Gene expression of periostin in the early stage of fracture healing detected by cDNA microarray analysis

Periostin Is a Biomarker for Anterior Shoulder Instability: Proteomic Analysis of Synovial Fluid

BACKGROUND

The incremental biological changes in the synovial microenvironment of the shoulder in acute and chronic instability that may contribute to joint degeneration are poorly understood. Proteomic analysis of synovial fluid in patients with shoulder instability may improve our understanding of proteins that are shed into shoulder synovial fluid after an injury.

HYPOTHESIS

Injury-specific factors such as the direction of instability and the severity of glenoid and humeral bone loss are associated with the proteome of synovial fluid in patients with shoulder instability.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Synovial fluid lavage samples were compared between patients with anterior (n = 12) and posterior (n = 8) instability and those without instability (n = 5). Synovial proteins were identified with liquid chromatography-tandem mass spectrometry. Orthogonal validation of protein targets found to be significant on tandem mass spectrometry was performed in a separate set of prospective patients with Western blotting. Data were processed and analyzed, and P values were adjusted with the Benjamini-Hochberg method for multiple comparisons.

RESULTS

A total of 25 patients were included. Tandem mass spectrometry identified 720 protein groups in synovial fluid of patients with shoulder instability. There were 4 synovial proteins that were significantly expressed in patients with anterior instability relative to posterior instability: periostin (POSTN) (adjusted P value = .03; log fold change [logFc] = 4.7), transforming growth factor beta-induced protein ig-h3 (adjusted P value = .05; logFc = 1.7), collagen type VI alpha-3 chain (adjusted P value = .04; logFc = 2.6), and coagulation factor V (adjusted P value = .04; logFc = -3.3). Among these targets, POSTN showed a moderate correlation with the Hill-Sachs lesion size (r = 0.7). Prospective validation with Western blotting confirmed a significantly higher level of POSTN in synovial fluid of patients with anterior instability (P = .00025; logFc = 5.1).

CONCLUSION

Proteomic analysis enriched our understanding of proteins that were secreted into shoulder synovial fluid of patients with shoulder instability. The identification of POSTN, a proinflammatory catabolic protein involved with tissue remodeling and repair, as a significant target in anterior shoulder instability is a novel finding. Therefore, further study is warranted to determine the role that POSTN may play in the progression of bone loss and posttraumatic osteoarthritis.

CLINICAL RELEVANCE

Proteomic analysis of synovial fluid in patients with shoulder instability improved our understanding of this abnormality after an injury.

Research progress of periostin and osteoporosis

Periostin, as a unique extracellular matrix, is mainly produced during ontogeny and in adult connective tissues that bear mechanical loads, such as heart valves, skin, periodontal ligaments, tendons, and bones. By binding to the integrin on the cell surface and activating Wnt/β-catenin, NF-κB, Fak and other signaling pathways, it regulates the tissues in vivo positively or negatively, and also has different effects on the occurrence and development of various diseases. Periostin is an important factor, which can promote cell proliferation, stimulate tissue repair and maintain the integrity of the structure and function of connective tissue. It also promotes the formation, regeneration and repairation of bone. Recent studies have shown that periostin is important in bone metabolic diseases. The increased expression of periostin can affect bone mineral density at different sites, and its relationship with traditional biochemical markers of bone turnover has not been conclusively established. This article reviews the research results and potential applications of periostin in osteoporosis.

Unraveling the role of the FHL family in cardiac diseases: Mechanisms, implications, and future directions

Heart diseases are a major cause of morbidity and mortality worldwide. Understanding the molecular mechanisms underlying these diseases is essential for the development of effective diagnostic and therapeutic strategies. The FHL family consists of five members: FHL1, FHL2, FHL3, FHL4, and FHL5/Act. These members exhibit different expression patterns in various tissues including the heart. FHL family proteins are implicated in cardiac remodeling, regulation of metabolic enzymes, and cardiac biomechanical stress perception. A large number of studies have explored the link between FHL family proteins and cardiac disease, skeletal muscle disease, and ovarian metabolism, but a comprehensive and in-depth understanding of the specific molecular mechanisms targeting FHL on cardiac disease is lacking. The aim of this review is to explore the structure and function of FHL family members, to comprehensively elucidate the mechanisms by which they regulate the heart, and to explore in depth the changes in FHL family members observed in different cardiac disorders, as well as the effects of mutations in FHL proteins on heart health.

Cells transiently expressing periostin are required for intramedullary intramembranous bone regeneration

Intramembranous bone regeneration plays an important role in fixation of intramedullary implants used in joint replacement and dental implants used in tooth replacement. Despite widespread recognition of the importance of intramembranous bone regeneration in these clinical procedures, the underlying mechanisms have not been well explored. A previous study that examined transcriptomic profiles of regenerating bone from the marrow space showed that increased periostin gene expression preceded increases in several osteogenic genes. We therefore sought to determine the role of cells transiently expressing periostin in intramedullary intramembranous bone regeneration. We used a genetic mouse model that allows tamoxifen-inducible fluorescent labeling of periostin expressing cells. These mice underwent ablation of the bone marrow cavity through surgical disruption, a well-established intramembranous bone regeneration model. We found that in intact bones, fluorescently labeled cells were largely restricted to the periosteal surface of cortical bone and were absent in bone marrow. However, following surgical disruption of the bone marrow cavity, cells transiently expressing periostin were found within the regenerating tissue of the bone marrow compartment even though the cortical bone remained intact. The source of these cells is likely heterogenous, including cells occupying the periosteal surface as well as pericytes and endothelial cells within the marrow cavity. We also found that diphtheria toxin-mediated depletion of cells transiently expressing periostin at the time of surgery impaired intramembranous bone regeneration in mice. These data suggest a critical role of periostin expressing cells in intramedullary intramembranous bone regeneration and may lead to novel therapeutic interventions to accelerate or enhance implant fixation.

Landscape of Well-Coordinated Fracture Healing in a Mouse Model Using Molecular and Cellular Analysis

The success of fracture healing relies on overlapping but coordinated cellular and molecular events. Characterizing an outline of differential gene regulation throughout successful healing is essential for identifying crucial phase-specific markers and may serve as the basis for engineering these in challenging healing situations. This study analyzed the healing progression of a standard closed femoral fracture model in C57BL/6N (age = 8 weeks) wild-type male mice. The fracture callus was assessed across various days post fracture (D = days 0, 3, 7, 10, 14, 21, and 28) by microarray, with D0 serving as a control. Histological analyses were carried out on samples from D7 until D28 to support the molecular findings. Microarray analysis revealed a differential regulation of immune response, angiogenesis, ossification, extracellular matrix regulation, mitochondrial and ribosomal genes during healing. In-depth analysis showed differential regulation of mitochondrial and ribosomal genes during the initial phase of healing. Furthermore, the differential gene expression showed an essential role of Serpin Family F Member 1 over the well-known Vascular Endothelial Growth Factor in angiogenesis, especially during the inflammatory phase. The significant upregulation of matrix metalloproteinase 13 and bone sialoprotein from D3 until D21 asserts their importance in bone mineralization. The study also shows type I collagen around osteocytes located in the ossified region at the periosteal surface during the first week of healing. Histological analysis of matrix extracellular phosphoglycoprotein and extracellular signal-regulated kinase stressed their roles in bone homeostasis and the physiological bone-healing process. This study reveals previously unknown and novel candidates, that could serve as a target for specific time points in healing and to remedy cases of impaired healing.

Serum periostin level is not sufficient to serve as a clinically applicable biomarker of osteoarthritis

BACKGROUND

Emerging knowledge has highlighted the role of periostin (POSTN) in osteoarthritis (OA) process; however, whether POSTN is suitable as a biomarker of OA remains unclear. This study aimed to investigate the potential value of POSTN as a biomarker of OA.

METHODS

Ten 6-month-old female Sprague-Dawley (SD) rats were used in this study. Five rats underwent ovariectomy (OVX) operation and the others were carried out sham operation. Thirty-two patients with OA and eighteen patients who had meniscus injuries or ligament injuries but with intact articular cartilages were recruited in this study from January to July 2019 at the Peking University International Hospital. We first detected the expression of POSTN in the cartilage of OVX induced OA rats and different compartments of the knee joint in patients with OA using immunohistochemistry. Besides, serum POSTN levels in patients with or without OA were examined using enzyme-linked immunosorbent assay (ELISA). The associations among serum POSTN levels, clinical symptoms, and radiological severity were assessed according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and, Kellgren-Lawrence (KL) grading, respectively. Finally, multivariable cumulative link models were established to evaluate the validity of serum POSTN level as a predictor of knee OA.

