Gut hormones and bone homeostasis: potential therapeutic implications.

Bone resorption follows a circadian rhythm, with a marked reduction in circulating markers of resorption (such as carboxy-terminal telopeptide region of collagen type I in serum) in the postprandial period. Several gut hormones, including glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP1) and GLP2, have been linked to this effect in humans and rodent models. These hormones are secreted from enteroendocrine cells in the gastrointestinal tract in response to a variety of stimuli and effect a wide range of physiological processes within and outside the gut. Single GLP1, dual GLP1-GIP or GLP1-glucagon and triple GLP1-GIP-glucagon receptor agonists have been developed for the treatment of type 2 diabetes mellitus and obesity. In addition, single GIP, GLP1 and GLP2 analogues have been investigated in preclinical studies as novel therapeutics to improve bone strength in bone fragility disorders. Dual GIP-GLP2 analogues have been developed that show therapeutic promise for bone fragility in preclinical studies and seem to exert considerable activity at the bone material level. This Review summarizes the evidence of the action of gut hormones on bone homeostasis and physiology.

Gut hormone analogues and skeletal health in diabetes and obesity: Evidence from preclinical models.

Diabetes mellitus and obesity are rapidly growing worldwide. Aside from metabolic disturbances, these two disorders also affect bone with a higher prevalence of bone fractures. In the last decade, a growing body of evidence suggested that several gut hormones, including ghrelin, gastrin, glucose-dependent insulinotropic polypeptide (GIP), glucagon, and glucagon-like peptide-1 and 2 (GLP-1 and GLP-2, respectively) may affect bone physiology. Several gut hormone analogues have been developed for the treatment of type 2 diabetes and obesity, and could represent a new alternative in the therapeutic arsenal against bone fragility. In the present review, a summary of the physiological roles of these gut hormones and their analogues is presented at the cellular level but also in several preclinical models of bone fragility disorders including type 2 diabetes mellitus, especially on bone mineral density, microarchitecture and bone material properties. The present review also summarizes the impact of GLP-1 receptor agonists approved for the treatment of type 2 diabetes mellitus and the more recent dual or triple analogue on bone physiology and strength.

Detection of hypophosphatasia in hospitalised adults in rheumatology and internal medicine departments: a multicentre study over 10 years.

INTRODUCTION: Hypophosphatasia (HPP) is a rare genetic disease caused by loss-of-function mutations in the ALPL gene encoding the tissue non-specific alkaline phosphatase (ALP). Mild HPP is usually misdiagnosed in adult age. While an elevated serum ALP value draws more attention than a low value, low serum ALP should be better recognised and may lead to HPP detection. METHODS: Patients were selected from the records of the biochemistry department of six University Hospitals in France. Patients were hospitalised in the departments of rheumatology and internal medicine between 2007 and 2017. RESULTS: 56 321 hospitalised patients had at least 2 serum ALP dosages and 664 of these patients had at least 2 low serum ALP≤35 UI/L. Among these 664 patients, 482 (72.6%) had fluctuating low values (mean age 62.9 years; 60% of women) and 182 patients (27.4%) had persistent low values below 35 IU/L (mean age 53.4 years; 67% of women). Among patients with persistent hypophosphatasaemia treated with bisphosphonates, 70.8% never had ALP measurement before treatment and 20.8% were treated despite an abnormal decrease of ALP. Genetic testing was performed in 18 patients and was positive in 11. Genetic diagnosis of HPP was at least 6.0% in persistent hypophosphatasaemia and at least 15.9% in patients with at least three symptoms suggestive of HPP. CONCLUSION: In this 10-year retrospective study, 0.32% of adult patients hospitalised in the rheumatology and internal medicine departments had persistently low serum ALP, and among them, 6% had genetically proven HPP. Reported hypophosphatasaemia represented only 3.6% of hospitalised patients.

Development of a First-in-Class Unimolecular Dual GIP/GLP-2 Analogue, GL-0001, for the Treatment of Bone Fragility.

