Glucagon-like peptide-1 receptor agonists:Exploring the mechanisms from glycemic control to treatment of multisystemic diseases

This editorial takes a deeper look at the insights provided by Soresi and Giannitrapani,which examined the therapeutic potential of glucagon-like peptide-1 receptor agonists(GLP-1RAs)for metabolic dysfunction-associated fatty liver disease.We provide supplementary insights to their research,highlighting the broader systemic implications of GLP-1RAs,synthesizing the current understanding of their mechanisms and the trajectory of research in this field.GLP-1RAs are revolutionizing the treatment of type 2 diabetes mellitus and beyond.Beyond glycemic control,GLP-1RAs demonstrate cardiovascular and renal protective effects,offering potential in managing diabetic kidney disease alongside renin–angiotensin–aldosterone system inhibitors.Their role in bone metabolism hints at benefits for diabetic osteoporosis,while the neuroprotective properties of GLP-1RAs show promise in Alzheimer's disease treatment by modulating neuronal insulin signaling.Additionally,they improve hormonal and metabolic profiles in polycystic ovary syndrome.This editorial highlights the multifaceted mechanisms of GLP-1RAs,emphasizing the need for ongoing research to fully realize their therapeutic potential across a range of multisystemic diseases.

Bone alterations in inflammatory bowel diseases

Inflammatory bowel diseases(IBDs)are characterized by a multifactorial partially unknown etiology that involves genetic,immunological and environmental factors.Up to 50%of IBD patients experience at least one extraintestinal manifestation;among them is the involvement of bone density which is referred to as metabolic bone disease(MBD),including osteopenia and osteoporosis.Bone alterations in IBDs population appear to have a multifactorial etiology:Decreased physical activity,inflammation-related bone resorption,multiple intestinal resections,dietary malabsorption of minerals and vitamin D deficiency,genetic factors,gut-bone immune signaling interaction,steroid treatment,microbiota and pathogenic micro-organisms interaction,and dietary malabsorption of minerals,that,all together or individually,may contribute to the alteration of bone mineral density.This review aims to summarize the prevalence and pathophysiology of metabolic bone alterations in IBD subjects outlining the main risk factors of bone fragility.We also want to underline the role of the screening and prophylaxis of bone alterations in Crohn’s disease and ulcerative colitis patients and the importance of treating appropriately MBD.

Roles and regulation of bone morphogenetic protein-7 in kidney development and diseases

The gene encoding bone morphogenetic protein-7(BMP7) is expressed in the developing kidney in embryos and also in the mature organ in adults. During kidney development, expression of BMP7 is essential to determine the final number of nephrons in and proper size of the organ. The secreted BMP7 acts on the nephron progenitor cells to exert its dual functions: To maintain and expand the progenitor population and to provide them with competence to respond to differentiation cues, each relying on distinct signaling pathways. Intriguingly, in the adult organ, BMP7 has been implicated in protection against and regeneration from injury. Exogenous administration of recombinant BMP7 to animal models of kidney diseases has shown promising effects in counteracting inflammation, apoptosis and fibrosis evoked upon injury. Although the expression pattern of BMP7 has been well described, the mechanisms by which it is regulated have remained elusive and the processes by which the secretion sites of BMP7 impinge upon its functions in kidney development and diseases have not yet been assessed. Understanding the regulatory mechanisms will pave the way towards gaining better insight into the roles of BMP7, and to achieving desired control of the gene expression as a therapeutic strategy for kidney diseases.

Bone loss in chronic liver diseases:Could healthy liver be a requirement for good bone health?

