Autophagy markers are decreased in bone of osteoporotic patients: a monocentric comparative study

BACKGROUND

Osteoporosis (OP) is a pathology characterized by bone fragility affecting 30% of postmenopausal women, mainly due to estrogen deprivation and increased oxidative stress. An autophagy involvement is suspected in OP pathogenesis but a definitive proof in humans remains to be obtained.

METHODS

Postmenopausal women hospitalized for femoral neck fracture (OP group) or total hip replacement (Control group) were enrolled using very strict exclusion criteria. Western blot was used to analyze autophagy level.

RESULTS

The protein expression level of the autophagosome marker LC3-II was significantly decreased in bone of OP patients relative to the control group. In addition, the protein expression of the hormonally upregulated neu-associated kinase (HUNK), which is upregulated by female hormones and promotes autophagy, was also significantly reduced in bone of the OP group.

CONCLUSIONS

These results demonstrate for the first time that postmenopausal OP patients have a deficit in bone autophagy level and suggest that HUNK could be the factor linking estrogen loss and autophagy decline.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT03175874, 2/6/2017.

Denosumab use in bone fibrous dysplasia refractory to bisphosphonate: A retrospective multicentric study

INTRODUCTION

Increased RANKL expression is observed in the bone tissue of fibrous dysplasia of bone/McCune-Albright syndrome (FD/MAS). In one animal model of FD/MAS, the inhibition of RANKL reduced tumor volume. A beneficial effect of denosumab on pain in patients refractory to bisphosphonates has been reported, but without systematic quantification of pain improvement. This work describes the clinical experience of our group on the efficacy on pain of denosumab treatment, along with safety, in FD/MAS patients refractory to bisphosphonates.

MATERIALS AND METHODS

We have conducted a retrospective multicenter study in 6 academic rheumatology centers in France. We have collected patients and FD/MAS characteristics, duration of prior exposure to bisphosphonates, denosumab treatment modalities (dosage - administration regimen - number of courses); evolution of pain evaluated by Visual Analogic Scale (VAS).

RESULTS

13 patients were included (10 women and 3 men) 45 years on average, 5 MAS, 4 monostotic and 4 polyostotic forms. The average duration post-diagnosis of FD/MAS was 25 years and the mean duration of prior exposure to bisphosphonates was 4.7 years. Pain could be analyzed in 7 patients, showing a significant improvement from a mean VAS of 7.8 to 2.9 (-4.9 points, p = 0.003). In one patient with fronto-orbital FD/MAS, a 30 % decrease in lesional volume, assessed by MRI, was observed within 6 months of treatment, that was sustained over the following 12 months. Treatment regimens were heterogeneous. No hypercalcemia was observed after treatment cessation and the clinical tolerance was good.

DISCUSSION

This study suggests that denosumab reduces pain in patients with DF/MAS refractory to bisphosphonates, and quantifies this improvement for the first time in a multicenter study. In our cohort, no patients who discontinued denosumab developed hypercalcemia and clinical tolerance was overall good. This study also provides encouraging data regarding lesion volume control. Further controlled studies are required to determine the place and modalities of the denosumab treatment of FD/MAS.

CONCLUSION

Denosumab significantly decreased pain in FD/MAS refractory to bisphosphonate. This study paves the way for a randomized clinical trial to validate and standardize the prescription of denosumab in FD/MAS.

Concentric or eccentric physical activity for patients with symptomatic osteoarthritis of the knee: a randomized prospective study

Background:

Knee osteoarthritis–related pain limits physical function and leads to functional disability. Physical activity is one of the central recommendations for the management of knee osteoarthritis. Although concentric muscle activities are often preferred to eccentric ones, the corresponding rationale remains controversial.

Objective:

To explore the effect of a 6-week exercise program on function, pain, and performance in patients with symptomatic knee osteoarthritis.

Methods:

Patients with symptomatic knee osteoarthritis were included in the prospective EX-ART project (Walking performance in osteoARThritic subjects: effect of an ECCentric muscle strengthening program) and randomized in a 6-week rehabilitation program including either eccentric or concentric activities. Metrics of interest chosen as end points measured before and after the rehabilitation were WOMAC score, pain, and muscular performance (quadriceps power P_MAX and contraction strength M_MAX). MRI was also used to assess muscle volume and fat infiltration changes.