Due to aging of the population, bone frailty is dramatically increasing worldwide. Although some therapeutic options exist, they do not fully protect or prevent against the occurrence of new fractures. All current drugs approved for the treatment of bone fragility target bone mass. However, bone resistance to fracture is not solely due to bone mass but relies also on bone extracellular matrix (ECM) material properties, i.e., the quality of the bone matrix component. Here, we introduce the first-in-class unimolecular dual glucose-dependent insulinotropic polypeptide/glucagon-like peptide-2 (GIP/GLP-2) analogue, GL-0001, that activates simultaneously the glucose-dependent insulinotropic polypeptide receptor (GIPr) and the glucagon-like peptide-2 receptor (GLP-2r). GL-0001 acts synergistically through a cyclic adenosine monophosphate-lysyl oxidase pathway to enhance collagen maturity. Furthermore, bilateral ovariectomy was performed in 32 BALB/c mice at 12 weeks of age prior to random allocation to either saline, dual GIP/GLP-2 analogues (GL-0001 or GL-0007) or zoledronic acid groups (n = 8/group). Treatment with dual GIP/GLP-2 analogues was initiated 4 weeks later for 8 weeks. At the organ level, GL-0001 modified biomechanical parameters by increasing ultimate load, postyield displacement, and energy-to-fracture of cortical bone. GL-0001 also prevented excess trabecular bone degradation at the appendicular skeleton and enhanced bone ECM material properties in cortical bone through a reduction of the mineral-to-matrix ratio and augmentation in enzymatic collagen cross-linking. These results demonstrate that targeting bone ECM material properties is a viable option to enhance bone strength and opens an innovative pathway for the treatment of patients suffering from bone fragility. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Objective structured clinical examination versus traditional written examinations: a prospective observational study.

BACKGROUND: Recently, Objective Structured Clinical Examinations (OSCE) became an official evaluation modality for 6-year medical students in France. Before, standard examination modalities were: written progressive clinical cases (PCC), written critical reading of scientific articles (CRA), and internship evaluation (IE). The aim of this study was to assess the performances of 6-year medical students in their final faculty tests by comparing OSCE-exams with standard examination modalities. METHODS: This was a prospective observational study. We included all 6-year medical students in our university from 2020 to 2021. The endpoints were the scores obtained at the following final faculty tests during the 6th year of medical studies: OSCE-training, OSCE-exams, written PCC, written CRA, and IE. All scores were compared in a paired-analysis. RESULTS: A total of 400 students were included in the study. No student was excluded in the final analysis. The mean scores obtained at the OSCE-exams were significantly different from those obtained at OSCE-training, PCC, CRA, and IE (12.6 ± 1.7, 11.7 ± 1.7, 13.4 ± 1.4, 13.2 ± 1.5, 14.7 ± 0.9, respectively; p < 0.001). OSCE-exams scores were moderately and significantly correlated with OSCE-training and PCC (Spearman rho coefficient = 0.4, p < 0.001); OSCE examination scores were lowly but significantly correlated with CRA and IE (Spearman rho coefficient = 0.3, p < 0.001). OSCE-scores significantly increased after an OSCE training session. CONCLUSION: In our faculty, 6-year medical students obtained lower scores at OSCE exams compared to other standard evaluation modalities. The correlation was weak to moderate but significant. These results suggest that OSCE are not redundant with the other evaluation modalities. Interestingly, a single OSCE training session led to an improvement in OSCE scores underlining the importance of a specific training.

Direct and Indirect Relationships Between Physical Activity, Fitness Level, Kinesiophobia, and Health-Related Quality of Life in Patients with Rheumatic and Musculoskeletal Diseases: A Network Analysis.