Given that the liver is involved in many metabolic mechanisms,it is not surprising that chronic liver disease(CLD)could have numerous complications.Secondary osteoporosis and increased bone fragility are frequently overlooked complications in CLD patients.Previous studies implied that up to one-third of these individuals meet diagnostic criteria for osteopenia or osteoporosis.Recent publications indicated that CLD-induced bone fragility depends on the etiology,duration,and stage of liver disease.Therefore,the increased fracture risk in CLD patients puts a severe socioeconomic burden on the health system and urgently requires more effective prevention,diagnosis,and treatment measures.The pathogenesis of CLD-induced bone loss is multifactorial and still insufficiently understood,especially considering the relative impact of increased bone resorption and reduced bone formation in these individuals.It is essential to note that inconsistent findings regarding bone mineral density measurement were previously reported in these individuals.Bone mineral density is widely used as the“golden standard”in the clinical assessment of bone fragility although it is not adequate to predict individual fracture risk.Therefore,microscale bone alterations(bone microstructure,mechanical properties,and cellular indices)were analyzed in CLD individuals.These studies further support the thesis that bone strength could be compromised in CLD individuals,implying that an individualized approach to fracture risk assessment and subsequent therapy is necessary for CLD patients.However,more well-designed studies are required to solve the bone fragility puzzle in CLD patients.

Clinical benefits of biochemical markers of bone turnover in Egyptian children with chronic liver diseases

AIM： To investigate the association between serum insulin-like growth factor 1 （IGF-1）, osteocalcin, and parathyroid hormone （PTH） levels with the etiology and clinical condition of patients with chronic liver disease. METHODS： Eighty children with hepatocellular damage were divided into 3 groups according to the etiology of disease infection： bilharziasis （9 patients）, hepatitis B virus （HBV, 12 patients） and hepatitis C virus （HCV, 29 patients）. The Child score index was found as A in 24 patients, B in 22 patients, C in 4 patients. Thirty healthy children served as control group.HBsAg, HBcAbIgM, HBcAbIgG, and anti-HCV were detected using ELISA technique. HCV-RNA was measured by reverse transcription polymerase chain reaction （RT-PCR）. Antibllharzial antibodies were detected by indirect haemagglutination test. Liver function tests were performed using autoanalyser. Serum IGF-1, osteocalcin and PTH levels were measured by ELISA technique. Abdominal ultrasonography was also conducted. RESULTS： Serum IGF-1 level was significantly lower in all patient groups with liver diseases, while serum osteocalcin and PTH levels were significantly elevated in patients with HBV and HCV infections compared with the control group. Serum osteocalcin and PTH concentrations were measured with the severity of liver disease from Child A to C. Child A patients unexpectedly showed significantly reduced IGF-1 levels in comparison to patients staged as Child B or C. Serum osteocalcin level was negatively correlated with albumin （14.7 ± 0.54 vs 3.6 ± 0.10, P 〈 0.05）, while that for PTH was positively correlated with total protein （70.1 ± 2.17 vs 6.7 ± 0.10, P 〈 0.05） in patients with HCV infection.

Epigenetic regulation by long noncoding RNAs in osteo-/adipogenic differentiation of mesenchymal stromal cells and degenerative bone diseases

Bone is a complex tissue that undergoes constant remodeling to maintain homeostasis,which requires coordinated multilineage differentiation and proper proliferation of mesenchymal stromal cells(MSCs).Mounting evidence indicates that a disturbance of bone homeostasis can trigger degenerative bone diseases,including osteoporosis and osteoarthritis.In addition to conventional genetic modifications,epigenetic modifications(i.e.,DNA methylation,histone modifications,and the expression of noncoding RNAs)are considered to be contributing factors that affect bone homeostasis.Long noncoding RNAs(lncRNAs)were previously regarded as‘transcriptional noise’with no biological functions.However,substantial evidence suggests that lncRNAs have roles in the epigenetic regulation of biological processes in MSCs and related diseases.In this review,we summarized the interactions between lncRNAs and epigenetic modifiers associated with osteo-/adipogenic differentiation of MSCs and the pathogenesis of degenerative bone diseases and highlighted promising lncRNA-based diagnostic and therapeutic targets for bone diseases.

Role of fibroblast growth factor receptor 1 in the bone development and skeletal diseases

Accumulating data suggest that FGFs/FGFR1 plays essential roles in the bone development and human skeletal diseases. Conditional inactivation of fgfrl caused different phenotypes displaying in different cells or specific organs and revealed some novel functions of FGFR1 in bone development. Fgfrl mutation mainly induced 2 types of human skeletal diseases, craniosynostosis syndrome and dysplasias. Similar mutation of fgfrl in mouse model just mimicked the phenotype that happened in human. These fa- cilitate the investigation on the underlying mechanism of the diseases. Here we mainly focused on the ad- vance of FGFR1 function in the bone development and its mutation caused skeletal diseases.

