Erosive Hand Osteoarthritis: Recent Advances and Future Treatments.

PURPOSE OF THE REVIEW: Erosive hand osteoarthritis (EHOA) is an aggressive form of hand osteoarthritis that leads to significant disability, and recent data suggests that it is increasing in prevalence. This review provides an update of our current understanding of epidemiology, genetic associations, biomarkers, pathogenesis, and treatment of EHOA, with particular focus on studies published within the last 5 years. RECENT FINDINGS: New studies of EHOA have identified new genetic loci associated with disease, including variants in genes involved in inflammation and bone remodeling. Preclinical studies implicate pathways of innate immunity, including some that may be causal in the condition. Recent novel studies showed that inflammatory features identified by ultrasound and MRI are associated with development of erosive lesions over time on conventional radiography. In the future, these imaging modalities may be useful in identifying patients at risk of adverse outcomes. Promising new findings in genetics, biomarkers, and treatment targets will hopefully allow for future therapeutic options for this debilitating condition.

Treat-to-target in real-life psoriatic arthritis patients: achieving minimal disease activity with bDMARDs/tsDMARDs and potential barriers.

OBJECTIVE: (1) to describe the frequency of minimal disease activity (MDA) in a real-life psoriatic arthritis (PsA) cohort, (2) to longitudinally explore predictors of MDA; (3) to examine frequency and predictors of low disease activity (LDA) in patients with axial involvement (axPsA). METHODS: consecutive PsA patients in stable biological/targeted-synthetic Disease-Modifying Anti-Rheumatic Drugs (bDMARDs/tDMARDs) who attended our center were enrolled. Disease activity indices, including MDA and ankylosing spondylitis disease activity score-LDA (ASDAS-LDA) for axPsA, were evaluated at baseline and every 6 months, up to 36 months or bDMARDs/tsDMARDs discontinuation. Patients' history, BMI, comorbidities - including osteoarthritis (OA) and fibromyalgia - were collected. Variables were compared between patients who achieved sustained MDA and those who did not. Multivariable generalized estimating equation (GEE) models were built to identify predictors of MDA and ASDAS-LDA over time. Data were expressed as beta coefficient (95%CI). RESULTS: 104 patients were enrolled, 54% males, mean age 55.7 years; 52% had axPsA. Across all evaluations, 52-61% reached MDA, and 17-24% achieved ASDAS-LDA. AxPsA, fibromyalgia, OA and BMI≥35 were less frequently observed in patients with sustained MDA. The GEE model confirmed the following factors were significantly and independently associated with MDA: age (Beta=-0.05), bDMARDs/tsDMARDs duration (Beta=+0.31), axPsA (Beta=-1.07), fibromyalgia (Beta=-3.35), OA (Beta=-1.87), BMI≥35 (Beta=-2.53). Age (Beta=-0.01), fibromyalgia (Beta=-2.03) and OA (Beta=-1.30) were also independently associated with ASDAS-LDA. CONCLUSIONS: MDA is an attainable target in real-life. AxPsA represents a difficult-to-treat subset. Sustained MDA depends on disease features (axPsA) as well as patients' characteristics (e.g. age, bDMARDs/tDMARDs duration, comorbidities).

Spondyloarthritis with inflammatory bowel disease: the latest on biologic and targeted therapies.

Spondyloarthritis (SpA) encompasses a heterogeneous group of chronic inflammatory diseases that can affect both axial and peripheral joints, tendons and entheses. Among the extra-articular manifestations, inflammatory bowel disease (IBD) is associated with considerable morbidity and effects on quality of life. In everyday clinical practice, treatment of these conditions requires a close collaboration between gastroenterologists and rheumatologists to enable early detection of joint and intestinal manifestations during follow-up and to choose the most effective therapeutic regimen, implementing precision medicine for each patient's subtype of SpA and IBD. The biggest issue in this field is the dearth of drugs that are approved for both diseases, as only TNF inhibitors are currently approved for the treatment of full-spectrum SpA-IBD. Janus tyrosine kinase inhibitors are among the most promising drugs for the treatment of peripheral and axial SpA, as well as for intestinal manifestations. Other therapies such as inhibitors of IL-23 and IL-17, phosphodiesterase 4 inhibitor, α4ß7 integrin blockers and faecal microbiota transplantation seem to only be able to control some disease domains, or require further studies. Given the growing interest in the development of novel drugs to treat both conditions, it is important to understand the current state of the art and the unmet needs in the management of SpA-IBD.