Results:

30 patients were included in each group; mean age was 74 (±7.6); 69% were women. At week 6, both groups showed a significant improvement in the WOMAC without difference between the two groups (p = 0.7). No difference between the two groups was identified for the pain reduction (p = 0.7). A significant improvement in the change in P_MAX and M_MAX at high velocity (p = 0.001 and p = 0.002) was observed in the eccentric group only. A vastus medialis hypertrophy was quantified in the eccentric group only (p = 0.002), whereas fat infiltration in the quadriceps muscles was unchanged.

Conclusion:

Physical activity, whether eccentric or concentric, has a benefit on function and pain in patients with symptomatic knee osteoarthritis. A few differences have been identified between the two types of rehabilitation. More particularly, a gain in muscle performance and vastus medialis volume was found with eccentric rehabilitation only.

Registration:

www.ClinicalTrials.gov, registration number NCT03167502.

Autophagy and bone diseases

Autophagy is a ubiquitous cellular process, allowing the removal and recycling of damaged proteins and organelles. At the basal level, this process plays a role in quality control, thus participating in cellular homeostasis. Autophagy can also be induced by various stresses, such as nutrient deprivation or hypoxia, to allow the cell to survive until conditions improve. In recent years, the role of this process has been widely studied in many pathologies such as neurodegenerative diseases or cancers. In bone tissue, various studies have shown that autophagy is involved in the survival, differentiation and activity of osteoblasts, osteocytes and osteoclasts. The evolution of this knowledge has led to the identification of new molecular pathophysiological mechanisms in bone pathologies. This review reports the current state of knowledge on the role of autophagy in 4 bone diseases: osteoporosis, which seems to be associated with a decrease in autophagy, osteopetrosis and Paget's disease where the course of the autophagic process is disturbed, and finally osteosarcoma where autophagy seems to play a protumoral role. A better understanding of the involvement of autophagy in these pathologies should eventually lead to the identification of new potential therapeutic targets.

Reverse shoulder arthroplasty in rheumatoid arthritis: survival and outcomes

BACKGROUND

Despite its potential biomechanical advantages, reverse shoulder arthroplasty (RSA) is still considered to be particularly high risk in rheumatoid patients who are osteoporotic and immunodeficient. Our purpose was to report prosthesis survival, complications, and outcomes of RSA in patients with rheumatoid arthritis (RA) at minimum 5-year follow-up.

METHODS

We conducted a retrospective multicenter study including 65 consecutive primary RSAs performed in 59 patients with RA between 1991 and 2010. We excluded rheumatoid patients with previous failed anatomic shoulder arthroplasty. Age at surgery averaged 69 years (range, 46-86 years). A structural bone grafting was performed in 18 cases (45%), using the humeral head in 15 cases (BIO-RSA technique), the iliac crest in 2 cases (Norris technique), and an allograft in 1 case. The mean follow-up was 92 months (range, 60-147 months) or until revision surgery.

RESULTS

Revision-free survivorship, using Kaplan-Meier curves, was 96% at 7 years. Two patients had revision surgeries for infections, with associated glenoid loosening in 1 case. No humeral loosening was recorded. The mean adjusted Constant score improved from 36% ± 23% preoperatively to 90% ± 26% postoperatively, and mean Subjective Shoulder Value improved from 21% ± 13% to 85% ± 12%, respectively (P < .001). Active anterior elevation increased from 65° ± 43° to 132° ± 27°, active external rotation increased from 10° ± 26° to 22° ± 27°, and internal rotation improved from buttocks to waist (P < .001). Stable fixation of the baseplate was achieved in all cases (including the 6 patients with end-stage RA), and we did not observe bone graft nonunion or resorption. Preoperative radiologic pattern (centered, ascending, or destructive), presence of acromial fractures or tilt (4 cases, 10%), and scapular notching (55%) on final radiographs were not found to influence outcomes or complication rate. Patients with absent/atrophied teres minor had lower functional results. Overall, 95% of the patients were satisfied with the procedure.

