الفهرس 
LIVER CIRRHOSIS & OSTEOPOROSISOnly 14 pages are availabe for public view
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Abstract
Cirrhosis is the leading cause of liver-related death globally which is the end-stage of CLD regardless the etiology. Almost all patients with CLD show altered bone metabolism.
Many risk factors share in the pathogenic mechanisms of osteoporosis in CLD with iron overload being a major cause of osteoporosis through inhibition of osteoblast function, in addition to promotion of osteoclastogenesis.
DMT1 is the primary importer of non-heme iron and is highly expressed in proximal duodenum (iron uptake) and liver (iron storage). Moreover, DMT1 was found to be expressed in various other tissues, such as bone and kidney. It was found that DMT1 is markedly increased in osteoporosis, and that loss of DMT1 can lead to loss of iron content in bone. Some studies suggested a link between DMT1 expression and autophagic activity in bone.
Autophagy is a lysosomal degradation pathway responsible for degradation and recycling of cellular components such as unnecessary organelles and proteins, and also serves to destroy intracellular pathogens, in addition to playing an important role in maintenance of bone homeostasis. Several studies have shown that iron overload was found to promote cell autophagy, which in turn can promote the development of hepatic fibrosis through activation of hepatic stellate cells.
DFO is a non-toxic iron chelator which is clinically approved and effective for long-term iron chelation therapy in beta-thalassemia and other iron overload cases. DFO has a remarkable effect on reduction of serum ferritin level and hepatic iron, which improves patients’ survival.
So the present study was conducted to test the effect of deferoxamine on a rat model of TAA induced liver cirrhosis associated with osteoporotic changes. Further, the effect on DMT1 and autophagy were studied.
The following parameters were measured:
1. Liver weight / Body weight ratio (Liver Index %).
2. Biochemical studies:
• Serum ALT, AST and Albumin.
• Serum Fe and Ferritin.
• Serum OC and HYP.
3. Molecular biology studies:
qPCR for DMT1 gene expression quantitation in liver tissue and bone tissue.
qPCR for Microtubule-associated protein 1A/1B-light chain 3 (LC3) (marker of autophagy) gene expression quantitation in liver tissue and bone tissue.
4. Histopathological studies:
Liver :
• H&E stain.
• Mallory’s stain for collagen detection.
• Prussian blue stain to detect iron deposits.
Bone :
• H&E stain for bone histomorphometry.
• Prussian blue stain to detect iron deposits.
Results can be summarized as follows:
1. Liver index:
TAA untreated group exhibited a significant increase in liver index as compared to naïve control group, while chronic treatment with DFO produced significant decrease in liver index as compared to TAA untreated group.
2. Biochemical studies:
A. Liver enzymes & serum albumin:
TAA untreated group exhibited a significant increase in liver enzymes and a significant decrease in serum albumin as compared to naïve control group.
Chronic treatment with DFO produced significant decrease in liver enzymes and a significant increase in serum albumin as compared to TAA untreated group.
B. Serum Fe & ferritin:
TAA untreated group exhibited a significant increase in serum Iron and ferritin as compared to naïve control group.
Chronic treatment with DFO produced significant decrease in serum iron and ferritin as compared to TAA untreated group.
C. Serum HYP & OC:
TAA untreated group exhibited a significant increase in serum HYP and a significant decrease in serum OC as compared to naïve control group.
Chronic treatment with DFO produced significant decrease in serum HYP and a significant increase in serum OC as compared to TAA untreated group.
3. Molecular Biology Studies:
DMT1 and LC3 gene expression in liver and bone tissues:
TAA untreated group exhibited a significant increase in DMT1 and LC3 gene expression in both liver and bone tissues as compared to naïve control group. While chronic treatment with DFO produced significant decrease in DMT1 and LC3 gene expression in both liver and bone tissues as compared to TAA untreated group.
4. Histopathological Studies:
A. Liver tissue:
I. H & E staining:
TAA untreated group showed liver cirrhosis with loss of architecture and periportal fibrosis. However, TAA DFO treated group showed apparent preservation of architecture with some mononuclear cellular infiltrates close to portal tracts.
II. Mallory staining:
TAA untreated group showed increased collagen fibers deposition in the periportal tract and between the hepatocytes. However, TAA DFO treated group showed few collagen fiber deposition mainly around portal tracts.
TAA untreated group exhibited a significant increase in collagen fiber content in liver tissue as compared to naïve control group. While chronic treatment with DFO produced significant decrease in collagen fiber content in liver tissue as compared to TAA untreated group.
III. Prussian blue staining:
TAA untreated group showed many Prussian blue positive granules within the cytoplasm of Kupffer cells. However, TAA DFO treated group showed some Prussian blue positive granules within the cytoplasm of some Kupffer cells and hepatocytes while absent within most of hepatocytes.
B. Bone tissue:
I. H & E staining:
TAA untreated group showed marked deminusion of the size of bony traceculae with increased bone marrow space. However, TAA DFO tretaed group showed increased bone trabeculae with osteocytes inside lacunae within the bone trabeculae.
Regarding Bone histomorphometry examination, TAA untreated group exhibited a significant decrease in cortical bone thickness and trabecular bone volume as compared to naïve control group. While chronic treatment with DFO produced significant increase in cortical bone thickness and trabecular bone volume as compared to TAA untreated group.
II. Prussian blue staining:
TAA untreated group showed increased Prussian blue positive granules, however few Prussian blue positive granules were noticed in TAA+DFO group.
CONCLUSION:
In conclusion, Autophagy induced by iron overload is a suspected mechanism that mediates the toxic effects on bone in thioacetamide induced model of liver cirrhosis. Iron chelation, in particular with deferoxamine, has the potential to alleviate bone changes and the suspected mechanism. Further work is still needed to be translated to a clinical trial for hepatic osteodystrophy.
RECOMMENDATIONS:
• This study recommends implementation of DFO as a potential treatment for iron overload-associated with liver cirrhosis.
• Despite its beneficial effects concluded in this study, further studies with larger sample sizes need to be carried out to explore the effects of this agent on various body systems and to assess its possible therapeutic uses together with its potential side effects.
• More studies are needed to identify other markers for liver cirrhosis-induced osteoporosis to allow for early diagnosis which helps in prompt management of patients.
• Effects of iron overload on various body systems need to be further studied to allow for identification of possible non-invasive diagnostic markers and also potential therapeutic interventions.