Hip Labral Morphological Changes in Patients with Femoroacetabular Impingement Speed Up the Onset of Early Osteoarthritis.

Over the last decade, evidence has mounted for a prominent etiologic role of femoroacetabular impingement (FAI) in the development of early hip osteoarthritis (OA). The aim of this study was to compare the ultrastructure and tissue composition of the hip labrum in healthy and pathological conditions, as FAI and OA, to provide understanding of structural changes which might be helpful in the future to design targeted therapies and improve treatment indications. We analyzed labral tissue samples from five healthy multi-organ donors (MCDs) (median age, 38 years), five FAI patients (median age, 37 years) and five late-stage OA patients undergoing total hip replacement (median age, 56 years). We evaluated morpho-functional by histology and transmission electron microscopy. Extracellular matrix (ECM) structure changes were similar in specimens from FAI compared to those from patients with OA (more severe in the latter) showing disorganization of collagen fibers and increased proteoglycan content. In FAI and in OA nuclei the chromatin was condensed, organelle degenerated and cytoplasm vacuolized. Areas of calcification were mainly observed in FAI and OA labrum, as well as apoptotic-like features. We showed that labral tissue of patients with FAI had similar pathological alterations of tissue obtained from OA patients, suggesting that FAI patients might have high susceptibility to develop OA.

Fetuin-A: A Novel Biomarker of Bone Damage in Early Axial Spondyloarthritis. Results of an Interim Analysis of the SPACE Study.

Our study aimed to evaluate the association between fetuin-A levels and the presence of radiographic sacroiliitis and syndesmophytes in patients with early axial spondyloarthritis (axSpA) and to identify potential predictors of radiographic damage in the sacroiliac joints (SIJs) after 24 months. Patients diagnosed with axSpA in the Italian cohort of the SpondyloArthritis-Caught-Early (SPACE) study were included. Physical examinations, laboratory tests (including fetuin-A), SIJ,+ and spinal X-rays and MRIs at T0 (diagnosis) and at T24 were considered. Radiographic damage in the SIJs was defined according to the modified New York criteria (mNY). Fifty-seven patients were included in this analysis (41.2% male, median (interquartile range), chronic back pain [CBP] duration of 12 (8-18) months). Fetuin-A levels were significantly lower in patients with radiographic sacroiliitis compared to those without at T0 (207.9 (181.7-215.9) vs. 239.9 (217.9-286.9), respectively, p < 0.001) and at T24 (207.6 (182.5-246.5) vs. 261.1 (210.2-286.6) µg/mL, p = 0.03). At T0, fetuin-A levels were significantly higher in non-smokers, in patients with heel enthesitis and in those with a family history of axSpA; fetuin-A levels at T24 were higher in females, in patients with higher ESR or CRP at T0 and in those with radiographic sacroiliitis at T0. Fetuin-A levels at T0 were independently negatively associated with the likelihood of radiographic sacroiliitis (OR = 0.9 per 10-unit increase (95% CI 0.8, 0.999), p = 0.048); but not with the presence of syndesmophytes. After adjustment for confounders, fetuin-A levels at T0 and T24 were also negatively associated with mNY at T0 (ß -0.5, p < 0.001) and at T24 (ß -0.3, p < 0.001), respectively. Among other variables at T0, fetuin-A levels did not achieve statistical significance in predicting mNY at T24. Fetuin-A levels were negatively associated with radiographic damage of the SIJs, but not of the spine, in early axSpA and after 2 years of follow-up. Our findings suggest that fetuin-A levels may serve as a biomarker to identify patients with a higher risk of developing severe disease and early structural damage.