RESULTS

The significantly higher POSTN expression was found in OVX-OA rats than Sham rats, while, the expression of POSTN was significantly higher in the torn cartilage of patients with OA. However, the serum POSTN level did not differ significantly between patients with and without OA. Additionally, we found no remarkable associations between serum POSTN level and WOMAC scores and KL grading. Subsequent analysis revealed that serum POSTN was not a significant predictor of OA.

CONCLUSION

Thus, although POSTN may be involved OA process and local POSTN is valuable in disease diagnosis and distinguishing of the severity of disease, its serum level is not sufficient to serve as a candidate biomarker of OA given the current analysis technology.

Can serum periostin predict bronchopulmonary dysplasia in premature infants?

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common morbidity complicating preterm birth and affects long-term respiratory outcomes. The objectives of this study were to establish whether serum periostin at birth, day of life (DOL) 28, and corrected 36 weeks' gestational age could be potential biomarkers for BPD.

METHODS

A total of 98 preterm Japanese infants born at <32 weeks and comparing 41 healthy controls born at term, were divided into BPD (n = 44) and non-BPD (n = 54) cohorts. Serum periostin levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

Among 98 preterm infants, the median serum periostin levels at birth were higher with BPD (338.0 ng/mL) than without (275.0 ng/mL, P < 0.001). Multivariate analysis revealed that serum periostin levels at birth were significantly associated with BPD (P = 0.013). Serum periostin levels at birth with moderate/severe BPD (345.0 ng/mL) were significantly higher than those with non-BPD/mild BPD (283.0 ng/mL, P = 0.006).

CONCLUSIONS

Serum periostin levels were significantly correlated with birth weight and gestational age, and serum periostin levels at birth in BPD infants were significantly higher than that in non-BPD infants.

IMPACT

This study found higher serum periostin levels at birth in preterm infants subsequently diagnosed with bronchopulmonary dysplasia. It also emerged that serum periostin levels at birth significantly correlated with gestational age and birth weight. The mechanism by which serum periostin is upregulated in BPD infants needs further investigation.

Periostin Contributes to Fibrocartilage Layer Growth of the Patella Tendon Tibial Insertion in Mice

Background and Objectives: The influence of periostin on the growth of the patella tendon (PT) tibial insertion is unknown. The research described here aimed to reveal the contribution of periostin to the growth of fibrocartilage layers of the PT tibial insertion using periostin knockout mice. Materials and Methods: In both the wild-type (WD; C57BL/6N, periostin +/+; n = 54) and periostin knockout (KO; periostin −/−; n = 54) groups, six mice were euthanized on day 1 and at 1, 2, 3, 4, 6, 8, 10, and 12 weeks of age. Chondrocyte proliferation and apoptosis, number of chondrocytes, safranin O-stained glycosaminoglycan (GAG) area, staining area of type II collagen, and length of the tidemark were investigated. Results: Chondrocyte proliferation and apoptosis in KO were lower than those in WD on day 1 and at 1, 4, and 8 weeks and on day 1 and at 4, 6, and 12 weeks, respectively. Although the number of chondrocytes in both groups gradually decreased, it was lower in KO than in WD on day 1 and at 8 and 12 weeks. In the extracellular matrix, the GAG-stained area in KO was smaller than that in WD on day 1 and at 1, 4, 8, 10, and 12 weeks. The staining area of type II collagen in KO was smaller than that in WD at 8 weeks. The length of the tidemark in KO was shorter than that in WD at 4 and 6 weeks. Conclusion: Loss of periostin led to decreased chondrocyte proliferation, chondrocyte apoptosis, and the number of chondrocytes in the growth process of the PT tibial insertion. Moreover, periostin decreased and delayed GAG and type II collagen production and delayed tidemark formation in the growth process of the PT tibial insertion. Periostin can, therefore, contribute to the growth of fibrocartilage layers in the PT tibial insertion. Periostin deficiency may result in incomplete growth of the PT tibial insertion.

Periostin as a biomarker in chronic rhinosinusitis: A contemporary systematic review

BACKGROUND

The role of periostin, a matricellular protein encoded by the POSTN gene, in chronic rhinosinusitis with nasal polyposis (CRSwNP) is reviewed. Periostin is considered a potential biomarker of endotype and may be useful for evaluating response to treatment.

METHODS

Search terms in PubMed and Web of Science (1990-March 2022) included: ((periostin) OR (POSTN)) AND ((sinusitis) OR (nasal polyp) OR (CRSwNP) OR (CRS). The primary outcomes were differences in tissue, serum, and nasal lavage between CRSwNP and CRS without NP (CRSsNP) or controls. Associated factors reported to affect periostin expression, data regarding participants' clinical characteristics, disease endotypes, laboratory methods, and samples' origin were also pooled. Studies on <10 patients were excluded.

RESULTS

Out of 101 records harvested through database searching, 29 prospective cross-sectional or case-control studies were eligible for review and qualitative analysis. Tissue sample origin, concurrent infection, current and past medication, primary or recurrent disease, allergic rhinitis, and smoking status should be considered as confounding factors for periostin levels. Periostin and POSTN messenger RNA (mRNA) levels were consistently and significantly higher in CRSwNP than CRSsNP and controls. Despite the distinctly different inflammation patterns among CRSwNP endotypes, periostin-related remodeling patterns seemed to be similar.

CONCLUSION

Tissue and serum periostin levels, and POSTN expression appear elevated in CRSwNP, especially in eosinophilic inflammation, compared to CRSsNP and controls. Disease severity and comorbidities are also reflected in periostin and POSTN values. Carefully designed prospective studies may establish the role of periostin as a biomarker in CRSwNP and allow its incorporation in clinical practice.

Serum Periostin Level and Genetic Polymorphisms Are Associated with Vertebral Fracture in Chinese Postmenopausal Women

Purposes: In order to investigate the association between serum periostin levels and the variation of its encoding gene POSTN and the prevalence of vertebral fractures and bone mineral density (BMD) in Chinese postmenopausal women, an association study was performed. Materials and Methods: 385 postmenopausal women were recruited. For participants without a history of vertebral fracture, lateral X-rays of the spine covering the fourth thoracic spine to the fifth lumbar spine were performed to detect any asymptomatic vertebral fractures. Ten tag-single nucleotide polymorphisms (SNP) of POSTN were genotyped. Serum periostin levels, biochemical parameters, and BMD were measured individually. Results: rs9603226 was significantly associated with vertebral fractures. Compared to allele G, the minor allele A carriers of rs9603226 had a 1.722-fold higher prevalence of vertebral fracture (p = 0.037). rs3923854 was significantly associated with the serum periostin level. G/G genotype of rs3923854 had a higher serum periostin level than C/C and C/G (67.26 ± 19.90 ng/mL vs. 54.57 ± 21.44 ng/mL and 54.34 ± 18.23 ng/mL). Furthermore, there was a negative correlation between the serum level of periostin and BMD at trochanter and total hip. Conclusion: Our study suggested that genetic variation of POSTN could be a predicting factor for the risk of vertebral fractures. The serum level of periostin could be a potential biochemical parameter for osteoporosis in Chinese postmenopausal women.

Longitudinal Changes in Serum Markers of Bone Metabolism and Bone Material Strength in Premenopausal Women with Distal Radial Fracture

BACKGROUND

Markers of bone metabolism (MBM) play an important role in fracture evaluation, and changes have been associated with increased fracture risk. The purpose of the present study was to describe changes in MBM in premenopausal women with distal radial fractures.

METHODS

Premenopausal women with distal radial fractures (n = 34) and without fractures (controls) (n = 39) were recruited. Serum MBM in patients with distal radial fractures were obtained at the time of the initial presentation, 6 weeks, and 3, 6, and 12 months. MBM included 25(OH) vitamin D, PTH, osteocalcin, P1NP, BSAP, CTX, sclerostin, DKK1, periostin, and TRAP5b. Areal bone mineral density (aBMD) was assessed with dual x-ray absorptiometry, and the bone material strength index (BMSi) was assessed with microindentation.

