Phenotypic alterations of neuropeptide Y and calcitonin gene-related peptide-containing neurons innervating the rat temporomandibular joint during carrageenan-induced arthritis

The aim of this study was to identify immunoreactive neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) neurons in the autonomic and sensory ganglia, specifically neurons that innervate the rat temporomandibular joint (TMJ). A possible variation between the percentages of these neurons in acute and chronic phases of carrageenan-induced arthritis was examined. Retrograde neuronal tracing was combined with indirect immunofluorescence to identify NPY-immuno-reactive (NPY-IR) and CGRP-immunoreactive (CGRP-IR) neurons that send nerve fibers to the normal and arthritic temporomandibular joint. In normal joints, NPY-IR neurons constitute 78 +/- 3%, 77 +/- 6% and 10 +/- 4% of double-labeled nucleated neuronal profile originated from the superior cervical, stellate and otic ganglia, respectively. These percentages in the sympathetic ganglia were significantly decreased in acute (58 +/- 2% for superior cervical ganglion and 58 +/- 8% for stellate ganglion) and chronic (60 +/- 2% for superior cervical ganglion and 59 +/- 15% for stellate ganglion) phases of arthritis, while in the otic ganglion these percentages were significantly increased to 19 +/- 5% and 13 +/- 3%, respectively. In the trigeminal ganglion, CGRP-IR neurons innervating the joint significantly increased from 31 +/- 3% in normal animals to 54 +/- 2% and 49 +/- 3% in the acute and chronic phases of arthritis, respectively. It can be concluded that NPY neurons that send nerve fibers to the rat temporomandibular joint are located mainly in the superior cervical, stellate and otic ganglia. Acute and chronic phases of carrageenan-induced arthritis lead to an increase in the percentage of NPY-IR parasympathetic and CGRP-IR sensory neurons and to a decrease in the percentage of NPY-IR sympathetic neurons related to TMJ innervation.

Risk factors for magnetic resonance imaging-detected patellofemoral and tibiofemoral cartilage loss during a six-month period: The Joints On Glucosamine study

Objective To assess several baseline risk factors that may predict patellofemoral and tibiofemoral cartilage loss during a 6-month period. Methods For 177 subjects with chronic knee pain, 3T magnetic resonance imaging (MRI) of both knees was performed at baseline and followup. Knees were semiquantitatively assessed, evaluating cartilage morphology, subchondral bone marrow lesions, meniscal morphology/extrusion, synovitis, and effusion. Age, sex, and body mass index (BMI), bone marrow lesions, meniscal damage/extrusion, synovitis, effusion, and prevalent cartilage damage in the same subregion were evaluated as possible risk factors for cartilage loss. Logistic regression models were applied to predict cartilage loss. Models were adjusted for age, sex, treatment, and BMI. Results Seventy-nine subregions (1.6%) showed incident or worsening cartilage damage at followup. None of the demographic risk factors was predictive of future cartilage loss. Predictors of patellofemoral cartilage loss were effusion, with an adjusted odds ratio (OR) of 3.5 (95% confidence interval [95% CI] 1.39.4), and prevalent cartilage damage in the same subregion with an adjusted OR of 4.3 (95% CI 1.314.1). Risk factors for tibiofemoral cartilage loss were baseline meniscal extrusion (adjusted OR 3.6 [95% CI 1.310.1]), prevalent bone marrow lesions (adjusted OR 4.7 [95% CI 1.119.5]), and prevalent cartilage damage (adjusted OR 15.3 [95% CI 4.947.4]). Conclusion Cartilage loss over 6 months is rare, but may be detected semiquantitatively by 3T MRI and is most commonly observed in knees with Kellgren/Lawrence grade 3. Predictors of patellofemoral cartilage loss were effusion and prevalent cartilage damage in the same subregion. Predictors of tibiofemoral cartilage loss were prevalent cartilage damage, bone marrow lesions, and meniscal extrusion.

Gender characterization in a large series of Brazilian patients with spondyloarthritis