CONCLUSION

RSA is a safe and effective procedure for the treatment of RA patients, with a low risk of complications and low rate of revision, regardless of the radiologic presentation and stage of the disease. Rheumatoid patients undergoing primary RSA, with or without glenoid bone grafting, can expect a revision-free survival rate of 96% at 7-year follow-up. RSA offers the benefit of solving 2 key problems encountered in rheumatoid shoulders: glenoid bone destruction and rotator cuff deficiency.

Autophagy in Osteosarcoma Cancer Stem Cells Is Critical Process which Can Be Targeted by the Antipsychotic Drug Thioridazine

Simple Summary

Cancer stem cells (CSCs) represent a minor population of cancer cells with stem cell-like properties and appear as a crucial target in oncology as they are the origin of relapses and resistance to current treatments. Autophagy, which allows the degradation and recycling of cellular components for survival purposes, has been shown to be upregulated in some CSCs, participating in the resistance of these cells. The aim of our study was to analyze the autophagy level and the consequences of targeting this process in osteosarcoma CSCs. Our results indicate that autophagy is a critical process in osteosarcoma CSCs and that targeting this pathway allows to switch their fate from survival to death.

Abstract

Cancer stem cells (CSCs) represent a minor population of cancer cells with stem cell-like properties which are able to fuel tumor growth and resist conventional treatments. Autophagy has been described to be upregulated in some CSCs and to play a crucial role by maintaining stem features and promoting resistance to both hostile microenvironments and treatments. Osteosarcoma (OS) is an aggressive bone cancer which mainly affects children and adolescents and autophagy in OS CSCs has been poorly studied. However, this is a very interesting case because autophagy is often deregulated in this cancer. In the present work, we used two OS cell lines showing different autophagy capacities to isolate CSC-enriched populations and to analyze the autophagy in basal and nutrient-deprived conditions. Our results indicate that autophagy is more efficient in CSCs populations compared to the parental cell lines, suggesting that autophagy is a critical process in OS CSCs. We also showed that the antipsychotic drug thioridazine is able to stimulate, and then impair autophagy in both CSC-enriched populations, leading to autosis, a cell death mediated by the Na+/K⁺ ATPase pump and triggered by dysregulated accumulation of autophagosomes. Taken together, our results indicate that autophagy is very active in OS CSCs and that targeting this pathway to switch their fate from survival to death could provide a novel strategy to eradicate these cells in osteosarcoma.

[Osteoporosis treatment]

Osteoporosis treatment. Osteoporosis treatment is a public health issue that requires a comprehensive approach combining drugs and lifestyle measures. Lifestyle measures (nutrition, prevention of falls, etc.) are essential. Pharmacological therapy are teriparatide, reimbursed in the presence of two vertebral fractures, raloxifene to be reserved for women under 70 years of age with a low risk of peripheral fracture, bisphosphonates (oral or IV) and denosumab, efficient to reduce all types of fractures and that require dental precautions. Zoledronic acid is the first choice recommended after femoral neck fracture. The patient must be informed of the benefits, risks, and duration of treatment and the consolidation treatment required after teriparatide or denosumab discontinuation. Adherence and tolerance to treatment must be monitored to ensure its efficiency.

An unusual Staphylococcus saccharolyticus spondylodiscitis post kyphoplasty: a case report

Background

Staphylococcus saccharolyticus is a rarely encountered coagulase-negative, which grows slowly and its strictly anaerobic staphylococcus from the skin. It is usually considered a contaminant, but some rare reports have described deep-seated infections. Virulence factors remain poorly known, although, genomic analysis highlights pathogenic potential.

Case presentation

We report a case of Staphylococcus saccharolyticus spondylodiscitis that followed kyphoplasty, a procedure associated with a low rate but possible severe infectious complication (0.46%), and have reviewed the literature. This case specifically stresses the risk of healthcare-associated S. saccharolyticus infection in high-risk patients (those with a history of alcoholism and heavy smoking).

Conclusion

S. saccharolyticus infection is difficult to diagnose due to microbiological characteristics of this bacterium; it requires timely treatment, and improved infection control procedure should be encouraged for high-risk patients.