The impact of diet on disease activity in spondyloarthritis: A systematic literature review.

OBJECTIVES: Our study aimed to systematically review the evidence about the effect of diet or dietary supplements on spondyloarthritis (SpA) disease activity. METHODS: a systematic literature review (SLR) was conducted in MEDLINE, EMBASE, Cochrane and SCOPUS according to the "PEO" format (Population, Exposure, Outcome). The population was SpA (axial or peripheral, axSpA/pSpA, including Psoriatic Arthritis-PsA); the intervention any kind of diet/dietary supplement; the outcome disease activity. Inclusion criteria were: adult patients, Randomized Controlled Trials (RCTs) and longitudinal studies (so that a pre-and post-intervention assessment were available), papers in English. Risk of bias (RoB) was conducted with different tools according to the design of the study. RESULTS: Literature search yielded 1390 publications, of which 15 were finally inlcuded: 12 interventional and 3 observational studies. Among those with the lower RoB: a) 2 RCTs, one at unclear and one at low RoB, failed to show benefit of probiotics in SpA b) Two RCTs at unclear RoB provided evidence that weight loss, but not hypocaloric diet, was associated to MDA achievement in PsA. The remaining interventional studies were at high RoB. Among the observational studies, one study on Mediterranean diet demonstrated an association between diet adherence and a ≥ 20% decrease of ASDAS in axSpA. The other two observational studies were judged of poor quality. CONCLUSIONS: weight loss seem to be able to impact disease activity in PsA, while probiotics do not seem useful in SpA; evidence for dietary behaviors is scarce and heterogeneous.

Predictors of disease activity in gout: a 12-month analysis of the ATTACk (Achieving improvement in the management of crystal-induced arthritis) multicentre cohort study.

OBJECTIVES: Gout treatment is largely suboptimal in clinical practice. We aimed to assess the predictors of disease-activity at 12 months in a real-life setting. METHODS: Consecutive patients referred to Rheumatology Units for suspected acute crystal-induced arthritis were enrolled in a multicentre-cohort study. Only patients with clinical diagnosis of gout were eligible. Disease-activity was evaluated by the Patient Acceptable Symptom State (PASS) on a visual analogue scale (VAS, 0=unsatisfactory, 100=satisfactory) at 0 (T0) and 12 months (T12), and the composite score called Gout Activity Score (GAS) calculated on the number of arthritic attacks (flare count), serum uric acid (sUA), cumulative number of tophi, VAS (T12), PtGA (T12). Multivariate linear regression model was performed to assess predictors of gout disease-activity at T12 with PASS and GAS as outcomes. RESULTS: 201 patients had gout (diagnosis on synovial fluid in 45%, tophi in 26%, mean sUA 7.4±1.9 mg/L, 85% with urate-lowering therapy (ULT) in progress/initiated at T0); mean age 63±13 years, 88% men, median (interquartile range) disease duration 2.9 years (0.7-9.4). Follow-up visits were performed in 113 (56%) patients at T12. Mean PASS observed at T0 and at T12 were 38±27 and 74±23, respectively, whereas GAS at T12 was 10±8. A significant association was observed between the presence of tophi and PASS at T12 (-15.3, 95% CI -25.5, -5.2; p=0.003) and GAS at T12 (+4.0, 95% CI 0.6,7.4; p=0.02), adjusted for age, sex, disease duration, sUA <6 mg/dL, tender joint count, PASS at T0, ULT). CONCLUSIONS: The baseline presence of tophi may predict high disease-activity at T12, thus worsening GAS and patients' pain perception.

Synovial Fluid from Patients with Osteoarthritis Shows Different Inflammatory Features Depending on the Presence of Calcium Pyrophosphate Crystals.

