Gene expression in human osteoblastic cells from normal and heterotopic ossification

Heterotopic ossification Post-Guillain-Barre syndrome in Saudi Arabia: a case report

Background

Heterotopic ossification (HO) is the formation of bone within the soft tissues. It can be a complication of Guillain-Barre syndrome (GBS). There are many risk factors for HO, including male sex, mechanical ventilation, and neurogenic trauma. Myelin and axons are the main targets and areas of injury in GBS, an autoimmune-inflammatory neuropathy. Literature shows that this may possibly be associated with the initial administration of the COVID-19 vaccine and GBS.

Presentation of the case

A 27-year-old male was diagnosed with bile reflux gastritis. Days later, he presented to the emergency room (ER) with progressive weakness and a critical condition that required ICU. The patient undergoes intubation and remains in the ICU for 4 months. The patient, after extensive rehabilitation, started to complain of left hip pain and limitations of motion. Radiographs confirmed the HO diagnosis. Past drug history showed patients received a single dose of the COVID-19 vaccine 15 days before presentation to the ER.

Discussion

There is no clear association between the COVID-19 vaccination and GBS. HO is the formation of abnormal bone within soft tissue. HO post-GBS usually affects large joints like the hips, knees, and shoulders. Researchers poorly understand the pathogenesis of GBS.

Conclusion

Despite the absence of a definitive correlation between GSB and the COVID-19 vaccine. Physicians should maintain a state of suspicion while treating patients with a progressive weakness. Additional research is required.

Choanal Polyps With Osseous Metaplasia From the Nasal Septum: A Case Report and the Literature Review

Choanal polyps belong to a special type of nasal polyps, which are quite uncommon if originating from the nasal septum, especially those with osseous metaplasia. In this article, we report the case of a 63-year-old male patient with persistent nasal obstruction on the right side. An irregular light yellow lobulated mass with smooth surface could be visualized in the nasal cavity through nasal endoscopy, arising from the right nasal septum and extending to the nasopharynx. Computed tomography scan showed a large soft tissue shadow of the nasal meatus, with ossified structure in the center. Histopathological biopsy revealed nasopharyngeal mucositis. The patient underwent functional endoscopic sinus surgery and the polypoidal mass sent for histopathological examination proved to be choanal polyps.

Osseous metaplasia of antrochoanal polyp: Case report and radiological-pathological correlation

Osseous metaplasia of inflammatory sinonasal polyp is an extremely rare entity. Correct preoperative diagnosis by noncontrast CT scan is needed to rule out other more common bony neoplasms in paranasal sinuses and for accurate surgical planning. Here, we present a case of 20-year-old patient with an antrochoanal polyp with osseous metaplasia. We describe the lesion and discuss the radiological differential diagnosis thereby providing a brief review of literature of the few published cases worldwide along with histopathological correlation.

A survey of proteomic biomarkers for heterotopic ossification in blood serum

Background

Heterotopic ossification (HO) is a significant problem for wounded warriors surviving high-energy blast injuries; however, currently, there is no biomarker panel capable of globally characterizing, diagnosing, and monitoring HO progression. The aim of this study was to identify biomarkers for HO using proteomic techniques and blood serum.

Methods

Isobaric tags for relative and absolute quantitation (iTRAQ) was used to generate a semi-quantitative global proteomics survey of serum from patients with and without heterotopic ossification. Leveraging the iTRAQ data, a targeted selection reaction monitoring mass spectrometry (SRM-MS) assay was developed for 10 protein candidates: alkaline phosphatase, osteocalcin, alpha-2 type I collagen, collagen alpha-1(V) chain isoform 2 preprotein, bone sialoprotein 2, phosphatidate phosphatase LPIN2, osteomodulin, protein phosphatase 1J, and RRP12-like protein.

Results

The proteomic survey of serum from both healthy and disease patients includes 1220 proteins and was enriched for proteins involved in the response to elevated platelet Ca⁺², wound healing, and extracellular matrix organization. Proteolytic peptides from three of the ten SRM-MS proteins, osteocalcin preprotein, osteomodulin precursor, and collagen alpha-1(v) chain isoform 2 preprotein from serum, are potential clinical biomarkers for HO.

Conclusions

This study is the first reported SRM-MS analysis of serum from individuals with and without heterotopic ossification, and differences in the serum proteomic profile between healthy and diseased subjects were identified. Furthermore, our results indicate that normal wound healing signals can impact the ability to identify biomarkers, and a multi-protein panel assay, including osteocalcin preproprotein, osteomodulin precursor, and collagen alpha-1(v) chain isoform 2 preprotein, may provide a solution for HO detection and monitoring.

Electronic supplementary material

The online version of this article (doi:10.1186/s13018-017-0567-2) contains supplementary material, which is available to authorized users.