Advances and perspectives on cellular therapy in acquired bone marrow failure diseases

Acquired bone marrow failure diseases(ABMFD) are a class of hematopoietic stem cell diseases with a commonality of non-inherited disruption of hematopoiesis that results in pancytopenia. ABMFDs also are a group of heterogeneous diseases with different etiologies and treatment options. The three most common ABMFDs are aplastic anemia, myelodysplastic syndrome, and paroxysmal nocturnal hemoglobinuria. Stem cell transplantation is the only treatment that can cure these diseases. However, due to high therapy-related mortality, stem cell transplantation has rarely been used as a first line treatment in treating ABMFD. With the advance of personalized medicine and precision medicine, various novel cellular therapy strategies are in trial to increase the efficiency and efficacy of ABMFD treatment. This article aims to review current available stem cell transplantation protocols and promising cellular therapy research in treating ABMFD.

Andrias davidianus bone peptides alleviates hyperuricemia-induced kidney damage in vitro and in vivo

Hyperuricemia(HUA)is a vital risk factor for chronic kidney diseases(CKD)and development of functional foods capable of protecting CKD is of importance.This paper aimed to explore the amelioration effects and mechanism of Andrias davidianus bone peptides(ADBP)on HUA-induced kidney damage.In the present study,we generated the standard ADBP which contained high hydrophobic amino acid and low molecular peptide contents.In vitro results found that ADBP protected uric acid(UA)-induced HK-2 cells from damage by modulating urate transporters and antioxidant defense.In vivo results indicated that ADBP effectively ameliorated renal injury in HUA-induced CKD mice,evidenced by a remarkable decrease in serum UA,creatinine and blood urea nitrogen,improving kidney UA excretion,antioxidant defense and histological kidney deterioration.Metabolomic analysis highlighted 14 metabolites that could be selected as potential biomarkers and attributed to the amelioration effects of ADBP on CKD mice kidney dysfunction.Intriguingly,ADBP restored the gut microbiome homeostasis in CKD mice,especially with respect to the elevated helpful microbial abundance,and the decreased harmful bacterial abundance.This study demonstrated that ADBP displayed great nephroprotective effects,and has great promise as a food or functional food ingredient for the prevention and treatment of HUA-induced CKD.

Bone mineral density and disorders of mineral metabolism in chronic liver disease

AIM： To estimate the prevalence and identify the risk factors for metabolic bone disease in patients with cirrhosis. METHODS： The study was performed on 72 Indian patients with cirrhosis （63 male, 9 female; aged 〈 50 years）. Etiology of cirrhosis was alcoholism （n = 37）, hepatitis B （n = 25） and hepatitis C （n = 10）. Twenty-three patients belonged to Child class A, while 39 were in class B and 10 in class C. Secondary causes for metabolic bone disease and osteoporosis were ruled out. Sunlight exposure, physical activity and dietary constituents were calculated. Complete metabolic profiles were derived, and bone mineral density （BMD） was measured using dual energy X ray absorptiometry. Low BMD was defined as a Z score below -2. RESULTS： Low BMD was found in 68% of patients. Lumbar spine was the most frequently and severely affected site. Risk factors for low BMD included low physical activity, decreased sunlight exposure, and low lean body mass. Calcium intake was adequate, with unfavorable calcium： protein ratio and calcium： phosphorus ratio. Vitamin D deficiency was highly prevalent （92%）. There was a high incidence of hypogonadism （41%）. Serum estradiol level was elevated significantly in patients with normal BMD. Insulin-like growth factor （IGF） 1 and IGF binding protein 3 levels were below the age-related normal range in both groups. IGF-1 was significantly lower in patients with low BMD. Serum osteocalcin level was low （68%） and urinary deoxypyridinoline to creatinine ratio was high （79%）, which demonstrated low bone formation with high resorption. CONCLUSION： Patients with cirrhosis have low BMD. Contributory factors are reduced physical activity, low lean body mass, vitamin D deficiency and hypogonadism and low IGF-1 level.