RESULTS

Most MBM reached peak levels at 6 weeks after the injury, including osteocalcin (+17.7%), sclerostin (+23.5%), and DKK1 (12.6%). Sclerostin was lower (-27.4%) and DKK1 was higher (+22.2%) at 1 year after the fracture. CTX declined below baseline levels at 6 and 12 months, whereas TRAP5b, BSAP, and periostin did not significantly change. At 12 months, sclerostin was lower (p = 0.003) and DKK1 was higher (p = 0.03) in the distal radial fracture group than in the control group. Greater fracture severity was associated with greater increases in P1NP and BSAP. aBMD and BMSi were not associated with fracture.

CONCLUSIONS

Distal radial fractures caused increases in several MBM, which typically peaked at 6 weeks after injury and gradually decreased over 6 months. Sclerostin and DKK1 remained below and above baseline at 1 year, respectively. Increasing fracture severity resulted in larger changes in MBM. aBMD and BMSi did not discriminate between patients with distal radial fractures and controls. Continued efforts to identify markers of skeletal fragility in young women are warranted to mitigate future fracture risk.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Absorbance or organization into ankylosis: a microarray analysis of haemarthrosis in a sheep model of temporomandibular joint trauma

Background

Traumatic haemarthrosis was hypothesized to be the etiology of temporomandibular (TMJ) ankylosis. Here, taking haematoma absorbance as a control, we aimed to reveal the molecular mechanisms involved in haematoma organizing into ankylosis using transcriptome microarray profiles.

Material/methods

Disk removal was performed to building haematoma absorbance (HA) in one side of TMJ, while removal of disk and articular fibrous layers was performed to induced TMJ ankylosis through haematoma organization (HO) in the contralateral side in a sheep model. Haematoma tissues harvested at days 1, 4 and 7 postoperatively were examined by histology, and analyzed by Affymetrix OviGene-1_0-ST microarrays. The DAVID were recruited to perform the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis for the different expression genes (DEGs). The DEGs were also typed into protein–protein interaction (PPI) networks to get the interaction data. Six significant genes screened from PPI analysis, were confirmed by real-time PCR.

Results

We found 268, 223 and 17 DEGs at least twofold at days 1, 4 and 7, respectively. At day 1, genes promoting collagen ossification (POSTN, BGN, LUM, SPARC), cell proliferation (TGF-β), and osteogenic differentiation of mesenchymal stem cells (BMP-2) were up-regulated in the HO side. At day 4, several genes involved in angiogenesis (KDR, FIT1, TEK) shower higher expression in the HO side. While HA was characterized by a continuous immune and inflammatory reaction.

Conclusions

Our results provide a comprehensive understanding of the role of haematoma in the onset and progress of TMJ ankylosis. The study will contribute to explaining why few injured TMJs ankylose and most do not from the molecular level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-02033-w.

Plasma periostin as a biomarker of osteoporosis in postmenopausal women with type 2 diabetes

INTRODUCTION

Periostin, as an emerging biomarker, is involved in multiple steps in bone metabolism. This study aimed to investigate the correlation between periostin levels and bone mineral density as well as bone turnover markers in postmenopausal women with type 2 diabetes (T2DM).

MATERIALS AND METHODS

This study was a cross-sectional study that included 164 postmenopausal women with T2DM as study subjects and 32 age-matched nondiabetic postmenopausal women with normal bone mineral density (BMD) as healthy control subjects. A total of 164 subjects with T2DM were then divided into three groups according to BMD: the normal BMD group (n = 29), the osteopenia group (n = 70), and the osteoporosis group (n = 65). The clinical data of all subjects along with the relevant biochemical parameter data were collected. Plasma periostin was detected using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Plasma periostin levels were significantly increased in T2DM patients with normal BMD compared with healthy controls (p < 0.05). In the diabetic group, plasma periostin levels were significantly elevated with decreased BMD, were positively correlated with osteocalcin levels (r = 0.162, p = 0.039) and were inversely associated with femoral neck BMD (r = - 0.308, p < 0.001) and total femur BMD (r = - 0.295, p < 0.001). In the case of chronic complications, periostin levels were slightly increased in individuals with complications of diabetic retinopathy, diabetic nephropathy and fracture (p > 0.05).

CONCLUSIONS

The current study demonstrated that plasma periostin levels were significantly associated with BMD in patients with T2DM, and periostin might act as a novel biochemical marker of osteoporosis in postmenopausal women with type 2 diabetes.

Expression of Musashi-1 Increases in Bone Healing

Musashi-1 (MSI1) is an RNA-binding protein that regulates progenitor cells in adult and developing organisms to maintain self-renewal capacities. The role of musashi-1 in the bone healing environment and its relation with other osteogenic factors is unknown. In the current study, we analyze the expression of MSI1 in an experimental model of rat femoral bone fractures. We also analyze the relation between MSI1 expression and the expression of two osteogenic markers: periostin (POSTN) and runt-related transcription factor 2 (RUNX2). We use histological, immunohistochemical, and qPCR techniques to evaluate bone healing and the expression of MSI1, POSTN, and RUNX2 over time (4, 7, and 14 days). We compare our findings with non-fractured controls. We find that in bone calluses, the number of cells expressing MSI1 and RUNX2 increase over time and the intensity of POSTN expression decreases over time. Within bone calluses, we find the presence of MSI1 expression in mesenchymal stromal cells, osteoblasts, and osteocytes but not in hypertrophic chondrocytes. After 14 days, the expression of MSI1, POSTN, and RUNX2 was significantly correlated. Thus, we conclude that musashi-1 potentially serves in the osteogenic differentiation of mesenchymal stromal cells and bone healing. Therefore, further studies are needed to determine the possibility of musashi-1′s role as a clinical biomarker of bone healing and therapeutic agent for bone regeneration.

Role of emerging vitamin K‑dependent proteins: Growth arrest‑specific protein 6, Gla‑rich protein and periostin (Review)

Vitamin K‑dependent proteins (VKDPs) are a group of proteins that need vitamin K to conduct carboxylation. Thus far, scholars have identified a total of 17 VKDPs in the human body. In this review, we summarize three important emerging VKDPs: Growth arrest‑specific protein 6 (Gas 6), Gla‑rich protein (GRP) and periostin in terms of their functions in physiological and pathological conditions. As examples, carboxylated Gas 6 and GRP effectively protect blood vessels from calcification, Gas 6 protects from acute kidney injury and is involved in chronic kidney disease, GRP contributes to bone homeostasis and delays the progression of osteoarthritis, and periostin is involved in all phases of fracture healing and assists myocardial regeneration in the early stages of myocardial infarction. However, periostin participates in the progression of cardiac fibrosis, idiopathic pulmonary fibrosis and airway remodeling of asthma. In addition, we discuss the relationship between vitamin K, VKDPs and cancer, and particularly the carboxylation state of VKDPs in cancer.

Knockdown of POSTN Inhibits Osteogenic Differentiation of Mesenchymal Stem Cells From Patients With Steroid-Induced Osteonecrosis

Steroid-induced osteonecrosis of femoral head (SONFH) is a common and serious complication caused by long-term and/or excessive use of glucocorticoids (GCs). The decreased activity and abnormal differentiation of bone marrow mesenchymal stem cells (BMSCs) are considered to be one of the major reasons for the onset and progression of this disease. Periostin (POSTN) is a matricellular protein which plays an important role in regulating osteoblast function and bone formation. Sclerostin (SOST) is a secreted antagonist of Wnt signaling that is mainly expressed in osteocytes to inhibit bone formation. However, the exact role of POSTN and SOST in SONFH has not been reported yet. Therefore, we detected the differential expression of POSTN and SOST in BMSCs of SONFH Group patients, and Control Group was patients with traumatic ONFH (TONFH) and developmental dysplasia of the hip (DDH). Furthermore, we used lentiviral transfection to knockdown POSTN expression in BMSCs of patients with SONFH to study the effect of POSTN knockdown on the SOST expression and osteogenic differentiation of BMSCs. The results indicated that the endogenous expression of POSTN and SOST in BMSCs of SONFH Group was upregulated, compared with Control Group. POSTN was upregulated gradually while SOST was downregulated gradually at days 0, 3, and 7 of osteogenic differentiation of BMSCs in Control Group. Contrarily, POSTN was gradually downregulated while SOST was gradually upregulated during osteogenic differentiation of BMSCs in SONFH Group. This could be due to increased expression of SOST in BMSCs, which was caused by excessive GCs. In turn, the increased expression of POSTN in BMSCs may play a role in antagonizing the continuous rising of SOST during the osteogenic differentiation of BMSCs in patients with SONFH. POSTN knockdown significantly attenuated osteo-specific gene expression, alkaline phosphatase activity, and calcium nodule formation in vitro; thus inhibiting the osteogenic differentiation of BMSCs in patients with SONFH. Besides, POSTN knockdown upregulated SOST expression, increased GSK-3β activity, and downregulated β-catenin. These findings suggest that POSTN have an essential role in regulating the expression of SOST and osteogenic differentiation of BMSCs in patients with SONFH, and POSTN knockdown suppresses osteogenic differentiation by upregulating SOST and partially inactivating Wnt/β-catenin signaling pathway. Therefore, targeting POSTN and SOST may serve as a promising therapeutic target for the prevention and treatment of SONFH.

