Etiopathogenesis of hepatic osteodystrophy in Wistar rats with cholestatic liver disease

Targeting hepatic oxidative stress rescues bone loss in liver fibrosis

OBJECTIVE

Chronic liver diseases often involve metabolic damage to the skeletal system. The underlying mechanism of bone loss in chronic liver diseases remains unclear, and appropriate therapeutic options, except for orthotopic liver transplantation, have proved insufficient for these patients. This study aimed to investigate the efficacy and mechanism of transplantation of immature hepatocyte-like cells converted from stem cells from human exfoliated deciduous teeth (SHED-Heps) in bone loss of chronic liver fibrosis.

METHODS

Mice that were chronically treated with CCl₄ received SHED-Heps, and trabecular bone density, reactive oxygen species (ROS), and osteoclast activity were subsequently analyzed in vivo and in vitro. The effects of stanniocalcin 1 (STC1) knockdown in SHED-Heps were also evaluated in chronically CCl₄ treated mice.

RESULTS

SHED-Hep transplantation (SHED-HepTx) improved trabecular bone loss and liver fibrosis in chronic CCl₄-treated mice. SHED-HepTx reduced hepatic ROS production and interleukin 17 (Il-17) expression under chronic CCl₄ damage. SHED-HepTx reduced the expression of both Il-17 and tumor necrosis factor receptor superfamily 11A (Tnfrsf11a) and ameliorated the imbalance of osteoclast and osteoblast activities in the bone marrow of CCl₄-treated mice. Functional knockdown of STC1 in SHED-Heps attenuated the benefit of SHED-HepTx including anti-bone loss effect by suppressing osteoclast differentiation through TNFSF11-TNFRSF11A signaling and enhancing osteoblast differentiation in the bone marrow, as well as anti-fibrotic and anti-ROS effects in the CCl₄-injured livers.

CONCLUSIONS

These findings suggest that targeting hepatic ROS provides a novel approach to treat bone loss resulting from chronic liver diseases.

Acacia sieberiana (Fabaceae) attenuates paracetamol and Bile Duct Ligation-Induced hepatotoxicity via modulation of biochemical and oxidative stress biomarkers

Background: The plant Acacia sieberiana (Fabaceae) is traditionally used to manage hepatitis. This research work aims to investigate the hepatoprotective effectiveness of root bark extract of Acacia sieberiana (ASE) against paracetamol (PCM) and bile duct ligation (BDL)-induced hepatotoxicity. The phytochemical and median lethal dose (LD50) investigations were conducted. The rats were pre-treated with the ASE (250, 750, and 1,500 mg/kg) once daily via oral route for 7 consecutive days. On the 8th day, liver injury was initiated by PCM administration (2 g/kg). Similarly, in the BDL-induced liver injury, the animals were administered ASE (125, 250, and 380 mg/kg) intraperitoneally for 7 consecutive days. After 24 h, blood samples and hepatic tissues were obtained for biochemical and histopathological investigations. Results: Phytocomponents determination revealed glycosides, triterpenes, glycosides, saponins, tannins, flavonoids and alkaloids. The oral and intraperitoneal LD50 values of the ASE were >5,000 and 1,300 mg/kg, respectively. The ASE efficiently (p < 0.05) decreased the alanine transaminase (ALT) and aspartate transaminase (AST) levels and elevated the albumin and total protein (TP) levels. The direct bilirubin effectively (p < 0.05) decreased at 750 mg/kg. Besides, the extract efficiently elevated the glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) in relation to the PCM hepatotoxic group. Also, the malondialdehyde (MDA) concentration was reduced by the ASE. Meanwhile, in the BDL-induced liver injury, the ASE remarkably (p < 0.05) declined the AST, ALP, bilirubin,and MDA. Besides, there was effective (p < 0.05) elevation in SOD, GPx and CAT in the ASE-treated groups. The morphology of liver tissue was preserved at 125 and 250 mg/kg ASE groups from BDL-induced necrosis and vascular congestion. Conclusion: The study shows that the ASE has hepatoprotective actions against liver damage by possible modulation of biochemical and oxidative stress biomarkers.

