Pro-inflammatory cytokines: The link between obesity and osteoarthritis

Pharmacological Targeting of Heme Oxygenase-1 in Osteoarthritis

Osteoarthritis (OA) is a common aging-associated disease that clinically manifests as joint pain, mobility limitations, and compromised quality of life. Today, OA treatment is limited to pain management and joint arthroplasty at the later stages of disease progression. OA pathogenesis is predominantly mediated by oxidative damage to joint cartilage extracellular matrix and local cells such as chondrocytes, osteoclasts, osteoblasts, and synovial fibroblasts. Under normal conditions, cells prevent the accumulation of reactive oxygen species (ROS) under oxidatively stressful conditions through their adaptive cytoprotective mechanisms. Heme oxygenase-1 (HO-1) is an iron-dependent cytoprotective enzyme that functions as the inducible form of HO. HO-1 and its metabolites carbon monoxide and biliverdin contribute towards the maintenance of redox homeostasis. HO-1 expression is primarily regulated at the transcriptional level through transcriptional factor nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), specificity protein 1 (Sp1), transcriptional repressor BTB-and-CNC homology 1 (Bach1), and epigenetic regulation. Several studies report that HO-1 expression can be regulated using various antioxidative factors and chemical compounds, suggesting therapeutic implications in OA pathogenesis as well as in the wider context of joint disease. Here, we review the protective role of HO-1 in OA with a focus on the regulatory mechanisms that mediate HO-1 activity.

Optimisation and feature selection of poly-beta-amino-ester as a drug delivery system for cartilage

Drug localisation is one of the main challenges in treating cartilage; poly-beta-amino-esters (PBAEs) drug conjugates are a possible solution; their efficacy depends on the polymer structure hence the full potential of this system is still unknown.

Drug localisation is still one of the main challenges in treating pathologies affecting cartilage; poly-beta-amino-esters (PBAEs) drug conjugates are a possible solution; however, their efficacy highly depends on the polymer structure hence the full potential of this delivery system is still unknown. For the purpose of optimising the delivery system design, a large library of PBAEs was synthesised and dexamethasone (DEX) uptake in cartilage was determined. All three components of PBAE (amine, acrylate and end-capping) impacted the outcome. The most effective PBAE identified enhanced DEX uptake by 8 folds compared to an equivalent dose of the commercial formulation and also prevented, through delivery of DEX, the cartilage degradation caused by IL-1α (interleukine1α). A chemometrics based predictive model was constructed and PBAEs properties most affecting the performance of the drug delivery systems were identified. This model will allow further computer based PBAEs optimisation and fast track the bench to market process for this delivery system.

Plaque control alleviated renal damage that was aggravated by experimental periodontitis in obese rats

OBJECTIVE

This study aimed to evaluate the influence of experimental periodontitis on renal damage in obese rats.

MATERIALS AND METHODS

Thirty-two male Sprague Dawley rats were randomly allocated into 4 groups with 8 animals each: obese rats (obese group), obese rats with periodontitis (periodontitis obese group), obese rats with periodontitis that underwent plaque control (plaque-control obese group), and healthy rats (healthy group). Rats were fed a high-fat diet to establish an obesity model. Experimental periodontitis was induced by local ligation with silk around the bilateral maxillary second molars. The plaque control was accomplished by removing ligations and local wiping with an antiseptic rinse. Histology was used to observe the gingival inflammation and clinical attachment level (CAL) to further assess bone loss and to also observe renal structure. Serum creatinine, urea nitrogen, and kidney injury molecule-1 (KIM-1) levels were measured to evaluate renal function. Renal Toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), serum C-reactive protein (CRP), lipopolysaccharides (LPS), and interleukin-1β (IL-1β) were measured to evaluate renal and systemic inflammation.

RESULTS

Periodontal histology showed that in the periodontitis obese group, the epithelial barrier was considerably eroded by inflammatory cells, which infiltrated into the subepithelial connective tissue and lamina propria. A periodontal pocket was forming accompanied by the loss of attachment. The extent of infiltration of inflammatory cells and the CAL were significantly higher than those of the obese group (p < .001). In the plaque-control obese group, although the inflammatory condition was significantly improved than in the periodontitis obese group, the clinical attachment level with the presence of fiber hyperplasia could not be restored. Renal histology showed that renal tubular structural damage was aggravated in the periodontitis obese group, including vacuolar degeneration, exfoliation of the proximal tubular epithelial cell lining, multifocal loss of the brush border, and movement of several nuclei from the basement membrane to the lumen. These alterations were improved in the plaque-control obese group. Kidney TLR4 and NF-κB mRNA levels increased significantly in the periodontitis obese group compared to the obese group (p = .015 and p = .015, respectively) and decreased significantly in the plaque-control obese group (p = .028 and p = .021, respectively). Kidney TLR4 and NF-κB protein expression in the plaque-control obese group were significantly lower than those in the periodontitis obese group (p < .001 and p = .043, respectively). Serum creatinine and KIM-1 levels significantly decreased in the plaque-control obese group compared to the periodontitis obese group (p = .001 and p = .002, respectively). At 21 weeks (1 week after periodontal ligation), serum CRP levels in the periodontitis obese group were significantly higher than that in the healthy group (p = .017). Other serum inflammatory markers (LPS and IL-1β) did not change significantly.

CONCLUSION

Experimental periodontitis induced dysfunction and structural destruction of the kidney in obese rats. Plaque control relieved renal damage.

MK801 regulates the expression of key osteoarthritis factors in osteoarthritis synovial fibroblasts through complement C5

BACKGROUND

Osteoarthritis is currently one of the most common chronic diseases. As life expectancy increases, its prevalence and incidence are expected to rise. At present, more and more evidences prove the correlation between the complement system and osteoarthritis (OA). This study aims to investigate complement C5's influence on the effect of MK801 on osteoarthritis synovial fibroblasts (OA-SFs).

METHODS

We used IL-1b to induce OA-SFs derived from mice to obtain OA-SFs. And we performed RT-PCR and Western Blot assays to evaluate the expression levels of associated mRNA and protein. The alteration of MAC expression on OA-SFs cell membrane was evaluated by immunofluorescence assay. The expression of related inflammatory factors of OA-SFs was evaluated by ELISA experiment.

RESULTS

MK801 could significantly inhibit the expression of osteoarthritis (OA) marker factors, such as: membrane attack complex (MAC), tumor necrosis factor-α (TNF-α) and matrix metalloproteinase-13 (MMP13). Meanwhile, MK801 can significantly inhibit the expression of complement C5 (C5) in OA-SFs. Immunofluorescence assay showed that MAC expression on OA-SFs cell membrane was significantly inhibited by MK801. The nucleo-plasmic separation experiment demonstrated that MK801 could significantly inhibit the activation of Nuclear factor-κB (NF-κB) signaling pathway in OA-SFs. Futhermore, koncking down the expression of C5 reversed the inhibition MK801 on the expression of OA-SFs inflammatory factors.

CONCLUSIONS

These results illustrated two points: first, MK801 inhibited the generation of MAC and the release of inflammation factors in OA-SFs through C5; second: MK801 inhibited the activation of NF-κB signaling pathway in OA-SFs.

The role of metabolism in chondrocyte dysfunction and the progression of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by low-grade inflammation and high levels of clinical heterogeneity. Aberrant chondrocyte metabolism is a response to changes in the inflammatory microenvironment and may play a key role in cartilage degeneration and OA progression. Under conditions of environmental stress, chondrocytes tend to adapt their metabolism to microenvironmental changes by shifting from one metabolic pathway to another, for example from oxidative phosphorylation to glycolysis. Similar changes occur in other joint cells, including synoviocytes. Switching between these pathways is implicated in metabolic alterations that involve mitochondrial dysfunction, enhanced anaerobic glycolysis, and altered lipid and amino acid metabolism. The shift between oxidative phosphorylation and glycolysis is mainly regulated by the AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) pathways. Chondrocyte metabolic changes are likely to be a feature of different OA phenotypes. Determining the role of chondrocyte metabolism in OA has revealed key features of disease pathogenesis. Future research should place greater emphasis on immunometabolism and altered metabolic pathways as a means to understand the pathophysiology of age-related OA. This knowledge will advance the development of new drugs against therapeutic targets of metabolic significance.