Circulating Myostatin Levels Decrease Transiently after Implantation of a Hip Hemi-Arthroplasty

INTRODUCTION

Muscle and bone metabolism are both important for the healing of fractures and the regeneration of injured muscle tissue. The aim of this investigation was to evaluate myostatin and other regulating factors in patients with hip fractures who underwent hemi-arthroplasty.

METHODS

Serum levels of myostatin (MSTN), follistatin (FSTN), dickkopf-1 (Dkk1), and periostin (PSTN) as well as markers of bone turnover were evaluated in patients with hip fractures before surgery and twice in the 2 weeks after surgery. These parameters were also evaluated in age- and gender-matched subjects without major musculoskeletal injury.

RESULTS

MSTN was transiently reduced; its opponent FSTN was transiently increased. Dkk1, the negative regulator of bone mass, and PSTN, a marker of subperiosteal bone formation, increased after surgery. With regard to markers of bone turnover, resorption was elevated during the entire period of observation whereas the early bone formation marker N-terminal propeptide of type I collagen was elevated 12 days after surgery.

CONCLUSIONS

Unexpectedly, MSTN, a negative regulator of muscle growth, was reduced after surgery compared with before surgery. As musculoskeletal markers are altered during bone healing, they do not reflect general bone metabolism after fracture or joint arthroplasty. This is important because many elderly patients receive treatment for osteoporosis.

Potential Biomarkers to Improve the Prediction of Osteoporotic Fractures

Osteoporotic fracture (OF) is associated with high disability and morbidity rates. The burden of OF may be reduced by early identification of subjects who are vulnerable to fracture. Although the current fracture risk assessment model includes clinical risk factors (CRFs) and bone mineral density (BMD), its overall ability to identify individuals at high risk for fracture remains suboptimal. Efforts have therefore been made to identify potential biomarkers that can predict the risk of OF, independent of or combined with CRFs and BMD. This review highlights the emerging biomarkers of bone metabolism, including sphongosine-1-phosphate, leucine-rich repeat-containing 17, macrophage migration inhibitory factor, sclerostin, receptor activator of nuclear factor-κB ligand, and periostin, and the importance of biomarker risk score, generated by combining these markers, in enhancing the accuracy of fracture prediction.

Periostin: An emerging biomarker for allergic diseases

Periostin is a matricellular protein as well as an extracellular matrix (ECM) protein belonging to the fasciclin family. Periostin plays important roles as a matricellular protein in the setting of allergic diseases by binding to several integrins on various cells. Since periostin is induced mainly by IL-4 and IL-13, signature type 2 cytokines, and it is highly expressed in the subepithelial regions of many chronic allergic diseases, periostin has emerged as a novel biomarker reflecting type 2 inflammation in allergic diseases. It has, moreover, been revealed that periostin has characteristics different from other type 2 biomarkers such as eosinophil count and fractional exhaled nitric oxide (FeNO), reflecting fibrosis or tissue remodeling. From this, we may say that serum periostin is a "chronic" type 2 biomarker, whereas FeNO and possibly the eosinophil count are "acute" type 2 biomarkers. In contrast, it is still uncertain how we can apply periostin measurement to the use of biologics for allergic diseases. By examining the roles of periostin in allergy and the utility and potential of periostin in developing diagnostics against allergic diseases, it is hoped that in the near future, we can develop a new strategy to treat allergic patients.

Periostin and sclerostin levels in individuals with spinal cord injury and their relationship with bone mass, bone turnover, fracture and osteoporosis status

BACKGROUND

Spinal cord injury (SCI) induces an acute alteration in bone metabolism. Although the aetiology of the bone disturbances is not precisely known, immobilisation reduces mechanical loading and the morphology of osteocytes, which are the primary mechanosensors. Periostin and sclerostin are secreted mostly by osteocytes and are involved in bone's mechanical response.

OBJECTIVE

The present study was conducted to determine whether individuals with SCI present alterations in serum periostin and sclerostin and to assess their relationships with bone mineral density, bone turnover markers, fracture status, time since injury, densitometric osteoporosis and paraplegic vs. tetraplegic status.

SUBJECTS AND METHODS

One hundred and thirty-one individuals with SCI (96 males and 35 females; 42.8 ± 13.7 yr old) with a mean 14.2 ± 12.1 years since the time of injury were evaluated and compared with 40 able-bodied controls in a cross-sectional study. Periostin and sclerostin were assayed by ELISA from Biomedica® (Vienna, Austria), and bone turnover markers and areal bone mineral density (aBMD) were concomitantly analysed.

RESULTS

Compared with controls, individuals with SCI presented higher periostin (p < 0.01), lower sclerostin (p < 0.001), similar markers of bone turnover levels and lower aBMD at the hip. Compared with chronic individuals, bone turnover markers, sclerostin excepted, values were higher as well as aBMD at hip in individuals with acute SCI. Moreover, the aBMD differences were more marked in tetraplegic than paraplegic individuals. Bone mineral density, fracture status, densitometric osteoporosis and paraplegia vs. tetraplegia did not seem to substantially influence the values of biological markers, sclerostin excepted.

CONCLUSION

This study showed for the first time that individuals with SCI presented higher periostin levels than healthy controls only during the acute phase. Conversely, sclerostin levels are lower whatever the post-injury time. Fractures and densitometric osteoporosis were not associated with differences in these two biological markers, whereas paraplegia vs. tetraplegia and fragility fracture status seemed to influence sclerostin levels only.

The attempt of spontaneous repair of rotator cuff tear: The role of periostin

The development of a periostin-rich microenvironment in areas associated with insult, orchestrating pathways of repair and rebuilding, is documented. Literature lacks information regarding the presence of periostin in the context of rotator cuff tear (RCT). 55 consecutive patients with RCT were enrolled. Immunohistochemical periostin detection was performed on tissue samples excised from tear margins. Our study documented the presence of periostin in the margins of RCT. It is plausible that, when a tear occurs, multiple stimuli, both mechanical and inflammatory, lead to the development of a periostin-rich microenvironment as an attempt to tendon healing.

Silencing long non-coding RNA MEG3 accelerates tibia fraction healing by regulating the Wnt/β-catenin signalling pathway

As fracture healing is related to gene expression, fracture healing is prospected to be implicated in long non‐coding RNAs (lncRNAs). This study focuses on the effects of epigenetic silencing of long non‐coding RNA maternally expressed gene 3 (lncRNA MEG3) on fracture healing by regulating the Wnt/β‐catenin signalling pathway. Genes expressed in fracture were screened using bioinformatics and the subcellular location of MEG3 was determined using FISH. Next, we successfully established tibia fracture (TF) models of C57BL/6J and Col2a1‐ICAT mice and the effect of silencing lncRNA MEG3 on fracture healing was detected after TF mice were treated with phosphate buffer saline (PBS), MEG3 siRNA and scramble siRNA. X‐ray imaging, Safranin‐O/fast green and haematoxylin‐eosin (HE) staining and histomorphometrical and biomechanical analysis were adopted to observe and to detect the fracture healing conditions. Additionally, the positive expression of collagen II and osteocalcin was examined using immunohistochemistry. At last, in the in vitro experiment, the relationship of MEG3 and the Wnt/β‐catenin signalling pathway in fraction healing was investigated. MEG3 was located in the cell nucleus. In addition, it was found that MEG3 and the Wnt/β‐catenin signalling pathway were associated with fraction healing. Moreover, silencing MEG3 was proved to elevate callus area and maximum bending load and to furthermore enhance the recanalization of bone marrow cavity. Finally, MEG3 knockdown elevated levels of Col10a1, Runx2, Osterix, Osteocalcin, Wnt10b and β‐catenin/β‐catenin whereas it reduced p‐GSK‐3β/GSK‐3β levels. Taken together, our data supported that epigenetic silencing of lncRNA MEG3 could promote the tibia fracture healing by activating the Wnt/β‐catenin signalling pathway.

