Involvement of endoplasmic reticulum stress in rotenone-induced leber hereditary optic neuropathy model and the discovery of new therapeutic agents

Leber hereditary optic neuropathy (LHON) is caused by mitochondrial DNA mutations and is the most common inherited mitochondrial disease. It is responsible for central vision loss in young adulthood. However, the precise mechanisms of onset are unknown. This study aimed to elucidate the mechanisms underlying LHON pathology and to discover new therapeutic agents. First, we assessed whether rotenone, a mitochondrial complex Ⅰ inhibitor, induced retinal degeneration such as that in LHON in a mouse model. Rotenone decreased the thickness of the inner retina and increased the expression levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and immunoglobulin heavy-chain binding protein (BiP). Second, we assessed whether rotenone reproduces LHON pathologies on RGC-5, a neural progenitor cell derived from the retina. Rotenone increased the cell death rate, ROS production and the expression levels of ER stress markers. During chemical compounds screening, we used anti-oxidative compounds, ER stress inhibitors and anti-inflammatory compounds in a rotenone-induced in vitro model. We found that SUN N8075, an ER stress inhibitor, reduced mitochondrial ROS production and improved the mitochondrial membrane potential. Consequently, the ER stress response is strongly related to the pathologies of LHON, and ER stress inhibitors may have a protective effect against LHON.

An unusual clinical presentation of lupus erythematosus tumidus localized on the thigh

A 44-year-old woman with seronegative polyarthritis presented with a 2-year history of a solitary, bluish-red, oedematous, nonscaly, annular and partially reticulated macule on her right thigh. Histopathological findings revealed perivascular and periadnexal lymphocytic infiltrate in the dermis. Alcian blue and colloidal iron stains highlighted mucinous deposit in the upper and mid dermis. Direct immunofluorescence showed a linear deposit of IgG and C3 along the basement membrane zone. Antinuclear antibody was positive at a titre of 1 : 80, with homogenous and speckled patterns. Except for its unusual localization and lack of photosensitivity, our case had the clinical and histopathological features of lupus erythematosus tumidus. These characteristics were also reminiscent of reticular erythematous mucinosis and erythema annulare centrifugum, both of which are considered to be associated with cutaneous lupus erythematosus (CLE). Hydroxychloroquine 200 mg daily led to improvement of the skin lesion. The unusual clinical presentation of our case emphasizes the heterogeneity of clinical manifestations of CLE.

Semi-mechanistic autoinduction model of midazolam in critically ill patients: population pharmacokinetic analysis

WHAT IS KNOWN AND OBJECTIVE

Midazolam (MDZ) is commonly used for sedating critically ill patients. The daily dose required for adequate sedation increases in increments over 100 h after administration. The objectives of this study were to characterize the MDZ pharmacokinetics in critically ill patients and to describe the phenomenon of increasing daily dose by means of population pharmacokinetic analysis.

METHODS

Data were obtained from 30 patients treated in an intensive care unit. The patients received MDZ intravenously as a combination of bolus and continuous infusion. Serum MDZ concentration was assayed by high-performance liquid chromatography. Population pharmacokinetic analysis was performed using the NONMEM software package. The alteration of clearance unexplained by demographic factors and clinical laboratory data was described as an autoinduction of MDZ clearance using a semi-mechanistic pharmacokinetic-enzyme turnover model.

RESULTS AND DISCUSSION

The final population pharmacokinetic model was a one-compartment model estimated by incorporating a semi-mechanistic pharmacokinetic-enzyme turnover model for clearance, taking autoinduction into account. A significant covariate for MDZ clearance was total bilirubin. An increase in total bilirubin indicated a reduction in MDZ clearance. From simulation using the population pharmacokinetic parameters obtained in this study, MDZ clearance increased 2·3 times compared with pre-induced clearance 100 h after the start of 12·5 mg/h continuous infusion.

WHAT IS NEW AND CONCLUSION

Autoinduction and total bilirubin were significant predictors of the clearance of MDZ in this population. Step-by-step dosage adjustment using this population pharmacokinetic model may be useful for establishing a MDZ dosage regimen in critically ill patients.

