Reduced Serum IGF-1 Associated With Hepatic Osteodystrophy Is a Main Determinant of Low Cortical but Not Trabecular Bone Mass

Liver function linked to bone health: A bibliometric of the liver-bone axis

BACKGROUND

The liver exerts profound influence on skeletal health, while osseous tissues reciprocally modulate hepatic function. This bidirectional metabolic axis between these two organ systems plays a pivotal role in both physiological homeostasis and pathological states.

AIM

To investigate and analyze the literatures on liver-bone axis using bibliometrics.

METHODS

A comprehensive literature search pertaining to the liver-bone axis was conducted using the Science Citation Index Expanded within the Web of Science Core Collection. Subsequently, visualization and bibliometric analyses were performed utilizing VOSviewer (version 1.6.20), Citespace (version 6.2.R4), and the R programming language.

RESULTS

This comprehensive analysis encompasses 855 publications, comprising 694 articles and 161 reviews, authored by 4988 researchers from 425 institutions across 61 countries. The United States and China emerge as the leading nations in terms of publication volume. The University of California system stands out as the most influential institution in liver-bone axis research. Guanabens N is identified as the most prolific author in this field. The annual increase in publications related to the liver-bone axis underscores its growing prominence as a research focus. The study highlights key areas of investigation, including osteoporosis, bone metabolism, non-alcoholic fatty liver disease, and insulin-like growth factor-1, which represent both current and prospective hot topics within this domain.

CONCLUSION

This investigation employs bibliometric methodologies to conduct a systematic analysis of liver-bone axis literature spanning from 2001 to 2024. The exponential growth in publications over the past two decades underscores the significance of synthesizing research outcomes in this domain. Through rigorous statistical analyses, we delineate fundamental contributions to the field while providing strategic direction for emerging scholars. Furthermore, we illuminate current research trajectories and identify promising future investigative directions. Investigation of the liver-bone axis enhances our comprehension of inter-organ communication networks. Conceptualizing these organs as an integrated system provides profound insights into pathophysiological mechanisms and disease management strategies. This paradigm not only facilitates the development of sophisticated diagnostic modalities but also catalyzes the discovery of novel therapeutic agents targeting these mechanistic pathways, thereby advancing our capacity to diagnose and treat hepatic and skeletal disorders.

Establishment of a human 3D in vitro liver-bone model as a potential system for drug toxicity screening

Drug toxicity is an important cause of chronic liver damage, which in the long term can lead to impaired bone homeostasis through an imbalance in the liver-bone axis. For instance, non-steroidal anti-inflammatory drugs (e.g., diclofenac), which are commonly used to control pain during orthopaedic interventions, are known to reduce bone quality and are the most prevalent causes of drug-induced liver damage. Therefore, we used human cell lines to produce a stable, reproducible, and reliable in vitro liver-bone co-culture model, which mimics the impaired bone homeostasis seen after diclofenac intake in vivo. To provide the best cell culture conditions for the two systems, we tested the effects of supplements contained in liver and bone cell culture medium on liver and bone cell lines, respectively. Additionally, different ratios of culture medium combinations on bone cell scaffolds and liver spheroids' viability and function were also analysed. Then, liver spheroids and bone scaffolds were daily exposed to 3-6 µM diclofenac alone or in co-culture to compare and evaluate its effect on the liver and bone system. Our results demonstrated that a 50:50 liver:bone medium combination maintains the function of liver spheroids and bone scaffolds for up to 21 days. Osteoclast-like cell activity was significantly upregulated after chronic exposure to diclofenac only in bone scaffolds co-cultured with liver spheroids. Consequently, the mineral content and stiffness of bone scaffolds treated with diclofenac in co-culture with liver spheroids were significantly reduced. Interestingly, our results show that the increase in osteoclastic activity in the system is not related to the main product of diclofenac metabolism. However, osteoclast activation correlated with the increase in oxidative stress and inflammation associated with chronic diclofenac exposure. In summary, we established a long-term stable liver-bone system that represents the interaction between the two organs, meanwhile, it is also an outstanding model for studying the toxicity of drugs on bone homeostasis.