Inhibitory Effect of Paeonol on Apoptosis, Oxidative Stress, and Inflammatory Response in Human Umbilical Vein Endothelial Cells Induced by High Glucose and Palmitic Acid Induced Through Regulating SIRT1/FOXO3a/NF-κB Pathway

Reactive oxygen species (ROS) induced by high glucose and high fat of diabetes mellitus (DM) finally caused the occurrence and progression of atherosclerosis and other macrovascular complications. Paeonol (Pae) exhibits anti-inflammation, antioxidation, and antiatherosclerosis activities. However, the role of Pae in diabetic cardiopathy has not been fully understood. Therefore, we aimed to investigate the role of Pae in diabetic cardiovascular diseases. Human umbilical vein endothelial cells (HUVECs) were exposed to high glucose and palmitic acid (HG/HP), a model DM environment and different doses of Pae. The viability and apoptotic rate of HUVECs were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and flow cytometry assay, respectively. Oxidative indicators (ROS, malondiadehyde [MDA], superoxide dismutase [SOD]), and inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, and interleukin-6) were detected by 2,7-dichlorodihydrofluorescein diacetate, colorimetry, and enzyme-linked immunosorbent assay. The protein levels of Sirtuin type 1 (SIRT1), Bcl-2, Bax, Cleaved caspase-3, p-p65, and p-65 were detected by Western blot. The mRNA levels of Bcl-2 and Bax were detected by quantitative real-time polymerase chain reaction. The acetylation and protein levels of forkhead box O3a (FOXO3a) were detected by immunoprecipitation assay. SIRT1 silencing was used to confirm the role of Pae in the resistance to apoptosis, oxidative stress, and inflammatory response. Pae increased SIRT1 expression, cell viability, and SOD activity and suppressed apoptosis, the levels of p-p65/p-65, ROS, MDA, and inflammatory cytokines, and the expression of acetylated-FOXO3a induced by HG/HP in HUVECs. SIRT1 silencing abrogated the effect of Pae on HG/HP-mediated HUVECs. Inhibitory effect of Pae on apoptosis, oxidative stress, and inflammatory response in HUVECs induced by HG/HP induced through regulating SIRT1/FOXO3a/NF-κB pathway.

Beneficial Effect of Tempol, a Membrane-Permeable Radical Scavenger, on Inflammation and Osteoarthritis in In Vitro Models

Osteoarthritis (OA) is one of the most common and widespread diseases which is highly disabling for humans. This makes OA a chronic disease for which it is urgent to find new therapeutic strategies. The inflammatory state in OA contributes to its progression through multiple mechanisms involving the recruitment of phagocytes and leukocytes, inflammatory response, and reactive oxygen species (ROS) production. Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) is classifiable as a piperidine nitroxide, with excellent antioxidant effects, while its anti-inflammatory role is not yet clear. On this basis, we explored its promising biological properties in two in vitro model:, macrophage (J774) and chondrocyte (CC) cell lines. With this aim in mind, we induced inflammation in J774 and CC using lipopolysaccharide (LPS) and Interleukin1β (IL-1β), and after 24, 72 and 168 h of tempol treatment analyzed their effects on cytotoxicity and anti-inflammatory activity. Our data suggested that tempol treatment is able to reduce inflammation and nitrite production in LPS-induced J774 as well as reducing the production of proinflammatory mediators including cytokines, enzymes, and metalloproteases (MMPs) in IL-1β-stimulated CC. Thus, since inflammation and oxidative stress have a crucial role in the pathogenesis and progression of OA, tempol could be considered as a new therapeutic approach for this pathology.

The use of glutathione to reduce oxidative stress status and its potential for modifying the extracellular matrix organization in cleft lip

OBJECTIVE

Cleft lip (CL) is a common congenital anomaly that can be syndromic or non-syndromic. It can be triggered by the mutation of gene or environmental factors. The incidence of CL is about 1 out of 700 live births. Facial development is a complex process, and there is no existing therapy to prevent the disease development. One of the characteristics in this facial malformation is the increased presence of reactive oxygen species (ROS). In this study, we hypothesize that the antioxidant glutathione (GSH) could help to attenuate the oxidative stress in this disease.

METHODS

Bioinformatics network pharmacology was applied to determine pharmacological targets and molecular mechanisms of GSH treatment for CL. Moreover, RNA-sequencing of the POLR1C knockdown osteoblast CL model was applied to validate the in silico data of using GSH in CL.

RESULTS

Twenty-two core targets of GSH and CL were identified via various bioinformatics tools. The GO and KEGG analysis indicated that GSH could modulate two major families (matrix metalloproteinase and integrins), which are related to extracellular matrix modification and composition for facial development in CL. The findings from POLR1C knockdown model further supported the rescue response of GSH in CL.

CONCLUSIONS

The study uncovered the possible pharmacological mechanism of GSH for treating CL. The data helps research group to focus on the specific pathways for understanding the biological action of GSH for treating the CL in the future.

Exosome-Encapsulated microRNA-127-3p Released from Bone Marrow-Derived Mesenchymal Stem Cells Alleviates Osteoarthritis Through Regulating CDH11-Mediated Wnt/β-Catenin Pathway

Objective

Exosome-encapsulated microRNAs (miRNAs) are being considered as either diagnostic or predictive markers in different types of diseases. Here, we discussed the effects of exosome-encapsulated miR-127-3p from bone marrow-derived mesenchymal stem cells (BM-MSCs) on osteoarthritis (OA).

Methods

BM-MSCs and primary chondrocytes were isolated from Sprague Dawley rats. IL-1β was utilized to treat chondrocytes to mimic an OA in vitro model, and exosomes extracted from BM-MSCs were utilized to treat chondrocytes so as to verify their protective effects on OA. Through online website prediction and experiments confirmation, we found the most significantly enriched miRNA in exosomes and elucidated the effect of this miRNA on the therapeutic effect of exosomes by interfering with its expression. Also, the genes targeted by the miRNA and the involved pathway were also found through bioinformatics analysis and experimental research, thereby probing into the protective mechanism of exosomes on chondrocytes.

Results

Exosomes derived from BM-MSCs restricted the IL-1β-induced chondrocytes damage. miR-127-3p was found to be enriched in exosomes, and the protective effect of exosomes was reversed by miR-127-3p inhibition. miR-127-3p targeted CDH11, and overexpressed CDH11 in chondrocytes weakened the therapeutic effect of exosomes. IL-1β treatment resulted in the activation of the Wnt/β-catenin pathway in chondrocytes. Exosomes treatment could inhibit the activation of this pathway, and overexpressed CDH11 reversed the inhibitory effect of exosomes on this pathway.

Conclusion

This study suggests that exosomal miR-127-3p derived from BM-MSCs inhibits CDH11 in chondrocytes, thereby blocking the Wnt/β-catenin pathway activation and relieving chondrocyte damage in OA.

Prospects of nutritional interventions in the care of COVID-19 patients

The novel coronavirus disease 2019 (COVID-19) has unfolded an unprecedented worldwide public health emergency with disastrous economic consequences. Around 96 million coronavirus cases have already been identified with over half a million deaths. Despite numerous efforts by the government as well as international organizations, these numbers are still increasing with a surprising rate. Although urgent and absolutely necessary, a reliable therapeutic or vaccine is still elusive and this status quo may remain for an uncertain period of time. Taken that into account, boosting up adaptive immunity through nutritional interventions may help subside this epidemic and save many lives. This review focuses on the nexus between a balanced diet and adaptive immunity, particularly, how a poor diet may lead to compromised immunity resulting in susceptibility to viral infections. Additionally, we discuss how nutrients (vitamins, minerals, trace elements) can be used as a tool to modulate immune response and thus impede viral infections. The study also summarizes nutritional recommendations to combat COVID-19 in different countries and territories as well as dietary sources of those key nutrients. Moreover, different nutritional intervention strategies based on different age groups, physiological and medical conditions were also included, and the challenges of nutritional interventions towards the care of COVID-19 patients are also discussed. Since the availability of a drug or vaccine is still uncertain, a balanced diet or nutrient therapy can be used as a robust strategy to combat COVID-19. Thus, we hope this review may help to make an informed decision with regard to diet choice both at individual level as well as clinical settings.