The role of calcium pyrophosphate (CPP) crystals in osteoarthritis (OA) is still a matter of debate. With this study we aimed to investigate the inflammatory features of synovial fluid (SF) collected from patients with OA with CPP crystals compared with those without crystals. We also explored the effect of OA SF on monocytes response. SFs were collected from adult patients with OA and subdivided according to the presence of crystals. Local cellular and humoral inflammatory mediators were analysed in the SF samples. The expression levels of IL-1ß, IL-18, CASP-1, NLRP3, and GAPDH were measured by RT-PCR in the cells obtained by pelleting the SF samples. For the in vitro study, a monocytic cell line was treated with selected SF samples. SF with CPP crystals showed a significant increase in inflammatory cellular indices and higher levels of IL-1ß, IL-8, and caspase-1 transcript with respect to SF without crystals. Higher concentrations of VEGF were also observed in the early stages of the whole OA patients. THP-1 cells stimulated with OA SF released a significant amount of IL-1 ß in culture supernatants. This study demonstrated that SF collected from patients with OA shows different inflammatory features depending on the presence of CPP crystals.

Macroscopic Synovial Inflammation Correlates with Symptoms and Cartilage Lesions in Patients Undergoing Arthroscopic Partial Meniscectomy: A Clinical Study.

BACKGROUND: The aim of the study was to examine the relationship among patients' characteristics, intraoperative pathology and pre/post-operative symptoms in a cohort of patients undergoing arthroscopic partial meniscectomy for symptomatic meniscal tears. METHODS: Clinical data were collected (age, sex, body mass index, time to surgery, trauma). Intraoperative cartilage pathology was assessed with Outerbridge score. Meniscal tears were graded with the ISAKOS classification. Synovial inflammation was scored using the Macro-score. Patient symptoms were assessed pre/post-operatively using the KOOS instrument. RESULTS: In the series of 109 patients (median age 47 years), 50% of the meniscal tears were traumatic; 85% of patients showed mild to moderate synovitis; 52 (47.7%) patients had multiple cartilage defects and 31 (28.4%) exhibited a single focal chondral lesion. Outerbridge scores significantly correlated with patient age, BMI and synovial inflammation. There was a correlation between severity of chondral pathology and high-grade synovial hyperplasia. Pre-operative KOOS correlated with BMI, meniscal degenerative changes and symptom duration. Obesity, time to surgery, presence of high-grade synovial hyperplasia and high-grade cartilage lesions were independent predictors of worse post-operative pain and function. CONCLUSION: We demonstrated that pre-operative symptoms and post-operative outcomes correlate with synovitis severity and cartilage pathology, particularly in old and obese patients that underwent arthroscopic partial meniscectomy. Importantly, patients with a degenerative meniscal pattern and with longer time to surgery experienced more severe cartilage damage and, consequentially, pain and dysfunction. These findings are fundamental to identify patients suitable for earlier interventions.

Infrapatellar Fat Pad-Synovial Membrane Anatomo-Fuctional Unit: Microscopic Basis for Piezo1/2 Mechanosensors Involvement in Osteoarthritis Pain.

The Infrapatellar Fat Pad (IFP) is a fibro-adipose tissue of the knee recently reconsidered as part of a single anatomo-functional unit (AFU) together with the synovial membrane (SM). Several evidence support the role of this unit in the mechanisms that trigger and perpetuate the onset and progression of osteoarthritis (OA) disease. Additionally, the contribution of IFP-SM AFU in OA-associated pain has also been supposed, but this assumption still needs to be fully elucidated. Within this context, the recent discovery of the mechanoceptive Piezo ion channels (i.e., Piezo1 and Piezo2) in mammals and consciousness on their role in mediating both mechanoceptive and inflammatory stimuli could shed some light on knee OA pain, as well as on the process leading from acute to chronic nociceptive responses. For this purpose, the IFP-SM AFUs of both healthy donors (non-OA IFP-SM AFUs, n = 10) and OA patients (OA IFP-SM AFUs, n = 10) were processed by histology and immunohistochemistry. After the attribution of a histopathological score to IFP-SM AFUs to confirm intrinsic differences between the two groups, the specimens were investigated for the expression and localization/distribution pattern of the mechanosensors Piezo1 and Piezo2. In addition, the presence of monocytes/macrophages (CD68), peripheral nerve endings (PGP9.5) and neoangiogenesis signs (YAP1) was evaluated for a broad tissue characterization. The study results lead to a better description of the IFP-SM AFU microscopic features in both healthy and pathological conditions, highlighting peculiar differences in the study cohort. Specifically, immunopositivity towards Piezo1/2, CD68 and YAP1 markers was detected at vessels level in the OA- IFP-SM AFUs compartments, differently from the non-OA-group. A correlation with pain was also inferred, paving the way for the identification of new and effective molecules in OA management.

