Serum Periostin Level Reflects Progression of Ossification of the Posterior Longitudinal Ligament

Thick Skin on the Dorsal Spine in Osteoproliferative Disease: Ossification of the Posterior Longitudinal Ligament and Diffuse Idiopathic Skeletal Hyperostosis

Background Although the correlation between reduced skin thickness and reduced bone density has been investigated, no study has evaluated skin thickness and osteoproliferative diseases, including ossification of the posterior longitudinal ligament (OPLL) and diffuse idiopathic skeletal hyperostosis (DISH). Methodology This retrospective cohort study consisted of 99 consecutive patients aged ≥60 years treated for spinal surgery at our hospital between January 2022 and March 2023. Skin thickness was measured at the dorsal side of the cervical, thoracic, and lumbar vertebrae on the sagittal cross-section image of whole-spine CT. Based on the median value, skin thickness was categorized into two groups based on a median thickness of 4 mm. Bone mineral density (BMD) was assessed. The sum of the vertebral body and intervertebral bridging osteophytes of the anterior longitudinal and posterior longitudinal ligament were defined as the OALL index and OPLL index. Serum levels of bone metabolism-related markers, such as tartrate-resistant acid phosphatase type 5b, procollagen I N-propeptide, 25-hydroxyvitamin D, and periostin, were measured. To assess the association between skin thickness and imaging findings, we calculated the adjusted odds ratios, adjusting for age, sex, and body mass index (BMI) and using univariate and multivariate logistic regression analyses. Results No significant differences were found in skin thickness in the three dorsal regions of the cervical, thoracic, and lumbar spine (median = 3.3 mm versus 3.5 mm versus 3.4 mm, p = 0.357) and bone metabolism-related markers. Adjusting for age, sex, and BMI, cervical, thoracic, and lumbar skin thicknesses were related to DISH, the OPLL index, and the OPLL and OPLL index, respectively. Conclusions Skin thickness did not correlate with BMD but with the amount of spinal ossification. A correlation was found between skin thickness and vertebral and intervertebral ossification; vertebral osteophytes, OPLL, and DISH may be more common in thicker skin.

A view on the skin-bone axis: unraveling similarities and potential of crosstalk

The phrase "skin as a mirror of internal medicine," which means that the skin reflects many of the diseases of the internal organs, is a well-known notion. Despite the phenotypic differences between the soft skin and hard bone, the skin and bone are highly associated. Skin and bone consist of fibroblasts and osteoblasts, respectively, which secrete collagen and are involved in synthesis, while Langerhans cells and osteoclasts control turnover. Moreover, the quality and quantity of collagen in the skin and bone may be modified by aging, inflammation, estrogen, diabetes, and glucocorticoids. Skin and bone collagen are pathologically modified by aging, drugs, and metabolic diseases, such as diabetes. The structural similarities between the skin and bone and the crosstalk controlling their mutual pathological effects have led to the advocacy of the skin-bone axis. Thus, the skin may mirror the health of the bones and conversely, the condition of the skin may be reflected in the bones. From the perspective of the skin-bone axis, the similarities between skin and bone anatomy, function, and pathology, as well as the crosstalk between the two, are discussed in this review. A thorough elucidation of the pathways governing the skin-bone axis crosstalk would enhance our understanding of disease pathophysiology, facilitating the development of new diagnostics and therapies for skin collagen-induced bone disease and of new osteoporosis diagnostics and therapies that enhance skin collagen to increase bone quality and density.

High Circulating FGF-23 and Its Relationship with Severity of Spinal Involvement in Diffuse Idiopathic Skeletal Hyperostosis

The primary objective of this study was to determine the role of fibroblast growth factor 23 (FGF-23) in the pathogenesis of diffuse idiopathic skeletal hyperostosis (DISH). A total of 61 patients with DISH and 61 age- and sex-matched control patients without DISH were included in this study. The serum FGF-23, creatinine, inorganic phosphate, calcium, albumin, albumin-adjusted calcium and alkaline phosphatase, and C-reactive protein were assessed in both groups. Based on the extent of ossification, DISH group was further divided into T-DISH and L-DISH subgroups. Data were comparatively analyzed between DISH and Non-DISH groups and among T-DISH, L-DISH, and Non-DISH groups, respectively. Besides, the number of ossification segments of all DISH patients was quantified and the correlation between the number of ossification segments and the serum concentration of FGF-23 was analyzed. The results revealed that serum FGF-23 was significantly higher in DISH group than in Non-DISH group, regardless of gender. Interestingly, serum Pi was significantly lower in DISH group than in Non-DISH group. Moreover, a significant difference in serum FGF-23 among T-DISH, L-DISH, and Non-DISH groups was also observed. In contrast to Non-DISH group, both T-DISH and L-DISH subgroups displayed significantly higher serum FGF-23 level. Although the mean value was relatively higher in L-DISH subgroup, no statistically significant difference was found between T-DISH and L-DISH subgroups. In addition, a moderately positive correlation was identified between the number of ossification segments and the serum level of FGF-23. It can be concluded that serum FGF-23 could serve as a positive biomarker for DISH and may play a significant role in ectopic ossification in DISH.

