Air pollution exposure and auto-inflammatory and autoimmune diseases of the musculoskeletal system: a review of epidemiologic and mechanistic evidence.

Auto-inflammatory and autoimmune diseases of the musculoskeletal system can be perceived as a spectrum of rheumatic diseases, with the joints and connective tissues are eroded severely that progressively develop chronic inflammation and lesion. A wide range of risk factors represented by genetic and environmental factors have been uncovered by population-based surveys and experimental studies. Lately, the exposure to air pollution has been found to be potentially involved in the mechanisms of occurrence or development of such diseases, principally manifest in oxidative stress, local and systemic inflammation, and epigenetic modifications, as well as the mitochondrial dysfunction, which has been reported to participate in the intermediate links. The lungs might serve as a starting area of air pollutants, which would cause oxidative stress-induced bronchial-associated lymphoid tissue (iBALT) to further to influence T, B cells, and the secretion of pro-inflammatory cytokines. The binding of aromatic hydrocarbon receptor (AhR) to the corresponding contaminant ligands tends to regulate the reaction of Th17 and Tregs. Furthermore, air pollution components might spur on immune and inflammatory responses by damaging mitochondria that could interact with and exacerbate oxidative stress and pro-inflammatory cytokines. In this review, we focused on the association between air pollution and typical auto-inflammatory and autoimmune diseases of the musculoskeletal system, mainly including osteoarthritis (OA), rheumatoid arthritis (RA), spondyloarthritis (SpA) and juvenile idiopathic arthritis (JIA), and aim to collate the mechanisms involved and the potential channels. A complete summary and in-depth understanding of the autoimmune and inflammatory effects of air pollution exposure should hopefully contribute new perspectives on how to formulate better public health policies to alleviate the adverse health effects of air pollutants.

Muscle Research: A Tour d'Horizon.

The Special Issue on the "Muscular Structure, Physiology and Metabolism" was proposed in order to maintain the referenced scientific community abreast with recent research advancements regarding the morphology, functionality, and metabolism of muscle tissue, including a total of eighteen published papers, of which twelve were original research manuscripts and six were review papers [...].

Ultrasound for the diagnosis of gout-the value of gout lesions as defined by the Outcome Measures in Rheumatology ultrasound group.

OBJECTIVE: To evaluate ultrasound for diagnosing gout using consensus-based Outcome Measures in Rheumatology ultrasound definitions of gout lesions. METHODS: Ultrasound was performed in patients with clinically suspected gout. Joints (28) and tendons (26) were binarily evaluated for the Outcome Measures in Rheumatology gout lesions-double contour (DC), tophus, aggregates and erosions. Ultrasound assessment was compared with two reference standards: (i) presence of MSU crystals in joint/tophus aspirate (primary outcome) and (ii) ACR/EULAR 2015 gout classification criteria (secondary outcome). Both reference standards were evaluated by rheumatologists blinded to ultrasound findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of each ultrasound lesion against both reference standards were determined. RESULTS: Eighty-two patients (70 men), mean age 62.4 (range 19-88) years, were included. Fifty-seven patients were MSU-positive whereas 25 patients were MSU-negative (no MSU crystals: 23; aspiration unsuccessful: 2). Of these 25 patients, three patients were classified as ACR/EULAR-positive (i.e. totally 60 ACR/EULAR-positive patients). All ultrasound lesions had high sensitivities for gout (0.77-0.95). DC and tophus showed high specificities (0.88-0.95), positive predictive values (0.94-0.98) and accuracies (0.82-0.84) when both reference standards were used. In contrast, low specificities were found for aggregates and erosions (0.32-0.59). Ultrasound of MTP joints for DC or tophus, knee joint for DC and peroneus tendons for tophus was sufficient to identify all MSU-positive patients with ultrasound signs of gout at any location. CONCLUSION: Ultrasound-visualized DC and tophus, as defined by the Outcome Measures in Rheumatology ultrasound group, show high specificities, positive predictive values and accuracies for diagnosing gout and are therefore valid tools in clinical practice.

Tissue-Specific Decellularization Methods: Rationale and Strategies to Achieve Regenerative Compounds.

The extracellular matrix (ECM) is a complex network with multiple functions, including specific functions during tissue regeneration. Precisely, the properties of the ECM have been thoroughly used in tissue engineering and regenerative medicine research, aiming to restore the function of damaged or dysfunctional tissues. Tissue decellularization is gaining momentum as a technique to obtain potentially implantable decellularized extracellular matrix (dECM) with well-preserved key components. Interestingly, the tissue-specific dECM is becoming a feasible option to carry out regenerative medicine research, with multiple advantages compared to other approaches. This review provides an overview of the most common methods used to obtain the dECM and summarizes the strategies adopted to decellularize specific tissues, aiming to provide a helpful guide for future research development.

