Famotidine suppresses osteogenic differentiation of tendon cells in vitro and pathological calcification of tendon in vivo

Pharmacological Treatment of Degenerative Cervical Myelopathy: A Critical Review of Current Evidence

Degenerative cervical myelopathy (DCM) is the leading cause of spinal cord dysfunction in adults, representing substantial morbidity and significant financial and resource burdens. Typically, patients with progressive DCM will eventually receive surgical treatment. Nonetheless, despite advancements in pharmacotherapeutics, evidence for pharmacological therapy remains limited. Health professionals from various fields would find interest in pharmacological agents that could benefit patients with mild DCM or enhance surgical outcomes. This review aims to consolidate all clinical and experimental evidence on the pharmacological treatment of DCM. We conducted a comprehensive narrative review that presents all pharmacological agents that have been investigated for DCM treatment in both humans and animal models. Riluzole exhibits effectiveness solely in rat models, but not in treating mild DCM in humans. Cerebrolysin emerges as a potential neuroprotective agent for myelopathy in animals but had contradictory results in clinical trials. Limaprost alfadex demonstrates motor function improvement in animal models and exhibits promising outcomes in a small clinical trial. Glucocorticoids not only fail to provide clinical benefits but may also lead to adverse events. Cilostazol, anti-Fas ligand antibody, and Jingshu Keli display promise in animal studies, while erythropoietin, granulocyte colony-stimulating factor and limaprost alfadex exhibit potential in both animal and human research. Existing evidence mainly rests on weak clinical data and animal experimentation. Current pharmacological efforts target ion channels, stem cell differentiation, inflammatory, vascular, and apoptotic pathways. The inherent nature and pathogenesis of DCM offer substantial prospects for developing neurodegenerative or neuroprotective therapies capable of altering disease progression, potentially delaying surgical intervention, and optimizing outcomes for those undergoing surgical decompression.

Administration of Cimetidine for Calcific Tendinitis of the Rectus Femoris: Five Cases

Calcific tendinitis of the rectus femoris is rare. This clinical report presents five cases of management of calcific tendinitis of the rectus femoris. Between July 2018 and March 2023, five patients visited our institution, where they were treated for calcific tendinitis of the rectus femoris. All patients presented with severe acute hip pain. Radiographs, computed tomography, magnetic resonance imaging, and an ultrasound examination of the hip showed calcification outside the joint, suggesting calcific tendinitis of the rectus femoris. All patients were orally administered 200 mg cimetidine and nonsteroidal anti-inflammatory drugs twice daily. A pain-free status was achieved in 2 weeks on average. Calcium deposits disappeared in three patients and decreased in two. Symptoms did not recur. Furthermore, no recurrence or enlargements in calcium deposits were observed. It appears to be an effective treatment for calcific tendinitis of the rectus femoris; however, the underlying mechanisms of action of cimetidine on calcific tendinitis have not yet been elucidated in detail.

PPP1R3A inhibits osteogenesis and negatively regulates intracellular calcium levels in calcific tendinopathy

Calcific tendinopathy (CT) is defined by the progressive accumulation of calcium crystals in tendonic regions that results in severe pain in patients. The etiology of CT is not fully elucidated. In this study, we elucidate the role of PPP1R3A in CT. A significant decrease in PPP1R3A expression was observed in CT patient tissues, which was further confirmed in tissues from a CT-induced rat model. Overexpression of PPP1R3A ex vivo reduced the expression of osteo/chondrogenic markers OCN and Sox9, improved tendon tissue architecture, and reduced intracellular Ca2+ levels. Overexpression of SERCA2 and knockdown of Piezo1 decreased expression of osteo/chondrogenic markers and intracellular calcium in PPP1R3A-knockdown tendon cells. Lastly, PPP1R3A expression was regulated at the posttranscriptional level by binding of HuR. Collectively, the present study indicates that PPP1R3A plays an important role in regulating calcium homeostasis in tendon cells via Piezo1/SERCA2, rendering it a promising target for therapeutic interventions of CT.

