Significant Improvement of Clinical Symptoms, Bone Lesions, and Bone Turnover after Long-Term Zoledronic Acid Treatment in Patients with a Severe Form of Camurati-Engelmann Disease

Zoledronic acid improves bone quality and muscle function in a high bone turnover state

SUMMARY

Zoledronic acid (ZA) prevents muscle weakness in mice with bone metastases; however, its role in muscle weakness in non-tumor-associated metabolic bone diseases and as an effective treatment modality for the prevention of muscle weakness associated with bone disorders, is unknown. We demonstrate the role of ZA-treatment on bone and muscle using a mouse model of accelerated bone remodeling, which represents the clinical manifestation of non-tumor associated metabolic bone disease. ZA increased bone mass and strength and rescued osteocyte lacunocanalicular organization. Short-term ZA treatment increased muscle mass, whereas prolonged, preventive treatment improved muscle mass and function. In these mice, muscle fiber-type shifted from oxidative to glycolytic and ZA restored normal muscle fiber distribution. By blocking TGFβ release from bone, ZA improved muscle function, promoted myoblast differentiation and stabilized Ryanodine Receptor-1 calcium channel. These data demonstrate the beneficial effects of ZA in maintaining bone health and preserving muscle mass and function in a model of metabolic bone disease.

Context and significance

TGFβ is a bone regulatory molecule which is stored in bone matrix, released during bone remodeling, and must be maintained at an optimal level for the good health of the bone. Excess TGFβ causes several bone disorders and skeletal muscle weakness. Reducing excess TGFβ release from bone using zoledronic acid in mice not only improved bone volume and strength but also increased muscle mass, and muscle function. Progressive muscle weakness coexists with bone disorders, decreasing quality of life and increasing morbidity and mortality. Currently, there is a critical need for treatments improving muscle mass and function in patients with debilitating weakness. Zoledronic acid's benefit extends beyond bone and could also be useful in treating muscle weakness associated with bone disorders.

Clinical characteristics and identification of a novel TGFB1 variant in three unrelated Chinese families with Camurati-Engelmann disease

Background

To investigate the clinical characteristics and molecular diagnosis of Camurati‐Engelmann disease (CAEND) in Chinese individuals.

Methods

We recruited six patients aged 14 to 45 years in three unrelated families with CAEND, including five females and one male. Clinical manifestations, biochemical tests, and radiographic examinations were analyzed. The TGFB1 gene variants were further identified by Sanger sequencing. In addition, one female patient was followed up for 5 years.

Results

The onset age of the patients ranged from 1 to 6 years. All of them had family histories and consisted of an autosomal dominant inheritance pattern. Gait disturbance, fatigue, progressive bone pain, muscle atrophy, and weakness were the main complaints. Laboratory examinations revealed that the inflammatory markers were at high levels, in addition to the increased bone metabolism indicators. The thickened diaphysis of long bones and the narrowed medullary cavity was observed by radiography. Furthermore, bone scintigraphy detected abnormal symmetrical radioactive concentrations in the affected regions of bone. Sanger sequencing identified a missense heterozygous variant in exon 4 of the TGFB1 gene in families 1 and 2, resulting in Arg218Cys, which confirmed CAEND. Moreover, one novel variant c.669C > G in exon 4 of the TGFB1 gene harboring Cys223Trp was detected in family 3. Subsequent bioinformatics software predicted that the novel variant was pathogenic. Of interest, III:2 in family 3 experienced heart valve defects and tachycardia at birth, which had never been reported in CAEND patients before. Moreover, the response to drug treatment is also full of contradictions and is worthy of further study.

Conclusion

Besides the typical CAEND manifestations, the new phenotypic characteristics of tachycardia and heart valve defects were first reported in one woman carrying the novel variant p.Cys223Trp in TGFB1 the gene. In addition, we demonstrated that increased bone metabolism indicators and inflammatory markers may possess auxiliary diagnosis for CAEND.

Improvement of Bone Health and Initiation of Puberty Development in Camurati-Engelmann Disease With Glucocorticoid and Losartan Treatment: A Case Report and Review of Literature

Camurati-Engelmann Disease (CED) is a rare sclerosing bone disease, sometimes associated delayed puberty. The treatment effect of glucocorticoid and angiotensin II receptor blocker (ARB) in bone health and puberty development remain unclear. We report a case of an 18-year-old girl who presented for a history of an enlarged head, pain of lower limbs, and no menstrual onset or breast development. Radiographs revealed thickening of skull and cortices in the diaphysis but sparse bone trabeculae in the spine and metaphysis. Sanger sequencing detected a mutation of c. 652C>T (p. R218C) in the gene TGFB1 and confirmed the diagnosis of CED. After treatment of a medium-to-small dosage of prednisone and losartan for 28 months, we observed improvement of bone mass in spine and hip and body fat mass and found initiation of puberty development. By a systemic review of current treatment strategies in patients with CED, we found that most cases reported relief of bone pain with treatment of glucocorticoid or ARB, but none has reported the outcome of hypogonadotropic hypogonadism. We propose that long-term use of glucocorticoid combined with ARB may inhibit the activation of TGFβ1 in CED, improve adipogenesis, and thus initiate puberty development and improve the bone mass in spine and hip.

Surgery Treatment of an Adult Patient with Camurati-Engelmann Disease: A Case Report

CASE

A 40-year-old Colombian woman presented with a 7-year history of progressive lower-limb pain. Sclerosis of the diaphyseal tibia and femur was observed in her latest x-ray images. A narrowing of the medullary canal is observed in Camurati-Engelmann disease (CED), a rare and progressive diaphyseal dysplasia that was confirmed in this patient by genetic testing. Medical treatment was unsuccessful; thus, surgical treatment consisted of decompression by drilling of the medullary canal was performed, achieving successful pain release.

CONCLUSION

Surgical treatment should be considered for patients with CED when the medical treatment is unsuccessful because doing so reduces bone overgrowth, leading to pain relief.

Efficacy of denosumab therapy after alendronate treatment for a 66-year-old woman with Camurati-Engelmann disease and osteoporosis: a case report

Camurati-Engelmann disease (CED) is characterized by hyperostois of multiple long bones. Although several treatments for CED complicated with osteoporosis have been described, it remains controversial whether such therapy is suitable for osteoporotic CED patients. We retrospectively enrolled a 66-year-old female patient with osteoporosis in CED who underwent denosumab therapy for 14 months. Denosumab was commenced after 3 years of alendronate treatment. Fourteen months later, lumbar and total hip bone mineral density showed gains of 5.9% and 6.4%, respectively. Bone turnover markers were also improved during follow-up. No fractures or other complications were recorded during the observational period. This is the first study describing denosumab treatment for an osteoporotic CED patient. Our findings indicate that denosumab is an effective therapy option for osteoporosis in CED.