Transcriptional response of human articular chondrocytes treated with fibronectin fragments: an in vitro model of the osteoarthritis phenotype

OBJECTIVE

Fibronectin is a matrix protein that is fragmented during cartilage degradation in osteoarthritis (OA). Treatment of chondrocytes with fibronectin fragments (FN-f) has been used to model OA in vitro, but the system has not been fully characterized. This study sought to define the transcriptional response of chondrocytes to FN-f, and directly compare it to responses traditionally observed in OA.

DESIGN

Normal human femoral chondrocytes isolated from tissue donors were treated with either FN-f or PBS (control) for 3, 6, or 18 h. RNA-seq libraries were compared between time-matched FN-f and control samples in order to identify changes in gene expression over time. Differentially expressed genes were compared to a published OA gene set and used for pathway, transcription factor motif, and kinome analysis.

RESULTS

FN-f treatment resulted in 3,914 differentially expressed genes over the time course. Genes that are up- or downregulated in OA were significantly up- (P < 0.00001) or downregulated (P < 0.0004) in response to FN-f. Early response genes were involved in proinflammatory pathways, whereas many late response genes were involved in ferroptosis. The promoters of upregulated genes were enriched for NF-κB, AP-1, and IRF motifs. Highly upregulated kinases included CAMK1G, IRAK2, and the uncharacterized kinase DYRK3, while growth factor receptors TGFBR2 and FGFR2 were downregulated.

CONCLUSIONS

FN-f treatment of normal human articular chondrocytes recapitulated many key aspects of the OA chondrocyte phenotype. This in vitro model is promising for future OA studies, especially considering its compatibility with genomics and genome-editing techniques.

Inflammation-Driven Breast Tumor Cell Plasticity: Stemness/EMT, Therapy Resistance and Dormancy

Cellular heterogeneity poses an immense therapeutic challenge in cancer due to a constant change in tumor cell characteristics, endowing cancer cells with the ability to dynamically shift between states. Intra-tumor heterogeneity is largely driven by cancer cell plasticity, demonstrated by the ability of malignant cells to acquire stemness and epithelial-to-mesenchymal transition (EMT) properties, to develop therapy resistance and to escape dormancy. These different aspects of cancer cell remodeling are driven by intrinsic as well as by extrinsic signals, the latter being dominated by factors of the tumor microenvironment. As part of the tumor milieu, chronic inflammation is generally regarded as a most influential player that supports tumor development and progression. In this review article, we put together recent findings on the roles of inflammatory elements in driving forward key processes of tumor cell plasticity. Using breast cancer as a representative research system, we demonstrate the critical roles played by inflammation-associated myeloid cells (mainly macrophages), pro-inflammatory cytokines [such as tumor necrosis factor α (TNFα) and interleukin 6 (IL-6)] and inflammatory chemokines [primarily CXCL8 (interleukin 8, IL-8) and CXCL1 (GROα)] in promoting tumor cell remodeling. These inflammatory components form a common thread that is involved in regulation of the three plasticity levels: stemness/EMT, therapy resistance, and dormancy. In view of the fact that inflammatory elements are a common denominator shared by different aspects of tumor cell plasticity, it is possible that their targeting may have a critical clinical benefit for cancer patients.

Association of diet quality and physical function among overweight and obese primarily African American older adults with lower extremity osteoarthritis

BACKGROUND:

Strategies to reduce osteoarthritis (OA) symptoms and increase physical function in persons with lower extremity (LE) OA is a public health priority.

OBJECTIVE:

To examine associations between diet quality and measures of physical function among overweight and obese older adults with self-reported LE OA.

METHODS:

413 overweight and obese primarily African American adults ≥60 years old with LE OA were assessed. Diet quality was quantified using the Healthy Eating Index-2010 (HEI-2010) and Alternative Healthy Eating Index-2010 (AHEI-2010). The six-minute walk, 30-second chair-stands, and timed up-and-go tests were used to assess physical function. Unadjusted and multivariable linear regressions were performed to assess associations between the diet quality and measures of physical function.

RESULTS:

The mean age of the subjects was 67.8 (SD 5.9) years and mean BMI was 34.8 (SD 5.5) kg/m². Adjusting for total calories, AHEI-2010 total score was associated with superior performance on the six-minute walk test. However, the association was attenuated when also controlling for age, gender, BMI, waist circumference, self-reported pain, and physical activity. HEI-2010 was not associated with the physical function measures.

CONCLUSION:

AHEI-2010 total score was positively associated with walking speed among older overweight and obese primarily AA older adults with LE OA. However, the association weakened when adjusting for subject covariates. The relationship between diet quality and physical function among health disparate populations should be further investigated in larger cohorts and using rigorous experimental study design.

Anti-Inflammatory and Analgesic Effects of TRPV1 Polypeptide Modulator APHC3 in Models of Osteo- and Rheumatoid Arthritis

Arthritis is a widespread inflammatory disease associated with progressive articular surface degradation, ongoing pain, and hyperalgesia causing the development of functional limitations and disability. TRPV1 channel is one of the high-potential targets for the treatment of inflammatory diseases. Polypeptide APHC3 from sea anemone Heteractis crispa is a mode-selective TRPV1 antagonist that causes mild hypothermia and shows significant anti-inflammatory and analgesic activity in different models of pain. We evaluated the anti-inflammatory properties of APHC3 in models of monosodium iodoacetate (MIA)-induced osteoarthritis and complete Freund’s adjuvant (CFA)-induced rheumatoid monoarthritis in comparison with commonly used non-steroidal anti-inflammatory drugs (NSAIDs) such as diclofenac, ibuprofen, and meloxicam. Subcutaneous administration of APHC3 (0.1 mg/kg) significantly reversed joint swelling, disability, grip strength impairment, and thermal and mechanical hypersensitivity. The effect of APHC3 was equal to or better than that of reference NSAIDs. Protracted treatment with APHC3 decreased IL-1b concentration in synovial fluid, reduced inflammatory changes in joints, and prevented the progression of cartilage degradation. Therefore, polypeptide APHC3 has the potential to be an analgesic and anti-inflammatory substance for the alleviation of arthritis symptoms.

Estrogen-related receptors: novel potential regulators of osteoarthritis pathogenesis

Osteoarthritis (OA) is a chronic inflammatory disease that is associated with articular cartilage destruction, subchondral bone alterations, synovitis, and even joint deformity and the loss of joint function. Although current basic research on the pathogenesis of OA has made remarkable progress, our understanding of this disease still needs to be further improved. Recent studies have shown that the estrogen-related receptor (ERR) family members ERRα and ERRγ may play significant roles in the pathogenesis of OA. In this review, we refer to the latest research on ERRs and the pathogenesis of OA, elucidate the structure and physiopathological functions of the ERR orphan nuclear receptor family, and systematically examine the relationship between ERRs and OA at the molecular level. Moreover, we also discuss and predict the capacity of ERRs as potential targets in the clinical treatment of OA.

