Hepatocyte autophagy is linked to C/EBP-homologous protein, Bcl2-interacting mediator of cell death, and BH3-interacting domain death agonist gene expression.

BACKGROUND: Endoplasmic reticulum (ER) stress and autophagy each play important roles in hepatocyte cell injury. We hypothesized that gene expression of C/EBP-homologous protein (CHOP) and the BH3 proteins Bcl2-interacting mediator of cell death (BIM) and BH3-interacting domain death agonist (BID) are involved in a complex interplay that regulates ER stress-induced autophagy and cell death. MATERIALS AND METHODS: Hepatocytes were cultured from lean Zucker rats. Confluent hepatocytes were incubated with single or combined small interfering RNA for CHOP, BIM, and/or BID for 24 h providing gene inhibition. Incubation with tunicamycin (TM) for another 24 h stimulated ER stress. Quantitative real-time polymerase chain reaction determined the expression levels of CHOP, BIM, and BID. Immunostaining with microtubule-associated protein 1 light chain 3 measured autophagy activity. Trypan blue exclusion determined the cell viability. RESULTS: TM treatment increased the messenger RNA levels of CHOP and BIM but decreased the messenger RNA levels of BID. TM increased autophagy and decreased cell viability. Individual inhibition of CHOP, BIM, or BID protected against autophagy and cell death. However, simultaneous treatment with any combination of CHOP, BIM, and BID small interfering RNAs reduced autophagy activity but increased cell death independent of ER stress induction. CONCLUSIONS: Autophagy in hepatocytes results from acute ER stress and involves interplay, at the gene expression level, of CHOP, BIM, and BID. Inhibition of any one of these individual genes during acute ER stress is protective against cell death. Conversely, inhibition of any two of the three genes results in increased nonautophagic cell death independent of ER stress induction. This study suggests interplay between CHOP, BIM, and BID expression that can be leveraged for protection against ER stress-related cell death. However, disruption of the CHOP/BH3 gene expression homeostasis is detrimental to cell survival independent of other cellular stress.

Autophagy is involved in endoplasmic reticulum stress-induced cell death of rat hepatocytes.

BACKGROUND: Both endoplasmic reticulum (ER) stress and autophagy have been shown to display dual roles in cell survival in multiple cell lines. There is a reported but poorly understood link between ER stress, autophagy, and cell death. We hypothesized that autophagy plays a role in ER stress-dependent cell death in rat hepatocytes. MATERIALS AND METHODS: Primary hepatocytes isolated from both lean and obese male Zucker rats were cultured and treated with tunicamycin (TM), tauroursodeoxycholic acid, 3-methyladenine, and wortmannin for 12 h. The ER stress-associated genes glucose-regulated protein 78 and C/EBP homologous protein were examined via quantitative real time polymerase chain reaction. Immunostaining with microtubule-associated protein 1 light chain 3 as well as electron microscopy were used to evaluate autophagy activity. Trypan blue exclusion was used to determine hepatocyte cell viability. RESULTS: In both lean and steatotic hepatocytes, we found that TM induced both C/EBP homologous protein and glucose-regulated protein 78 messenger RNA expression. Cells with increased ER stress were undergoing increased autophagy and had a significant decrease in cell viability. Both tauroursodeoxycholic acid and 3-methyladenine treatments attenuated TM induced ER stress, autophagy, and cell death, whereas wortmannin treatment reduced autophagy and cell death but without changing ER stress. CONCLUSIONS: These data suggest that autophagy is a likely downstream mediator of ER stress-induced cell death in rat hepatocytes. Further exploration of the link between autophagy and ER stress in hepatocyte injury will yield important information that may be leveraged for treatment of liver injuries such as ischemia/reperfusion.

Considering Q fever when working with laboratory sheep.

The sheep (Ovis aries) is somewhat less common than smaller species in laboratory settings, but personnel who work with sheep or in a facility that houses sheep should be aware that certain zoonotic diseases are common in sheep. They should also know how to prevent transmission of zoonotic disease in facilities that house or work with small ruminants. Knowledge of diseases such as query fever (Q fever), which can cause severe human morbidity (and in some cases death), needs to be especially emphasized. In this paper, the author describes potential causes, transmission and manifestations of Q fever in humans and other animals and then discusses strategies for preventing the spread of Q fever.

New Topical Agents for Treatment of Partial-thickness Burns in Children: A Review of Published Outcome Studies.