Vanishing bone disease(Gorham-Stout syndrome): A review of a rare entity

Vanishing bone disease(Gorham-Stout syndrome) is a rare entity of unknown etiology, characterized by de struction of osseous matrix and proliferation of vascula structures, resulting in destruction and absorption o bone. Despite the extensive investigation of the patho genetic mechanisms of the disease, its etiology hasn'been clarified and several theories exist. The syndrome can affect one or multiple bones of the patient, includ ing the skull, the upper and lower extremities, the spine and pelvis. The clinical presentation of a patient suffer ing from vanishing bone disease includes, pain, func tional impairment and swelling of the affected region although asymptomatic cases have been reported, as well as cases in which the diagnosis was made after a pathologic fracture. In this short review we summarize the theories regarding the etiology as well as the clini cal presentation, the diagnostic approach and treat ment options of this rare disease.

TGF-β and BMP signaling in osteoblast,skeletal development,and bone formation,homeostasis and disease

INTRODUCTIONThe transforming growth factor-β （TGF-β） superfamily com- prises TGF-βs, Activin, bone morphogenetic proteins （BMPs） and other related proteins. TGF-β superfamily members act through a heteromeric receptor complex,, comprised of type I and type II receptors at the cell surface that transduce intracellular signals via Smad complex or mitogen-activated protein kinase （MAPK） cascade.

Osteoporosis and bone fractures in alcoholic liver disease:A meta-analysis

AIM: To evaluate the association between alcoholic liver disease(ALD) and bone fractures or osteoporosis. METHODS: Non-randomized studies were identified from databases(Pub Med, EMBASE, and the Cochrane Library). The search was conducted using Boolean operators and keywords, which included "alcoholic liver diseases", "osteoporosis", or "bone fractures". The prevalence of any fractures or osteoporosis, and bone mineral density(BMD) were extracted and analyzed using risk ratios and standardized mean difference(SMD). A random effects model was applied. RESULTS: In total, 15 studies were identified and analyzed. Overall, ALD demonstrated a RR of 1.944(95%CI: 1.354-2.791) for the development of bone fractures. However, ALD showed a RR of 0.849(95%CI: 0.523-1.380) for the development of osteoporosis. BMD was not significantly different between the ALD and control groups, although there was a trend toward lower BMD in patients with ALD(SMD in femur-BMD:-0.172, 95%CI:-0.453-0.110; SMD in spine-BMD:-0.169, 95%CI:-0.476-0.138). Sensitivity analyses showed consistent results. CONCLUSION: Current publications indicate significant associations between bone fractures and ALD, independent of BMD or the presence of osteoporosis.

Multiple myeloma mesenchymal stromal cells: Contribution to myeloma bone disease and therapeutics

Multiple myeloma is a hematological malignancy inwhich clonal plasma cells proliferate and accumulate within the bone marrow. The presence of osteolytic le-sions due to increased osteoclast(OC) activity and sup-pressed osteoblast(OB) function is characteristic of the disease. The bone marrow mesenchymal stromal cells(MSCs) play a critical role in multiple myeloma patho-physiology, greatly promoting the growth, survival, drug resistance and migration of myeloma cells. Here, we specifically discuss on the relative contribution of MSCs to the pathophysiology of osteolytic lesions in light of the current knowledge of the biology of my-eloma bone disease(MBD), together with the reported genomic, functional and gene expression differences between MSCs derived from myeloma patients(pMSCs) and their healthy counterparts(dMSCs). Being MSCs the progenitors of OBs, pMSCs primarily contribute to the pathogenesis of MBD because of their reduced osteogenic potential consequence of multiple OB inhibi-tory factors and direct interactions with myeloma cells in the bone marrow. Importantly, pMSCs also readily contribute to MBD by promoting OC formation and ac-tivity at various levels(i.e., increasing RANKL to OPG expression, augmenting secretion of activin A, uncou-pling ephrinB2-EphB4 signaling, and through augment-ed production of Wnt5a), thus further contributing to OB/OC uncoupling in osteolytic lesions. In this review, we also look over main signaling pathways involved in the osteogenic differentiation of MSCs and/or OB activity, highlighting amenable therapeutic targets; in parallel, the reported activity of bone-anabolic agents(at preclinical or clinical stage) targeting those signaling pathways is commented.