Mendelian randomization to evaluate the causal relationship between liver enzymes and the risk of six specific bone and joint-related diseases

Background

Studies of liver dysfunction in relation to bone and joint-related diseases are scarce, and its causality remains unclear. Our objective was to investigate whether serum liver enzymes are causally associated with bone and joint-related diseases using Mendelian randomization (MR) designs.

Methods

Genetic data on serum liver enzymes (alkaline phosphatase (ALP); alanine transaminase (ALT); gamma-glutamyl transferase (GGT)) and six common bone and joint-related diseases (rheumatoid arthritis (RA), osteoporosis, osteoarthritis (OA), ankylosing spondylitis, psoriatic arthritis, and gout) were derived from independent genome-wide association studies of European ancestry. The inverse variance-weighted (IVW) method was applied for the main causal estimate. Complementary sensitivity analyses and reverse causal analyses were utilized to confirm the robustness of the results.

Results

Using the IVW method, the positive causality between ALP and the risk of osteoporosis diagnosed by bone mineral density (BMD) at different sites was indicated (femoral neck, lumbar spine, and total body BMD, odds ratio (OR) [95% CI], 0.40 [0.23-0.69], 0.35 [0.19-0.67], and 0.33 [0.22-0.51], respectively). ALP was also linked to a higher risk of RA (OR [95% CI], 6.26 [1.69-23.51]). Evidence of potential harmful effects of higher levels of ALT on the risk of hip and knee OA was acquired (OR [95% CI], 2.48 [1.39-4.41] and 3.07 [1.49-6.30], respectively). No causal relationship was observed between GGT and these bone and joint-related diseases. The study also found that BMD were all negatively linked to ALP levels (OR [95% CI] for TBMD, FN-BMD, and LS-BMD: 0.993 [0.991-0.995], 0.993 [0.988-0.998], and 0.993 [0.989, 0.998], respectively) in the reverse causal analysis. The results were replicated via sensitivity analysis in the validation process.

Conclusions

Our study revealed a significant association between liver function and bone and joint-related diseases.

The roles of hepatokine and osteokine in liver-bone crosstalk: Advance in basic and clinical aspects

Both the liver and bone are important secretory organs in the endocrine system. By secreting organ factors (hepatokines), the liver regulates the activity of other organs. Similarly, bone-derived factors, osteokines, are created during bone metabolism and act in an endocrine manner. Generally, the dysregulation of hepatokines is frequently accompanied by changes in bone mass, and osteokines can also disrupt liver metabolism. The crosstalk between the liver and bone, particularly the function and mechanism of hepatokines and osteokines, has increasingly gained notoriety as a topic of interest in recent years. Here, based on preclinical and clinical evidence, we summarize the potential roles of hepatokines and osteokines in liver-bone interaction, discuss the current shortcomings and contradictions, and make recommendations for future research.

The role of insulin-like growth factor-1 in bone remodeling: A review

Insulin-like growth factor (IGF)-1 is a polypeptide hormone with vital biological functions in bone cells. The abnormal expression of IGF-1 has a serious effect on bone growth, particularly bone remodeling. Evidence from animal models and human disease suggested that both IGF-1 deficiency and excess cause changes in bone remodeling equilibrium, resulting in profound alterations in bone mass and development. Here, we first introduced the functions and mechanisms of the members of IGFs in bone. Subsequently, the critical role of IGF-1 in the process of bone remodeling were emphasized from the aspects of bone resorption and bone formation respectively. This review explains the mechanism of IGF-1 in maintaining bone mass and bone homeostasis to a certain extent and provides a theoretical basis for further research.