Acute joint swelling in psoriatic arthritis: Flare or "psout"-A 10-year-monocentric study on synovial fluid.

Psoriatic arthritis (PsA) is a multifaceted inflammatory disease associated with psoriasis that can affect peripheral joints, entheses, and the axial skeleton with a variable clinical course. Acute episodes of joint swelling in PsA patients can have different causes and require specific treatments. We aimed to describe the acute joint swelling in PsA patients via synovial fluid (SF) analyses, assessing in particular the presence of pathogenic crystals, to determine whether it is a flare or an acute episode of gout ("psout") during the course of the disease. This retrospective study was based on the results of SF analysis of samples collected from unselected adult PsA patients referred to our clinic for acute joint swelling. Demographic characteristics, disease involvement, laboratory findings on SF, and treatment options were recorded and reviewed. Among 5,478 SF samples analyzed in a 10-year time span, 213 complete SF records from PsA patients were evaluated. Overall, after adjustment for the degree of synovial inflammation, significant differences were observed in term of sex (p = 0.0017) and ongoing therapy (p = 0.0246). Non-inflammatory SFs, indeed, were mainly described for female PsA patients under therapy. Regarding serum uric acid levels, there were 19/213 (8.9%) PsA with hyperuricemia (HU), who were older, mostly male, patients with mild articular involvement and rare pathogenic crystals in their SF. Although it is known that the risk of gout is higher among patients with PsA ("psout"), monosodium urate crystals were reported only in 5/213 SFs (2.4%) of our cohort and in 2/19 SFs (10.5%) of HU PsA patients. Moreover, hyperuricemia seems not to modify the SF features in PsA patients. This study results seem to suggest that the convergence of gout and PsA, involving the role of urate crystals, is a more intricate relationship, which needs further insights to be unraveled.

Exploring Anatomo-Morphometric Characteristics of Infrapatellar, Suprapatellar Fat Pad, and Knee Ligaments in Osteoarthritis Compared to Post-Traumatic Lesions.

Several studies have investigated cartilage degeneration and inflammatory subchondral bone and synovial membrane changes using magnetic resonance (MR) in osteoarthritis (OA) patients. Conversely, there is a paucity of data exploring the role of knee ligaments, infrapatellar fat pad (IFP), and suprapatellar fat pad (SFP) in knee OA compared to post-traumatic cohorts of patients. Therefore, the aim of this study was to analyze the volumetric and morphometric characteristics of the following joint tissues: IFP (volume, surface, depth, femoral and tibial arch lengths), SFP (volume, surface, oblique, antero−posterior, and cranio−caudal lengths), anterior (ACL) and posterior cruciate ligament (PCL) (volume, surface, and length), and patellar ligament (PL) (volume, surface, arc, depth, and length). Eighty-nine MR images were collected in the following three groups: (a) 32 patients with meniscal tears, (b) 29 patients with ACL rupture (ACLR), and (c) 28 patients affected by end-stage OA. Volume, surface, and length of both ACL and PCL were determined in groups a and c. A statistical decrease of IFP volume, surface, depth, femoral and tibial arch lengths was found in end-stage OA compared to patients with meniscal tear (p = 0.002, p = 0.008, p < 0.0001, p = 0.028 and p < 0.001, respectively) and patients with ACLR (p < 0.0001, p < 0.0001, p = 0.008 and p = 0.011, respectively). An increment of volume and surface SFP was observed in group b compared to both groups a and c, while no differences were found in oblique, antero−posterior, and cranio−caudal lengths of SFP among the groups. No statistical differences were highlighted comparing volume, surface, arc, and length of PL between the groups, while PL depth was observed to be decreased in end-OA patients compared with meniscal tear patients (p = 0.023). No statistical differences were observed comparing ACL and PCL lengths between patients undergoing meniscectomy and TKR. Our study confirms that IFP MR morphometric characteristics are different between controls and OA, supporting an important role of IFP in OA pathology and progression in accordance with previously published studies. In addition, PL depth changes seem to be associated with OA pathology. Multivariate analysis confirmed that OA patients had a smaller IFP compared to patients with meniscal tears, confirming its involvement in OA.