Assessing the sensitivity to change of the OMERACT ultrasound structural gout lesions during urate-lowering therapy.

OBJECTIVES: To evaluate the sensitivity to change of ultrasound structural gout lesions, as defined by the Outcome Measures in Rheumatology (OMERACT) ultrasound group, in patients with gout during urate-lowering therapy (ULT). METHODS: Ultrasound (28 joints, 26 tendons) was performed in patients with microscopically verified gout initiating or increasing ULT and repeated after 3 and 6 months. Joints and tendons were evaluated by ultrasound for presence of the OMERACT structural gout lesions-double contour sign (DC), tophus, aggregates and erosion-scored binarily. A sum score was calculated at patient and lesion level. Changes at 3 and 6 months in patient sum scores and lesion scores at different locations were evaluated. RESULTS: 50 patients (48 men), mean age 68.9 (range, 30-88) years, were included. Ultrasound showed a statistically significant decrease in DC and tophus sum scores from 0 months (3.16 and 2.68, respectively) to 3 months (2.33 and 2.43) and 6 months (1.34 and 1.83) (all p<0.002). The aggregate sum score only decreased significantly from 3 to 6 months (6.02 to 5.02, p=0.002), whereas erosion sum score remained almost unchanged. All four structural lesions were most commonly found in metatarsophalangeal (MTP) 1 joints (>1 lesions bilaterally), and furthermore MTP2-4 and knee joints were common sites especially for DC. Likewise, these regions were the locations with most pronounced changes in scores. CONCLUSION: Ultrasound assessment of the OMERACT structural gout lesions scored binarily seems to be a useful tool for monitoring urate depositions during ULT. Particularly DC and tophus showed sensitivity to change after only 3 months of treatment.

Chemical composition of human and canine fascia lata.

The fascial system is an integral part of the musculoskeletal system. It is a three-dimensional network of connective tissue spreading ubiquitously throughout the body, surrounding muscles, bones, internal organs, nerves, vessels, and other structures. The basic biophysical properties of the fascial system are determined by its structure and chemical composition. This study aimed to determine the elemental composition of pathologically unchanged fascia lata of the thigh, collected during autopsies on humans and dogs. The wide spectrum of elements analysed included both macro and micro elements. The analyses were conducted using scanning electron microscopy with X-ray microanalysis (SEM-EDS). Concentrations of the following macro and micro elements were determined: C, N, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Fe Co, Ni, Cu, and Zn. The obtained results showed significant differences between human and canine fascia lata regarding the content of most of the examined elements (p < 0.05), except for N. These data may in future provide a starting point for the establishment of reference values for the content of various elements in normal fascial tissue and may also serve to verify the usefulness of experimental animal material as a substitute for human tissue.

Room temperature DNA preservation of soft tissue for rapid DNA extraction: an addition to the disaster victim identification investigators toolkit?

In mass fatality incidents, for example following a vehicle accident or terrorist event, severe fragmentation of bodies may occur, making identification by the use of traditional techniques such as fingerprinting or odontology difficult. In such situations DNA profiling can be employed for individualization and re-association of fragmented remains. As at times disrupted soft tissue may be the predominate tissue type requiring identification and re-association. We have investigated the use of two buffer solutions for preservation of soft tissue samples that may be collected during such investigations, when buccal cells, blood samples or teeth or bone may not be available. Both buffer solutions have shown sufficient DNA preservation over a 12-month period of storage at room temperature to allow for DNA profiling to be successfully performed when 5-1000 mg muscle tissue was stored in each solution.

Expression profiling of peroxisome proliferator-activated receptor-delta (PPAR-delta) in mouse tissues using tissue microarray.

Peroxisome proliferator-activated receptor-delta (PPAR-delta) is known as a transcription factor involved in the regulation of fatty acid oxidation and mitochondrial biogenesis in several tissues, such as skeletal muscle, liver and adipose tissues. In this study, to elucidate systemic physiological functions of PPAR-delta, we examined the tissue distribution and localization of PPAR-delta in adult mouse tissues using tissue microarray (TMA)-based immunohistochemistry. PPAR-delta positive signals were observed on variety of tissues/cells in multiple systems including cardiovascular, urinary, respiratory, digestive, endocrine, nervous, hematopoietic, immune, musculoskeletal, sensory and reproductive organ systems. In these organs, PPAR-delta immunoreactivity was generally localized on the nucleus, although cytoplasmic localization was observed on several cell types including neurons in the nervous system and cells of the islet of Langerhans. These expression profiling data implicate various physiological roles of PPAR-delta in multiple organ systems. TMA-based immunohistochemistry enables to profile comprehensive protein localization and distribution in a high-throughput manner.