The Impacts of Combined Blood Flow Restriction Training and Betaine Supplementation on One-Leg Press Muscular Endurance, Exercise-Associated Lactate Concentrations, Serum Metabolic Biomarkers, and Hypoxia-Inducible Factor-1α Gene Expression

The purpose of this investigation was to compare the impacts of a potential blood flow restriction (BFR)-betaine synergy on one-leg press performance, lactate concentrations, and exercise-associated biomarkers. Eighteen recreationally trained males (25 ± 5 y) were randomized to supplement 6 g/day of either betaine anhydrous (BET) or cellulose placebo (PLA) for 14 days. Subsequently, subjects performed four standardized sets of one-leg press and two additional sets to muscular failure on both legs (BFR [LL-BFR; 20% 1RM at 80% arterial occlusion pressure] and high-load [HL; 70% 1RM]). Toe-tip lactate concentrations were sampled before (PRE), as well as immediately (POST0), 30 min (POST30M), and 3 h (POST3H) post-exercise. Serum homocysteine (HCY), growth hormone (GH) and insulin-like growth factor-1 concentrations were additionally assessed at PRE and POST30M. Analysis failed to detect any significant between-supplement differences for total repetitions completed. Baseline lactate changes (∆) were significantly elevated from POST0 to POST30 and from POST30 to POST3H (p < 0.05), whereby HL additionally demonstrated significantly higher ∆Lactate versus LL-BFR (p < 0.001) at POST3H. Although serum ∆GH was not significantly impacted by supplement or condition, serum ∆IGF-1 was significantly (p = 0.042) higher in BET versus PLA and serum ∆HCY was greater in HL relative to LL-BFR (p = 0.044). Although these data fail to support a BFR-betaine synergy, they otherwise support betaine’s anabolic potential.

Emerging roles of growth factors in osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a potentially disabling orthopedic condition that requires total hip arthroplasty in most late-stage cases. However, mechanisms underlying the development of ONFH remain unknown, and the therapeutic strategies remain limited. Growth factors play a crucial role in different physiological processes, including cell proliferation, invasion, metabolism, apoptosis, and stem cell differentiation. Recent studies have reported that polymorphisms of growth factor-related genes are involved in the pathogenesis of ONFH. Tissue and genetic engineering are attractive strategies for treating early-stage ONFH. In this review, we summarized dysregulated growth factor-related genes and their role in the occurrence and development of ONFH. In addition, we discussed their potential clinical applications in tissue and genetic engineering for the treatment of ONFH.

Musculoskeletal Effects of Altered GH Action

Growth hormone (GH) is a peptide hormone that can signal directly through its receptor or indirectly through insulin-like growth factor 1 (IGF-1) stimulation. GH draws its name from its anabolic effects on muscle and bone but also has distinct metabolic effects in multiple tissues. In addition to its metabolic and musculoskeletal effects, GH is closely associated with aging, with levels declining as individuals age but GH action negatively correlating with lifespan. GH’s effects have been studied in human conditions of GH alteration, such as acromegaly and Laron syndrome, and GH therapies have been suggested to combat aging-related musculoskeletal diseases, in part, because of the decline in GH levels with advanced age. While clinical data are inconclusive, animal models have been indispensable in understanding the underlying molecular mechanisms of GH action. This review will provide a brief overview of the musculoskeletal effects of GH, focusing on clinical and animal models.

Osteosarcopenia in autoimmune cholestatic liver diseases: Causes, management, and challenges

Primary biliary cholangitis and primary sclerosing cholangitis (PSC) are the most common cholestatic liver diseases (CLD) in adults and are both characterized by an immune pathogenesis. While primary biliary cholangitis is a model autoimmune disease, with over 90% of patients presenting very specific autoantibodies against mitochondrial antigens, PSC is considered an immune mediated disease. Osteoporosis is the most common bone disease in CLD, resulting in frequent fractures and leading to significant morbidity. Further, sarcopenia is emerging as a frequent complication of chronic liver diseases with a significant prognostic impact and severe implications on the quality of life of patients. The mechanisms underlying osteoporosis and sarcopenia in CLD are still largely unknown and the association between these clinical conditions remains to be dissected. Although timely diagnosis, prevention, and management of osteosarcopenia are crucial to limit the consequences, there are no specific guidelines for management of osteoporosis and sarcopenia in patients with CLD. International guidelines recommend screening for bone disease at the time of diagnosis of CLD. However, the optimal monitoring strategies and treatments have not been defined yet and vary among centers. We herein aim to comprehensively outline the pathogenic mechanisms and clinical implications of osteosarcopenia in CLD, and to summarize expert recommendations for appropriate diagnostic and therapeutic approaches.