Do Synovial Inflammation and Meniscal Degeneration Impact Clinical Outcomes of Patients Undergoing Arthroscopic Partial Meniscectomy? A Histological Study.

The menisci exert a prominent role in joint stabilization and in the distribution of mechanical loading. Meniscal damage is associated with increased risk of knee OA. The aim of this study was to characterize the synovial membrane and meniscal tissues in patients undergoing arthroscopic partial meniscectomy for meniscal tear and to evaluate association with clinical outcomes. A total of 109 patients were recruited. Demographic and clinical data were collected. Visual Analogic Scale (VAS) measuring pain and Knee injury and Osteoarthritis Outcome Score (KOOS) were recorded at baseline and at 2-years follow-up. Histological and immunohistochemical characterizations were performed on synovial membranes and meniscal tissues. More than half of the patients demonstrated synovial mononuclear cell infiltration and hyperplasia. Synovial fibrosis was present in most of the patients; marked vascularity and CD68 positivity were observed. Inflammation had an impact on both pain and knee symptoms. Patients with synovial inflammation had higher values of pre-operative VAS and inflammation. Higher pre-operative pain was observed in patients with meniscal MMP-13 production. In conclusion, multivariate analysis showed that synovial inflammation was associated with pre-operative total KOOS scores, knee symptoms, and pain. Moreover, meniscal MMP-13 expression was found to be associated with pre-operative pain in multivariate analysis. Thus, targeting inflammation of the synovial membrane and meniscus might reduce clinical symptoms and dysfunction at the time of surgery.

Erosive hand osteoarthritis: latest findings and outlook.

Osteoarthritis (OA) most commonly affects knee joints, and the next most commonly affected sites are the hands and hips. Three distinct hand OA phenotypes have been described: erosive hand OA (EHOA), nodal hand OA - also known as non-erosive hand OA (non-EHOA) - and first carpometacarpal joint OA. EHOA predominantly affects women and is the most aggressive form of hand OA, characterized by a severe clinical onset and progression, leading to joint damage, disability and reduction of quality of life. Clinical signs of inflammation associated with EHOA include the acute onset of pain, swelling and redness. Moreover, EHOA is characterized by radiographic features such as central erosion, saw-tooth and gull-wing lesions and, rarely, ankylosis. The aim of this Review is to report the latest findings on epidemiology, clinical features, pathology and aetiopathogenesis, biomarkers, imaging modalities and treatments for EHOA. The ongoing development of new hand OA classification criteria should facilitate standardization between studies.

Impact of disease duration and gender on the sensitivity and specificity of 2015 ACR/EULAR classification criteria for gout. Cross-sectional results from an Italian multicentric study on the management of crystal-induced arthritis (ATTACk).