Analysis of the protective effects of a neuronal Cav2.1 calcium channel in brain injury

We previously reported that rolling Nagoya mice carrying a mutation in the α1 subunit of the Cav2.1 channel protective from ischemia- and kainate-induced neuronal damage. However, the protective effect of this mutation and its relationship to brain injury recovery have not been examined. To examine the relationship between Cav2.1 channel function and brain injury, we induced cryogenic brain damage in homozygous rolling Nagoya (rol/rol), control wild-type (+/+), ω-agatoxin IVA-pretreated +/+ (ω-aga +/+), and ω-agatoxin IVA-post-treated +/+ (ω-aga-post-treated +/+) mice. We measured the lesion area, blood brain-barrier permeability and performed immunohistochemistry and western blot analysis. The lesions of rol/rol and ω-aga +/+ mice were significantly smaller than those observed in +/+ mice at both day 1 and day 7 after injury. Similar results were shown in blood-brain barrier permeability. We observed more reactive astrogliosis in +/+ mice than in rol/rol or ω-aga +/+ mice. rol/rol and ω-aga +/+ mice had fewer degenerating cells due to cryogenic injury than did +/+ mice at both day 1 and day 7. ω-Aga-post-treated +/+ mice 24h after injury were sacrificed on day 7. The lesions were smaller in ω-aga-post-treated +/+ mice than those in vehicle-treated +/+ mice. We also examined phosphorylated p38 (pp38) at the injured site. ω-Aga-post-treated +/+ mouse brain slices showed weak pp38 signal; vehicle-treated +/+ mouse brain slices were pp38-positive. These findings demonstrate that the mutant Cav2.1 channel exerts a protective effect against cryogenic brain injury in rolling Nagoya mice. Our results indicate that inhibitors of the Cav2.1-dependent p38 signaling cascade would be useful as therapeutic agents in the treatment of brain injury.

Reflux esophagitis after esophagectomy: impact of duodenogastroesophageal reflux

Reflux esophagitis (RE) is a known complication disturbing patients' quality of life after esophageal resection. It is generally recognized that bile reflux as well as acid reflux cause RE. However, the clinical influence of acid and bile reflux, and Helicobacter pylori (H. pylori) infection on RE in the cervical esophagus after esophagectomy is not yet clarified. Sixty patients who underwent cervical esophagogastrostomy following esophagectomy were enrolled in this study. They underwent examination for H. pylori infection, endoscopic examination, and continuous 24-hour pH and bilirubin monitoring, at 1 month after surgery. The influence of acid and/or bile reflux, H. pylori infection, and others on the development of RE were investigated. RE was observed in 19 patients (32%) at 1 month after esophagogastrostomy, mild RE in 16 (27%), and severe RE in 3 (5%). The percentage of time duration of both acid and bile reflux into the cervical esophagus was higher in patients with RE than in those without (P = 0.027, P < 0.001). A significant difference in %time pH < 4 acid reflux was found between mild RE and severe RE (P = 0.014), and a statistical difference in %time abs. > 0.14 between non-RE and mild RE (P = 0.017). Acid and/or bile reflux was observed in 31 patients (52%), acid-only reflux in 6 (10%), bile-only reflux in 15 (25%), and acid-and-bile reflux in 10 (17%). Severe RE was observed only in patients having acid-and-bile reflux. On the univariate analysis, no infection of H. pylori, acid reflux, and bile reflux were determined to be the influencing factors to RE among the clinical factors including age, gender, route of esophageal reconstruction, H. pylori infection, and acid-and-bile reflux. In the subanalysis using the logistic model, there were significant correlations between bile reflux and RE irrespective of the presence of H. pylori infection (P = 0.016, P = 0.007). On the other hand, there was a significant correlation between acid reflux and RE only in patients without H. pylori infection (P = 0.039). In the early period after esophagogastrostomy, bile reflux could cause RE irrespective of H. pylori infection, while acid reflex could cause RE only in patients without H. pylori infection. There is a possibility that bile reflux plays an important role in the development of RE after esophagectomy.

Detection of antibodies against the non-calcium-dependent epitopes of desmoglein 3 in pemphigus vulgaris and their pathogenic significance

BACKGROUND

Antidesmoglein (anti-Dsg) 3 serum antibody titres are usually correlated with the disease activity of pemphigus vulgaris (PV), but some patients retain high titres even in remission.

OBJECTIVES

The aim of our study was to determine whether anti-Dsg3 antibodies in PV sera recognized calcium (Ca(2+) )-dependent or non-Ca(2+) -dependent epitopes, and to evaluate their pathogenicity.

