Protection of HLE B-3 cells against hydrogen peroxide- and naphthalene-induced lipid peroxidation and apoptosis by transfection with hGSTA1 and hGSTA2

PURPOSE: To investigate the physiological role of two major alpha-class glutathione S-transferases (GSTs), hGSTA1-1 and hGSTA2-2 in protection against oxidative stress and lipid peroxidation (LPO) in human lens epithelial (HLE B-3) cells. METHODS: Total GSTs were purified from HLE B-3 cells by glutathione (GSH)-affinity chromatography and characterized by Western blot analysis, isoelectric focusing, and kinetic studies. The relative contributions of the alpha-class GSTs and the Se-dependent glutathione peroxidase (GPx)-1 in GSH-dependent reduction of phospholipid hydroperoxide (PL-OOH) were quantitated through immunoprecipitation studies using separately the specific polyclonal antibodies against human alpha-class GSTs and GPx-1. HLE B-3 cell membranes were prepared, peroxidized, and used to examine whether hGSTA1-1 and hGSTA2-2 catalyzes the reduction of membrane PL-OOH in situ using the microiodometric and spectrophotometric assays. The protective effects of the alpha-class GSTs against H2O2- and naphthalene-induced LPO and apoptosis were examined by transfecting HLE B-3 cells with cDNAs of hGSTA1 and hGSTA2. RESULTS. HLE B-3 cells expressed only the alpha and pi class GSTs. The Michaelis-Menten constant (k(m)) and turnover number (k(cat)) of purified total GSTs toward phosphatidylcholine hydroperoxide (PC-OOH) were found to be 30 +/- 4 microM and 1.95 +/- 0.26 seconds, respectively. The alpha-class GSTs accounted for approximately 65% of the total GPx activity of HLE B-3 cells toward PC-OOH. Our results demonstrate for the first time that hGSTA1-1 and hGSTA2-2 effectively catalyzed GSH-dependent reduction of membrane PL-OOH in situ in HLE B-3 cells. Transfection with hGSTA1 or hGSTA2 protected these cells from H2O2- and naphthalene-induced LPO and attenuated H2O2- and naphthalene-induced apoptosis through inhibiting caspase 3 activation. CONCLUSIONS: These results demonstrate that the alpha-class GSTs hGSTA1-1 and hGSTA2-2 play a major role as antioxidant enzymes and are the main determinants of the levels of LPO caused by oxidative stress in human lens epithelial cells.     

I-cell disease (Mucolipidosis II)

I-cell disease (Mucolipidosis II) is one of the lysosomal storage diseases which presents in the neonatal period, and within six months will phenotypically resemble the severe forms of the group of disorders called the “mucopolysaccharidoses” but without mucopolysacchariduria. In Mucolipidosis II, fibrocytes exhibit “abnormal lysosomes”. Activities of several lysosomal enzymes are low in fibroblast cultures but high in mucolipidosis II serum. We present a patient with I-cell disease diagnosed on the basis of clinical, radiological and biochemical features. The mother of this child was pregnant and the fetus was also found to be affected.     

Developing drug therapies in bronchiectasis

Introduction: Bronchiectasis is a chronic respiratory condition characterised by cough, sputum production and recurrent chest infections. There are multiple aetiologies; but in up to 50% of patients, the aetiology is unknown. The treatment is largely symptomatic with regular chest physiotherapy and antibiotics for infective exacerbations. Research is being directed towards breaking the ‘vicious circle’ of bronchiectasis with therapies directed at improving mucociliary clearance, treating chronic infection and reducing inflammation in the airways.

Areas covered: This review highlights the current status of bronchiectasis research, summarising reported and ongoing studies of potential therapeutic agents not yet assessed in large trials or licensed for treatment. A literature review was performed using the PubMed database and upcoming trials were sought on the ClinicalTrials.gov website. The article is limited to studies in preclinical to Phase II clinical trials. The trials highlighted in this article offer insight into potential therapeutic agents for the future and help highlight areas in need of further targeted research.

Expert opinion: There are promising new anti-infective and anti-inflammatory therapies for more advanced bronchiectasis. That being said, Phase III studies are still needed to investigate these agents further, as well as at what stage therapy should be implemented.     

Non-cirrhotic portal fibrosis (idiopathic portal hypertension): experience with 151 patients and a review of the literature

BACKGROUND: Non-cirrhotic portal fibrosis (NCPF), the equivalent of idiopathic portal hypertension in Japan and hepatoportal sclerosis in the United States of America, is a common cause of portal hypertension in India. The clinical features, portographic and histological findings, and management of 151 patients with non-cirrhotic portal fibrosis are presented. METHODS: The disease is diagnosed by the presence of unequivocal evidence of portal hypertension in the definite absence of liver cirrhosis and extrahepatic portal vein obstruction (EHPVO). Retrospective analysis of records of 151 patients with NCPF was analyzed for the clinical presentation, physical findings, laboratory tests, radiological and histological findings, and for the outcome of treatment. RESULTS: The disease is characterized by massive splenomegaly with anemia, preserved liver function and benign prognosis in a majority of patients. Splenoportovenography (SPV) showed massive dilatation of the portal and splenic veins, and the presence of collaterals. Twenty-four (15.9%) patients showed evidence of natural/spontaneous shunts (splenorenal 15, umbilical nine) on SPV; these patients had a lower incidence of variceal bleeding. Liver histology demonstrated maintained lobular architecture, portal fibrosis of variable degree, sclerosis and obliteration of small-sized portal vein radicles, and subcapsular scarring with the collapse of the underlying parenchyma. Piecemeal or hepatocytic necrosis was absent in all histology specimens. Three patients showed nodular transformation along with abnormal liver functions, and may represent late manifestation of NCPF where features are similar to those seen in patients with incomplete septal cirrhosis. In the initial part of the study, surgery (side-to-side lieno-renal shunt) was the preferred modality of treatment, however, endoscopic sclerotherapy or variceal ligation has now become the preferred first line of management of variceal bleeding. CONCLUSIONS: The epidemiological and clinical features of NCPF have more similarity to IPH than has previously been documented. The development of spontaneous shunts tends to protect these patients from variceal bleeding.     

Blepharoptosis following anterior segment surgery: a new theory for an old problem

Blepharoptosis is a well-known complication following anterior segment surgery. However, its precise aetiology remains elusive. There are currently two widely held views on the pathogenesis of persistent postoperative ptosis, namely the speculum and bridle suture theories. However, both suggested explanations fail to address important anatomical and epidemiological features of this condition. Until now, the majority of published literature describing persistent postoperative ptosis following anterior segment surgery has largely concentrated on dehiscence of the levator aponeurosis as the common mechanism underlying this postoperative complication. However, numerous studies have failed to show any correlation between pre or postoperative skin crease positions in such patients. This review article discusses previously proposed mechanisms responsible for both transient and persistent ptosis. Furthermore, we propose an alternative mechanism for the development of ptosis following anterior segment surgery, namely horizontal stretch of the upper eyelid induced by the use of the speculum. This mechanism also provides a plausible explanation for less commonly described oculoplastic complications, such as lower lid malpositions, following anterior segment surgery. Postoperative ptosis may also act as a paradigm for the development of involutional ptosis in general. In view of the frequency with which ophthalmologists perform anterior segment procedures such as cataract surgery, postoperative ptosis represents a significant concern for all ocular surgeons. Identifying the underlying mechanism is imperative, not only to identify those patients at greatest risk, but also to perhaps provide novel surgical approaches to the management of this complication.