Bardet-Biedl Syndrome ciliopathy is linked to altered hematopoiesis and dysregulated self-tolerance

Bardet-Biedl Syndrome (BBS) is a pleiotropic genetic disease caused by the dysfunction of primary cilia. The immune system of patients with ciliopathies has not been investigated. However, there are multiple indications that the impairment of the processes typically associated with cilia may have influence on the hematopoietic compartment and immunity. In this study, we analyze clinical data of BBS patients and corresponding mouse models carrying mutations in Bbs4 or Bbs18. We find that BBS patients have a higher prevalence of certain autoimmune diseases. Both BBS patients and animal models have altered red blood cell and platelet compartments, as well as elevated white blood cell levels. Some of the hematopoietic system alterations are associated with BBS-induced obesity. Moreover, we observe that the development and homeostasis of B cells in mice is regulated by the transport complex BBSome, whose dysfunction is a common cause of BBS. The BBSome limits canonical WNT signaling and increases CXCL12 levels in bone marrow stromal cells. Taken together, our study reveals a connection between a ciliopathy and dysregulated immune and hematopoietic systems.

Iron Overload Is Associated With Accelerated Progression of Osteoarthritis: The Role of DMT1 Mediated Iron Homeostasis

Objective: Iron overload is common in elderly people which is associated with an increased prevalence of osteoarthritis (OA), but the exact role of iron in the development of OA has not been established. The aim of the present study is to elucidate the connection between iron overload and OA using an iron overloaded mice model, as well as to explore the role of iron homeostasis, iron transporters dependent iron influx in OA pathogenesis. Methods: The iron overloaded mice model was established and OA was surgically induced. OA progression was assessed at 8 weeks after surgery. Next, primary chondrocytes were treated with pro-inflammatory cytokines and iron regulators mediated iron homeostasis were evaluated. Involvement of iron transporters was analyzed using chondrocytes mimicking an osteoarthritis-related phenotype in vitro. Results: Iron overloaded mice exhibited greater cartilage destruction and elevated ADAMTS5 as well as MMP13 expression along with increased iron accumulation and dysregulated iron regulators. Pro-inflammatory cytokines could disturb cellular iron homeostasis via upregulating iron import proteins, TFR1 and DMT1, downregulating iron efflux protein FPN, thus result in cellular iron overload. Among iron transporters, DMT1 was found to play pivotal roles in iron overload induced OA progress. Inhibition of DMT1 suppressed IL-1β induced inflammatory response and ECM degradation via blockade of MAPK and PI3K/AKT/NF-κB pathways. Conclusions: Our results suggest that iron takes parts in the development of OA and cutting iron influx via inhibiting DMT1 activity could be an attractive new target for OA treatment.

Review on experimental study and clinical application of low-intensity pulsed ultrasound in inflammation

Low-intensity pulsed ultrasound (LIPUS), as physical therapy, is widely used in both research and clinical settings. It induces multiple bioeffects, such as alleviating pain, promoting tissue repair, and shortening disease duration. LIPUS can also mediate inflammation. This paper reviews the application of LIPUS in inflammation and discusses the underlying mechanism. In basic experiments, LIPUS can regulate inflammatory responses at the cellular level by affecting some signaling pathways. In a clinical trial, LIPUS has been shown to alleviate inflammatory responses efficiently. As a cheap, safe, and convenient physical method, LIPUS is promising as anti-inflammatory therapy.

Causal Association of Coffee Consumption and Total, Knee, Hip and Self-Reported Osteoarthritis: A Mendelian Randomization Study

BACKGROUND

The causal association between coffee consumption and the risk of OA is limited. This study was conducted to identify the potential causal effects of coffee consumption on total, knee, hip, and self-reported OA.

METHODS

Genome-wide association studies (GWAS) of OA were derived from the UK Biobank, comprising 50,508 participants of European ancestry (10,083 with cases and 40,425 controls), and genetic data for specific diagnosed knee OA (4462 cases and 17,885 controls), hip OA (12,625 cases and 50,898 controls), and self-reported OA (12,658 cases and 50,898 controls). Primary and secondary genetic instruments (11 SNPs and 8 SNPs) were selected as instrumental variants from GWAS among 375,833 and 91,462 participants. Two-sample Mendelian randomization (MR) analyses were performed to test the effects of the selected single nucleotide polymorphisms (SNPs) and the OA risk. The causal effects were primarily estimated using weighted median and inverse-variance weighted method with several sensitivity analyses.

RESULTS

The MR analyses suggested that genetically predicted 1% increase of coffee consumption was associated with an increased risk of overall OA (OR:1.009, 95% CI:1.003-1.016), knee OA (OR:1.023, 95% CI:1.009-1.038), self-reported OA (OR:1.007, 95% CI:1.003-1.011), but not hip OA (OR: 1.012, 95%CI:0.999-1.024) using primary genetic instruments. Similar results were found when using secondary genetic instruments that genetically predicted coffee consumption (cups/day). Additionally, the sensitivity analyses for leave-one-out methods supported a robust association between exposure traits and OA.

CONCLUSION

Our findings indicate that genetically predicted coffee consumption exerts a causal effect on total, knee, and self-reported OA risk, but not at the hip. Further research is required to unravel the role of coffee consumption in OA prevention.

Immunity and the carotid body: implications for metabolic diseases

Neuro-immune communication has gained enormous interest in recent years due to increasing knowledge of the way in which the brain coordinates functional alterations in inflammatory and autoimmune responses, and the mechanisms of neuron-immune cell interactions in the context of metabolic diseases such as obesity and type 2 diabetes. In this review, we will explain how this relationship between the nervous and immune system impacts the pro- and anti-inflammatory pathways with specific reference to the hypothalamus-pituitary-adrenal gland axis and the vagal reflex and will explore the possible involvement of the carotid body (CB) in the neural control of inflammation. We will also highlight the mechanisms of vagal anti-inflammatory reflex control of immunity and metabolism, and the consequences of functional disarrangement of this reflex in settlement and development of metabolic diseases, with special attention to obesity and type 2 diabetes. Additionally, the role of CB in the interplay between metabolism and immune responses will be discussed, with specific reference to the different stimuli that promote CB activation and the balance between sympathetic and parasympathetic in this context. In doing so, we clarify the multivarious neuronal reflexes that coordinate tissue-specific responses (gut, pancreas, adipose tissue and liver) critical to metabolic control, and metabolic disease settlement and development. In the final section, we will summarize how electrical modulation of the carotid sinus nerve may be utilized to adjust these reflex responses and thus control inflammation and metabolic diseases, envisioning new therapeutics horizons.

Obesity and Bone Health: A Complex Link

So far, the connections between obesity and skeleton have been extensively explored, but the results are inconsistent. Obesity is thought to affect bone health through a variety of mechanisms, including body weight, fat volume, bone formation/resorption, proinflammatory cytokines together with bone marrow microenvironment. In this review, we will mainly describe the effects of adipokines secreted by white adipose tissue on bone cells, as well as the interaction between brown adipose tissue, bone marrow adipose tissue, and bone metabolism. Meanwhile, this review also reviews the evidence for the effects of adipose tissue and its distribution on bone mass and bone-related diseases, along with the correlation between different populations with obesity and bone health. And we describe changes in bone metabolism in patients with anorexia nervosa or type 2 diabetes. In summary, all of these findings show that the response of skeleton to obesity is complex and depends on diversified factors, such as mechanical loading, obesity type, the location of adipose tissue, gender, age, bone sites, and secreted cytokines, and that these factors may exert a primary function in bone health.

Inflammation initiates a vicious cycle between obesity and nonalcoholic fatty liver disease

Low‐level of chronic inflammation activation is characteristic of obesity. Nonalcoholic fatty liver disease (NAFLD) is closely linked to obesity and is an emerging health problem, it originates from abnormal accumulation of triglycerides in the liver, and sometimes causes inflammatory reactions that could contribute to cirrhosis and liver cancer, thus its pathogenesis needs to be clarified for more treatment options. Once NAFLD is established, it contributes to systemic inflammation, the low‐grade inflammation is continuously maintained during NAFLD causing impaired resolution of inflammation in obesity, which subsequently exacerbates its severity. This study focuses on the effects of obesity‐induced inflammations, which are the underlying causes of the disease progression and development of more severe inflammatory and fibrotic stages. Understanding the relationship between obesity and NAFLD could help in establishing attractive therapeutic targets or diagnostic markers in obesity‐induced inflammation response and provides new approaches for the prevention and treatment of NAFLD in obesity.