INTRODUCTION: Using a network analysis, the present study investigated the extent to which physical activity (PA), objective fitness level, kinesiophobia, and health-related quality of life (HRQoL) interact in patients with rheumatic and musculoskeletal diseases. The objectives were twofold: 1) to clarify the direct and indirect relationships between these variables while controlling for the shared variance between them, and 2) to establish a potential ranking of influence among them. METHODS: This cross-sectional design study involved patients recruited from a rheumatology unit. One hundred and twenty patients completed self-reported measures of PA, the Tampa scale of kinesiophobia and the 36-item Short-Form Health Survey, and ninety-seven of those patients performed the six-minute walking test and the thirty-second sit-to-stand test. Network analyses were conducted using bootnet and qgraph packages. RESULTS: Weekly time spent on PA, as well as physical fitness measures, were directly linked to kinesiophobia and the HRQoL physical dimension, but indirectly linked to HRQoL mental dimension through the mediation of kinesiophobia. Specifically, weekly PA time had direct relationships to physical functioning, vitality, and role limitations due to physical and emotional problems. Fitness measures had direct relationships with physical functioning, bodily pain, and mental health. The analyses did not clearly highlight one variable as the most influential in the network. DISCUSSION: The study highlights the complexities of direct and indirect biopsychosocial relationships that are at the core of patients' daily functioning. Measurement of PA, use of a longitudinal design, and interventions are discussed.

[Gly²]-GLP-2, But Not Glucagon or [D-Ala²]-GLP-1, Controls Collagen Crosslinking in Murine Osteoblast Cultures.

Bone tissue is organized at the molecular level to resist fracture with the minimum of bone material. This implies that several modifications of the extracellular matrix, including enzymatic collagen crosslinking, take place. We previously highlighted the role of several gut hormones in enhancing collagen maturity and bone strength. The present study investigated the effect of proglucagon-derived peptides on osteoblast-mediated collagen post-processing. Briefly, MC3T3-E1 murine osteoblasts were cultured in the presence of glucagon (GCG), [D-Ala²]-glucagon-like peptide-1 ([D-Ala²]-GLP-1), and [Gly²]-glucagon-like peptide-2 ([Gly²]-GLP-2). Gut hormone receptor expression at the mRNA and protein levels were investigated by qPCR and Western blot. Extent of collagen postprocessing was examined by Fourier transform infrared microspectroscopy. GCG and GLP-1 receptors were not evidenced in osteoblast cells at the mRNA and protein levels. However, it is not clear whether the known GLP-2 receptor is expressed. Nevertheless, administration of [Gly²]-GLP-2, but not GCG or [D-Ala²]-GLP-1, led to a dose-dependent increase in collagen maturity and an acceleration of collagen post-processing. This mechanism was dependent on adenylyl cyclase activation. In conclusion, the present study highlighted a direct effect of [Gly²]-GLP-2 to enhance collagen post-processing and crosslinking maturation in murine osteoblast cultures. Whether this effect is translatable to human osteoblasts remains to be elucidated.

Features and Outcomes of Microcrystalline Arthritis Treated by Biologics: A Retrospective Study.

OBJECTIVES: The usual treatments for crystal-associated arthritis are sometimes contraindicated; thus, new therapies against interleukin-1beta (IL-1) have been developed. We evaluated the characteristics of patients who received biological treatment for crystal-associated arthritis. PATIENTS AND METHODS: We conducted a multicentric retrospective observational study in six rheumatology units in western France. Patients receiving a biological treatment for crystal-associated arthritis between 1 January 2010 and 31 December 2018 were included. Improvement was defined as at least a 50% decrease in the count of synovitis and C-reactive protein level. RESULTS: Forty-six patients were included: 31 (67.4%) were treated for gouty arthritis, and 15 (32.6%) for calcium pyrophosphate crystal deposition disease (CCPD). The first biotherapy used was anakinra for 14 patients (93.3%) with CCPD and 31 patients (100.0%) with gout. The first biotherapy course was more efficient in treating gout than in treating CCPD, with success in 28 patients (90.3%) and 5 patients (35.7%), respectively (p = 0.001). Six patients (42.9%) with CCPD stopped their first biotherapy course because of side effects. Among the patients with gout, urate-lowering therapy was more frequently used after (100%) than before the first biotherapy course (67.7%) (p = 0.002). CONCLUSION: Anakinra was prescribed for cases of refractory crystal-associated arthritis or cases with contraindications for usual treatments. The efficacy of anakinra in treating CCPD was not obvious. Patients with CCPD had more side effects. The biotherapy was introduced with a long-term objective, while anti-IL-1 therapies are approved for acute crises only.