Osseous Metaplasia in an Inflammatory Polyp of the Rectum: A Case Report and Review of the Literature

Osseous metaplasia is a rare finding in colonic neoplasms. We report a case osseous metaplasia in a 74 year-old male who underwent surveillance colonoscopy and found to have a 7 mm rectal polyp. Histopathologic examination revealed an inflammatory polyp with osseous metaplasia.

IL-33 is expressed in human osteoblasts, but has no direct effect on bone remodeling

The aim of the present study was to investigate the potential role of the recently discovered IL-1 family member IL-33 in bone remodeling. Our results indicate that IL-33 mRNA is expressed in osteocytes in non-inflammatory human bone. Moreover, IL-33 levels are increased by TNF-α and IL-1β in human bone marrow stromal cells, osteoblasts and adipocytes obtained from three healthy donors. Experiments with the inhibitor GW-9662 suggested that expression of IL-33, in contrast to that of IL-1β, is not repressed by PPARγ likely explaining why IL-33, but not IL-1β, is expressed in adipocytes. The IL-33 receptor ST2L is not constitutively expressed in human bone marrow stromal cells, osteoblasts or CD14-positive monocytes, and IL-33 has no effect on these cells. In addition, although ST2L mRNA is induced by TNF-α and IL-1β in bone marrow stromal cells, IL-33 has the same effects as TNF-α and IL-1β, and, therefore, the biological activity of IL-33 may be redundant in this system. In agreement with this hypothesis, MC3T3-E1 osteoblast-like cells constitutively express ST2L mRNA, and IL-33 and TNF-α/IL-1β similarly decrease osteocalcin RNA levels in these cells. In conclusion, our results suggest that IL-33 has no direct effects on normal bone remodeling.

Effects of time of initial exposure to MSV sarcoma on bone induction by dentine matrix implants and on orthotopic femora

HCl-demineralized murine lower incisors were implanted intramuscularly into syngeneic BALB/c mice to induce heterotopic osteogenesis. Implants were exposed at the early, preosteogenic stage (4), or at the later, osteogenic stage (12) to the Moloney sarcoma virus (MSV), which within 3–4 days results in a sarcoma. The yield of bone induction was determined by weight of dry bone mass following NaOH hydrolysis of soft tissues. To verify the effect of this sarcoma on orthotopic local femoral bone, the dry mass of the tumor-exposed femora was measured and compared with the weight of MSV-unexposed contralateral controls. MSV-sarcoma or cells involved with their spontaneous rejection have a stimulatory effect on the periosteal membrane of the tumor-adjacent femoral bones, increasing their dry mass on average by 18%. No stimulatory effect on heterotopic bone induction was observed when the MSV sarcoma grew during the early, preosteogenic stage (4 onward), but when the tooth matrix had been exposed to such tumor at the already bone-forming stage, (12 onward), the yield of bone induction was enhanced. Thus, it is postulated that lesions induced by MSV during the early, preosteogenic stage inhibit recruitment of osteoprogenitor cells or degrade Bone Morphogenetic Proteins (BMPs) released by matrix resorbing inflammatory cells, whereas when acting on already existing bone they have a stimulatory effect.

Leptin receptors and beta2-adrenergic receptor mRNA expression in brain injury-related heterotopic ossification

Heterotopic ossification (HO) frequently occurs after brain injury. Recently, we found that leptin levels were decreased in the serum of patients with HO. Data suggest two mechanisms mediating leptin effects: a central suppressive mechanism acting via the beta(2)-adrenergic system and a direct stimulatory action starting when leptin binds to its receptors in osteoblastic cells. In this study, we analyzed leptin and beta(2)-adrenergic receptors mRNA expression in osteocytes originated from normal or heterotopic bone biopsies to investigate whether direct or indirect pathway signaling might be implicated in this pathological bone formation. We report for the first time the mRNA expression of the leptin receptor isoforms in osteocytes isolated from all biopsies. Moreover, quantitative reverse transcription-polymerase chain reaction allowed us to measure a significant decrease in the level of beta(2)-adrenergic receptor mRNA in cells isolated from heterotopic bone biopsies. These results could suggest an association between hypothalamic leptin signaling and brain injury-related HO.

Gene expression in normotopic and heterotopic human bone: increased level of SP7 mRNA in pathological tissue

Head injury-induced heterotopic ossification (HO) develops at vicinity of joints and in severe cases requires surgical intervention. Our previous study demonstrated high mRNA levels of osteocalcin (OC), type 1 collagen (COL1), osteonectin and RUNX2/CBFA1 in osteocytes and lining osteoblasts from non-evolutive HO compared to equivalent healthy cells from the proximal femoral shaft of patients receiving prosthesis. This allowed a first molecular characterisation of this pathological bone. The aims of this study is to extend the analysis to 10 more genes and determine those involved in the high OC mRNA level observed in pathological bone samples. RNAs were prepared from normotopic and heterotopic human bone samples digested by collagenase. After cDNA synthesis, mRNA levels were determined by real-time PCR and normalised using beta actin and glyceraldehyde-3-phosphate dehydrogenase. OSTERIX/SP7 expression was observed for the first time in human adult bone biopsies. In HO samples higher levels of SP7 (four- to sevenfold increase) and 1alpha,25-dihydroxy vitamin D(3) receptor (VDR) (two- to threefold increase) were observed compared to control samples. Moreover, SP7 level was correlated to OC and RUNX2 levels. In control samples, OC and SP7 levels were correlated. Our study further confirms that the involvement of SP7 in bone physiology is not only limited to the developmental step. Moreover, our results support the hypothesis that in HO the high level of OC expression could be due not only to an increase in RUNX2, but also in SP7 or VDR or to an imbalance in their respective activities.