Reverse cholesterol transport and hepatic osteodystrophy

In this issue of Cell Metabolism, Lu et al. show that chronic liver disease increases the expression and activity of PP2Ac, a phosphatase that downregulates the excretion of lecithin-cholesterol aceyltransferase (LCAT). LCAT, a liver-derived enzyme, protects bone and prevents bone loss, and its lowered levels in progressive liver injury cause hepatic osteodystrophy (HOD) and worsen liver fibrosis. These discoveries open the possibility that recombinant LCAT may be a treatment for both HOD and liver fibrosis.

Induction of somatopause in adult mice compromises bone morphology and exacerbates bone loss during aging

Somatopause refers to the gradual declines in growth hormone (GH) and insulin‐like growth factor‐1 throughout aging. To define how induced somatopause affects skeletal integrity, we used an inducible GH receptor knockout (iGHRKO) mouse model. Somatopause, induced globally at 6 months of age, resulted in significantly more slender bones in both male and female iGHRKO mice. In males, induced somatopause was associated with progressive expansion of the marrow cavity leading to significant thinning of the cortices, which compromised bone strength. We report progressive declines in osteocyte lacunar number, and increases in lacunar volume, in iGHRKO males, and reductions in lacunar number accompanied by ~20% loss of overall canalicular connectivity in iGHRKO females by 30 months of age. Induced somatopause did not affect mineral/matrix ratio assessed by Raman microspectroscopy. We found significant increases in bone marrow adiposity and high levels of sclerostin, a negative regulator of bone formation in iGHRKO mice. Surprisingly, however, despite compromised bone morphology, osteocyte senescence was reduced in the iGHRKO mice. In this study, we avoided the confounded effects of constitutive deficiency in the GH/IGF‐1 axis on the skeleton during growth, and specifically dissected its effects on the aging skeleton. We show here, for the first time, that induced somatopause compromises bone morphology and the bone marrow environment.

Influencing Factors and Molecular Pathogenesis of Sarcopenia and Osteosarcopenia in Chronic Liver Disease

The liver plays a pivotal role in nutrient/energy metabolism and storage, anabolic hormone regulation, ammonia detoxification, and cytokine production. Impaired liver function can cause malnutrition, hyperammonemia, and chronic inflammation, leading to an imbalance between muscle protein synthesis and proteolysis. Patients with chronic liver disease (CLD) have a high prevalence of sarcopenia, characterized by progressive loss of muscle mass and function, affecting health-related quality of life and prognosis. Recent reports have revealed that osteosarcopenia, defined as the concomitant occurrence of sarcopenia and osteoporosis, is also highly prevalent in patients with CLD. Since the differentiation and growth of muscles and bones are closely interrelated through mechanical and biochemical communication, sarcopenia and osteoporosis often progress concurrently and affect each other. Osteosarcopenia further exacerbates unfavorable health outcomes, such as vertebral fracture and frailty. Therefore, a comprehensive assessment of sarcopenia, osteoporosis, and osteosarcopenia, and an understanding of the pathogenic mechanisms involving the liver, bones, and muscles, are important for prevention and treatment. This review summarizes the molecular mechanisms of sarcopenia and osteosarcopenia elucidated to data in hopes of promoting advances in treating these musculoskeletal disorders in patients with CLD.