METHODS

Dsg3 baculoprotein-coated enzyme-linked immunosorbent assay (ELISA) plates were treated with 0.5 mmol L(-1) ethylenediaminetetraacetic acid (EDTA). The binding ability of anti-Dsg3 monoclonal antibodies (mAbs) was analysed. Eight of the 83 patients with PV who were screened had elevated Dsg3 ELISA index values > 00 in remission. The binding ability of these PV sera was analysed. We evaluated the pathogenicity of anti-Dsg3 serum antibodies against the non-Ca(2+) -dependent epitopes using a dissociation assay.

RESULTS

The reactivity of pathogenic anti-Dsg3 mAbs against the Ca(2+) -dependent epitopes diminished markedly in the EDTA-treated ELISA, whereas no such reduction was observed in mAbs against the non-Ca(2+) -dependent epitopes. The sera of all the patients contained antibodies against both Ca(2+) -dependent and non-Ca(2+) -dependent epitopes. In six out of the eight patients, the ratio of antibodies against Ca(2+) -dependent to non-Ca(2+) -dependent epitopes decreased in remission. EDTA-treated Dsg3 baculoproteins adsorbed anti-Dsg3 serum antibodies against the non-Ca(2+) -dependent epitopes, but the remnant PV antibodies retained the ability to induce acantholysis in the dissociation assay.

CONCLUSIONS

We have established an assay to measure indirectly the titres of anti-Dsg3 serum antibodies against the Ca(2+) -dependent epitopes, based on the differences between EDTA-untreated and EDTA-treated ELISA index values, as a routine laboratory test to reflect the pathogenic anti-Dsg3 serum antibody titres more accurately.

What influences the acidity in the gastric conduit in patients who underwent cervical esophagogastrostomy for cancer?

The aim of this study was to determine the factors influencing acidity in the gastric conduit after esophagectomy for cancer. Acidity and bile reflux in the stomach and in the gastric conduit were examined by 24-h pH monitoring and bilimetry in 40 patients who underwent transthoracic subtotal esophagectomy followed by esophageal reconstruction using a gastric conduit, which was pulled up to the neck through a posterior mediastinal route in 17 patients, through a retrosternal route in 10 patients, and through a subcutaneous route in 13 patients. They were examined at 1 week before surgery, at 1 month after surgery, and at 1 year after surgery. Helicobacter pylori infection was examined pathologically and using the (13) C-urea breath test. The factors influencing acidity of the gastric conduit were analyzed using the stepwise regression model. Gastric acidity assessed by percentage (%) time of pH < 4 was reduced after surgery and was significantly less in patients with H. pylori infection compared with those without H. pylori infection throughout the period from 1 week before surgery to 1 year after surgery. Duodenogastric reflux (DGR) assessed by % time absorbance > 0.14 into the lower portion of the gastric conduit was significantly increased after surgery throughout the period from 1 month after surgery to 1 year after surgery. Multivariate analysis showed that the acidity in the gastric conduit was influenced by H. pylori infection and DGR at 1 month after surgery, and by H. pylori infection and the route for esophageal reconstruction at 1 year after surgery. Acidity in the gastric conduit was significantly decreased after surgery. Acidity in the gastric conduit for esophageal substitutes is influenced by H. pylori infection and surgery. DGR influences the gastric acidity in the short-term after surgery, but not in the long-term after surgery.

Helicobacter pylori infection influences the acidity in the gastric tube as an esophageal substitute after esophagectomy