Magnetic resonance imaging of entheses using ultrashort TE (UTE) pulse sequences.

The attachment of tendons, ligaments, and joint capsule to bone (entheses) is reviewed and new options for visualizing key components of entheses provided by ultrashort TE (UTE) pulse sequences are described. Many features of entheses are adapted to the dispersion of stress at the boundary between tendons/ligaments and bone. Of particular interest is fibrocartilage, which has mechanical properties different from those of both "pure" tendon/ligament and bone. Features typical of entheses can also be seen at sites where tendons or ligaments are in contact with (but not attached to) bone, and the concept of a "functional enthesis" has been developed to emphasize the similarities. The enthesis concept has also been broadened to include the idea of an "enthesis organ" in which many tissues play a role in dissipating stress concentration. UTE pulse sequences can specifically identify the calcified and uncalcified fibrocartilage tissue components of entheses and differentiate these from fibrous connective tissue and bone. These tissues cannot be separately visualized at entheses with conventional pulse sequences. Entheses are involved in overuse syndromes and seronegative spondyloarthropathies (SpA) and there are important issues related to tissue repair and healing following surgery.

Mapping lubricin in canine musculoskeletal tissues.

Lubricin, also known as superficial zone protein or PRG4, has many distinct biological functions, including lubrication, antiadhesion, and as a regulator of cell growth. This study investigated lubricin in canine musculoskeletal tissues using RT-PCR and immunohistochemistry. One or more variants were noted in canine flexor digitorum profundus (FDP) tendon, Achilles tendon, patellar tendon, A2 pulley, anterior cruciate ligament (ACL), knee lateral collateral ligament (LCL), articular cartilage, meniscus, muscle, and skin. We found 6 N-terminal lubricin splicing variants. The variants with larger sizes were identified in FDP tendon, ACL, LCL, A2 pulley, and cartilage. Lubricin was distributed both on the tissue surfaces and at the interface of fiber bundles within tissues, but this distribution varied by tissue type. We conclude that lubricin is present in many tissues; variations in splicing and physical distribution suggest that the variants of lubricin may play different roles in different locations.

Characterization of two new zebrafish members of the hedgehog family: atypical expression of a zebrafish indian hedgehog gene in skeletal elements of both endochondral and dermal origins.

We have characterized two new members of the Hedgehog (Hh) family in zebrafish, ihha and dhh, encoding for orthologues of the tetrapod Indian Hedgehog (Ihh) and Desert Hedgehog (Dhh) genes, respectively. Comparison of ihha and Type X collagen (col10a1) expression during skeletal development show that ihha transcripts are located in hypertrophic chondrocytes of cartilaginous elements of the craniofacial and fin endoskeleton. Surprisingly, col10a1 expression was also detected in cells forming intramembranous bones of the head and in flat cells surrounding cartilaginous structures. The expression of col10a1 in both endochondral and intramembranous bones reflects an atypical composition of the extracellular matrix of the zebrafish craniofacial skeleton. In addition, during fin ray regeneration, both ihha and col10a1 are detected in scleroblasts, osteoblast-like cells secreting the matrix of the dermal bone fin ray. The presence of cartilage markers suggests that the dermal fin ray possesses an intermediate phenotype between cartilage and bone.

An evaluation of dual-energy X-Ray absorptiometry and underwater weighing to estimate body composition by means of carcass analysis in piglets.

To evaluate the use of dual-energy X-ray absorptiometry (DXA) and underwater weighing (UWW) for body-composition measurements, the carcasses of eight piglets (12-wk old, 15-22 kg in weight) were dissected into muscle, fat and bone. Thereafter, the components were homogenized and chemically analyzed for fat and bone mineral mass. Body components as measured by DXA correlated closely to the carcass analysis (r = 0.90-1.0). However, DXA still overestimated significantly the bone mineral mass, lean mass and total weight, and underestimated fat mass. The reproducibility of measurements, expressed as the CV for fat mass was 13.5%, whereas for total weight, lean mass and bone mineral mass, the CV was 0.74-1.9%. Fat mass was overestimated by UWW using the equations of Siri or Kraybill (r = 0. 77), but not by the equation of Lohman et al. (r = 0.69). The difference between the estimation of fat by chemical analysis and estimations by DXA and UWW was significantly affected by the amount of water in lean mass and fat-free mass.