An increasing number of women have been diagnosed with spondyloarthritis (SpA) in recent decades. While a few studies have analyzed gender as a prognostic factor of the disease, no studies have addressed this matter with a large number of patients in South America, which is a peculiar region due to its genetic heterogeneity. The aim of the present study was to analyze the influence of gender on disease patterns in a large cohort of Brazilian patients with SpA. A prospective study was carried out involving 1,505 patients [1,090 males (72.4%) and 415 females (27.6%)] classified as SpA according to the European Spondyloarthropaties Study Group criteria who attended at 29 reference centers for rheumatology in Brazil. Clinical and demographic variables were recorded and the following disease indices were administered: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Radiologic Index (BASRI), Maastricht Ankylosing Spondylitis Enthesitis Score (MASES), and Ankylosing Spondylitis Quality of Life (ASQoL). Ankylosing spondylitis (AS) was the most frequent disease in the group (65.4%), followed by psoriatic arthritis (18.4%), undifferentiated SpA (6.7%), reactive arthritis (3.3%), arthritis associated to inflammatory bowel disease (3.2%), and juvenile SpA (2.9%). The male-to-female ratio was 2.6:1 for the whole group and 3.6:1 for AS. The females were older (p<0.001) and reported shorter disease duration (p=0.002) than the male patients. The female gender was positively associated to peripheral SpA (p<0.001), upper limb arthritis (p<0.001), dactylitis (p=0.011), psoriasis (p<0.001), nail involvement (p<0.001), and family history of SpA (p=0.045) and negatively associated to pure axial involvement (p< 0.001), lumbar inflammatory pain (p=0.042), radiographic sacroiliitis (p<0.001), and positive HLA-B27 (p=0.001). The number of painful (p<0.001) and swollen (p=0.006) joints was significantly higher in the female gender, who also achieved higher BASDAI (p<0.001), BASFI (p=0.073, trend), MASES (p=0.019), ASQoL (p=0.014), and patient's global assessment (p=0.003) scores, whereas the use of nonsteroidal anti-inflammatory drugs (p<0.001) and biological agents (p=0.003) was less frequent in the female gender. Moreover, BASRI values were significantly lower in females (p<0.001). The female gender comprised one third of SpA patients in this large cohort and exhibited more significant peripheral involvement and less functional disability, despite higher values in disease indices.

Experimental diabetes modulates collagen remodelling of joints in rats

The aim of this study was to evaluate extracellular matrix components in articular cartilage, ligaments and synovia in an experimental model of diabetes. Young Wistar rats were divided into a streptozotocin-induced (STZ; 35 mg/kg) diabetic group (DG; n=15) and a control group (CG; n=15). Weight, blood glucose and plasma anti-carboxymethyllysine were measured 70 days after STZ infusions. Knee joints, patellar ligaments, and lateral and medial collateral ligaments were isolated and stained with hematoxylineosin and Picrosirius. The total collagen content was determined by morphometry. Immunofluorescence was employed to evaluate types I, III, and V collagen in ligaments and synovial tissues and types II and XI collagen in cartilage. Results: Higher blood glucose levels and plasma anti-carboxymethyllysine were observed in DG rats when compared to those in CG rats. The final weight was significantly lower in the DG rats than in the CG rats. Histomorphometric evaluation depicted a small quantity of collagen fibers in ligaments and articular cartilage in DG rats, as well as increased collagen in synovial tissue. There was a decrease in cartilage proteoglycans in DG rats when compared with CG rats. Immunofluorescence staining revealed an increase of collagen III and V in ligaments, collagen XI in cartilage, and collagen I in synovial tissue of DG rats compared with CG rats. Conclusion: The ligaments, cartilage and synovia are highly affected following STZ-induced diabetes in rats, due the remodeling of collagen types in these tissues. This process may promote the degradation of the extracellular matrix, thus compromising joint function. Our data may help to better understand the pathogenesis of joint involvement related to diabetes.

Fat infiltration in the lumbar multifidus and erector spinae muscles in subjects with sway-back posture

Decreased activity of the lumbar stabilizer muscles has been identified in individuals with sway-back posture. Disuse can predispose these muscles to atrophy, which is characterized by a reduced cross-sectional area (CSA) and by fat infiltration. The aim of this study was to evaluate the amount of fat infiltration in the lumbar multifidus and lumbar erector spinae muscles as a sign of the muscle atrophy in individuals with sway-back posture, with and without low back pain. Forty-five sedentary individuals between 16 and 40 years old participated in this study. The sample was divided into three groups: symptomatic sway-back (SSBG) (n = 15), asymptomatic sway-back (ASBG) (n = 15), and control (CG) (n = 15). The individuals were first subjected to photographic analysis to classify their postures and were then referred for a magnetic resonance imaging (MRI) examination of the lumbar spine. The total (TCSA) and functional (FCSA) cross-sectional areas of the lumbar erector spinae together with lumbar multifidus and isolated lumbar multifidus muscles were measured from L1 to S1. The amount of fat infiltration was estimated as the difference between the TCSA and the FCSA. Greater fat deposition was observed in the lumbar erector spinae and lumbar multifidus muscles of the individuals in the sway-back posture groups than in the control group. Pain may have contributed to the difference in the amount of fat observed in the groups with the same postural deviation. Similarly, sway-back posture may have contributed to the tissue substitution relative to the control group independently of low back pain. The results of this study indicate that individuals with sway-back posture may be susceptible to morphological changes in their lumbar erector spinae and lumbar multifidus muscles, both due to the presence of pain and as a consequence of their habitual posture.