of HC, a hyperlipidemia microenvironment induces an oxidative stress state that enhances the inflammatory process mediated by adipokines secretion in HC.

Polymorphic variation of hypoxia inducible factor-1 A (HIF1A) gene might contribute to the development of knee osteoarthritis: a pilot study.

BACKGROUND: Osteoarthritis (OA) is a multifactorial degenerative condition of the whole joint with a complex pathogenesis whose development and progression is significantly mediated by interactions between the joint cartilage and articular tissues, particularly, proinflammatory mediators and oxidative stress, which results in cartilage deterioration and subchondral bone destruction. HIF-1 alpha regulates oxygen homeostasis in hypoxic tissues such as joint cartilage; efficiency of transcriptional activity of the HIF1A gene is strongly influenced by the presence of polymorphic variants. Given the loss of articular cartilage and with intention to restore damaged tissue, WISP-1 participates in the development of subchondral bone; further, its expression is highly increased in chondrocytes of OA patients. The aim of this study was to evaluate gene frequencies of HIF1A and WISP1 polymorphisms in Mexican patients suffering from knee OA. METHODS: We determined HIF1A rs11549465 (P582S), rs11549467 (A588T), and rs2057482 (C191T), and WISP1 rs2929970 (A2364G) polymorphisms in 70 Mexican patients with knee OA and compare them to those present in 66 ethnically matched healthy controls. Genotyping for these polymorphisms was performed by Real-Time PCR using TaqMan probes. RESULTS: Gene frequencies exhibited a significant increase of the CC genotype of rs11549465 polymorphism in knee OA patients as compared with those present in controls (P = 0.003 OR = 5.7, 95% CI = 1.7-21.6); CT genotype and T allele showed decreased frequency in the knee OA group vs. the controls (P = 0.003 OR = 0.2, CI = 0.05-0.6; and P = 0.004 OR = 0.2, CI = 0.05-0.65, respectively). Allele frequencies of the other polymorphic variants were similar in both patients and controls. CONCLUSIONS: These results suggest that the presence of the rs11549465 SNP (HIF1A) plays a role protective in the loss of articular cartilage in our population, and offers the possibility to further study the molecular mechanisms within cartilage and subchondral bone.