Rheumatological features of Whipple disease.

Whipple disease (WD) is a rare infectious systemic disease. Rheumatologists are at the frontline of WD diagnosis due to the early rheumatological manifestations. An early diagnosis is crucial, as usual anti-rheumatic drugs, especially TNF inhibitors, may worsen the disease course. We conducted a retrospective multicentre national study from January 2010 to April 2020 to better characterize the rheumatological features of WD. Classic WD (CWD) was defined by positive periodic acid-Schiff (PAS) staining of a small-bowel biopsy sample, and non-CWD (NCWD) was defined by negative PAS staining of a small-bowel biopsy sample but at least one positive Tropheryma whipplei (TW) polymerase chain reaction (PCR) for a digestive or extradigestive specimen. Sixty-eight patients were enrolled, including 11 CWD patients. Twenty patients (30%) received TNF inhibitors during the WD course, with inefficacy or symptom worsening. More digestive symptoms and systemic biological features were observed in CWD patients than in NCWD patients, but both patient groups had similar outcomes, especially concerning the response to antibiotics and relapse rate. Stool and saliva TW PCR sensitivity were both 100% for CWD and 75% for NCWD and 89% and 60% for small-bowel biopsy sample PCR, respectively. WD encountered in rheumatology units has many presentations, which might result from different pathophysiologies that are dependent on host immunity. Given the heterogeneous presentations and the presence of chronic carriage, multiple TW PCR tests on samples from specific rheumatological sites when possible should be performed, but samples from nonspecific digestive and extradigestive sites also have great value.

Osteoporosis in older adults.

The incidence of fragility fractures increases progressively with advance in age after 50 years, and the phenomenon of population ageing will lead to an increased proportion of the world population having osteoporosis and fractures. The consequences of fractures are more serious in older adults: all low-trauma fractures were associated with increased mortality risk and the risk of a second major osteoporotic fracture after a first one also increased with advance in age. Along with the decrease in bone mineral density, falls play an essential role in the occurrence of fragility fractures in older adults, and the assessment of the risk of falling is part of the fracture risk assessment. Despite advances in the diagnosis of osteoporosis, the assessment of fracture risk, and a wide range of effective anti-osteoporosis medications, with parenteral route which can improve observance, many data indicate that the therapeutic care gap is particularly wide in the elderly in whom the importance and impact of a treatment are high and even more in those living in institutions.

Update on: effects of anti-diabetic drugs on bone metabolism.

INTRODUCTION: Preclinical, clinical, and population-based studies have provided evidence that anti-diabetic drugs affect bone metabolism and may affect the risk of fracture in diabetic patients. AREAS COVERED: An overview of the skeletal effects of anti-diabetic drugs used in type 2 diabetes is provided. Searches on AdisInsight, PubMed, and Medline databases were conducted up to 1st July 2020. The latest evidence from randomized clinical trials and population-based studies on the skeletal safety of the most recent drugs (DPP-4i, GLP-1RA, and SGLT-2i) is provided. EXPERT OPINION: Diabetic patients present with a higher risk of fracture for a given bone mineral density suggesting a role of bone quality in the etiology of diabetic fracture. Bone quality is difficult to assess in human clinical practice and the use of preclinical models provides valuable information on diabetic bone alterations. As several links have been established between bone and energy homeostasis, it is interesting to study the safety of anti-diabetic drugs on the skeleton. So far, evidence for the newest molecules suggests a neutral fracture risk, but further studies, especially in different types of patient populations (patients at risk or with history of cardiovascular disease, renal impairment, neuropathy) are required to fully appreciate this matter.