OBJECTIVES: We aimed to assess the performance of the 2015 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) gout classification criteria in an Italian cohort of patients with crystal-induced arthritis stratified by disease duration and gender in a real-life setting. METHODS: Consecutive patients referred to Rheumatology Units for suspected acute crystal-induced arthritis were enrolled in a multicentre cohort study by the Italian Society of Rheumatology which was designed to improve the management of crystal-induced arthritis (ATTACk). To test the performance of the criteria (sensitivity and specificity), the presence of monosodium urate (MSU) crystals in synovial fluid (SF) was used as gold standard. Subgroup analyses by gender and disease duration were performed. RESULTS: Two hundred and seventy-seven patients were enrolled. SF analysis was available in 137 (49%) patients. Complete SF analysis and ACR/EULAR scores were obtained in 44% of patients. MSU crystals were found in 66% of patients. The sensitivity and the specificity of all criteria sets were 78% (95%CI, 67-86) and 98% (95%CI, 87-100), respectively; only clinical criteria yielded 70% (95%CI, 59-80) sensitivity and 93% (95%CI, 80-98) specificity, respectively. In early-stage disease (<2 years), the sensitivity dropped to 58% (95%CI, 39-75), while the specificity was 100% (95%CI, 85-100). CONCLUSIONS: The ACR/EULAR criteria showed good performance in patients presenting with acute arthritis; changes were observed when a subset of criteria were used, especially in early-stage disease.

Mechanical behavior of infrapatellar fat pad of patients affected by osteoarthritis.

The infrapatellar fat pad (IFP) is an adipose tissue present in the knee that lies between the patella, femur, meniscus and tibia, filling the space between these structures. IFP facilitates the distribution of the synovial fluid and may act to absorb impulsive actions generated through the joint. IFP in osteoarthritis (OA) pathology undergoes structural changes characterized by inflammation, hypertrophy and fibrosis. The aim of the present study is to analyze the mechanical behavior of the IFP in patients affected by end-stage OA. A specific test fixture was designed and indentation tests were performed on IFP specimens harvested from OA patients who underwent total knee arthroplasty. Experiments allowed to assess the typical features of mechanical response, such as non-linear stress-strain behavior and time-dependent effects. Results from mechanical experimentations were implemented within the framework of a visco-hyperelastic constitutive theory, with the aim to provide data for computational modelling of OA IFP role in knee mechanics. Initial and final indentation stiffness were calculated for all subjects and statistical results reveled that OA IFP mechanics was not significantly influenced by gender, BMI and sample preparation. OA IFP mechanical behavior was also compared to that of other adipose tissues. OA IFP appeared to be a stiffer adipose tissue compared to subcutaneous, visceral adipose tissues and heel fat pads. It is reasonable that fibrosis induces a modification of the tissue destabilizing the normal distribution of forces in the joint during movement, causing a worsening of the disease.

Mediterranean diet in axial spondyloarthritis: an observational study in an Italian monocentric cohort.

BACKGROUND: Little evidence is available about the impact of diet on disease activity of axial spondyloarthritis (axSpA). This study evaluated the impact of a 6-month nutritional advice based on the Mediterranean diet on the disease activity of axSpA. METHODS: We prospectively collected the information of a group of axSpA patients who were offered nutritional advice for a 6-month period, who were compared to axSpA patients followed at the same center who were not on a specific diet. A nutritionist gave suggestions for dietary modification at baseline and thereafter every 2 months until month 6. Adherence to the Mediterranean diet was evaluated with the PREDIMED questionnaire ranging from 0 (no adherence) to 10 (optimal adherence); disease activity was evaluated with ASDAS-CRP. A multivariable regression analysis was conducted to identify independent predictors of PREDIMED and of ASDAS-CRP improvement (improvement ≥ 20% of each score). RESULTS: A total of 161 patients were included: 81 receiving nutritional advice and 80 controls; 47 in the nutritional group and 63 controls had complete information until month 6. Overall, 40 (36.4%) were females, the mean age was 51.7 ± 1.3 years, and 58 (52.7%) were affected with psoriasis. No relevant change of anthropometric or laboratory measures was observed in either group. Adherence to the Mediterranean diet was moderate (PREDIMED score 6.7 ± 1.8 at baseline; 7.6 ± 2.1 at month 6) and improved more in the nutritional group compared to controls (p = 0.020). Predictors of a PREDIMED improvement ≥ 20% were receiving nutritional advice (OR 4.53, 1.36-15.1, p = 0.014), age (per 10-year increase OR 1.05, 1.02-1.68, p = 0.007), and BMI (OR 0.77, 0.63-0.9, p = 0.006). An ASDAS-CRP improvement ≥ 20% was more frequent in the nutritional group compared to controls (p = 0.020). A PREDIMED improvement ≥ 20% was associated with a ASDAS-CRP improvement ≥ 20% (OR 6.75,1.8-25.3, p = 0.005). Psoriasis and disease duration were negatively but not significantly associated to the ASDAS-CRP improvement. CONCLUSIONS: Improving adherence to the Mediterranean diet may have a beneficial impact on the activity of axSpA. Patients with a lower BMI and older patients are less prone to modify their diet towards the Mediterranean diet following nutritional advice. Patients with psoriasis may have a limited benefit from dietary improvement. STUDY REGISTRATION: Protocol No. 52723, Padova Hospital Medical Ethical Committee (October 11, 2010).