GH directly inhibits steatosis and liver injury in a sex-dependent and IGF1-independent manner

A reduction in hepatocyte growth hormone (GH)-signaling promotes non-alcoholic fatty liver disease (NAFLD). However, debate remains as to the relative contribution of the direct effects of GH on hepatocyte function vs indirect effects, via alterations in insulin-like growth factor 1 (IGF1). To isolate the role of hepatocyte GH receptor (GHR) signaling, independent of changes in IGF1, mice with adult-onset, hepatocyte-specific GHR knockdown (aHepGHRkd) were treated with a vector expressing rat IGF1 targeted specifically to hepatocytes. Compared to GHR-intact mice, aHepGHRkd reduced circulating IGF1 and elevated GH. In male aHepGHRkd, the shift in IGF1/GH did not alter plasma glucose or non-esterified fatty acids (NEFA), but was associated with increased insulin, enhanced systemic lipid oxidation and reduced white adipose tissue (WAT) mass. Livers of male aHepGHRkd exhibited steatosis associated with increased de novo lipogenesis, hepatocyte ballooning and inflammation. In female aHepGHRkd, hepatic GHR protein levels were not detectable, but moderate levels of IGF1 were maintained, with minimal alterations in systemic metabolism and no evidence of steatosis. Reconstitution of hepatocyte IGF1 in male aHepGHRkd lowered GH and normalized insulin, whole body lipid utilization and WAT mass. However, IGF1 reconstitution did not reduce steatosis or eliminate liver injury. RNAseq analysis showed IGF1 reconstitution did not impact aHepGHRkd-induced changes in liver gene expression, despite changes in systemic metabolism. These results demonstrate the impact of aHepGHRkd is sexually dimorphic and the steatosis and liver injury observed in male aHepGHRkd mice is autonomous of IGF1, suggesting GH acts directly on the adult hepatocyte to control NAFLD progression.

Potential applications for rhIGF-I: Bone disease and IGFI

Growth hormone (GH) and insulin like growth factor-I (IGFI) are key bone trophic hormones, whose rising levels during puberty are critical for pubertal bone accrual. Conditions of GH deficiency and genetic resistance impact cortical and trabecular bone deleteriously with reduced estimates of bone strength. In humans, conditions of undernutrition (as in anorexia nervosa (AN), or subsequent to chronic illnesses) are associated with low IGF-I levels, which correlate with disease severity, and also with lower bone mineral density (BMD), impaired bone structure and lower strength estimates. In adolescents and adults with AN, studies have demonstrated a nutritionally acquired GH resistance with low IGF-I levels despite high concentrations of GH. IGF-I levels go up with increasing body weight, and are associated with rising levels of bone turnover markers. In short-term studies lasting 6-10 days, recombinant human IGF-I (rhIGF-I) administration in physiologic replacement doses normalized IGF-I levels and increased levels of bone formation markers in both adults and adolescents with AN. In a randomized controlled trial in adults with AN in which participants were randomized to one of four arms: (i) rhIGF-I with oral estrogen-progesterone (EP), (ii) rhIGF-I alone, (iii) EP alone, or (iv) neither for 9 months, a significant increase in bone formation markers was noted in the groups that received rhIGF-I, and a significant decrease in bone resorption markers in the groups that received EP. The group that received both rhIGF-I and EP had a significant increase in bone density at the spine and hip compared to the group that received neither. Side effects were minimal, with no documented fingerstick glucose of <50 mg/dl. These data thus suggest a potential role for rhIGF-I administration in optimizing bone accrual in states of undernutrition associated with low IGF-I.

Comparative assessment of sarcopenia using the JSH, AWGS, and EWGSOP2 criteria and the relationship between sarcopenia, osteoporosis, and osteosarcopenia in patients with liver cirrhosis

BACKGROUND

Sarcopenia and osteoporosis reduce life quality and worsen prognosis in patients with liver cirrhosis (LC). When these two complications coexist, a diagnosis of osteosarcopenia is made. We aimed to investigate the actual situations of sarcopenia, osteoporosis, osteosarcopenia, and vertebral fracture, and to clarify the relationship among these events in patients with LC.