A novel pharmacological mechanism of anti-cancer drugs that induce pyroptosis

Pyroptosis is an inflammasome-induced lytic form of programmed cell death, and its main effect involves the release of inflammatory mediators when a cell dies, resulting in an inflammatory response in the body. The key to pyroptosis is the cleavage of GSDMD or other gasdermin families. Some drugs can cause cleavage GSDMD or other gasdermin members cause pyroptosis and suppress cancer growth and development. This review explores several drugs that may induce pyroptosis, thereby contributing to tumor treatment. Pyroptosis-inducing drugs, such as arsenic, platinum, and doxorubicin, were used originally in cancer treatment. Other pyroptosis-inducing drugs, such as metformin, dihydroartemisinin, and famotidine, were used to control blood glucose, treat malaria, and regulate blood lipid levels and are effective tumor treatments. By summarizing drug mechanisms, we provide a valuable basis for treating cancers by inducing pyroptosis. In future, the use of these drugs may contribute to new clinical treatments.

Chronic calcific periarthritis of the elbow treated by cimetidine administration: Five cases

Calcific periarthritis or calcific tendinitis occurs most frequently in the shoulder and rarely in the elbow. Cimetidine was previously reported to be effective for chronic calcific periarthritis of the shoulder. Here, we present five patients with chronic calcific periarthritis of the elbow treated by administration of cimetidine; there were six affected elbows in these five patients. Although all patients had been treated with nonsteroidal anti-inflammatory drugs for at least 3 months, their symptoms were not relieved. All patients took oral administration of cimetidine 400 mg daily. The pain was completely relieved in an average of 1.8 months after the administration of cimetidine, and the calcification of the elbow disappeared in an average of 5.1 months. During the follow-up period, there were no symptoms suggesting a recurrence. Although the detailed mechanism of action of cimetidine on periarticular calcifications remains to be understood, cimetidine appears to be a potential therapeutic agent for chronic calcific periarthritis.

Suppression of osteogenic differentiation in mesenchymal stem cells from patients with ossification of the posterior longitudinal ligament by a histamine-2-receptor antagonist

Mesenchymal stem cells (MSCs) in ossification of the posterior longitudinal ligament (OPLL) patients have a high propensity toward osteogenesis. Histamine receptor H2 (H2R) antagonists (H2 blockers) like famotidine decrease ossification in patients, by an unclear mechanism. To confirm that MSCs express H2R and to clarify how H2 blockers suppress osteogenic differentiation, we used spinal-ligament MSCs from patients with OPLL or with cervical spondylotic myelopathy (CSM) (control). The MSCs were treated with 10, 30, or 100nM famotidine for 7 or 21 days. Flow cytometry revealed that cells from both groups expressed MSC surface markers CD44, CD90, and CD105 (> 97.5%) but not CD34 or CD45 (< 2.5%). Immunoblotting showed that the MSCs from both groups expressed H2R, but those from OPLL patients expressed it at higher levels. Real-time qPCR indicated the H2R expression was significantly suppressed by 30nM famotidine for 7 days or by 30 or 100nM for 21 days. However, histidine decarboxylase, a key enzyme in histamine production, did not change significantly after famotidine addition. Famotidine treatment at 100nM for 21 days significantly suppressed mRNA expression of the osteogenic markers osteocalcin (OCN), bone morphogenetic protein 2 (BMP2), and runt-related transcription factor 2 (RUNX2) only in OPLL-derived MSCs. Immunoblots showed that famotidine suppressed BMP2 and OCN in the OPLL group and H2R and RUNX2 in both groups. These results suggest famotidine inhibits osteogenic differentiation in OPLL-derived MSCs by acting as an H2R antagonist, but also by decreasing H2R expression, and support the clinical use of famotidine to treat OPLL.

The H2 blocker famotidine suppresses progression of ossification of the posterior longitudinal ligament in a mouse model

Background

Ossification of the posterior longitudinal ligament (OPLL) of the spine is a common human myelopathy that leads to spinal cord compression. No disease-modifying drug for OPLL has been identified, whereas surgery and conservative management have been established.

Objectives

To evaluate the therapeutic potential of the H2 blocker famotidine for ectopic ossification in the cervical spine in an OPLL mouse model.

Methods

The H2 blocker famotidine was orally administered to Enpp1^ttw/ttw mice, a model of OPLL, at either 4 or 15 weeks of age. Radiological and survival rate analyses were performed to assess the effects of famotidine on OPLL-like lesions and mortality in Enpp1^ttw/ttw mice.

Results

Oral administration of famotidine suppressed the progression of OPLL-like ectopic ossification and reduced mortality in Enpp1^ttw/ttw mice when administration began at 4 weeks of age, early in the development of ossification.

Conclusions

This study points to the use of famotidine as a disease-modifying drug for ectopic ossification of spinal soft tissue, including OPLL.