Understanding the Heterogeneity of Obesity and the Relationship to the Brain-Gut Axis

Obesity is best understood as a multifactorial metabolic imbalances disorder. In a cross-sectional study, we aimed to explore sociodemographic and dietary determinants of obesity in relation to brain-gut homeostasis among overweight and obese individuals. Multivariate logistic regression models were used to examine obesity and its association with sociodemographic and dietary factors. Biological variables examined included the gut microbiome, fecal amino acid metabolites and brain structural volumes. Among 130 participants, there were higher odds of obesity if individuals were Hispanic (adjusted odds ratio (aOR) 1.56, p = 0.014). Compared to non-Hispanics, Hispanics differed in gut microbial composition (p = 0.046) with lower microbial species richness (Chao1) (p = 0.032) and evenness (Shannon) (p = 0.0029). Fourteen of the twenty fecal amino acids including branch-chain- and aromatic- amino acids were increased among Hispanics (q < 0.05). Brain structural volumes in reward regions were decreased in Hispanics (pallidum, q = 0.036; brainstem, q = 0.011). Correlation patterns suggest complex brain-gut interactions differ by Hispanic ethnicity. In conclusion, Hispanics expressed a unique brain-gut microbial signature, which was associated with obesity despite sociodemographic and dietary differences. Addressing ethnic disparities guided by biologic phenotypes may unlock novel understanding of obesity heterogeneity and treatment strategies.

A Representative GIIA Phospholipase A2 Activates Preadipocytes to Produce Inflammatory Mediators Implicated in Obesity Development

Adipose tissue secretes proinflammatory mediators which promote systemic and adipose tissue inflammation seen in obesity. Group IIA (GIIA)-secreted phospholipase A₂ (sPLA₂) enzymes are found to be elevated in plasma and adipose tissue from obese patients and are active during inflammation, generating proinflammatory mediators, including prostaglandin E₂ (PGE₂). PGE₂ exerts anti-lipolytic actions and increases triacylglycerol levels in adipose tissue. However, the inflammatory actions of GIIA sPLA₂s in adipose tissue cells and mechanisms leading to increased PGE₂ levels in these cells are unclear. This study investigates the ability of a representative GIIA sPLA₂, MT-III, to activate proinflammatory responses in preadipocytes, focusing on the biosynthesis of prostaglandins, adipocytokines and mechanisms involved in these effects. Our results showed that MT-III induced biosynthesis of PGE₂, PGI₂, MCP-1, IL-6 and gene expression of leptin and adiponectin in preadipocytes. The MT-III-induced PGE₂ biosynthesis was dependent on cytosolic PLA₂ (cPLA₂)-α, cyclooxygenases (COX)-1 and COX-2 pathways and regulated by a positive loop via the EP₄ receptor. Moreover, MT-III upregulated COX-2 and microsomal prostaglandin synthase (mPGES)-1 protein expression. MCP-1 biosynthesis induced by MT-III was dependent on the EP4 receptor, while IL-6 biosynthesis was dependent on EP3 receptor engagement by PGE₂. These data highlight preadipocytes as targets for GIIA sPLA₂s and provide insight into the roles played by this group of sPLA₂s in obesity.

Comparisons of various anthropometric indexes with localized Stage II/III periodontitis in young adults: The CHIEF oral health study

BACKGROUND

A J-shaped relationship of body mass index (BMI) with severe periodontitis has been reported. However, it is unknown for other anthropometric indexes in young adults.

METHODS

A cross-sectional study examined the relationships in 325 military men and women, aged 20 to 45 years in Taiwan. Anthropometric indexes included BMI, waist circumference (WC), and waist-to-height ratio (WHtR). The severity of localized periodontitis was defined as healthy (n = 42), Stage I (initial) (n = 228), and Stage II/III (moderate/severe) (n = 55) according to the 2017 Periodontal Diseases Classification. Smooth curve fitting and multiple logistic regression analyses adjusting for age, sex, betel nut consumption, and smoking were used to determine the threshold effect between various anthropometric and the risk of localized Stage II/III periodontitis.

RESULTS

In the spline smoothing plot, the turning points for BMI, WC, and WHtR were 26.1 kg/m² , 90.0 cm, and 0.50, respectively, and a J-shaped relationship was found for BMI (the likelihood ratio test, P <0.001). In the multiple logistic regressions, BMI ≥27.0 kg/m² , WC ≥90.0 cm and WHtR ≥0.50 were associated with higher risk of localized Stage II/III periodontitis than their counterparts (24.0 to 26.9 kg/m² for BMI) (odds ratios [OR] and 95% confidence intervals: 4.16 [1.39 to 12.49], 2.65 [1.01 to 7.11], and 2.95 [1.20 to 7.24], respectively; all P values <0.05). However, the risk for BMI <24.0 kg/m² was not significant (OR, 1.47 [0.47 to 4.54]).

CONCLUSION

In young adults, obesity defined by various anthropometrics was consistently associated with localized Stage II/III periodontitis and a J-shaped association was suggestive for BMI.

Breast Cancer and Microcalcifications: An Osteoimmunological Disorder?

The presence of microcalcifications in the breast microenvironment, combined with the growing evidences of the possible presence of osteoblast-like or osteoclast-like cells in the breast, suggest the existence of active processes of calcification in the breast tissue during a woman’s life. Furthermore, much evidence that osteoimmunological disorders, such as osteoarthritis, rheumatoid arthritis, or periodontitis influence the risk of developing breast cancer in women exists and vice versa. Antiresorptive drugs benefits on breast cancer incidence and progression have been reported in the past decades. More recently, biological agents targeting pro-inflammatory cytokines used against rheumatoid arthritis also demonstrated benefits against breast cancer cell lines proliferation, viability, and migratory abilities, both in vitro and in vivo in xenografted mice. Hence, it is tempting to hypothesize that breast carcinogenesis should be considered as a potential osteoimmunological disorder. In this review, we compare microenvironments and molecular characteristics in the most frequent osteoimmunological disorders with major events occurring in a woman’s breast during her lifetime. We also highlight what the use of bone anabolic drugs, antiresorptive, and biological agents targeting pro-inflammatory cytokines against breast cancer can teach us.

Effects of Edible Oils with Different n-6/n-3 PUFA Ratios on Articular Cartilage Degeneration via Regulating the NF-κB Signaling Pathway

Osteoarthritis (OA), a common chronic disease, is characterized by articular cartilage degeneration and inflammation. Recent studies report that n-3 polyunsaturated fatty acids (PUFAs) exhibit protective effects against OA, while n-6 PUFAs are more likely to damage cartilage. However, the effects of edible oils with different n-6/n-3 PUFA ratios on OA are rarely reported. This study investigates the effect of linseed oil (LO), soybean oil (SO), and peanut oil (PO) on cartilage changes in mice joints following destabilization of the medial meniscus. We determined the n-6/n-3 PUFA ratios of LO, SO, and PO used in this experiment to be 1:3.85, 9.15:1, and 372.73:1, respectively. After 12 weeks of LO or SO feeding, OA mice showed increased cartilage thickness and decreased TNF-α in both the serum and cartilage, whereas no improvement was found in the PO group. This may be due to the fact that LO and SO optimized the fatty acid composition of articular cartilage. We further demonstrated that LO or SO activated GPR120 and attenuated EP4, which was followed by inhibition of the NFκB pathway and its downstream matrix-degrading enzymes: MMP13 and ADAMTS5. In conclusion, edible oils with low n-6/n-3 PUFA retard OA progression via inhibiting the NFκB pathway. This study provides a dietary guidance for OA patients.