Fibronectin synthesis, but not α-smooth muscle expression, is regulated by periostin in gingival healing through FAK/JNK signaling

During skin healing, periostin facilitates myofibroblast differentiation through a β1 integrin/FAK dependent mechanism and continued expression is associated with scarring. In contrast to skin, gingival tissue does not typically scar upon injury, but the role of periostin in gingival healing has never been investigated. Using a rat gingivectomy model, we show that the gingival architecture is re-established within 14 days of wounding. Periostin mRNA levels peak at day 7 post-wounding, with persistence of periostin protein in the connective tissue through day 14. Collagen type I and lysyl oxidase mRNA levels peak at day 7 post wounding, which corresponded with the peak of fibroblast proliferation. Although α-smooth muscle actin mRNA levels increased 200-fold in the tissue, no myofibroblasts were detected in the regenerating tissue. In vitro, human gingival fibroblast adhesion on periostin, but not collagen, was inhibited by blocking β1 integrins. Fibroblasts cultured on periostin exhibited similar rates of proliferation and myofibroblast differentiation to cells cultured on collagen only. However, human gingival fibroblasts cultured in the presence of periostin exhibited significantly increased fibronectin and collagen mRNA levels. Increases in fibronectin production were attenuated by pharmacological inhibition of FAK and JNK signaling in human gingival fibroblasts. In vivo, mRNA levels for fibronectin peaked at day 3 and 7 post wounding, with protein immunoreactivity highest at day 7, suggesting periostin is a modulator of fibronectin production during gingival healing.

Measuring Calumenin Impact on ER-Calcium Depletion Using Transient Calumenin Overexpression and Silencing

Calumenin is a secretory pathway protein regulating different endoplasmic reticulum (ER) proteins such as the sarco-endoplasmic reticulum calcium ATPase (SERCA) pumps. Combined with its diverse cellular distribution, its calcium-binding ability, and its interaction with proteins involved in calcium signaling, it is easy to speculate on future description of important roles of calumenin in calcium homeostasis in many cell types, as it was initially observed in muscle cells. In this chapter, we describe basic techniques to modulate calumenin expression and detect its impact on ER calcium content using classic transfection and Western blot techniques, as well as ER calcium measurement using microplate reader.

Functions of Periostin in Dental Tissues and Its Role in Periodontal Tissue Regeneration

The goal of periodontal regeneration therapy is to reliably restore teeth's supporting periodontal tissue, while aiding the formation of new connective tissue attached to the periodontal ligament (PDL) fibers and new alveolar bone. Periostin is a matricellular protein, primarily expressed in the periosteum and PDL of adult mice. Its biological functions have been extensively studied in the fields of cardiovascular physiology and oncology. Despite being initially identified in bone and dental tissue, the function of Periostin in PDL and the pathophysiology associated with alveolar bone are scarcely studied. Recently, several studies have suggested that Periostin may be an important regulator of periodontal tissue formation. By promoting collagen fibrillogenesis and the migration of fibroblasts and osteoblasts, Periostin might play a key role in the regeneration of PDL and alveolar bone after periodontal surgery. In this chapter, the implications of Periostin in periodontal tissue biology and its potential use in periodontal tissue regeneration are reviewed.

Practical Application of Periostin as a Biomarker for Pathological Conditions

In physiological condition, periostin is expressed in limited tissues such as periodontal ligament, periosteum, and heart valves. Periostin protein is mainly localized on extracellular collagen bundles and in matricellular space. On the other hand, in pathological condition, expression of periostin is induced in disordered tissues of human patients. In tumor development and progression, periostin is elevated mainly in its microenvironment and stromal tissue rich in extracellular matrix. Tumor stromal fibroblasts highly express periostin and organize the tumor-surrounding extracellular matrix architecture. In fibrosis in lung, liver, and kidney, proliferating activated fibroblasts express periostin and replace normal functional tissues with dense connective tissues. In inflammation and allergy, inflammatory cytokines such as IL-4 and IL-13 induce expression of periostin that plays important roles in pathogenesis of these diseases. The elevated levels of periostin in human patients could be detected not only in tissue biopsy samples but also in peripheral bloods using specific antibodies against periostin, because periostin secreted from the disordered tissues is transported into blood vessels and circulates in the cardiovascular system. In this chapter, I introduce the elevated expression of periostin in pathological conditions, and discuss how periostin could be utilized as a biomarker in disease diagnosis.

Periostin in Bone Regeneration

Bone regeneration is an efficient regenerative process depending on the recruitment and activation of skeletal stem cells that allow cartilage and bone formation leading to fracture consolidation. Periosteum, the tissue located at the outer surface of bone is now recognized as an essential player in the bone repair process and contains skeletal stem cells with high regenerative potential. The matrix composition of the periosteum defines its roles in bone growth, in cortical bone modeling and remodeling in response to mechanical strain, and in bone repair. Periostin is a key extracellular matrix component of the periosteum involved in periosteum functions. In this chapter, we summarize the current knowledge on the bone regeneration process, the role of the periosteum and skeletal stem cells, and Periostin functions in this context. The matricellular protein Periostin has several roles through all stages of bone repair: in the early days of repair during the initial activation of stem cells within periosteum, in the active phase of cartilage and bone deposition in the facture callus, and in the final phase of bone bridging and reconstitution of the stem cell pool within periosteum.

[Progress relationship between periostin and periodontitis]

Periostin, a kind of matricellular protein highly expressed in periodontal ligament and periosteum, is an important regulator of the integrity of periodontal ligament and periodontitis processes. Periostin has been shown to play a positive role in the recovery of periodontitis. This paper reviews relevant literature about the role of periostin in periodontal tissue and periodontitis.

Longitudinal evaluation of serum periostin levels in patients after large-artery atherosclerotic stroke: A prospective observational study

Increasing evidence supports the involvement of periostin in the pathophysiological processes of stroke and atherosclerosis. The aim of this study was to assess circulating periostin levels at different times after large-artery atherosclerotic (LAA) stroke and their association with stroke. Serum periostin levels were measured using enzyme-linked immunosorbent assay on day 1 in 162 patients with LAA stroke and in 108 age- and sex-matched controls, on day 6 after stroke in 134 patients, and during the 4th week after stroke in 46 of the 162 patients. Stroke severity was determined using the National Institutes of Health Stroke Scale (NIHSS), and the stroke volume was measured. Outcome at 3 months was measured using the modified Rankin Scale (mRS). Our results indicated that periostin levels increased significantly on day 6 after stroke, and this increasing trend persisted for at least 4 weeks after the event. In addition, the increase in periostin levels was positively correlated with the NIHSS scores and stroke volume, but not with the mRS scores after adjusting for the NIHSS scores. In conclusion, these findings suggest that the increase in serum periostin levels observed after stroke may be associated with the stroke severity in patients with LAA stroke.

Serum periostin levels following small bone fractures, long bone fractures and joint replacements: an observational study

BACKGROUND

In asthma, serum periostin may potentially be used as a biomarker in the management of patients with Type-2 eosinophilic airway inflammation. However, serum periostin may be influenced by factors other than Type 2 inflammation, potentially confounding its interpretation. We aimed to measure change in periostin following bone injury.

METHODS

102 adults without asthma were recruited into three groups: joint replacement surgery, long bone fracture, short bone fracture. Participants underwent seven measurements of serum periostin over 26 weeks after bone injury, and prior to surgery in the joint replacement group. Differences in periostin were measured using a ratio of geometric mean (RGM), with comparison made with pre-surgery (joint replacement) or 26 week (long and short fracture) reference measurements.

RESULTS

In the joint replacement group, periostin fell within 48 h (RGM 0.80, 95% CI 0.75-0.86), then increased to a maximum at 8 weeks (RGM 1.89, 1.77-2.02) and by 26 weeks remained above the reference measurement (RGM 1.27, 1.19-1.36). In the long bone fracture group, periostin was reduced at 48 h (RGM 0.76, 0.71-0.83) and then progressively increased to a maximum at 8 weeks (RGM 1.15, 1.06-1.23) compared with the reference measurement. In the short bone fracture group, periostin was reduced at 48 h (RGM 0.9, 0.85-0.95) but was not different from after week 1 compared with the reference measurement.