Evaluation of dual-energy X-Ray absorptiometry for body-composition assessment in rats.

Recent developments in dual-energy X-ray absorptiometry (DXA) have rendered feasible the determination of whole-body composition in small laboratory animals by directly measuring fat, fat-free and mineral bone masses. Our aim was to evaluate this technique by cross-calibrating the DXA method with the carcass chemical analysis in a heterogeneous population of nondiabetic Wistar and diabetic GK rats (21 animals were used for precision error and reproducibility determinations and 26 were used for accuracy studies). We report that this technique is optimized for weights >200 g. The respective CV for lean mass, fat mass and percentage of fat mass determined in short-term or transversal studies was 1.1 +/- 0.1, 3.0 +/- 1.3 and 3. 1 +/- 0.4% (mean +/- SD) respectively. Further, this technique is valid for rats weighing from 130 to 200 g by using three successive scans. In longitudinal studies, daily calibrations significantly increased the percentage of fat mass CV to 6.6 +/- 3.3%, but it was significantly decreased to 3.0 +/- 2.7% by the use of triplicate scans. The accuracy for DXA was excellent in reference to the chemical extraction technique (r2 = 0.95 for percentage of fat mass, P < 0.0001), using an adjustment factor of 0.75 (limits of agreement between the two methods for percentage of fat mass = -1.7-2.3%). Mimicry of longitudinal changes in body composition with intraperitoneal injections of saline solution demonstrated a satisfactory detection of body component changes (

A comparative study of the expression patterns for vegf, vegf-b/vrf and vegf-c in the developing and adult mouse.

With the goal of better understanding the function and regulation of the different members of the VEGF family this study reports mapping of vegf, vegf-b and vegf-c mRNA expression in developing and adult mice. On embryonic day 14 (E14) there is a high expression of vegf and vegf-b, vegf-b being exceptionally high in heart and CNS. The vegf-c expression is lower with distinct signals in CNS and heart. Prior to birth (E17), vegf and vegf-b expression is moderately downregulated. Overlapping expression is present in intrascapular fat and heart. vegf dominates in thyroid and lung, while vegf-b appears to be the only VEGF member expressed at detectable levels in the CNS. In young adult mouse vegf and vegf-b show partly overlapping expression patterns particularly in kidney, heart and in the thymus, vegf displays higher levels in lung and liver, vegf-b appears to be dominating in brain, heart, testis and kidney. In brain the highest levels of vegf-b is present in the hippocampus. No vegf-c mRNA expression could be detected in the adult. Taken together, these results illustrate, in detail, the different regulations of the members of the VEGF gene family. There are at present at least three specific effectors of vascular proliferation with clear differences in their expression.

Pasteurella multocida in psittacines: prevalence, pathology, and characterization of isolates.

Although the pathogenicity of Pasteurella multocida for psittacines (parrots and their relatives) has been documented in several case reports, the associated pathologic syndromes have not been well defined nor have the isolates been characterized. In addition, the prevalence of P. multocida in psittacines has not been determined. Three hundred twenty-eight psittacines (253 clinically healthy and 75 clinically ill) were cultured for P. multocida. Pasteurella multocida was not isolated from the pharynx, choana, or cloaca of psittacines. However, in five dead psittacines submitted for necropsy, P. multocida was isolated. These isolates were characterized, and all belonged to either somatic serotype 3 or 4,7. Pasteurella multocida somatic serotype 3 was isolated from psittacines with septicemia, whereas P. multocida somatic serotype 4,7 was isolated from psittacines with cutaneous lesions. The majority (four out of five) of the P. multocida isolates belonged to the subspecies multocida, and all isolates were susceptible to penicillin G, sulfisoxazole, gentamicin, erythromycin, tetracycline, and trimethoprim-sulfamethoxazole but resistant to streptomycin. DNA fingerprints demonstrated that isolates belonging to the same somatic serotype were genetically related. The isolate from a cockatiel that had been caught by a cat belonged to somatic serotype 3 and was not genetically related to the other two isolates belonging to this somatic serotype.

Immunohistochemical analysis of Mcl-1 protein in human tissues. Differential regulation of Mcl-1 and Bcl-2 protein production suggests a unique role for Mcl-1 in control of programmed cell death in vivo.