Effects of lateral ventricular transplantation of bone marrow-derived mesenchymal stem cells modified with brain-derived neurotrophic factor gene on cognition in a rat model of Alzheimer's disease

In the present study, transplantation of bone marrow-derived mesenchymal stem cells modified with brain-derived neurotrophic factor gene into the lateral ventricle of a rat model of Alzheimer＇s disease, resulted in significant attenuation of nerve cell damage in the hippocampal CA1 region. Furthermore, brain-derived neurotrophic factor and tyrosine kinase B mRNA and protein levels were significantly increased, and learning and memory were significantly improved. Results indicate that transplantation of bone marrow-derived mesenchymal stem cells modified with brain-derived neurotrophic factor gene can significantly improve cognitive function in a rat model of Alzheimer＇s disease, possibly by increasing the levels of brain-derived neurotrophic factor and tyrosine kinase B in the hippocampus.

Assessment of bone turnover and bone quality in type 2 diabetic bone disease： current concepts and future directions

Substantial evidence exists that in addition to the well-known complications of diabetes, increased fracture risk is an important morbidity. This risk is probably due to altered bone properties in diabetes. Circulating biochemical markers of bone turnover have been found to be decreased in type 2 diabetes （T2D） and may be predictive of fractures independently of bone mineral density （BMD）. Serum sclerostin levels have been found to be increased in T2D and appear to be predictive of fracture risk independent of BMD. Bone imaging technologies, including trabecular bone score （TBS） and quantitative CT testing have revealed differences in diabetic bone as compared to non-diabetic individuals. Specifically, high resolution peripheral quantitative CT （HRpQCT） imaging has demonstrated increased cortical porosity in diabetic postmenopausal women. Other factors such as bone marrow fat saturation and advanced glycation endproduct （AGE） accumulation might also relate to bone cell function and fracture risk in diabetes. These data have increased our understanding of how T2D adversely impacts both bone metabolism and fracture risk.

Non-alcoholic fatty liver disease connections with fat-free tissues: A focus on bone and skeletal muscle

The estimates of global incidence and prevalence of non-alcoholic fatty liver disease(NAFLD) are worrisome, due to the parallel burden of obesity and its metabolic complications. Indeed, excess adiposity and insulin resistance represent two of the major risk factors for NAFLD; interestingly, in the last years a growing body of evidence tended to support a novel mechanistic perspective, in which the liver is at the center of a complex interplay involving organs and systems, other than adipose tissue and glucose homeostasis. Bone and the skeletal muscle are fat- free tissues which appeared to be independently associated with NAFLD in several cross-sectional studies. The deterioration of bone mineral density and lean body mass, leading to osteoporosis and sarcopenia, respectively, are age-related processes. The prevalence of NAFLD also increases with age. Beyond physiological aging, the three conditions share some common underlying mechanisms, and their elucidations could be of paramount importance to design more effective treatment strategies for the management of NAFLD. In this review, we provide an overview on epidemiological data as well as on potential contributors to the connections of NAFLD with bone and skeletal muscle.

Bone changes in alcoholic liver disease

Alcoholism has been associated with growth impairment, osteomalacia, delayed fracture healing, and aseptic necrosis(primarily necrosis of the femoral head), but the main alterations observed in the bones of alcoholic patients are osteoporosis and an increased risk of fractures. Decreased bone mass is a hallmark of osteoporosis, and it may be due either to decreased bone synthesis and/or to increased bone breakdown. Ethanol may affect both mechanisms. It is generally accepted that ethanol decreases bone synthesis, and most authors have reported decreased osteocalcin levels(a "marker" of bone synthesis), but some controversy exists regarding the effect of alcohol on bone breakdown, and, indeed, disparate results have been reported for telopeptide and other biochemical markers of bone resorption. In addition to the direct effect of ethanol, systemic alterations such as malnutrition, malabsorption, liver disease, increased levels of proinflammatory cytokines, alcoholic myopathy and neuropathy, low testosterone levels, and an increased risk of trauma, play contributory roles. The treatment of alcoholic bone disease should be aimed towards increasing bone formation and decreasing bone degradation. In this sense, vitamin D and calcium supplementation, together with biphosphonates are essential, but alcohol abstinence and nutritional improvement are equally important. In this review we study the pathogenesis of bone changes in alcoholic liver disease and discuss potential therapies.