CONCLUSIONS

Serum periostin levels are influenced by bone injury. The timing and extent of bone injury needs consideration if periostin is used as a biomarker in the management of eosinophilic asthma.Trial registration This trial was prospectively registered with the Australia New Zealand Trials Registry on Feb 7 2014, (ACTRN12614000151639: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=363881).

Up-regulation of serum periostin and squamous cell carcinoma antigen levels in infants with acute bronchitis due to respiratory syncytial virus

BACKGROUND

Periostin and squamous cell carcinoma antigen (SCCA) are involved in the pathogenesis of asthma. Acute bronchitis due to respiratory syncytial virus (RSV) infection during infancy exhibits an asthma-like pathogenesis, suggesting that it may be associated with the subsequent development of asthma. However, the mechanism by which RSV infection leads to development of asthma has not yet been fully elucidated.

METHODS

Infants younger than 36 months were enrolled and classified into three groups. Group I included patients hospitalized with RSV-induced bronchitis. These patients were further stratified into two sub-groups according to whether the criteria for the modified Asthma Predictive Index (mAPI) had been met: Group I consisted of mAPI (+) and mAPI (-) patients; Group II included patients with food allergy as a positive control group; and Group III included children with no allergy as a negative control group. Serum periostin and SCCA levels were measured in the groups. This study was registered as a clinical trial (UMIN000012339).

RESULTS

We enrolled 14 subjects in Group I mAPI (+), 22 in Group I mAPI (-), 18 in Group II, and 18 in Group III. In Group I, the serum periostin and SCCA levels were significantly higher during the acute phase compared with the recovery phase. However, no significant differences were found between Group I mAPI (+) and mAPI (-).

CONCLUSIONS

The serum periostin and SCCA levels increased during acute RSV bronchitis. Both periostin and SCCA may play a role in the pathogenesis of acute bronchitis due to RSV.

Evaluation of gingival crevicular fluid and peri-implant sulcus fluid levels of periostin: A preliminary report

BACKGROUND

Periostin is a protein present in alveolar bone and periodontal ligament whose function is related to response to external forces. The aims of this study are to detect levels of periostin in peri-implant sulcular fluid (PISF) and gingival crevicular fluid (GCF) and to evaluate the relationship between periostin, pyridinoline cross-linked carboxyterminal telopeptide of Type I collagen (ICTP), and C-terminal cross-linked telopeptide of Type I collagen (CTX) levels and clinical inflammatory symptoms and duration of functional loading.

METHODS

The study population comprised nine women and four men with mean age 43.23 ± 12.48. Twenty "bone-level designed" dental implants (DIs) placed in molar or premolar sites, without any signs of peri-implant bone loss and with a restoration in function for at least 12 months, were included in the study with 20 contralateral natural teeth (NT) as controls. Clinical parameters and restoration dates of the implants were recorded. PISF, GCF, ICTP, CTX, and periostin levels were evaluated using enzyme-linked immunosorbent assay.

RESULTS

ICTP, CTX, and periostin levels were similar between DI and NT groups. There were no statistically significant differences between PISF and GCF values. When implants were grouped as healthy (gingival index [GI] = 0) and inflamed (GI ≥0), ICTP levels and PISF volume were lower in healthy implants compared with the inflamed group. Both periostin and CTX levels were negatively correlated with functioning time, suggesting less bone remodeling around DIs at later stages of functioning.

CONCLUSION

Findings of this study suggest collagen breakdown products may be used as markers to evaluate peri-implant metabolism.

Functions of Periostin in dental tissues and its role in periodontal tissues' regeneration

The goal of periodontal regenerative therapy is to predictably restore the tooth's supporting periodontal tissues and form a new connective tissue attachment of periodontal ligament (PDL) fibers and new alveolar bone. Periostin is a matricellular protein so named for its expression primarily in the periosteum and PDL of adult mice. Its biological functions have been widely studied in areas such as cardiovascular physiology and oncology. Despite being initially identified in the dental tissues and bone, investigations of Periostin functions in PDL and alveolar-bone-related physiopathology are less abundant. Recently, several studies have suggested that Periostin may be an important regulator of periodontal tissue formation. By promoting collagen fibrillogenesis and the migration of fibroblasts and osteoblasts, Periostin might play a pivotal part in regeneration of the PDL and alveolar bone following periodontal surgery. The aim of this article is to provide an extensive review of the implications of Periostin in periodontal tissue biology and its potential use in periodontal tissue regeneration.

Evaluation of periostin and factors associated with new bone formation in ankylosing spondylitis: Periostin may be associated with the Wnt pathway

OBJECTIVE

Periostin has been shown to be involved in bone anabolism through the regulation of Wnt-β-catenin signaling. It may be one of the pathogenic mechanisms in syndesmophyte formation in ankylosing spondylitis (AS). The aim of this study was to evaluate serum periostin levels in patients with AS and to assess relationships among biomarkers of bone formation and periostin in disease outcomes, particularly radiographic changes.

METHODS

Ninety-seven consecutive AS patients (78% male) and 48 healthy controls (75% male) were included in the study. Serum periostin, dickkopf-1 (DKK-1), sclerostin and vascular endothelial growth factor (VEGF) levels were measured using commercially available enzyme-linked immunosorbent assay kits. Disease-related characteristics of patients were assessed using Ankylosing spondylitis disease activity score - C-reactive protein (ASDAS-CRP), Bath AS Disease Activity Index, Bath AS Functional Index and Bath AS metrology index. Radiographs were scored using the modified New York criteria and modified Stokes AS spinal score (mSASSS).

RESULTS

Compared with control subjects, patients with AS had significantly lower serum levels of periostin (P < 0.001) and sclerostin (P < 0.001), but higher serum levels of VEGF (P < 0.001) and high-sensitivity CRP (P < 0.001). Serum periostin (P = 0.005) and sclerostin levels (P = 0.016) were significantly lower in patients with very high disease activity according to ASDAS-CRP. Current age (P = 0.009), age at symptom onset (P = 0.021) and hip joint involvement (P = 0.012) were independently associated with the development of syndesmophyte, in contrast to biomarkers of bone metabolism that we evaluated.

CONCLUSION

Our results suggest that periostin is down-regulated in AS patients with highly active disease and may contribute to disease pathogenesis through an interaction with Wnt signaling.

Circulating periostin levels increase in association with bone density loss and healing progression during the early phase of hip fracture in Chinese older women

The present study shows that hip fracture women had higher serum periostin (sPostn) levels. The elevation of sPostn is associated with bone density loss, yet fracture itself may even increase sPostn levels during early healing phase.

INTRODUCTION

The study aims to quantify the associations of sPostn levels with bone density loss and the possible effect on the fracture healing.

METHODS

This study enrolled 261 older women with osteoporotic hip fracture and 106 age-matched women without fracture serving as controls. Clinical features, bone mineral density (BMD), and bone turnover markers including sPostn level were measured after fracture within 2 days. Follow-up sPostn levels during 1 year after 2 days were available for 128 patients.

RESULTS

Initial levels of sPostn after fracture were significantly higher in patients than controls. sPostn was correlated with BMD of femoral neck (r = -0.529, P < 0.001), β-isomerized C-terminal crosslinking of type I collagen (β-CTX) (r = 0.403, P = 0.008), and N-terminal procollagen of type I collagen (PINP) (r = 0.236, P = 0.042) in the entire cohort. After multivariate analysis, sPostn remained as an independent risk factor for femoral neck BMD, which explained 19.1% of the variance in BMD. sPostn sampled within 7 days after fracture were acutely increasing from day 2 and then decreased and maintained at slightly high levels at 360 days. The percentage changes of sPostn positively correlated with the variation in β-CTX (r = 0.396, P = 0.002) and PINP (r = 0.180, P = 0.033) at day 7 after fracture.

CONCLUSIONS

High sPostn levels were an independent predictor of femoral neck BMD in older women presenting with an acute hip fracture. Increased sPostn levels during early healing phase may imply that Postn play a role in bone repair.

Characterization of a sandwich ELISA for the quantification of all human periostin isoforms

BACKGROUND

Periostin (osteoblast-specific factor OSF-2) is a secreted protein occurring in seven known isoforms, and it is involved in a variety of biological processes in osteology, tissue repair, oncology, cardiovascular and respiratory systems or allergic manifestations. To analyze functional aspects of periostin, or the ability of periostin as potential biomarker in physiological and pathological conditions, there is the need for a precise, well-characterized assay that detects periostin in peripheral blood.