Age-Dependent Remodeling in Infrapatellar Fat Pad Adipocytes and Extracellular Matrix: A Comparative Study.

The infrapatellar fat pad (IFP) is actively involved in knee osteoarthritis (OA). However, a proper description of which developmental modifications occur in the IFP along with age and in absence of joint pathological conditions, is required to adequately describe its actual contribution in OA pathophysiology. Here, two IFP sources were compared: (a) IFP from healthy young patients undergoing anterior-cruciate ligament (ACL) reconstruction for ACL rupture (n = 24); (b) IFP from elderly cadaver donors (n = 23). After histopathological score assignment to confirm the absence of inflammatory features (i.e., inflammatory infiltrate and increased vascularity), the adipocytes morphology was determined; moreover, extracellular matrix proteins were studied through histology and Second Harmonic Generation approach, to determine collagens content and orientation by Fast Fourier Transform and OrientationJ. The two groups were matched for body mass index. No inflammatory signs were observed, while higher area, perimeter, and equivalent diameter and volume were detected for the adipocytes in the elderly group. Collagen III displayed higher values in the young group and a lower total collagen deposition with aging was identified. However, collagen I/III ratio and the global architecture of the samples were not affected. A higher content in elastic fibers was observed around the adipocytes for the ACL-IFPs and in the septa cadaver donor-IFPs, respectively. Age affects the characteristics of the IFP tissue also in absence of a pathological condition. Variable mechanical stimulation, depending on age-related different mobility, could be speculated to exert a role in tissue remodeling.

Phagocytosis and inflammation in crystal-induced arthritis: a synovial fluid and in vitro study.

OBJECTIVES: The aim of this study was to investigate the relationship between the degree of crystal phagocytosis and the magnitude of the local inflammatory process using fresh synovial fluid (SF) collected from patients with crystal-induced arthritis. In parallel, an in vitro model of crystal-induced inflammation was used to assess the effect of cell priming on crystal phagocytosis and IL-1ß production. METHODS: SF was collected from 20 patients with gout and 20 with pyrophosphate crystal-induced arthritis and examined under ordinary and polarised light microscopy for total and differential white blood cell (WBC) count and crystal search. The total phagocytosis index was determined in SF along with IL-1ß, IL-8, IL-10, and TGFß levels. The in vitro studies were performed using primed or unprimed THP-1 cells stimulated with calcium pyrophosphate (CPP) crystals, monosodium urate (MSU) crystals and/or cytochalasin D. RESULTS: We demonstrated that the phagocytosis index calculated on the total number of cells was independent from the inflammatory local indices such as WBC and the percentage of polymorphonuclear cells but showed a positive correlation with pro-inflammatory cytokines. By contrast, the local inflammatory indices (WBC and IL-1ß) showed a strong positive correlation with the percentage of polymorphonuclear cells with crystals internalised and a negative correlation with the percentage of mononuclear cells with crystals internalised. The in vitro study showed that phagocytosis represents a fundamental step in the induction of the inflammatory response to MSU and CPP crystals, but it also occurs in absence of cell priming. CONCLUSIONS: The results of this study indicate a possible role of non-inflammatory phagocytosis in limiting the acute attack of crystal-induced arthritis.