Bone formation zones in heterotopic ossifications: histologic findings and increased expression of bone morphogenetic protein 2 and transforming growth factors beta2 and beta3

Heterotopic ossifications (HOs) formed after total endoprosthetic replacement of the hip joint were collected during revision surgery (n = 7). Tissues collected during regular hip arthroplasty (n = 12) were used as reference. Histomorphometric analysis was performed for assessment of bone formation activity in HOs and reference bone. HOs were dissected with histological guidance into three zones: formed bone, zone of active bone formation, and zone with fibrous connective and fibrocartilagineous tissue. Relative expression of the mRNA for bone morphogenetic protein 2 (BMP-2), transforming growth factor beta2 (TGF-beta2), and TGF-beta3 was determined by reverse-transcription polymerase chain reaction relative to beta-actin. Expression of all three growth factors was higher than in orthotopic bone. Similarly, the osteoid surface density was increased in HOs. The levels of all growth factors were higher in the zone of active bone formation or remodeling than in the zone of formed bone. In matured HOs, the osteoid surface density as well as mRNA levels were lower, although still significantly raised, indicating that bone formation slows down after 2 years. Immunohistochemical analysis demonstrated the presence of TGF-beta1, TGF-beta2, TGF-beta3, and BMP-2 proteins in the zone of bone formation. We conclude that bone formation after heterotopic bone induction is initially intense, slows down within 2 years, and thereupon continues as active remodeling mainly on the border of HO. Our data indicate that BMP-2, TGF-beta2, and TGF-beta3 are involved in bone formation in HO.

A comparative analysis of phenotype expression in human osteoblasts from heterotopic ossification and normal bone

BACKGROUND AND AIMS

Heterotopic ossification (HO) is a pathological bone formation process in which ectopic bone is formed in soft tissue. The formation of bone depends on the expression of the osteoblast phenotype. Earlier studies have shown conflicting results on the expression of phenotype markers of cells originating from HO and normal bone. The hypothesis of the present study is that cells from HO show an altered expression of osteoblast-specific phenotype markers compared to normal osteoblasts. The aims of the study were to further characterize the expression of osteoblast phenotypemarkers and to provide a comparison with other study results.

PATIENTS AND METHODS

Using an in vitro technique, reverse transcription polymerase chain reaction (RT-PCR), real-time PCR and immunohistochemistry, we compared the phenotype gene expression (type I collagen, alkaline phosphatase, Cbfa-1, osteocalcin) of osteoblasts from resected HO and normal bone (iliac crest).

RESULTS

Cells from HO expressed the osteoblast phenotype (type I collagen, alkaline phosphatase) but were characterized by a depleted osteocalcin expression. The expression of Cbfa-1 (osteocalcin transcription gene) showed a large variety in our study. Preoperative radiotherapy had no effect on phenotype expression in cells from HO.

CONCLUSION

Our results provide a characterization of cells originating from HO and support the thesis of an impaired osteoblast differentiation underlying the formation of HO. The transcription axis from Cbfa-1 to osteocalcin could be involved in the pathogenesis of HO.

Heterotopic Ossification in Guillain-Barré Syndrome: Incidence and Effects on Functional Outcome With Long-Term Follow-Up

OBJECTIVE

To define the incidence, effects on functional abilities, and possible causation of heterotopic ossification (HO) in Guillain-Barré syndrome (GBS) patients admitted for inpatient rehabilitation.

DESIGN

Long-term prospective study on neurologic and functional outcome of GBS patients admitted for rehabilitation.

SETTING

Rehabilitation department, inpatient and outpatient, within a university-affiliated medical center.

PARTICIPANTS

All GBS patients admitted for rehabilitation and followed for a minimum of 3 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Presence of HO, factors that may be etiologically significant, and effects on functionality. Data included: medical interventions, Disability Grading Scale, need for assisted ventilation, electrodiagnostic findings, autonomic function, standard neuro-musculo-skeletal evaluation, and hospital length of stay.

RESULTS

Four (6%) of 65 patients had HO, 24 of whom required mechanical ventilation. All had decreased range of motion in the involved hips that affected mobility.

CONCLUSIONS

Even though it has been rarely reported, HO does occur in GBS and affects functional outcome.