Portulaca oleracea methanolic extract attenuate bile duct ligation-induced acute liver injury through hepatoprotective and anti-inflammatory effects

Introduction

Cholestasis is a liver disease caused by a malfunction of the hepato-biliary system. Oxidative stress as a systemic complication is the main characteristic of cholestasis. The aim of this study was to evaluate the anti-inflammatory and hepatoprotective effects of Portulaca oleracea (PO) methanolic extract on liver dysfunction and tissue damage induced by bile duct ligation (BDL) in rats.

Materials and methods

Twenty-eight male Wistar rats were randomly divided into four groups: sham control (SC), BDL alone, SC plus 500 mg/kg methanolic extract of PO orally for 1 week, and BDL plus 500 mg/kg methanolic extract of PO orally for 1 week. After 1 week, the animals were anesthetized, and the liver and blood samples were taken from each animal. Biochemical parameters, oxidative stress biomarkers, histopathological changes, as well as the gene expression of IL-1, TNF-α, TGF-β, and α-SMA have been evaluated.

Results

The methanolic extract of PO at a dose of 500 mg/kg significantly decreased the plasma levels of aminotransferases, alkaline phosphatase as compared to BDL group (P < 0.05), while it had no significant effect on the levels of oxidative stress markers in the hepatic tissue. The plasma level of malondialdehyde and ferric-reducing antioxidant power were markedly elevated in the BDL group in comparison to SC group (P < 0.05), while treatment with PO significantly reduced these markers (P < 0.05). The administration of PO attenuated hydroxyproline content, bile duct proliferation, and inflammation score in the cholestatic liver in contrast to non-treated BDL rats (P < 0.05). Moreover, the methanolic extract of PO markedly declined the expression of TNF-α and TGF-β pro inflammatory genes in contrast to BDL rats.

Conclusions

Taken together, our findings showed that PO attenuated liver injury by decreasing liver function tests, inflammation, and hydroxyproline content. As a result, it is suggested that PO can be applied in cholestatic liver damage as a therapeutic or adjuvant agent.

Ex vivo vibro-acoustography characterization of osteoporosis in an experimental mice model

Background

Osteoporosis is a highly prevalent multifactorial osteometabolic disease, classically diagnosed, in vivo, by dual energy X-ray absorptiometry (DXA). This study evaluated osteoporosis, ex vivo, using vibro-acoustography (VA), an elastographic technique based on ultrasound radiation force.

Methods

Three groups of mice femurs were used: (I) control group (CG), (II) osteoporosis group (OG) and (III) treated osteoporosis group (TOG), in which the animals received pamidronate, an antiresorptive drug. Evaluation was performed in an acoustic tank, using two high frequency focused beams produced by a confocal ultrasonic transducer. A hydrophone registered the low frequency acoustic response (AR) of bone samples. We used micro-computed tomography (microCT) as the reference standard and evaluated the correlation between VA and microCT parameters.

Results

The spectral analyses of the ARs with estimated area under the curve (AUC) values (mean; st. dev.) were, respectively, 1.29e^-07 and 9.32e^-08 for the CG, 3.25e^-08 and 2.16e^-08 for the OG, and 1.50e^-07 and 8.37e^-08 for the TOG. VA differentiated the experimental groups (P<0.01) and the results were reproducible [interclass correlation coefficient (ICC): 0.43 (95% CI: 0.15-0.71)]. There was also a statistically significant association between VA and microCT connectivity (Conn.) (r=0.80; P<0.01) and connectivity density (Conn. D) (r=0.76; P<0.01).

Conclusions

These results encourage further studies aimed at evaluating the potential use of VA for the diagnosis of osteoporosis as a relatively low-cost and radiation-free alternative to DXA.

Osteoporosis and Hepatic Steatosis: 2 Closely Related Complications in Short-Bowel Syndrome

BACKGROUND

Osteoporosis has scarcely been prospectively investigated in short-bowel syndrome (SBS). This prospective study was designed to evaluate incretins, adipokines, bone mass, and lipid deposits from marrow adipose tissue (MAT), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and liver (IHLs).

