Caspase-dependent apoptosis in fulminant hepatic failure induced by herpes simplex virus in mice

The Protective Effects of Silymarin on Thioacetamide-Induced Liver Damage: Measurement of miR-122, miR-192, and miR-194 Levels

This study aims to investigate the protective effects of silymarin (Sm) in thioacetamide (TAA)-related liver damage. What makes this study special is that it attempts to determine the expression of changes in the liver at the level of gene expression. Routine liver damage markers were compared with changes in the levels of microRNA (miRNA) known as new biomarkers. With this in mind, we divided the rats into four groups including control, TAA, Sm + TAA (50 + 50 mg/kg), and Sm + TAA (100 + 50 mg/kg). Blood and tissue samples belonging to the rats were collected in consideration of morphological, immunohistochemistry, miRNAs levels, and biochemical evaluations. Our study results showed that miR-122, miR-192, and miR-194 levels had decreased in the experimental groups given TAA, whereas miR-122, miR-192, and miR-194 levels had increased in the doses of Sm + TAA-given group. Therefore, Sm treatment undertaken before exposure to the toxin successfully altered its effects upon the study animals.

Programmed cell death: the battlefield between the host and alpha-herpesviruses and a potential avenue for cancer treatment

Programed cell death is an antiviral mechanism by which the host limits viral replication and protects uninfected cells. Many viruses encode proteins resistant to programed cell death to escape the host immune defenses, which indicates that programed cell death is more favorable for the host immune defense. Alpha-herpesviruses are pathogens that widely affect the health of humans and animals in different communities worldwide. Alpha-herpesviruses can induce apoptosis, autophagy and necroptosis through different molecular mechanisms. This review concisely illustrates the different pathways of apoptosis, autophagy, and necroptosis induced by alpha-herpesviruses. These pathways influence viral infection and replication and are a potential avenue for cancer treatment. This review will increase our understanding of the role of programed cell death in the host immune defense and provides new possibilities for cancer treatment.

Educational case series: Mechanisms of drug allergy

Once administered, a drug can activate the immune system by various mechanisms and lead to a large range of clinical manifestations closely related to the type of immune reaction elicited. Administration of the drug can classically result in an immunoglobulin E (IgE)-type sensitization, but can also result in more complex activation of the immune system potentially resulting in severe syndromes, such as the drug-induced hypersensitivity syndrome (DIHS). Although there has been a major increase in our knowledge over the last years, the exact mechanisms of drug allergy are not well understood for most clinical manifestations. A complex interaction between individual characteristics, environmental factors, and the drug itself is usually responsible for adverse reactions to drugs. In this educational review series, we described three cases of drug allergy: first, a child with a typical IgE-mediated drug allergy, second, a child with a non-immediate reaction to penicillin, and in the third patient, we will discuss the drug-induced hypersensitivity syndrome, which is rare but potentially fatal. These cases are correlated to the immune mechanism potentially involved.

Intrahepatic activation of caspases in human fulminant hepatic failure

BACKGROUND/AIMS

Apoptosis has been implicated in the pathogenesis of fulminant hepatic failure (FHF) potentially involving caspases. Thus far, apoptosis in FHF has mainly been studied in animal models while human data are sparse.

METHODS

Caspases-3, -8 and -9 activities and Fas expression were analyzed in correlation to TdT-mediated dUTP nick end labelling (TUNEL) positive apoptotic cells in livers of patients with FHF (n=26), chronic liver disease (CLD) (n=60) and normal controls (NC) (n=10).

RESULTS

Numbers of TUNEL-positive cells were higher in FHF than in CLD and NC (P<0.001) correlating to the intrahepatic activities of caspase-3. The highest caspase-3 activities were found in fulminant hepatitis B, significantly surpassing those in FHF of any other etiology. In fulminant hepatitis B, caspase-9 activity was also higher than in controls, while caspase-8 activation was not higher than in NC. Unlike caspase-3, caspases -8 and -9 activities were not correlated to the numbers of TUNEL positive cells. Fas expression was also the highest in FHF but did not differ between hepatitis B virus-FHF and other FHF.

CONCLUSIONS

Our data indicate differential activation of intrahepatic caspases in FHF depending on the underlying etiology. Massive activation of caspases in fulminant hepatitis B confirms a pivotal role of apoptotic pathways in the pathogenesis of human fulminant hepatitis B.

Induction of apoptosis by herpes simplex virus-1 in neonatal, but not adult, neutrophils

We report a study on the effect of herpes simplex virus 1 (HSV-1) infection on apoptosis of neutrophils from both adults and neonates and present evidence showing that HSV-1 enhances apoptosis in neonatal, but not adult, neutrophils. HSV-1 enhanced the expression of both Fas and Fas ligand on the surface of neonatal neutrophils. Treatments with anti-Fas antibody and a Fas ligand inhibitor significantly reduced the induction of apoptosis by HSV-1. Using an ELISA assay, it was found that HSV-1 infection also leads to increased release of soluble FasL from HSV-1-infected neonatal neutrophils. Increased neonatal neutrophil apoptosis following HSV-1 infection may represent an important mechanism by which HSV-1 may diminish the antiviral response of neonatal neutrophils and might explain, at least in part, the severity of infections that are caused in newborns by this herpesvirus.

Caspase-3-dependent apoptosis in cardiac myxoma: not associated with human papillomavirus or Epstein-Barr virus

Cardiac myxoma is the most common tumor of the heart, has a variable clinical presentation and immunohistochemical profile. Viral infections, such as herpes simplex virus, human papillomavirus (HPV), and Epstein-Barr virus (EBV), may play an important role in the causes of cardiac myxoma. This investigation will demonstrate caspase-3-dependent apoptosis in cardiac myxoma without HPV or EBV infection. This study included 15 patients with cardiac myxoma, who were treated with surgical excision of the lesion. Data were collected on detailed clinical parameters. Terminal deoxynucleotidyl transferase nick-end labeling assay, electrophoresis, and caspase-3 immunohistochemical studies were performed to characterize apoptosis. Genechip containing 39 subtypes was used to elucidate HPV; and polymerase chain reaction to detect LMP-1 gene of EBV. The patient population comprised of eight (53%) women and seven (47%) men. The mean age of patient participants was 45 years, with an age range of 30-70 years. All patient cases were sporadic myxomas rather than familial myxomas. The patient presentations included dyspnea (53%), asymptomatic (27%), stroke (7%), chest pain (7%), and fever (7%). All lesions were located in the left atrium. The individual patient cases of myxoma did not differ in location or clinical event in terms of pathological scores, such as vascular proliferation, inflammation, cellularity, hyaline, calcification, or thrombosis. Cardiac myxoma is characterized by apoptosis through caspase-dependent pathway. HPV or EBV was not detected in any of the study patient samples. In conclusion, no viral genomes of HPV or EBV were detected in these 15 patients. This study demonstrates that caspase-3-dependent apoptosis in cardiac myxoma is not dependent on concurrence of previous HPV and/or EBV infection.