Simvastatin impairs growth hormone-activated signal transducer and activator of transcription (STAT) signaling pathway in UMR-106 osteosarcoma cells.

Recent studies have demonstrated that statins reduce cell viability and induce apoptosis in various types of cancer cells. The molecular mechanisms underlying these effects are poorly understood. The JAK/STAT pathway plays an important role in the regulation of proliferation and apoptosis in many tissues, and its deregulation is believed to be involved in tumorigenesis and cancer. The physiological activation of STAT proteins by GH is rapid but transient in nature and its inactivation is regulated mainly by the expression of SOCS proteins. UMR-106 osteosarcoma cells express a GH-responsive JAK2/STAT5 signaling pathway, providing an experimental model to study the influence of statins on this system. In this study we investigated the actions of simvastatin on cell proliferation, migration, and invasion on UMR-106 cells and examined whether alterations in GH-stimulated JAK/STAT/SOCS signaling may be observed. Results showed that treatment of osteosarcoma cells with simvastatin at 3 to 10 µM doses decreases cell proliferation, migration, and invasion in a time- and dose-dependent manner. At the molecular level, although the mechanisms used by simvastatin are not entirely clear, the effect of the statin on the reduction of JAK2 and STAT5 phosphorylation levels may partially explain the decrease in the GH-stimulated STAT5 transcriptional activity. This effect correlated with a time- and dose-dependent increase of SOCS-3 expression levels in cells treated with simvastatin, a regulatory role that has not been previously described. Furthermore, the finding that simvastatin is capable of inducing SOCS-3 and CIS genes expression shows the potential of the JAK/STAT pathway as a therapeutic target, reinforcing the efficacy of simvastatin as chemotherapeutic drug for the treatment of osteosarcoma.

Autologous platelet-poor plasma decreases the bronchial stump necrosis in rat.

BACKGROUND: Necrosis of the bronchial stump is a very important trigger for bronchopleural fistula. The administration of local autologous platelet-poor plasma (PPP) could protect the bronchial stump. MATERIALS AND METHODS: Left pneumonectomy was performed in 25 Sprague-Dawley rats. Animals were randomly assigned to a control group (n=13) and PPP group (n=12). PPP was locally administered on the bronchial stump after pneumonectomy. We analyzed histologic changes in the bronchial stump and messenger RNA expression changes of genes involved in wound repair at 10 and 20 d. RESULTS: Local PPP treatment produced a mass of fibrous tissue surrounding the bronchial stump and significantly decreased the presence of necrosis at 20 d. PPP increased the expression of insulin like growth factor 1 at 10 d although it did not reach statistical significance. CONCLUSIONS: Our findings indicate that local PPP treatment of the bronchial stump after pneumonectomy decreased necrosis and could have a protective effect on the bronchial stump.

Inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase and application of statins as a novel effective therapeutic approach against Acanthamoeba infections.

Acanthamoeba is an opportunistic pathogen in humans, whose infections most commonly manifest as Acanthamoeba keratitis or, more rarely, granulomatous amoebic encephalitis. Although there are many therapeutic options for the treatment of Acanthamoeba, they are generally lengthy and/or have limited efficacy. Therefore, there is a requirement for the identification, validation, and development of novel therapeutic targets against these pathogens. Recently, RNA interference (RNAi) has been widely used for these validation purposes and has proven to be a powerful tool for Acanthamoeba therapeutics. Ergosterol is one of the major sterols in the membrane of Acanthamoeba. 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is an enzyme that catalyzes the conversion of HMG-CoA to mevalonate, one of the precursors for the production of cholesterol in humans and ergosterol in plants, fungi, and protozoa. Statins are compounds which inhibit this enzyme and so are promising as chemotherapeutics. In order to validate whether this enzyme could be an interesting therapeutic target in Acanthamoeba, small interfering RNAs (siRNAs) against HMG-CoA were developed and used to evaluate the effects induced by the inhibition of Acanthamoeba HMG-CoA. It was found that HMG-CoA is a potential drug target in these pathogenic free-living amoebae, and various statins were evaluated in vitro against three clinical strains of Acanthamoeba by using a colorimetric assay, showing important activities against the tested strains. We conclude that the targeting of HMG-CoA and Acanthamoeba treatment using statins is a novel powerful treatment option against Acanthamoeba species in human disease.

Severe compensatory hyperhidrosis following thoracic sympathectomy successfully treated with low doses of botulinum toxin A.

Compensatory hyperhidrosis is an adverse effect of thoracic sympathectomy that can be debilitating, which is why an efficient treatment is demanded. Botulinum toxin is an emerging treatment, not well known yet. We report two cases of compensatory hyperhidrosis following thoracic sympathectomy which were both treated with low doses of botulinum toxin A. The patients, a male and a female, noted a high level of satisfaction with the abolishment of sweating that was maintained up to 10 months. We consider that low doses of botulinum toxin A is a well tolerated, safe and effective treatment for compensatory hyperhidrosis and should be offered as an alternative treatment.