The dependences of osteocyte network on bone compartment, age, and disease

Osteocytes, the most abundant bone cells, form an interconnected network in the lacunar-canalicular pore system （LCS） buried within the mineralized matrix, which allows osteocytes to obtain nutrients from the blood supply, sense external mechanical signals, and communicate among themselves and with other cells on bone surfaces. In this study, we examined key features of the LCS network including the topological parameter and the detailed structure of individual connections and their variations in cortical and cancellous compa~ tments, at different ages, and in two disease conditions with altered mechanosensing （perlecan deficiency and diabetes）. LCS network showed both topological stability, in terms of conservation of connectivity among osteocyte lacunae （similar to the ＂nodes＂ in a computer network）, and considerable variability the pericellular annular fluid gap surrounding lacunae and canaliculi （similar to the ＂bandwidth＂ of individual links in a computer network）. Age, in the range of our study （15-32 weeks）, affected only the pericellular fluid annulus in cortical bone but not in cancellous bone. Diabetes impacted the spacing of the lacunae, while the perlecan deficiency had a profound influence on the pericellular fluid annulus. The LCS network features play important roles in osteocyte signaling and regulation of bone growth and adaptation.

Systematic review of the prevalence and development of osteoporosis or low bone mineral density and its risk factors in patients with inflammatory bowel disease

BACKGROUND The inflammatory bowel diseases(IBD),Crohn’s disease(CD)and ulcerative colitis(UC)are chronic,immune-mediated disorders of the digestive tract.IBD is considered to be a risk factor for developing osteoporosis;however current literature on this matter is inconsistent.AIM To assess prevalence and development of osteoporosis and low bone mineral density(BMD),and its risk factors,in IBD patients.METHODS Systematic review of population-based studies.Studies were identified by electronic(January 2018)and manual searches(May 2018).Databases searched included EMBASE and PubMed and abstracts from 2014-2018 presented at the United European Gastroenterology Week,the European Crohn’s and Colitis Organisation congress,and Digestive Disease Week were screened.Studies were eligible for inclusion if they investigated either the prevalence of osteoporosis or osteopenia and/or risk factors for osteoporosis or low BMD in IBD patients.Studies on children under the age of 18 were excluded.Only population-based studies were included.All risk factors for osteoporosis and low BMD investigated in any included article were considered.Study quality and the possibility of bias were analysed using the Newcastle-Ottawa scale.RESULTS Twelve studies including 3661 IBD patients and 12789 healthy controls were included.Prevalence of osteoporosis varied between 4%-9%in studies including both CD and UC patients;2%-9% in studies including UC patients, and 7%-15% instudies including CD patients. Among healthy controls, prevalence ofosteoporosis was 3% and 10% in two studies. CD diagnosis, lower body massindex (BMI), and lower body weight were risk factors associated withosteoporosis or low BMD. Findings regarding gender showed inconsistent results.CD patients had an increased risk for osteoporosis or low BMD over time, whileUC patients did not. Increased age was associated with decreased BMD, and therewas a positive association between weight and BMI and BMD over time. Greatheterogeneity was found in the included studies in terms of study methodologies,definitions and the assessment of osteoporosis, and only a small number ofpopulation-based studies was available.CONCLUSIONThis systematic review found a possible increase of prevalence of osteoporosis inCD cohorts when compared to UC and cohorts including both disease types.Lower weight and lower BMI were predictors of osteoporosis or low BMD in IBDpatients. The results varied considerably between studies.