Mechanisms of tissue degeneration mediated by periostin in spinal degenerative diseases and their implications for pathology and diagnosis: a review

Periostin (POSTN) serves a dual role as both a matricellular protein and an extracellular matrix (ECM) protein and is widely expressed in various tissues and cells. As an ECM protein, POSTN binds to integrin receptors, transduces signals to cells, enabling cell activation. POSTN has been linked with various diseases, including atopic dermatitis, asthma, and the progression of multiple cancers. Recently, its association with orthopedic diseases, such as osteoporosis, osteoarthritis resulting from cartilage destruction, degenerative diseases of the intervertebral disks, and ligament degenerative diseases, has also become apparent. Furthermore, POSTN has been shown to be a valuable biomarker for understanding the pathophysiology of orthopedic diseases. In addition to serum POSTN, synovial fluid POSTN in joints has been reported to be useful as a biomarker. Risk factors for spinal degenerative diseases include aging, mechanical stress, trauma, genetic predisposition, obesity, and metabolic syndrome, but the cause of spinal degenerative diseases (SDDs) remains unclear. Studies on the pathophysiological effects of POSTN may significantly contribute toward the diagnosis and treatment of spinal degenerative diseases. Therefore, in this review, we aim to examine the mechanisms of tissue degeneration caused by mechanical and inflammatory stresses in the bones, cartilage, intervertebral disks, and ligaments, which are crucial components of the spine, with a focus on POSTN.

Periostin Augments Vascular Smooth Muscle Cell Calcification via β-Catenin Signaling

Medial vascular calcification is common in chronic kidney disease (CKD) and is closely linked to hyperphosphatemia. Vascular smooth muscle cells (VSMCs) can take up pro-calcific properties and actively augment vascular calcification. Various pro-inflammatory mediators are able to promote VSMC calcification. In this study, we investigated the effects and mechanisms of periostin, a matricellular signaling protein, in calcifying human VSMCs and human serum samples. As a result, periostin induced the mRNA expression of pro-calcific markers in VSMCs. Furthermore, periostin augmented the effects of β-glycerophosphate on the expression of pro-calcific markers and aggravated the calcification of VSMCs. A periostin treatment was associated with an increased β-catenin abundance as well as the expression of target genes. The pro-calcific effects of periostin were ameliorated by WNT/β-catenin pathway inhibitors. Moreover, a co-treatment with an integrin αvβ3-blocking antibody blunted the pro-calcific effects of periostin. The silencing of periostin reduced the effects of β-glycerophosphate on the expression of pro-calcific markers and the calcification of VSMCs. Elevated serum periostin levels were observed in hemodialysis patients compared with healthy controls. These observations identified periostin as an augmentative factor in VSMC calcification. The pro-calcific effects of periostin involve integrin αvβ3 and the activation of the WNT/β-catenin pathway. Thus, the inhibition of periostin may be beneficial to reduce the burden of vascular calcification in CKD patients.

Biomarker Research Approach to the Pathogenesis of Ossification of the Spinal Ligament: A Review

The ossification of the spinal ligaments (OSL) is characterized by ectopic new bone formation in the spinal ligament. However, the etiology of OSL has not yet been fully elucidated. This review paper summarizes the contents of previous reviews, introduces recent advances in the study of OSL and discusses future perspectives. A review of the literature that investigated the biomarkers involved in OPLL was published in 2019. The review cited 11 reports in which a calcium phosphate metabolism marker, bone turnover markers, sclerostin, dickkopf-1, secreted frizzled-related protein-1, fibroblast growth factor-23, fibronectin, menatetrenone, leptin, pentosidine, and hypersensitive C-reactive protein were examined as markers. Data published in 2021 noted that non-coding RNAs might be useful biomarkers for OSL. In addition, triglycerides, uric acid, gene expression levels of interleukin-17 receptor C, chemokine (C-X-C motif) ligand 7 (CXCL7) in the serum reportedly are biomarkers of OSL. However, several issues have been raised in previous studies. Therefore, biomarkers have yet to be conclusively investigated. Research using biomarkers is very important in clarifying pathomechanisms. Results for studies using biomarkers might also be useful for the treatment of patients with OSL in the near future.