Osteopontin expression in the liver with severe perisinusoidal fibrosis: autopsy case of Down syndrome with transient myeloproliferative disorder

A rare case of hepatic sinusoidal occlusive syndrome in a premature neonate with trisomy 21

Trisomy 21 (Down Syndrome) may lead to multiple hematological and hepatobiliary manifestations including the development of transient abnormal myelopoiesis. While many cases resolve, transient abnormal myelopoiesis may lead to significant morbidity and mortality in a small percentage of patients. This condition may present a diagnostic challenge for physicians and currently there is only limited data on effective treatments, particularly with low blast percent transient abnormal myelopoiesis. We present a case of a neonate with trisomy 21 and multiple congenital anomalies who consequently developed hepatic failure with evidence of non-cirrhotic portal hypertension likely due to transient abnormal myelopoiesis. This clinical scenario highlights the need for additional evaluation for transient abnormal myelopoiesis associated hepatic disorder and possibly hepatic sinusoidal occlusive syndrome among trisomy 21 neonates particularly with low blast percentage.

A humanized osteopontin mouse model and its application in immunometabolic obesity studies

Osteopontin (OPN) is a multifunctional protein involved in several inflammatory processes and pathogeneses including obesity-related disorders and cancer. OPN binds to a variety of integrin receptors and CD44 resulting in a proinflammatory stimulus. Therefore, OPN constitutes a novel interesting target to develop new therapeutic strategies, which counteract OPN's proinflammatory properties. We established a humanized SPP1 (hSPP1) mouse model and evaluated its suitability as a model for obesity and insulin resistance. Unchallenged hSPP1 animals did not significantly differ in body weight and gross behavioral properties compared to wild-type (WT) animals. High-fat diet-challenged hSPP1 similarly developed obesity and inflammation, whereas insulin resistance was markedly changed. However, OPN expression profile in tissues was significantly altered in hSPP1 compared to WT depending on the diet. In conclusion, we developed a versatile humanized model to study the action of OPN in vivo and to develop strategies that target human OPN in a variety of pathologies.

Osteopontin: A novel regulator at the cross roads of inflammation, obesity and diabetes

Since its first description more than 20 years ago osteopontin has emerged as an active player in many physiological and pathological processes, including biomineralization, tissue remodeling and inflammation. As an extracellular matrix protein and proinflammatory cytokine osteopontin is thought to facilitate the recruitment of monocytes/macrophages and to mediate cytokine secretion in leukocytes. Modulation of immune cell response by osteopontin has been associated with various inflammatory diseases and may play a pivotal role in the development of adipose tissue inflammation and insulin resistance. Here we summarize recent findings on the role of osteopontin in metabolic disorders, particularly focusing on diabetes and obesity.

Correlation between expression of osteopontin and activation of hepatic stellate cells in hepatic fibrosis

AIM: To investigate the expression of osteopontin (OPN) in hepatic fibrosis and explore its correlation with the expression of alpha-smooth muscle actin (α-SMA) and transforming growth factor beta 1 (TGF-β1) as well as the activation of hepatic stellate cells (HSCs).

METHODS: Forty healthy male SD rats were randomly divided into a normal control group and a carbon tetrachloride treatment group. The rats in the treatment group were given a subcutaneous injection of carbon tetrachloride, and sacrificed at weeks 2, 4 and 6 after injection. The mRNA and protein expression of OPN, α-SMA and TGF-β1 was assayed by reverse transcription-polymerase chain reaction, Western blot and immunohistochemistry.

RESULTS: PN, α-SMA and TGF-β1 were slightly expressed in normal liver tissues. After injection of carbon tetrachloride, the expression of OPN, α-SMA and TGF-β1 began to increase at week 2 and was significantly higher at weeks 4 and 6 (P < 0.05), showing a gradually rising trend. The expression of OPN was positively correlated with that of α-SMA and TGF-β1 (r = 0.625, 0.587, both P < 0.05).

CONCLUSION: The expression of OPN, α-SMA and TGF-β1 increases with the development of hepatic fibrosis. OPN probably participates in the activation of HSCs and the synthesis of extracellular matrix (ECM) in the development of hepatic fibrosis.

Activation of peroxisome proliferator activated receptor alpha ameliorates ethanol mediated liver fibrosis in mice

BACKGROUND

Peroxisome proliferator activated receptor alpha (PPARα) ameliorates ethanol induced hepatic steatohepatitis. However, its role in alcoholic liver fibrosis has not been fully clarified. The aim of this study was to elucidate the effect and the molecular basis of PPARα in ethanol induced liver fibrosis in mice.

METHODS

C57BL/6J mice were fed with 4% ethanol-containing Lieber-DeCarli liquid diet for eight weeks, and intraperitoneal injected with 5% carbon tetrachloride (CCl4) for the last four weeks to induce alcoholic liver fibrosis. PPARα agonist WY14643 was administered to mice during the last couple of weeks. The effects of PPARα induction on liver histology, activation of hepatic stellate cells (HSCs), as well as hepatic expression of inflammatory and fibrogenic factors were assessed.

RESULTS

The ethanol plus CCl4 treated mice exhibited progressive liver injury including piecemeal necrosis of hepatocytes, severe inflammatory cells infiltration and bridging fibrosis. This was accompanied by down-regulated hepatic expression of PPARα and the protective cytokines adiponectin, heme oxygenase-1 and interleukin-10. Additionally, up-regulation of the proinflammatory cytokine tumor necrosis factor-alpha, as well as the profibrogenic genes osteopontin, transforming growth factor-beta 1, visfatin, phosphatidylinositol 3-kinase, matrix metalloproteinase-2 (MMP-2) and MMP-9 was observed. WY14643 treatment restored expression of cytokines altered by ethanol plus CCl4 treatment and concomitantly ameliorated the liver injury.

CONCLUSIONS

The present study provides evidence for the protective role of PPARα induction in ameliorating ethanol mediated fibrosis through mediation of inflammatory and fibrogenic factors.