The mcl-1 gene encodes an approximately 37-kd protein that has significant homology with Bcl-2, an inhibitor of programmed cell death that is expressed in many types of long-lived cells. In this study we determined the in vivo patterns of Mcl-1 protein production in normal human tissues by immunohistochemical means, using specific polyclonal antisera, and made comparisons with Bcl-2. Like Bcl-2, Mcl-1 immunostaining was observed in epithelial cells in a variety of tissues, including prostate, breast, endometrium, epidermis, stomach, intestine, colon, and respiratory tract. However, often the expression of mcl-1 and bcl-2 in complex epithelia occurred in gradients with opposing directions, such that Bcl-2 immunostaining tended to be higher in the less differentiated cells lining the basement membrane, whereas Mcl-1 immunostaining was more intense in the differentiated cells located in the upper layers of these epithelia. The in vivo patterns of mcl-1 and bcl-2 expression were also strikingly different in several other tissues as well. Within the secondary follicles of lymph nodes and tonsils, for example, germinal center lymphocytes were Mcl-1 positive but mostly lacked Bcl-2; whereas mantle zone lymphocytes expressed bcl-2 but not mcl-1. Intense Mcl-1 immunoreactivity was also detected in several types of neuroendocrine cells, including the adrenal cortical cells that are Bcl-2 negative, sympathetic neurons that also contain Bcl-2, a subpopulation of cells in the pancreatic islets, Leydig cells of the testis, and granulosa lutein cells of the ovarian corpus luteum but not in thyroid epithelium, which is strongly Bcl-2 positive. Little or no Mcl-1 was detected in neurons in the brain and spinal cord, in contrast to Bcl-2, which is present in several types of central nervous system neurons. Conversely, strong Mcl-1 immunostaining was found in cardiac and skeletal muscle, which contain comparatively less Bcl-2. Additional types of cells that are Bcl-2-negative but that expressed mcl-1 include chondrocytes and hepatocytes. These findings demonstrate that mcl-1 expression is widespread in vivo and imply that the Mcl-1 and Bcl-2 proteins fulfill different roles in the overall physiology of cell death regulation.

Developmental patterns of histamine-like immunoreactivity in the mouse.

We studied the appearance and distribution of histamine (HA) during mouse embryogenesis, neonatal period, and adulthood using a specific rabbit HA antiserum and indirect immunofluorescence. HA first appeared on the Embryonic Day 13 (E13) in scattered mast cells in the gastrointestinal (GI) muscularis externa and liver. The splenic primordium contained a dense population of intensely HA-immunoreactive (HA-ir) cells from E13 on. From E15 to the birth, HA was detected in many embryonic cell types. On E15, the first HA-ir epithelial endocrine cells appeared in the oxyntic mucosa. In addition to the HA-ir cells in GI tract and liver, some nerve cells in ganglia of the peripheral nervous system (PNS), some fibers in spinal and cranial nerves, nerve fibers in mesenterium, and nerve plexuses of the gastrointestinal muscularis externa were HA-ir from E15 on. Occasional HA-ir nerve fibers were detected within the glandular epithelium of the oxyntic mucosa, pancreas, and salivary glands during late embryogenesis. During the same period, bright fluorescence was observed in cells of the kidney convoluted tubules and pancreatic islet cells. From E14 on, mast cells exhibiting bright fluorescence were scattered throughout the connective tissue of the fetus, and their number increased rapidly with age. Their density was especially high in subcutaneous connective tissue. Embryonic epidermal cells showed faint HA immunoreactivity. In musculoskeletal tissues, developing bone and occasional striated muscle cells exhibited HA immunoreactivity. Interestingly, most cells in liver showed transiently weak HA immunoreactivity during embryogenesis. In adult mouse, HA was stored only by scattered mast cells, oxyntic epithelial cells, and neurons in the tuberomamillary nucleus of the brain. The other HA-containing embryonic cells were negative for HA in adult mouse. In conclusion, HA immunoreactivity is widely distributed in epithelial, neuronal, and mast cells in various organs during mouse embryogenesis.

Comparison of DNA extraction and amplification from ancient human bone and mummified soft tissue.

South american precolumbian male mummies were employed as source material for a comparative investigation of bone and soft tissues by DNA analysis. The suitability of the DNA extracts from both sources was tested and evaluated by their effectiveness as target DNA in PCR amplifications. The results suggest that skeletal material should be given preference over soft tissues for PCR analysis if the material is severely degraded. This seems to be independent of the specific anatomical origin of the samples.