METHODS

The study comprised 2 groups matched by gender, height, and age: the control group (CG) (9 males, 9 females) and the SBS group (SBSG) (6 males, 5 females). The SBSG was evaluated twice in an interval of 1 year (SBSG₀ and SBSG₁ ). The biochemical evaluation included incretins, leptin, and adiponectin. Dual-energy x-ray absorptiometry and magnetic resonance were, respectively, used to measure BMD and lipid deposits.

RESULTS

Bone mineral density (BMD) was lower in the SBSG than in the CG, but there was no difference between SBSG₀ and SBSG₁ . There was no difference in MAT, SAT, and VAT, but IHL was lower in CG than in SBSG₀ and SBSG₁ . A negative correlation between MAT and third lumbar vertebrae BMD was found in the CG but not in SBSG₀ or SBSG₁ . There was a negative association between IHL and bone mass considering all participants (CG and SBSG₀ ) (R² = 0.38; P < .05).

CONCLUSION

Appropriate nutrition assistance recovers body composition, reverts the relationship of bone mass and MAT, and mitigates bone loss in SBS. In spite of this, osteoporosis seems to be an early and persistent complication in SBS. Curiously, SBS seems to be a highly vulnerable condition for the development of hepatic steatosis and shows an association between bone mass and IHL.

Hepatic Osteodystrophy: The Mechanism of Bone Loss in Hepatocellular Disease and the Effects of Pamidronate Treatment

OBJECTIVES:

The present study was designed to evaluate the bone phenotypes and mechanisms involved in bone disorders associated with hepatic osteodystrophy. Hepatocellular disease was induced by carbon tetrachloride (CCl4). In addition, the effects of disodium pamidronate on bone tissue were evaluated.

METHODS:

The study included 4 groups of 15 mice: a) C = mice subjected to vehicle injections; b) C+P = mice subjected to vehicle and pamidronate injections; c) CCl4+V = mice subjected to CCl4 and vehicle injections; and d) CCl4+P = mice subjected to CCl4 and pamidronate injections. CCl4 or vehicle was administered for 8 weeks, while pamidronate or vehicle was injected at the end of the fourth week. Bone histomorphometry and biomechanical analysis were performed in tibiae, while femora were used for micro-computed tomography and gene expression.

RESULTS:

CCl4 mice exhibited decreased bone volume/trabecular volume and trabecular numbers, as well as increased trabecular separation, as determined by bone histomorphometry and micro-computed tomography, but these changes were not detected in the group treated with pamidronate. CCl4 mice showed increased numbers of osteoclasts and resorption surface. High serum levels of receptor activator of nuclear factor-κB ligand and the increased expression of tartrate-resistant acid phosphatase in the bones of CCl4 mice supported the enhancement of bone resorption in these mice.

CONCLUSION:

Taken together, these results suggest that bone resorption is the main mechanism of bone loss in chronic hepatocellular disease in mice.

Osteodystrophy in Cholestatic Liver Diseases Is Attenuated by Anti-γ-Glutamyl Transpeptidase Antibody

BACKGROUND

Cholestatic liver diseases exhibit higher levels of serum γ-glutamyl transpeptidase (GGT) and incidence of secondary osteoporosis. GGT has been identified as a novel bone-resorbing factor that stimulates osteoclast formation. The aim of this study was to elucidate the interaction of elevated GGT levels and cholestatic liver disease-induced bone loss.

METHODS

Wistar rats were divided into three groups: sham-operated control (SO) rats, bile duct ligation (BDL) rats, and anti-GGT antibody-treated BDL rats (AGT). Serum GGT level was measured. Bone mineral density (BMD) was analyzed by dual-energy X-ray absorptiometry. Bone morphometric parameters and microarchitectural properties were determined by micro-computed tomography and histomorphometry of the distal metaphysis of femurs. Alterations of bone metabolism-related factors were evaluated by cytokine array. Effects of GGT on osteoblasts or stromal cells were evaluated by RT-PCR, enzyme activity, and mineralization ability.