Enteroendocrine K Cells Exert Complementary Effects to Control Bone Quality and Mass in Mice.

The involvement of a gut-bone axis in controlling bone physiology has been long suspected, although the exact mechanisms are unclear. We explored whether glucose-dependent insulinotropic polypeptide (GIP)-producing enteroendocrine K cells were involved in this process. The bone phenotype of transgenic mouse models lacking GIP secretion (GIP-GFP-KI) or enteroendocrine K cells (GIP-DT) was investigated. Mice deficient in GIP secretion exhibited lower bone strength, trabecular bone mass, trabecular number, and cortical thickness, notably due to higher bone resorption. Alterations of microstructure, modifications of bone compositional parameters, represented by lower collagen cross-linking, were also apparent. None of these alterations were observed in GIP-DT mice lacking enteroendocrine K cells, suggesting that another K-cell secretory product acts to counteract GIP action. To assess this, stable analogues of the known K-cell peptide hormones, xenin and GIP, were administered to mature NIH Swiss male mice. Both were capable of modulating bone strength mostly by altering bone microstructure, bone gene expression, and bone compositional parameters. However, the two molecules exhibited opposite actions on bone physiology, with evidence that xenin effects are mediated indirectly, possibly via neural networks. Our data highlight a previously unknown interaction between GIP and xenin, which both moderate gut-bone connectivity. © 2020 American Society for Bone and Mineral Research.

Synchronous development and recurrence of multiple myeloma and clear cell renal cell carcinoma: Report of two cases.

The combined presence of two cancers in a single patient is rare. Usually, the second cancer is caused by immunosuppression resulting from treatment (chemotherapy, radiotherapy) of the first neoplasia. Multiple myeloma and kidney cancer share similar risk factors (obesity, smoking, hypertension), and several cases involving the combination of these two neoplasias have been described in the literature. We are reporting, for the first time, two clinical cases involving the combined presence of multiple myeloma and clear cell renal cell carcinoma discovered synchronously, with concomitant bone recurrence some time after the initial diagnosis. Pathophysiological mechanisms have been described that are common to renal carcinoma and multiple myeloma; in particular, the role of interleukin-6, which is produced by the renal cells and stimulates the proliferation of myeloma cells. Clinicians must be aware of the possibility of this disease combination and, in the event of an obvious recurrence of one of these two diseases, should search systematically for recurrence of the other disease.

Implication of IL-17 in Bone Loss and Structural Damage in Inflammatory Rheumatic Diseases.

Proinflammatory cytokines play an important role in the systemic and focal bone loss associated with chronic inflammatory diseases. Targeting these cytokines with biologics and small molecules has led to a major improvement of the bone health of patients with inflammatory arthritis. Cytokines from the IL-17 family have been shown to be involved in the pathogenesis of several diseases such as spondyloarthritis, psoriatic arthritis, or psoriasis. IL-17A has been the first described and the most studied. The recent development of targeted therapies against IL-17A or its receptor and their efficacy has confirmed the importance of this cytokine in the development of inflammatory diseases. The aim of this review was to describe the effects of the IL-17 family and more particularly of IL-17A on bone and cartilage tissues. At the cellular level, IL-17A is proosteoclastogenic whereas its effects on osteoblasts depend on the stage of differentiation of these cells. In vivo, IL-17A is not required for normal bone homeostasis but plays an important role in bone loss notably in an ovariectomized mouse model of osteoporosis. Preliminary data from clinical trials showed a stabilisation of bone density in patients treated with anti-IL-17A antibodies. IL-17A plays a central role in the cartilage damage through the induction of collagenases and by decreasing the expression of their inhibitors in synergy with the other proinflammatory cytokines. The prevention of structural damage by anti-IL-17A therapies has been demonstrated in several pivotal clinical trials. Overall, blocking the IL-17A pathway seems to have a positive effect on the bone and cartilage damage observed in inflammatory arthritis. Differences and specificity of these effects compared to those already described with other biologics such as anti-TNF therapies remain to be explored.