It is commonly considered that acidity in a gastric tube used as an esophageal substitute after esophagectomy decreases due to truncal vagotomy. However, there have been few, if any, studies on the factors influencing the acidity in the gastric tube. It is well known that Helicobacter pylori (H. pylori) plays an important role in acid secretion of the stomach. The aim of this study was to investigate whether or not H. pylori infection also influenced the acidity in the gastric tube as an esophageal substitute. We investigated the changes in the levels of gastric acidity and the status of H. pylori infection from the preoperative period to 1 year after surgery. In 65 Japanese patients who underwent resection of esophageal cancer followed by reconstruction using a gastric tube, 24-h gastric pH monitoring and examination of H. pylori infection using the 13C-urea breath test and biopsy specimen obtained from the gastric mucosa under upper gastrointestinal endoscopy were performed pre- and postoperatively. Twenty-seven among the 65 patients underwent the same examinations at 1 year after surgery. The levels of postoperative gastric acidity and at 1 year after surgery were significantly lower than that of preoperative gastric acidity (P = 0.031, P = 0.001, respectively). There was no difference in the levels of gastric acidity between 1.5 months and 1 year after surgery (P = 0.282). The levels of gastric acidity in the stomach and in the gastric tube were significantly influenced by H. pylori infection, while age, gender, and past history of peptic ulcer showed no influence. The level of gastric acidity in patients who had H. pylori infection pre- and postoperatively were significantly lower than that in patients who had no H. pylori infection pre- and postoperatively (P < 0.0001). H. pylori infection was indicated to be an important factor influencing the levels of gastric acidity in the reconstructed esophagus as well as in the stomach before surgery.

Are desmoglein autoantibodies essential for the immunopathogenesis of pemphigus vulgaris, or just ‘witnesses of disease'?

Pemphigus vulgaris (PV) is fascinating to dermatologists, epithelial biologists and immunologists alike, as its pathogenesis has been clarified to a much greater extent than that of most other organ-specific autoimmune diseases, and as it has provided abundant novel insights into desmoglein biology and pathology along the way. Historically, the most influential PV pathogenesis concept is that of Stanley and Amagai. This concept holds that autoantibodies against desmogleins are both essential and sufficient for epidermal blister formation (acantholysis) by impeding the normal functioning of these major adhesion proteins. However, as with most good theories, this landmark concept has left a number of intriguing and important questions open (or at least has not managed to answer these to everyone's satisfaction). Moreover, selected dissenting voices in the literature have increasingly called attention to what may or may not be construed as inconsistencies in this dominant PV pathogenesis paradigm of the recent past. The present debate feature therefore bravely rises to the challenge of re-examining the entire currently available evidence, as rationally and as undogmatically as possible, by provocatively asking a carefully selected congregation of experts (who have never before jointly published on this controversial topic!) to discuss how essential anti-desmoglein autoantibodies really are in the immunopathogenesis of PV. Not surprisingly, some of our expert "witnesses" in this animated debate propose diametrically opposed answers to this question. While doing so, incisive additional questions are raised that relate to the central one posed, and our attention is called to facts that may deserve more careful consideration than they have received so far. Together with the intriguing (often still very speculative) complementary or alternative pathogenesis scenarios proposed in the following pages, this offers welcome "food for thought" as well as very specific suggestions for important future research directions--within and beyond the camp of PV aficionados. The editors trust that this attempt at a rational public debate of the full evidence that is currently at hand will constructively contribute to further dissecting the exciting--and clinically very relevant!--immunopathogenesis of PV in all its complexity.

A steroidogenic cell line with differentiation potential from mouse granulosa cells, transfected with Ad4BP and SV40 large T antigen genes

Several steroidogenic cell lines of granulosa cells (GC) have been used to elucidate differentiation mechanisms of GC during folliculogenesis. These cell lines, however, are of limited usefulness since they have lost some of their differentiation potential. The transcription factor adrenal-4 binding protein (Ad4BP), also known as steroidogenic factor-1 or NR5A1, is essential for the expression of all P-450 steroidogenic enzymes. By transfection with the Ad4BP gene together with SV40 DNA, we have generated several steroidogenic cell lines. One selective clone, named 4B2, retained its steroidogenic potential and was therefore analyzed in depth. This cell line responded to 8-Br-cAMP by displaying differentiation characteristics similar to those occurring in the differentiation process of primary cultured GC, including enhanced progesterone secretion, a cell shape change from a fibroblastic to epithelioid conformation, elongated mitochondria, increased gap junction formation and inhibition of cell proliferation. Prostaglandin E2 (PGE2), an intraovarian regulator of GC, stimulated cAMP production, and this eicosanoid, like 8-Br-cAMP, induced differentiation properties with the exception of cell conformation in 4B2 cells. These results suggest that expression of Ad4BP may provide the basis for a repertoire of cAMP-sensitive differentiation properties, including morphological alterations and growth inhibition. Thus, the 4B2 cell line may serve as a tool for elucidation of differentiation mechanisms that are under the control of Ad4BP.