Acacetin Suppresses IL-1β-Induced Expression of Matrix Metalloproteinases in Chondrocytes and Protects against Osteoarthritis in a Mouse Model by Inhibiting NF-κB Signaling Pathways

Osteoarthritis (OA) is a very common chronic joint dysfunction, and there is currently a poor understanding of its etiology and pathogenesis. Therefore, there are no active disease-modifying drugs currently available for clinical treatment. Several natural compounds have been shown to play a role in inhibiting OA progression. The present study is aimed at investigating the curative effects of acacetin, a natural flavonoid compound, against OA. Our results demonstrated that MMP-1, MMP-3, and MMP-13 were highly expressed in OA specimens. Acacetin inhibited the interleukin-1β- (IL-1β-) induced expression of MMP-1, MMP-3, and MMP-13in chondrocytes by blocking nuclear factor-κB (NF-κB) signaling pathways. Furthermore, we found that acacetin suppressed OA progression and inhibited the expression of MMP-1, MMP-3, and MMP-13 in ACLT-induced OA mice. Taken together, our study revealed that acacetin may serve as a potential drug for treating OA.

Secreted Frizzled-Related Protein 1 as a Biomarker against Incomplete Age-Related Lobular Involution and Microcalcifications' Development

As a downregulator of the Wnt signaling pathway, SFRP1 is involved in several components of the age-related lobular involution process such as inflammation, apoptosis, and adipogenesis. Because microcalcifications are associated with inflammation, we aimed to demystify the cross talk between SFRP1, inflammatory markers, and microcalcifications by assessing SFRP1 expression (immunohistochemistry) in a cohort of 162 women with different degrees of lobular involution. SFRP1 expression was inversely associated with the degree of lobular involution (OR = 0.84; p-value < 0.01). SFRP1 expression, age at mastectomy, and waist circumference taken together predicted the degree of lobular involution (AUC = 78.1). This predictive model was best in patients with microcalcifications (AUC = 81.1) and in parous women (AUC = 87.8). SFRP1 expression was correlated with leptin (rho = 0.32), TNF-α (rho = 0.21), and IL-6 (rho = 0.21) expression by epithelial cells (all p-values <0.001). SFRP1 expression was lower in nulliparous women with involuted breast tissue compared with parous women with involuted breast tissue (Δmean = -2.31; p-value < 0.01) and was higher in nulliparous women with microcalcifications compared with nulliparous women without microcalcifications (Δmean = 2.4; p-value < 0.05). In this study, we highlighted two SFRP1-based predictive models for incomplete lobular involution and the development of microcalcifications and identified two distinct inflammatory profiles associated with age-related lobular involution in parous and nulliparous women.

Characterization and Proteomic Analysis of Decellularized Adipose Tissue Hydrogels Derived from Lean and Overweight/Obese Human Donors

While decellularized adipose tissue (DAT) has potential as an "off-the-shelf" biomaterial product for regenerative medicine, it remains to be determined if donor-source body mass index (BMI) impacts the functionality of DAT. This study set out to comparatively characterize lean versus overweight/obese-donor derived DAT hydrogel based on proteome and to analyze their respective effects on adipose stromal/stem cell (ASC) viability, and differentiation in vitro. Decellularized adipose tissue from lean (lDAT) and overweight/obese (oDAT) donors is produced and characterized. Variability in the fibril microstructures is found, with dense fibrotic fiber clusters and large pore area uniquely present in the oDAT samples. Proteomic analysis reveals that lDAT contains a greater proportion of enriched extracellular proteins and a smaller proportion of enriched intracellular proteins relative to oDAT. Biocompatibility studies show that ASCs cultured in lDAT and oDAT hydrogels remain viable. The adipogenic and osteogenic differentiation capability of ASCs seeded in lDAT and oDAT hydrogels is confirmed by an upregulation in marker gene expression and phenotypic analysis. In conclusion, this study establishes that DAT hydrogels derived from lean and overweight/obese adipose donors present similar physicochemical profiles with some distinctive features while comparably supporting the viability and adipogenic differentiation of ASCs in vitro.

Effects of Casein, Chicken, and Pork Proteins on the Regulation of Body Fat and Blood Inflammatory Factors and Metabolite Patterns Are Largely Dependent on the Protein Level and Less Attributable to the Protein Source

The impact of meat protein on metabolic regulation is still disputed and may be influenced by protein level. This study aimed to explore the effects of casein, pork, and chicken proteins at different protein levels (40% E vs 20% E) on body weight regulation, body fat accumulation, serum hormone levels, and inflammatory factors/metabolites in rats maintained on high-fat (45% E fat) diets for 84 d. Increased protein levels resulted in a significant reduction in body fat mass and an increase in the serum levels of the anti-inflammatory cytokine IL-10, independent of protein source. Analysis of blood via untargeted metabolomics analysis identified eight, four, and four metabolites significantly altered by protein level, protein source, and a protein level-source interaction, respectively. Together, the effects of casein, chicken, and pork protein on the regulation of body fat accumulation and blood metabolite profile are largely dependent on protein level and less attributable to the protein source.

Adipocytokines: Are they the Theory of Everything?

INTRODUCTION

Adipose tissue secretes various bioactive peptides/proteins, immune molecules and inflammatory mediators which are known as adipokines or adipocytokines. Adipokines play important roles in the maintenance of energy homeostasis, appetite, glucose and lipid metabolism, insulin sensitivity, angiogenesis, immunity and inflammation. Enormous number of studies from all over the world proved that adipocytokines are involved in the pathogenesis of diseases affecting nearly all body systems, which raises the question whether we can always blame adipocytokines as the triggering factor of every disease that may hit the body.

OBJECTIVE

Our review targeted the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems including diabetes mellitus, kidney diseases, gynecological diseases, rheumatologic disorders, cancers, Alzheimer's, depression, muscle disorders, liver diseases, cardiovascular and lung diseases.

METHODOLOGY

We cited more than 33 recent literature reviews that discussed the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems.

CONCLUSION

More evidence is being discovered to date about the role played by adipocytokines in more diseases and extra research is needed to explore hidden roles played by adipokine imbalance on disease pathogenesis.

Impact of chitosan membrane culture on the expression of pro- and anti-inflammatory cytokines in mesenchymal stem cells

Osteoarthritis (OA) is a chronic inflammatory joint condition caused by various inflammatory cytokines. The pro-inflammatory cytokines controlling OA include interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6 and IL-18. The anti-inflammatory cytokines include IL-4, IL-10, IL-13, leukemia inhibitory factor (LIF), glycoprotein 130 (IL6ST), TNF-α-stimulated gene 6 and transforming growth factor (TGF)-β1. Mesenchymal stem cells (MSCs) serve an anti-inflammatory role in the treatment of OA by secreting various cytokines. Previous studies demonstrated that the anti-inflammatory ability of MSCs decreased rapidly in a traditional plate culture. Maintaining the anti-inflammatory properties of MSCs in vitro remains challenging. Therefore, it is necessary to develop a more stable and efficient method to culture MSCs in vitro. Chitosan is a deacetylated derivative of chitin and is the second most abundant natural polysaccharide worldwide. The present study demonstrated that that MSCs cultured on chitosan membranes (CM) spontaneously formed multicellular spheroids. Compared with the control group without CM, the formation of multicellular spheres in the CM enhanced the anti-inflammatory properties of MSCs. Expression levels of pro- and anti-inflammatory genes mRNA and their proteins in MSCs were detected by reverse transcription-quantitative PCR, western blot analysis and immunofluorescence assay. Protein and mRNA expression levels of pro-inflammatory cytokines IL-1β, TNF-α, IL-6 and IL-18 were significantly decreased in CM-cultured MSCs compared with the control group (P<0.05). Furthermore, mRNA and protein expression levels of anti-inflammatory cytokines TGF-β1 in CM-cultured MSCs were significantly increased compared with the control group (P<0.01). These results indicated that the formation of multicellular spheroids by CM-cultured MSCs aided in maintaining anti-inflammatory effects.