 Evidence-based choices for treating burns in children are not well defined. Skin substitutes and contemporary dressings offer potential advantages over traditional treatment with topical antimicrobial agents in treating partial-thickness burns. Newer treatment modalities may reduce morbidity, financial burdens, and scarring by accelerating healing. Reports of pediatric burn management from 1997 to 2007 were reviewed to compare agent performance with outcome measures such as healing time, pain moderation, cosmetic results, and hospital costs. Transcyte™ (Smith & Nephew, London), Biobrane® (Bertek Pharmaceuticals Inc, Morgantown, WV), beta-glucan collagen, and Mepitel® (Mölnlycke, Göteborg, Sweden) have been reported as superior to silver sulfadiazine (SSD) in achieving faster healing times and decreased pain in pediatric patients. Initial reports describing the outcomes achieved with these new agents indicate that they may offer clinical advantages in the treatment of partial-thickness burns in children. Increased costs of the new products appeared to be offset by decreases in hospital stay, nursing care time and pain medications. The existing literature is not conclusive, and prospective trials with standardized outcome measures are needed to better define the role of these agents. .

Sex hormones and aortic wall remodeling in an arteriovenous fistula.

BACKGROUND: An arteriovenous fistula (AVF) creates high blood flow through the artery and fistula. With this high flow, there is flow-induced remodeling and an increase in diameter, but no intimal hyperplasia. Estrogen has been shown to modify vascular remodeling, decreasing intimal hyperplasia after endothelial injury. OBJECTIVE: These experiments tested the hypothesis that estrogen administration would decrease wall thickness in an AVF model. Because estrogen may decrease wall thickness, we also tested the hypothesis that testosterone would increase wall thickness. METHODS: A fistula was created between the abdominal aorta and the inferior vena cava in Sprague-Dawley rats to generate high blood flow conditions in the aorta. Four groups of female animals were examined: sham, control with AVF ovariectomized (OVX) with AVF and OVX plus testosterone with AVF Four groups of male animals were also examined: sham, control with AVF castrated with AVF and castrated plus estrogen with AVF Five weeks after creation of the AVF, the aortas were collected and fixed; wall thickness was measured both proximal and distal to the AVF. RESULTS: Ovariectomy resulted in a significant decrease in estrogen levels (P < 0.01). Testosterone administration tended to increase testosterone levels in the OVX females, but values did not approach levels observed in the control males. No difference was noted in the proximal wall thickness between the control and the OVX animals. The OVX females receiving testosterone exhibited a significant increase in both proximal and distal wall thickness compared with control females (P < 0.001). In the male animals, there was no significant change in aortic wall thickness in the castrated rats compared with the controls. Estrogen administration in the castrated males resulted in a significant decrease in wall thickness in the proximal and distal aorta (P < 0.05). CONCLUSION: These studies suggest that, in a model of vascular remodeling, estrogen administration decreases wall thickness, and testosterone administration increases wall thickness.

Review of microsurgery and arteriovenous fistulae for hemodialysis.

Patient comorbities, a patient's age and weight, the experience of the surgeon, and state of current vascular access are all factors used in determining the employment of microsurgical techniques to create or salvage an arteriovenous fistula (AVF) for hemodialysis. The aim of this study was to provide an overview of the literature concerning the use of microsurgery for AVFs as the permanent vascular access for both adults and children with end-stage renal disease (ESRD). The patient's overall state of health and long-term survival are always prime considerations in any medical management situation, and any technique that can make these goals more easily attainable by more patients is to be highly valued. Microsurgery for the establishment and repair of AVFs is another useful tool which is available if needed, depending on the unique needs of the patient, to aid the medical community in providing the best possible healthcare.

Rat models of skin wound healing: a review.

Rats have been widely used in the study of skin wound healing and the efficacy of different treatment modalities. This particular animal species is often selected for its availability, low cost, and small size. To define the current use of rat skin wound healing models, this manuscript provides a review of articles published between 2000 and 2003 that chose rats as their research animals. Of the 55 articles reviewed, it was found that 38.2% of the studies used incisional models and 38.2% used excisional models, with some studies using combinations. The majority of the studies (78.2%) used the rat's dorsum as the wound location. Male Sprague Dawley in the 250-300 gram weight range were the most preferred rats. Sodium pentobarbital/pentobarbitone was the most commonly used anesthetic choice. Similarities and differences in the selected experimental conditions are noted and questions are raised with regard to comparability between studies and the ability to transfer the data from the animal model to the human clinical situation. Attempts to compare studies for the advancement of wound healing knowledge are being hampered by the differences found between the studies. Standardization in reporting could facilitate comparisons and may instigate additional research that favors the inevitable comparisons between the studies. Thus, universal reporting requirements need to be developed for animal wound healing studies.