METHODS

We describe a cross-sectional study of 142 patients with LC. Sarcopenia was defined according to the Japan Society of Hepatology (JSH) criteria, Asian Working Group for Sarcopenia (AWGS) criteria, and European Working Group on Sarcopenia in Older People (EWGSOP2) criteria. The skeletal muscle mass index (SMI) and handgrip strength were assessed using bioelectrical impedance analysis and a digital grip strength dynamometer, respectively. Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry, and vertebral fracture was evaluated using spinal lateral X-rays. The severity of LC was assessed using the Child-Pugh classification.

RESULTS

Among the 142 patients, the prevalence of sarcopenia was 33.8% (48/142) according to the JSH and AWGS criteria and 28.2% (40/142) according to the EWGSOP2 criteria. The number of patients with osteoporosis, osteosarcopenia, and vertebral fracture was 49 (34.5%), 31 (21.8%), and 41 (28.9%), respectively. Multivariate analysis revealed a close association between sarcopenia and osteoporosis. Osteoporosis was independently associated with sarcopenia [odds ratio (OR) = 3.923, P = 0.010]. Conversely, sarcopenia was independently associated with osteoporosis (OR = 5.722, P < 0.001). Vertebral fracture occurred most frequently in patients with osteosarcopenia (19/31; 61.3%) and least frequently in those without both sarcopenia and osteoporosis (12/76; 15.8%). The SMI and handgrip strength values were significantly correlated with the BMD of the lumbar spine (r = 0.55 and 0.51, respectively; P < 0.001 for both), femoral neck, (r = 0.67 and 0.62, respectively; P < 0.001 for both), and total hip (r = 0.67 and 0.61, respectively; P < 0.001 for both).

CONCLUSIONS

Sarcopenia, osteoporosis, osteosarcopenia, and vertebral fracture were highly prevalent and closely associated with one another in patients with LC. Specifically, patients with osteosarcopenia had the highest risk of vertebral fractures. Early diagnosis of these complications is essential for treatment intervention.

IGF-1 polymorphisms modulate the susceptibility to osteonecrosis of the femoral head among Chinese Han population

The study was performed to investigate the genetic associations of IGF-1 polymorphisms rs35767, rs5742714, and rs972936 with susceptibility to osteonecrosis of the femoral head (ONFH) among Chinese Han population.Totally, 101 ONFH patients and 128 healthy controls were enrolled. Hardy-Weinberg equilibrium (HWE) was detected with chi-square test in control group. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated to estimate the relationship between IGF-1 polymorphisms and ONFH risk. Besides, hyplotype analysis was performed to examine linkage disequilibrium between the studied polymorphisms.Genotype AA and allele A of polymorphism rs35767 were more frequent in control group, and offered protection for ONFH onset (AA: OR = 0.382, 95% CI = 0.158-0.923; A: OR = 0.650, 95% CI = 0.442-0.956). Furthermore, the negative relationship was also observed between ONFH risk and polymorphism rs5742714 under the comparisons CG vs CC, and G vs C (OR = 0.395, 95%CI = 0.199-0.787; OR = 0.346, 95%CI = 0.191-0.627). While the polymorphism rs972936 significantly enhanced the disease risk (CT vs CC: OR = 2.434, 95% CI = 1.184-5.003; TT vs CC: OR = 2.497, 95% CI = 1.040-5.990). Furthermore, haplotype analysis demonstrated that C-T (rs5742714-rs972936) could increase ONFH risk (OR = 2.177, 95% CI = 1.444-3.283), while G-T might be a protective factor for ONFH (OR = 0.472, 95% CI = 0.254-0.878).IGF-1 polymorphisms rs35767, rs5742714, and rs972936 show significant association with ONFH risk.