RESULTS

Serum levels of GGT were significantly elevated in the BDL-group. In the BDL group, BMD, bone mass percentage, and osteoblast number were significantly decreased, whereas osteoclast number was significantly increased. These alterations were markedly attenuated in the AGT group. The mRNA levels of vascular endothelial growth factor-A, LPS-induced CXC chemokine, monocyte chemoattractant protein-1, tumor necrosis factor-α interleukin-1β and receptor activator of nuclear factor-kappa B ligand were upregulated, and those of interferon-γ and osteoprotegerin were downregulated in the GGT-treated stromal cells. Furthermore, GGT inhibited mineral nodule formation and expression of alkaline phosphatase and bone sialo-protein in osteoblastic cells.

CONCLUSION

Our results indicate that elevated GGT level is involved in hepatic osteodystrophy through secretion of bone resorbing factor from GGT-stimulated osteoblasts/bone marrow stromal cells. In addition, GGT also possesses suppressive effects on bone formation. Managing elevated GGT levels by anti-GGT antibody may become a novel therapeutic agent for hepatic osteodystrophy in chronic liver diseases.

Pamidronate for the treatment of osteoporosis secondary to chronic cholestatic liver disease in Wistar rats

Osteoporosis is a major complication of chronic cholestatic liver disease (CCLD). We evaluated the efficacy of using disodium pamidronate (1.0 mg/kg body weight) for the prevention (Pr) or treatment (Tr) of cholestasis-induced osteoporosis in male Wistar rats: sham-operated (Sham = 12); bile duct-ligated (Bi = 15); bile duct-ligated animals previously treated with pamidronate before and 1 month after surgery (Pr = 9); bile duct-ligated animals treated with pamidronate 1 month after surgery (Tr = 9). Rats were sacrificed 8 weeks after surgery. Immunohistochemical expression of IGF-I and GH receptor was determined in the proximal growth plate cartilage of the left tibia. Histomorphometric analysis was performed in the right tibia and the right femur was used for biomechanical analysis. Bone material volume over tissue volume (BV/TV) was significantly affected by CCLD (Sham = 18.1 ± 3.2 vs Bi = 10.6 ± 2.2%) and pamidronate successfully increased bone volume. However, pamidronate administered in a preventive regimen presented no additional benefit on bone volume compared to secondary treatment (BV/TV: Pr = 39.4 ± 12.0; Tr = 41.2 ± 12.7%). Moreover, the force on the momentum of fracture was significantly reduced in Pr rats (Sham = 116.6 ± 23.0; Bi = 94.6 ± 33.8; Pr = 82.9 ± 22.8; Tr = 92.5 ± 29.5 N; P < 0.05, Sham vs Pr). Thus, CCLD had a significant impact on bone histomorphometric parameters and pamidronate was highly effective in increasing bone mass in CCLD; however, preventive therapy with pamidronate has no advantage regarding bone fragility.

Hepatic osteodystrophy: An important matter for consideration in chronic liver disease

Hepatic osteodystrophy (HO) is the generic term defining the group of alterations in bone mineral metabolism found in patients with chronic liver disease. This paper is a global review of HO and its main pathophysiological, epidemiological and therapeutic aspects. Studies examining the most relevant information concerning the prevalence, etiological factors, diagnostic and therapeutic aspects involved in HO were identified by a systematic literature search of the PubMed database. HO generically defines overall alterations in bone mineral density (BMD) (osteoporosis or osteopenia) which appear as a possible complication of chronic liver disease. The origin of HO is multifactorial and its etiology and severity vary in accordance with the underlying liver disease. Its exact prevalence is unknown, but different studies estimate that it could affect from 20% to 50% of patients. The reported mean prevalence of osteoporosis ranges from 13%-60% in chronic cholestasis to 20% in chronic viral hepatitis and 55% in viral cirrhosis. Alcoholic liver disease is not always related to osteopenia. HO has been commonly studied in chronic cholestatic disease (primary biliary cirrhosis and primary sclerosing cholangitis). Several risk factors and pathogenic mechanisms have been associated with the loss of BMD in patients with chronic liver disease. However, little information has been discovered in relationship to most of these mechanisms. Screening for osteopenia and osteoporosis is recommended in advanced chronic liver disease. There is a lack of randomized studies assessing specific management for HO.