Osteopontin: The Molecular Bridge between Fat and Cardiac-Renal Disorders

Osteopontin (OPN) is a multifaceted matricellular protein, with well-recognized roles in both the physiological and pathological processes in the body. OPN is expressed in the main organs and cell types, in which it induces different biological actions. During physiological conditioning, OPN acts as both an intracellular protein and soluble excreted cytokine, regulating tissue remodeling and immune-infiltrate in adipose tissue the heart and the kidney. In contrast, the increased expression of OPN has been correlated with the severity of the cardiovascular and renal outcomes associated with obesity. Indeed, OPN expression is at the “cross roads” of visceral fat extension, cardiovascular diseases (CVDs) and renal disorders, in which OPN orchestrates the molecular interactions, leading to chronic low-grade inflammation. The common factor associated with OPN overexpression in adipose, cardiac and renal tissues seems attributable to the concomitant increase in visceral fat size and the increase in infiltrated OPN⁺ macrophages. This review underlines the current knowledge on the molecular interactions between obesity and the cardiac–renal disorders ruled by OPN.

Pathogenesis of Osteoarthritis: Risk Factors, Regulatory Pathways in Chondrocytes, and Experimental Models

As the most common chronic degenerative joint disease, osteoarthritis (OA) is the leading cause of pain and physical disability, affecting millions of people worldwide. Mainly characterized by articular cartilage degradation, osteophyte formation, subchondral bone remodeling, and synovial inflammation, OA is a heterogeneous disease that impacts all component tissues of the articular joint organ. Pathological changes, and thus symptoms, vary from person to person, underscoring the critical need of personalized therapies. However, there has only been limited progress towards the prevention and treatment of OA, and there are no approved effective disease-modifying osteoarthritis drugs (DMOADs). Conventional treatments, including non-steroidal anti-inflammatory drugs (NSAIDs) and physical therapy, are still the major remedies to manage the symptoms until the need for total joint replacement. In this review, we provide an update of the known OA risk factors and relevant mechanisms of action. In addition, given that the lack of biologically relevant models to recapitulate human OA pathogenesis represents one of the major roadblocks in developing DMOADs, we discuss current in vivo and in vitro experimental OA models, with special emphasis on recent development and application potential of human cell-derived microphysiological tissue chip platforms.

Elucidation of the Mechanism by Which a ADAMTS5 Gene MicroRNA-Binding Site Single Nucleotide Polymorphism Affects the Risk of Osteoarthritis

Purpose: The aim of this study was to investigate the relationship between single nucleotide polymorphisms (SNPs) within the 3' untranslated region of the microRNA (miRNA)-binding site of the ADAM metallopeptidase with thrombospondin type 1 motif 5 (ADAMTS5) gene and the risk of knee osteoarthritis (KOA) and its mechanism. Materials and Methods: Sanger sequencing was used to determine the genotypes of three ADAMTS5 gene SNPs (rs3171407, rs229071, and rs229077) from 310 patients suffering from osteoarthritis of the knee joint (KOA) and 310 healthy controls. The levels of the miRNAs, thsa-miR-103b, hsa-miR-144-3p, and hsa-miR-105-5p in plasma, and the level of ADAMTS5 mRNA in the articular cartilage of 132 patients with KOA were detected by real-time quantitative PCR. Results: The G allele at the rs3171407 locus of the ADAMTS5 gene was demonstrated to be a protective genetic factor for KOA. In addition, the risk of developing KOA was significantly increased in subjects carrying the C allele at the rs229071 locus. The risk of developing KOA in carriers of the G allele at locus rs229077 was 1.49 times greater than those with the A allele. The level of the hsa-miR-144-3p was increased, and the expression level of the ADAMTS5 protein was decreased in carriers of the T allele at the rs229071 locus. In carriers of rs229077 locus A allele the hsa-miR-105-5p level was increased and the expression level of ADAMTS5 protein was decreased. Conclusion: SNPs at the rs3171407, rs229071, and rs229077 loci of the ADAMTS5 gene are related to the risk of OA. The likely mechanism underlying these observations is that these SNPs affect the regulation of ADAMTS5 protein expression through miRNAs; however, this needs to be verified using in vivo models.

Brown adipose tissue ameliorates autoimmune arthritis via inhibition of Th17 cells

The functions of adipose tissue are associated with autoimmune diseases, such as rheumatoid arthritis (RA). Some studies have shown that the three compositions of adipose tissue (white, brown, and beige) have different functions. Brown adipose tissue (BAT) is known to secrete several factors that differ from those in white adipose tissue. This suggests that BAT might have potential positive advantages in the physiology of autoimmune diseases. We compared the functions of collagen-induced arthritis mice-derived BAT (CIA BAT) with normal mice-derived BAT. DBA/1J mice (6-7 weeks of age) were immunized by intradermal injection at the base of the tail with 100 μg of bovine type II collagen (CII) emulsified in complete Freund's adjuvant. Immunized mice then received booster immunizations by intraperitoneal injection with 100 μg of CII in incomplete Freund's adjuvant. We transplanted CIA BAT and normal BAT into CIA recipient mice. After transplantation, we measured the functions of CIA BAT and normal BAT in mice. Normal BAT-transplanted mice showed significantly lower scores of bone damage, inflammation, and cartilage damage. The proinflammatory cytokines in normal BAT-transplanted mice, such as IL-12, IL-17, IL-6, and tumor necrosis factor-α (TNF-α), tended to decrease. Microarray analysis showed that the PI3K-AKT signaling pathway and IL-17 levels of CIA BAT tissues were significantly higher than those of normal BAT tissues. These results suggest that the transplantation of normal brown fat may have a therapeutic effect in RA patients.

Interleukin-6 in Rheumatoid Arthritis

The role of interleukin (IL)-6 in health and disease has been under a lot of scrutiny in recent years, particularly during the recent COVID-19 pandemic. The inflammatory pathways in which IL-6 is involved are also partly responsible of the development and progression of rheumatoid arthritis (RA), opening interesting perspectives in terms of therapy. Anti-IL-6 drugs are being used with variable degrees of success in other diseases and are being tested in RA. Results have been encouraging, particularly when anti-IL-6 has been used with other drugs, such as metothrexate (MTX). In this review we discuss the main immunologic aspects that make anti-IL-6 a good candidate in RA, but despite the main therapeutic options available to target IL-6, no gold standard treatment has been established so far.

The emerging role of fibroblast-like synoviocytes-mediated synovitis in osteoarthritis: An update

Osteoarthritis (OA), the most ubiquitous degenerative disease affecting the entire joint, is characterized by cartilage degradation and synovial inflammation. Although the pathogenesis of OA remains poorly understood, synovial inflammation is known to play an important role in OA development. However, studies on OA pathophysiology have focused more on cartilage degeneration and osteophytes, rather than on the inflamed and thickened synovium. Fibroblast-like synoviocytes (FLS) produce a series of pro-inflammatory regulators, such as inflammatory cytokines, nitric oxide (NO) and prostaglandin E₂ (PGE₂ ). These regulators are positively associated with the clinical symptoms of OA, such as inflammatory pain, joint swelling and disease development. A better understanding of the inflammatory immune response in OA-FLS could provide a novel approach to comprehensive treatment strategies for OA. Here, we have summarized recently published literatures referring to epigenetic modifications, activated signalling pathways and inflammation-associated factors that are involved in OA-FLS-mediated inflammation. In addition, the current related clinical trials and future perspectives were also summarized.