Hepatic Osteodystrophy-Molecular Mechanisms Proposed to Favor Its Development

Almost all patients with chronic liver diseases (CLD) show altered bone metabolism. Depending on the etiology, this manifests in a severe osteoporosis in up to 75% of the affected patients. Due to high prevalence, the generic term hepatic osteodystrophy (HOD) evolved, describing altered bone metabolism, decreased bone mineral density, and deterioration of bone structure in patients with CLD. Once developed, HOD is difficult to treat and increases the risk of fragility fractures. Existing fractures affect the quality of life and, more importantly, long-term prognosis of these patients, which presents with increased mortality. Thus, special care is required to support the healing process. However, for early diagnosis (reduce fracture risk) and development of adequate treatment strategies (support healing of existing fractures), it is essential to understand the underlying mechanisms that link disturbed liver function with this bone phenotype. In the present review, we summarize proposed molecular mechanisms favoring the development of HOD and compromising the healing of associated fractures, including alterations in vitamin D metabolism and action, disbalances in transforming growth factor beta (TGF-β) and bone morphogenetic protein (BMP) signaling with histone deacetylases (HDACs) as secondary regulators, as well as alterations in the receptor activator of nuclear factor kappa B ligand (RANKL)–osteoprotegerin (OPG) system mediated by sclerostin. Based on these mechanisms, we give an overview on the limitations of early diagnosis of HOD with established serum markers.

Osteoporosis and Jaw Abnormalities in Panoramic Radiography of Chronic Liver Failure Patients

INTRODUCTION

Patients with chronic liver failure (CLF) are faced with many complications, because this organ is involved in various metabolic activities. Hepatic osteodystrophy is one of the major health issues encountered by this group of patients. The current study evaluated osteoporosis and bone changes in oral panoramic radiographies of cirrhotic patients.

MATERIALS AND METHODS

In this study, 138 panoramic views of CLF patients, candidates for liver transplant (65 females, 73 males, aged 19-68 years) referred to Shiraz University Dental Clinic (Shiraz, Iran) for pretransplant oral examination, were evaluated. Also 138 healthy individuals (69 females, 69 males, aged 18-70 years) referred to the same clinic were examined. Abnormalities such as osteoporosis, pathologic radiolucencies, pathologic calcifications, tonsilloliths, condylar degeneration, and other findings in the alveolar bones were recorded.

RESULTS

Osteoporosis was a common finding in CLF patients (p<0.001), and the probability of detecting low bone density in the panoramic view was 20.37 times higher among patients than healthy subjects. The probability of detecting pathologic jaw radiolucencies was 8.92 times higher in the case group than in the controls (p<0.001). Other bone abnormalities such as condylar degeneration and idiopathic osteosclerosis were also more prevalent in CLF patients compared to healthy subjects (p<0.001).

CONCLUSION

Cirrhotic patients are prone to osteoporosis of the alveolar bones. Also, pathologic jaw radiolucencies as a result of oral infections are more prevalent in this group of patients. Routine oral panoramic views are acceptable and cost-effective radiographies for use in detecting such abnormalities in the alveolar bones as well as overall dental health. These findings also support the importance of dental health examinations prior to liver transplantation to reduce the risk of organ rejection.

Insulin-like growth factors: actions on the skeleton

The discovery of the growth hormone (GH)-mediated somatic factors (somatomedins), insulin-like growth factor (IGF)-I and -II, has elicited an enormous interest primarily among endocrinologists who study growth and metabolism. The advancement of molecular endocrinology over the past four decades enables investigators to re-examine and refine the established somatomedin hypothesis. Specifically, gene deletions, transgene overexpression or more recently, cell-specific gene-ablations, have enabled investigators to study the effects of the Igf1 and Igf2 genes in temporal and spatial manners. The GH/IGF axis, acting in an endocrine and autocrine/paracrine fashion, is the major axis controlling skeletal growth. Studies in rodents have clearly shown that IGFs regulate bone length of the appendicular skeleton evidenced by changes in chondrocytes of the proliferative and hypertrophic zones of the growth plate. IGFs affect radial bone growth and regulate cortical and trabecular bone properties via their effects on osteoblast, osteocyte and osteoclast function. Interactions of the IGFs with sex steroid hormones and the parathyroid hormone demonstrate the significance and complexity of the IGF axis in the skeleton. Finally, IGFs have been implicated in skeletal aging. Decreases in serum IGFs during aging have been correlated with reductions in bone mineral density and increased fracture risk. This review highlights many of the most relevant studies in the IGF research landscape, focusing in particular on IGFs effects on the skeleton.