METHODS

In this study the development of a sandwich ELISA using monoclonal and affinity-purified polyclonal anti-human periostin antibodies was described. Antibodies were characterized by mapping of linear epitopes with microarray technology, and by analyzing cross-reactive binding to human periostin isoforms with western blot. The assay was validated according to ICH/EMEA guidelines.

RESULTS

The monoclonal coating antibody binds to a linear epitope conserved between the isoforms. The polyclonal detection antibody recognizes multiple conserved linear epitopes. Therefore, the periostin ELISA detects all known human periostin isoforms. The assay is optimized for human serum and plasma and covers a calibration range between 125 and 4000 pmol/L for isoform 1. Assay characteristics, such as precision (intra-assay: ≤3%, inter-assay: ≤6%), spike-recovery (83%-106%), dilution linearity (95%-126%), as well as sample stability meet the standards of acceptance. Periostin levels of apparently healthy individuals are 864±269 pmol/L (serum) and 817±170 pmol/L (plasma) respectively.

CONCLUSION

This ELISA is a reliable and accurate tool for determination of all currently known periostin isoforms in human healthy and diseased samples.

Poly (glycerol sebacate) elastomer supports bone regeneration by its mechanical properties being closer to osteoid tissue rather than to mature bone

Mechanical load influences bone structure and mass. Arguing the importance of load-transduction, we investigated the mechanisms inducing bone formation using an elastomeric substrate. We characterized Poly (glycerol sebacate) (PGS) in vitro for its mechanical properties, compatibility with osteoprogenitor cells regarding adhesion, proliferation, differentiation under compression versus static cultures and in vivo for the regeneration of a rabbit ulna critical size defect. The load-transducing properties of PGS were compared in vitro to a stiffer poly lactic-co-glycolic-acid (PLA/PGA) scaffold of similar porosity and interconnectivity. Under cyclic compression for 7days, we report focal adhesion kinase overexpression on the less stiff PGS and upregulation of the transcription factor Runx2 and late osteogenic markers osteocalcin and bone sialoprotein (1.7, 4.0 and 10.0 folds increase respectively). Upon implanting PGS in the rabbit ulna defect, histology and micro-computed tomography analysis showed complete gap bridging with new bone by the PGS elastomer by 8weeks while minimal bone formation was seen in empty controls. Immunohistochemical analysis demonstrated the new bone to be primarily regenerated by recruited osteoprogenitors cells expressing periostin protein during early phase of maturation similar to physiological endochondral bone development. This study confirms PGS to be osteoconductive contributing to bone regeneration by recruiting host progenitor/stem cell populations and as a load-transducing substrate, transmits mechanical signals to the populated cells promoting differentiation and matrix maturation toward proper bone remodeling. We hence conclude that the material properties of PGS being closer to osteoid tissue rather than to mineralized bone, allows bone maturation on a substrate mechanically closer to where osteoprogenitor/stem cells differentiate to develop mature load-bearing bone.

SIGNIFICANCE OF SIGNIFICANCE

The development of effective therapies for bone and craniofacial regeneration is a foremost clinical priority in the mineralized tissue engineering field. Currently at risk are patients seeking treatment for craniofacial diseases, traumas and disorders including birth defects such as cleft lip and palate, (1 in 525 to 714 live births), craniosynostosis (300-500 per 1,000,000 live births), injuries to the head and face (20 million ER visits per year), and devastating head and neck cancers (8000 deaths and over 30,000 new cases per year). In addition, approximately 6.2 million fractures occur annually in the United States, of which 5-10% fail to heal properly, due to delayed or non-union [1], and nearly half of adults aged 45-65 have moderate to advanced periodontitis with associated alveolar bone loss, which, if not reversed, will lead to the loss of approximately 6.5 teeth/individual [2]. The strategies currently available for bone loss treatment largely suffer from limitations in efficacy or feasibility, necessitating further development and material innovation. Contemporary materials systems themselves are indeed limited in their ability to facilitate mechanical stimuli and provide an appropriate microenvironment for the cells they are designed to support. We propose a strategy which aims to leverage biocompatibility, biodegradability and material elasticity in the creation of a cellular niche. Within this niche, cells are mechanically stimulated to produce their own extracellular matrix. The hypothesis that mechanical stimuli will enhance bone regeneration is supported by a wealth of literature showing the effect of mechanical stimuli on bone cell differentiation and matrix formation. Using mechanical stimuli, to our knowledge, has not been explored in vivo in bone tissue engineering applications. We thus propose to use an elastomeric platform, based on poly(glycerol sebacate (PGS), to mimic the natural biochemical environment of bone while enabling the transmission of mechanical forces. In this study we report the material's load-transducing ability as well as falling mechanically closer to bone marrow and osteoid tissue rather than to mature bone, allowed osteogenesis and bone maturation. Defying the notion of selecting bone regeneration scaffolds based on their relative mechanical comparability to mature bone, we consider our results in part novel for the new application of this elastomer and in another fostering for reassessment of the current selection criteria for bone scaffolds.

Influence of IL13 on Periostin Secretion by Synoviocytes in Osteoarthritis

BACKGROUND

Our previous research provided evidence of periostin increase in parallel with interleukin-13 (IL13) increase in the synovial fluid of patients with osteoarthritis (OA). The reaction cascade from IL13 to periostin, however, remains unidentified. We, therefore, tested the hypothesis that periostin secretion is affected downstream of IL13.

MATERIALS AND METHODS

OA synoviocytes were cultured under different concentrations of IL13. Periostin content in culture supernatants and the level of signal transducer and activator of transcription 6 (STAT6) in the cultured cells were measured using enzyme-linked immunosorbent assay (ELISA). Moreover, the influence of dexamethasone and leflunomide on periostin production in relation to the effect of IL13 on the cells was also examined.

RESULTS

Periostin content in culture supernatants and the level of STAT6 in cultured cells were significantly increased by IL13. The increase of periostin was significantly inhibited by dexamethasone and leflunomide.

CONCLUSION

Periostin may be up-regulated in OA synoviocytes via STAT6 downstream of IL13.

Changes in Transcriptome-Wide Gene Expression of Anterior Cruciate Ligament Tears Based on Time From Injury

BACKGROUND

Anterior cruciate ligament (ACL) tears are a common injury. The healing potential of the injured ACL is poorly understood and is considered limited. Therefore, most ACL tears that are treated surgically undergo reconstruction rather than repair. However, there has been renewed interest recently in repairing ACL tears despite unanswered questions regarding the healing capacity of the ACL.

HYPOTHESIS

Gene expression in the injured ACL varies with time from injury.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Transcriptome-wide expression profiles of 24 human ACL remnants recovered at the time of surgical reconstruction were analyzed using the Agilent human 8x60K microarray platform. Gene ontology was performed on differentially expressed transcripts based on time from injury (acute, <3 months; intermediate, 3-12 months; chronic, >12 months). A subset of transcripts with large fold changes in expression between any 2 categories was validated via microfluidic digital polymerase chain reaction.

RESULTS

Numerous transcripts representing important biological processes were differentially expressed by time from injury. The most significant changes were noted between the acute and chronic groups. Expression of several extracellular matrix genes- namely, POSTN, COL5A1, COL1A1, and COL12A1-was lower in the chronic tears compared with acute and intermediate tears. In acute tears, processes representing angiogenesis and stem cell differentiation were affected. In intermediate tears, processes representing stem cell proliferation concomitant with cellular component organization/cellular localization were altered. In ACL tears more than 12 months out from injury, processes denoting myosin filament organization, cellular component organization/cell localization, and extracellular matrix organization were affected.

CONCLUSION

These findings are consistent with initial repair activity in the injured ACL, which declines with time from injury. Individual genes identified in this study, such as periostin, deserve further investigation into their role in tissue repair.

CLINICAL RELEVANCE

The decreased healing capacity of ACL tears over time is relevant to the development of effective techniques for repairing ACL tears and may have some significance for ACL reconstruction techniques as well. The potential for healing appears to be greatest in acute ACL tears, suggesting this window should be the focus of research for ACL repair.

Regression of an ossifying fibroma of the tibia after a fracture involving the lesion. Possible role of the periostina

Ossifying fibroma (OF) of the long bones is a benign fibro-osseous lesion typically seen in the first decade of life. OF usually progresses until the age of 10 years, but is occasionally found to regress spontaneously after puberty. The pathogenesis of OF is unknown; however, it has been suggested that the basic defect is in the periosteum. We present the radiological course of an OF of the tibia in a young patient, showing a rapid almost complete regression of the lesion after a tibial fracture at the lesion site. We postulate that the fracture-induced activation of the periosteum in a growing skeleton was fundamental to the regression of the lesion.