Technical modifications of the orthotopic lung transplantation model in rats with brain-dead donors.

BACKGROUND: Microsurgical lung transplantation in rats has allowed us to obtain new knowledge about lung transplantation. However, some aspects in human transplantation technique still have not been included in this model, which could interfere with the clinical interpretation and extrapolation of results. METHODS: Twenty left lung transplantations were performed with a cuff technique and technical modifications, such as brain death induction, the control of ischemia time and retrograde perfusion in the donor and the controlled sequential reperfusion of the implanted lung in the recipient. RESULTS: Survival rate was 80%. The transplanted lungs showed proper perfusion and ventilation with good permeability of the anastomoses. Signs of ischemia-reperfusion injury were observed in all animals while mild acute rejection was seen in half of them. CONCLUSIONS: The model shown proves valid and is very similar to the procedure carried out in humans, which would reduce the number of possible variables derived from the surgical technique when extrapolating the study results to clinical use.

Estradiol worsens the syndrome of ischemia-reperfusion injury in an experimental lung transplantation model.

Ischemia-reperfusion injury (IRI) is a common complication after lung transplantation. There is evidence that reactive oxygen species are involved in its pathogenesis. We designed an experimental study to evaluate whether the administration of antioxidants to lung transplantation recipients protects against IRI and early acute rejection (AR). Twenty-five rats received left lung transplants after 6 h of ischemia. Fifty minutes before the reperfusion, groups of five rats received a single dose of desferrioxamine (20 mg/kg), estradiol (25 mg/kg), or melatonin (10 mg/kg). The animals were killed 48 h after surgery and the postoperative outcome, IRI, and AR were evaluated. The frequency of severe injury and of moderate-to-severe edema was higher in animals treated with estradiol than in the control group (P = 0.022 and P = 0.026, respectively). No significant changes in the degree of IRI or AR were observed in the groups treated with desferrioxamine or melatonin. In our study, treatment with the antioxidants melatonin or desferrioxamine before reperfusion had no effects on IRI damage or on AR frequency or severity. However, treatment with estradiol resulted in a worse postoperative outcome and in severe edema. Therefore, despite the antioxidant capacity of estradiol, it is recommended that an evaluation of these adverse effects of estradiol in human lung transplant recipients be performed.

Partial recessive IFN-γR1 deficiency: genetic, immunological and clinical features of 14 patients from 11 kindreds.

We report a series of 14 patients from 11 kindreds with recessive partial (RP)-interferon (IFN)-γR1 deficiency. The I87T mutation was found in nine homozygous patients from Chile, Portugal and Poland, and the V63G mutation was found in five homozygous patients from the Canary Islands. Founder effects accounted for the recurrence of both mutations. The most recent common ancestors of the patients with the I87T and V63G mutations probably lived 1600 (875-2950) and 500 (200-1275) years ago, respectively. The two alleles confer phenotypes that are similar but differ in terms of IFN-γR1 levels and residual response to IFN-γ. The patients suffered from bacillus Calmette-Guérin-osis (n= 6), environmental mycobacteriosis (n= 6) or tuberculosis (n= 1). One patient did not suffer from mycobacterial infections but had disseminated salmonellosis, which was also present in two other patients. Age at onset of the first environmental mycobacterial disease differed widely between patients, with a mean value of 11.25 ± 9.13 years. Thirteen patients survived until the age of 14.82 ± 11.2 years, and one patient died at the age of 7 years, 9 days after the diagnosis of long-term Mycobacterium avium infection and the initiation of antimycobacterial treatment. Up to 10 patients are currently free of infection with no prophylaxis. The clinical heterogeneity of the 14 patients was not clearly related to either IFNGR1 genotype or the resulting cellular phenotype. RP-IFN-γR1 deficiency is, thus, more common than initially thought and should be considered in both children and adults with mild or severe mycobacterial diseases.

Hypoxia markers in human osteosarcoma: an exploratory study.

Neoplastic cells growing under hypoxic conditions exhibit a more aggressive phenotype by activating a cascade of molecular events partly mediated by hypoxia-inducible transcription factor (HIF-1alpha) and vascular endothelial growth factor (VEGF). The roles of these markers have been studied previously in several cancer lines. We ascertained the frequency of HIF-1alpha expression, VEGF expression, the degree of neovascularization, and cell proliferation in osteosarcoma samples. Samples from osteosarcoma patients were assessed for HIF-1alpha and VEGF protein expression using immunohistochemistry, neovascularization using antibodies for Factor VIII, and cell proliferation using the Ki-67 labeling index. Associations between these parameters and clinical features were examined. HIF-1alpha staining was positive in 35% of patients and metastases were present in 61% of these HIF-1alpha-positive patients. VEGF protein expression was detected in 69% of patients, 92% of whom were female. We observed an insignificant trend for a higher frequency of VEGF expression in the high-grade as compared to low-grade osteosarcoma. We observed no association between vascular density and proliferation index and any clinical parameters. We found an association between HIF-1alpha expression and metastatic disease and between VEGF expression and female gender.