Anti-obesity potential of Moringa olifera seed extract and lycopene on high fat diet induced obesity in male Sprauge Dawely rats

Present research explored the anti-obesity effect of Moringa olifera seed oil extract and lycopene (LYC). Forty eight male Sprauge Dawely rats were divided equally into 6 groups. Group Ι (C) served as control, group ΙΙ (MC) was given Moringa olifera seed oil extract (800 mg/kg b.wt) for 8 weeks, group ΙΙΙ (LC) was given (20 mg/kg b.wt) LYC for 8 weeks, group ΙV (O) received high fat diet (HFD) for 20 weeks, group Ѵ (MO), was given HFD for 20 weeks and received (800 mg/kg b.wt) Moringa olifera seed oil extract for last 8 weeks and group ѴΙ (LO), received HFD for 20 weeks and was given (20 mg/kg b.wt) LYC for last 8 weeks. Hematology, lipid peroxidation and antioxidants, non-esterified fatty acids (NEFA), glucose, lipid profile, serum liver and kidney biomarkers, inflammatory markers, leptin, resistin and heart fatty acid binding protein (HFABP) were determined. Also histopathology for liver, kidney and aorta were performed besides immunohistochemistry (IHC) for aortic inducible nitric oxide synthase (iNOS). Administration of Moringa olifera seed oil extract and LYC significantly ameliorated the HFD induced hematological and metabolic perturbations as well as reduced leptin and resistin. Both treatments exerted these effects through promotion of antioxidant enzymes and reducing lipid peroxidation as well as inflammatory cytokines along with reduced iNOS protein expression. Administration of Moringa olifera seed oil extract and LYC have anti-obesity potential in HFD induced obesity in male Sprauge Dawely rats.

Leveraging Electrostatic Interactions for Drug Delivery to the Joint

Arthritis is a debilitating joint disease with a high economic burden and prevalence. There are many challenges delivering therapeutics to the joint, including low bioavailability when administered systemically and low joint retention after intra-articular injection. Therefore, drug delivery systems such as nanoparticles, liposomes, dendrimers, and carrier proteins have been utilized to overcome some of these limitations. To enhance joint tissue localization and retention, there are opportunities to leverage electrostatic interactions between drug carriers and various tissues and cells. These opportunities, as they pertain to specific joint tissues, are explored in this review. Further, the impact that electrostatic interactions has on various drug delivery parameters, such as the formation of a protein corona, the uptake and cytotoxicity, and the biodistribution of the drug delivery systems, is discussed. Lastly, this review summarizes key findings from studies that have investigated the use of electrostatic interactions to increase targeting of specific joint tissues and limitations in preclinical investigations are identified. As more novel targets are discovered in treating arthritis, there will be a continued need to localize therapeutics to specific tissues for greater therapeutic outcomes and hence attention must be paid in designing the drug delivery systems.

Particulate matter exposure aggravates osteoarthritis severity

Several diseases have been linked to particulate matter (PM) exposure. Outdoor activities, such as road running or jogging, are popular aerobic exercises due to few participatory limitations. Osteoarthritis (OA) is a progressive degenerative joint disease, usually observed at age 40, and not noticed before pain or diagnosis. Although exercise has health benefits, it is unclear whether outdoor jogging in higher PM (standard reference material 1649b, SRM 1649b) concentration environments could affect OA development or severity. Hence, a PM exposure monosodium iodoacetate (MIA)-induced OA animal jogged model was established for investigation. Results showed that high doses of PM (5 mg) significantly increased pro-inflammatory factors such as tumor necrosis factor α (TNF-α), interleukin (IL)-1β, and IL-6, and M1 macrophages in the lung region, also obtained in systemic IL-6 and TNF-α expressions in this MIA-OA rat model. Moreover, levels of osteocalcin, cartilage oligomeric matrix protein (COMP), and N-telopeptides of type I collagen were especially influenced in MIA+PM groups. Morphological and structural changes of the knee joint were detected by micro-computed tomography images (micro-CT) and immunohistochemistry. MIA + PM rats exhibited severe bone density decrease, cartilage wear, and structure damages, accompanied by lower levels of physical activity, than the sham group and groups receiving MIA or PM alone. The findings suggest that the severity of OA could be promoted by PM exposure with a PM concentration effect via systemic inflammatory mechanisms. To the best of our knowledge, this is the first study to provide direct effects of PM exposure on OA severity.

Cardiovascular Changes Related to Metabolic Syndrome: Evidence in Obese Zucker Rats

Metabolic syndrome (MetS) is a predictor of cardiovascular diseases, commonly associated with oxidative stress and inflammation. However, the pathogenic mechanisms are not yet fully elucidated. The aim of the study is to evaluate the oxidative status and inflammation in the heart of obese Zucker rats (OZRs) and lean Zucker rats (LZRs) at different ages. Morphological and morphometric analyses were performed in the heart. To study the oxidative status, the malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), protein oxidation, and antioxidant enzymes were measured in plasma and heart. To elucidate the inflammatory markers involved, immunohistochemistry and Western blot were performed for cellular adhesion molecules and proinflammatory cytokines. OZRs were characterized by hypertension, hyperlipidemia, hyperglycemia, and insulin resistance. The obesity increased MDA and decreased the activities of superoxide dismutase (SOD) in plasma as well as in the heart, associated with cardiomyocytes hypertrophy. OxyBlot in plasma and in heart showed an increase of oxidativestate proteins in OZRs. Vascular cell adhesion molecule-1, interleukin-6, and tumor necrosis factor-α expressions in OZRs were higher than those of LZRs. However, these processes did not induce apoptosis or necrosis of cardiomyocytes. Thus, MetS induces the lipid peroxidation and decreased antioxidant defense that leads to heart tissue changes and coronary inflammation.

Apelin Affects the Progression of Osteoarthritis by Regulating VEGF-Dependent Angiogenesis and miR-150-5p Expression in Human Synovial Fibroblasts

Synovium-induced angiogenesis is central to osteoarthritis (OA) pathogenesis and thus a promising therapeutic target. The adipokine apelin (APLN) is involved in both OA pathogenesis and angiogenesis. We examined the role of APLN in synovium-induced angiogenesis by investigating the crosstalk between APLN and vascular endothelial growth factor (VEGF) expression in human OA synovial fibroblasts (OASFs). We found higher levels of APLN and VEGF expression in OA samples compared with normal samples. APLN-induced stimulation of VEGF expression and VEGF-dependent angiogenesis in OASFs was mitigated by FAK/Src/Akt signaling. APLN also inhibited levels of microRNA-150-5p (miR-150-5p), which represses VEGF production and angiogenesis. Analyses of an OA animal model showed that shAPLN transfection of OASFs rescued pathologic changes in OA cartilage and histology. Here, we found APLN enhances VEGF expression and angiogenesis via FAK/Src/Akt cascade and via downstream suppression of miR-150-5p expression. These findings help to clarify the pathogenesis of adipokine-induced angiogenesis in OA synovium.

Dietary Saturated Fatty Acids Modulate Pain Behaviour in Trauma-Induced Osteoarthritis in Rats

Osteoarthritis (OA) is a degenerative condition of joints, causing pain and swelling, and can be caused or worsened by trauma and obesity. The objectives of this study were to determine whether pain behaviour and progression of OA were increased in rats with trauma-induced OA fed dietary saturated fatty acids (SFA). Male Wistar rats were fed either a corn starch diet (C) or high-carbohydrate high-fat diet (H) with either 20% beef tallow or SFA (lauric (HLA), myristic (HMA), palmitic (HPA) or stearic (HSA) acids) for 16 weeks prior to and 8 weeks after excision of the medial meniscus of right knee joint to initiate OA when pain behaviour, glial activity, progression of knee OA, inflammatory mediators and signs of metabolic syndrome were assessed. Rats fed beef tallow, palmitic or stearic acids showed increased pain symptoms characterised by decreased hind paw/limb withdrawal thresholds and grip strengths and increased spinal astrogliosis and microgliosis compared to rats fed lauric or myristic acids. However, the severity of OA joint damage was unchanged by these dietary manipulations. We conclude that pain symptoms of trauma-induced OA in rats worsen with increased dietary beef tallow or palmitic or stearic acids, but improve with lauric or myristic acids, despite unchanged OA cartilage damage.