Role of Periostin in Adhesion and Migration of Bone Remodeling Cells

Periostin is an extracellular matrix protein highly expressed in collagen-rich tissues subjected to continuous mechanical stress. Functionally, periostin is involved in tissue remodeling and its altered function is associated to numerous pathological processes. In orthodontics, periostin plays key roles in the maintenance of dental tissues and it is mainly expressed in those areas where tension or pressing forces are taking place. In this regard, high expression of periostin is essential to promote migration and proliferation of periodontal ligament fibroblasts. However little is known about the participation of periostin in migration and adhesion processes of bone remodeling cells. In this work we employ the mouse pre-osteoblastic MC3T3-E1 and the macrophage-like RAW 264.7 cell lines to overexpress periostin and perform different cell-based assays to study changes in cell behavior. Our data indicate that periostin overexpression not only increases adhesion capacity of MC3T3-E1 cells to different matrix proteins but also hampers their migratory capacity. Changes on RNA expression profile of MC3T3-E1 cells upon periostin overexpression have been also analyzed, highlighting the alteration of genes implicated in processes such as cell migration, adhesion or bone metabolism but not in bone differentiation. Overall, our work provides new evidence on the impact of periostin in osteoblasts physiology.

Plasma periostin associates significantly with non-vertebral but not vertebral fractures in postmenopausal women: Clinical evidence for the different effects of periostin depending on the skeletal site

BACKGROUND

Periostin is preferentially expressed by the periosteum, which mainly covers the long bones. Therefore, the role of periostin in osteoporotic fracture (OF) may differ depending on bone type. We performed a case-control study to investigate whether periostin can serve as a predictor of OF risk, particularly after dividing OFs into non-vertebral and vertebral fractures.

METHODS

Among 532 consecutive postmenopausal women not taking any drug or without any disease that could affect bone metabolism, 133 cases with OF (i.e., non-vertebral and/or vertebral fractures) and 133 age- and body mass index-matched controls were enrolled. Non-vertebral (i.e., forearm, humerus, hip, and pelvis; n=81) and morphological vertebral (n=62) fractures were identified by an interviewer-assisted questionnaire and lateral thoracolumbar radiographs, respectively. Bone mineral density (BMD) and plasma periostin levels were also measured.

RESULTS

Plasma periostin was markedly higher in subjects with non-vertebral fracture than their controls even after adjustment for BMD and potential confounders (P=0.006). Each standard deviation increment of plasma periostin was associated with a multivariable-adjusted odds ratio of 1.59 for non-vertebral fracture. The odds for non-vertebral fracture were 2.48-fold higher in subjects in the highest periostin tertile compared with those in the lowest periostin tertile (95% confidence interval=1.10-5.61). However, associations between plasma periostin and vertebral fracture were not observed, regardless of the adjustment model used. Consistently, plasma periostin levels were inversely associated with proximal femur BMD (P=0.007 to 0.030) but not lumbar spine BMD. In subgroup analyses, plasma periostin had no correlation with the levels of classical bone turnover markers.

CONCLUSIONS

Plasma periostin may be a potential biomarker of the risk of OF, especially in non-spinal skeletal sites, such as the limbs, rather than spine.

Critical roles of periostin in the process of orthodontic tooth movement

AIM

The process of orthodontic tooth movement (OTM) involves multiple mechanisms of action including bone and extracellular matrix remodelling, although the role of periodontal ligament (PDL) in this process is largely unknown. Periostin, which is highly expressed in the PDL, is known to be responsible for mechanical stimulation in maintaining the integrity of periodontal tissues. We hypothesize that this protein plays an important role during OTM.

MATERIAL AND METHODS

By using spring in 4-week-old wild-type (WT) and periostin null mice, the rate of tooth movement and mineralization were evaluated. For the evaluation, double labelling, expression of sclerostin (SOST), number of TRAP-positive cells, and quality of collagen fibrils by Sirius red were analysed and compared between these two groups.

RESULTS

Our findings showed that the distance of the tooth movement and mineral deposition rates were significantly reduced in periostin null mice (P < 0.05), with a lack of expression changes in SOST as observed in the WT group. The arrangement, digestion, and integrity of collagen fibrils were impaired in periostin null mice. The number of osteoclasts reflected by expressions of TRAP (tartrate-resistant acid phosphatase) in the null mice was also significantly lower than the WT control (P < 0.05).

CONCLUSION

Periostin plays a stimulatory role in both SOST and TRAP responses to OTM in the compassion site, although it is not clear if this role is direct or indirect during orthodontic loading.

Expression and pathological effects of periostin in human osteoarthritis cartilage

BACKGROUND

Osteoarthritis (OA) is one of the most common joint diseases in elderly people, however, the underlying mechanism of OA pathogenesis is not completely clear. Periostin, the extracellular protein, has been shown by cDNA array analysis to be highly expressed in OA, but its function is not fully understood. The purpose of this study was to examine the expression and function of periostin in human OA.

METHODS

Human cartilage and synovia samples were used for the analysis of periostin expression and function. The human cartilage samples were obtained from the knees of patients undergoing total knee arthroplasty as OA samples and from the femoral bone head of patients with femoral neck fracture as control samples. Quantitative RT-PCR, ELISA, and immunohistochemistry were used for analysis of periostin expression in cartilage and synovia. Human primary chondrocytes isolated from control cartilage were stimulated by periostin, and the alteration of OA related gene expression was examined using quantitative RT-PCR. Immunocytochemistry of p65 was performed for the analysis of nuclear factor kappa B (NFκB) activation.

RESULTS

The periostin mRNA was significantly higher in OA cartilage than in control cartilage. Immunohistochemical analysis of periostin showed that the main positive signal was localized in chondrocytes and their periphery matrix near the erosive area, with less immunoreactivity in deeper zones. There was positive correlation between Mankin score and periostin immunoreactivity. The periostin expression was also detected in the fibrotic cartilage and tissue of subchondral bone. In cultured human chondrocytes, periostin induced the expression of interleukin (IL)-6, IL-8, matrix metalloproteinase (MMP)-1, MMP-3, MMP-13, and nitric oxide synthase-2 (NOS2) in a dose- and time-dependent manner. The activation of NFκB signaling was recognized by the nuclear translocation of p65. Periostin-induced upregulation of these genes was suppressed by NFκB inactivation in chondrocytes.

CONCLUSION

Periostin was upregulated in OA cartilage, and it may amplify inflammatory events and accelerate OA pathology.

CALU polymorphism A29809G affects calumenin availability involving vascular calcification

Calumenin inhibits gamma-carboxylation of matrix-Gla-protein preventing BMP2-dependent calcification. Our aim was to explore the clinical relevance and functionality of the CALU polymorphism rs1043550, and the relationship of calumenin time-dependent expression profile with the active calcification of human vascular smooth muscle cells (hVSMC). Coronary artery calcium score and lesion severity were assessed by cardiac computed tomography in 139 consecutive low-risk patients genotyped for rs1043550. Polymorphic (G) allele carriage was associated with lower calcium (OR: 6.19, p=0.042). Calcified arteries from CALU 'A' allele carriers undergoing cardiovascular surgery exhibited higher residual calcification, higher calumenin immunostaining and lower matrix-Gla-protein, contrary to 'G' allele carriers. In a luciferase reporter system in vascular cells, polymorphic 'G' allele reduced the mRNA stability by 30% (p < 0.05). Osteogenic high-phosphate media induced active differentiation of hVSMC onto functional osteoblast-like cells as demonstrated by extracellular matrix mineralization and osteoblast markers expression. Calumenin was early over-expressed at day 3 (p < 0.05), but decreased thereafter (mRNA and protein) with implications on gamma-carboxylation system. Calumenin was found released and co-localizing with extracellular matrix calcifications. The CALU polymorphism rs1043550 affects mRNA stability and tissue availability of calumenin thus supporting the protective clinical significance. Calumenin shows a time-dependent profile during induced calcification. These data demonstrate a novel association of vascular calcification with the VSMC phenotypic transition into osteoblast-like cells. Moreover, hyperphosphatemic stimuli render calumenin accumulation in the mineralized extracellular matrix.