French recommendations on strategies for preventing and treating osteoporosis induced by adjuvant breast cancer therapies.

Standard adjuvant therapies for breast cancer such as chemotherapy or aromatase inhibitor and LH-RH agonist hormone therapy are associated with significant survival gains but also induce bone loss by aggravating the estrogen deprivation. The bone loss may be substantial, notably during early treatment, and occurs regardless of the baseline bone mineral density values. The objective of developing these recommendations was to achieve a practical consensus among various scientific societies, based on literature review, about osteoporosis prevention and treatment in these patients. The following scientific societies contributed to the work: Société Française de Rhumatologie (SFR), Groupe de Recherche et d'Information sur les Ostéoporoses (GRIO), Groupe Européen d'Etudes des Métastases Osseuses (GEMO), Association Francophone pour les Soins Oncologiques de Support (AFSOS), Société Française de Sénologie et de Pathologie Mammaire (SFSPM), Société Française de Radiothérapie Oncologique (SFRO). Drug prescription and reimbursement modalities in France were taken into account. These recommendations apply to postmenopausal women taking systemic chemotherapy and/or aromatase inhibitor therapy, non-postmenopausal women taking LH-RH agonist therapy, and non-postmenopausal women with persistent amenorrhea 1 year after chemotherapy completion. All women in these three categories should undergo an evaluation of bone health and receive interventions to combat risk factors for bone loss. Patients with a history of severe osteoporotic fracture and/or a T-score value <-2.5 should receive osteoporosis drug therapy. The FRAX® score should be used to guide treatment decisions in patients whose T-score is between -1 and -2.5. General osteoporosis prevention measures should be applied in patients without criteria for osteoporosis drug therapy, who should undergo bone mineral density measurements 18-24 months later if the baseline T-score is<-1 and 3-5 years later if the baseline T-score is>-1. The anti-tumor effect of bisphosphonates and denosumab was not considered when establishing these recommendations.

French recommendations for osteoporosis prevention and treatment in patients with prostate cancer treated by androgen deprivation.

Androgen-deprivation therapy (ADT) in patients with prostate cancer can be achieved surgically or chemically, notably by prescribing LHRH analogs. Major bone loss occurs rapidly in both cases, due to the decrease in testosterone levels, and can increase the fracture risk. The objective of developing these recommendations was to achieve a practical consensus among various scientific societies, based on a literature review, about osteoporosis prevention and treatment in patients on ADT. The following scientific societies contributed to the work: Société française de rhumatologie (SFR), Groupe de recherche et d'information sur les ostéoporoses (GRIO), Groupe européen d'études des métastases osseuses (GEMO), Association francophone pour les soins de support (AFSOS), Association française d'urologie (AFU), Société française de radiothérapie oncologique (SFRO). Medication prescription and reimbursement modalities in France were taken into account. The recommendations state that a fracture-risk evaluation and interventions targeting risk factors for fractures should be provided to all patients on ADT. Those patients with a history of severe osteoporotic fracture and/or a T-score < -2.5 should receive osteoporosis therapy. Patients whose T-score is between -1.5 and -2.5 should be treated if they exhibit at least two other risk factors among the following: age ≥ 75 years, history of non-severe fracture after 50 years of age, body mass index < 19 kg/m2, at least three comorbidities (e.g., cardiovascular disease, depression, Parkinson's disease, and dementia), current glucocorticoid therapy, and repeated falls. When the decision is difficult, FRAX® score determination and an assessment by a bone disease specialist may be helpful. When osteoporosis therapy is not indicated, general measures should be applied, and bone mineral density measured again after 12-24 months. The anti-tumor effects of bisphosphonates and denosumab fall outside the scope of these recommendations.