Stimulation of mTORC2 by integrin αIIbβ3 is required for PI3Kβ-dependent activation of Akt but is dispensable for platelet spreading on fibrinogen

Abstract

Phosphatidylinositol 3 kinase (PI3K) is a major player in platelet activation and regulates thrombus formation and stabilization. The β isoform of PI3K is implicated in integrin αIIbβ3 outside-in signaling, is required for the phosphorylation of Akt, and controls efficient platelet spreading upon adhesion to fibrinogen. In this study we found that during integrin αIIbβ3 outside-in signaling PI3Kβ-dependent phosphorylation of Akt on Serine473 is mediated by the mammalian target of rapamycin complex 2 (mTORC2). The activity of mTORC2 is stimulated upon platelet adhesion to fibrinogen, as documented by increased autophosphorylation. However, mTORC2 activation downstream of integrin αIIbβ3 is PI3Kβ-independent. Inhibition of mTORC2, but not mTORC1, also prevents Akt phosphorylation of Threonine308 and affects Akt activity, resulting in the inhibition of GSK3α/β phosphorylation. Nevertheless, mTORC2 or Akt inhibition does not alter PI3Kβ-dependent platelet spreading on fibrinogen. The activation of the small GTPase Rap1b downstream of integrin αIIbβ3 is regulated by PI3Kβ but is not affected upon inhibition of either mTORC2 or Akt. Altogether, these results demonstrate for the first time the activation of mTORC2 and its involvement in Akt phosphorylation and stimulation during integrin αIIbβ3 outside-in signaling. Moreover, the results demonstrate that the mTORC2/Akt pathway is dispensable for PI3Kβ-regulated platelet spreading on fibrinogen.     

Corrosion Behavior of Titanium Dental Implants with Implantoplasty

The procedure generally used to remove bacterial biofilm adhering to the surface of titanium on dental implants is implantoplasty. This treatment is based on the machining of the titanium surface to remove bacterial plaque. In this study, we used 60 grade 4 titanium implants and performed the implantoplasty protocol. Using X-ray diffraction, we determined the stresses accumulated in each of the as-received, machined and debris implants. The resistance to corrosion in open circuit and potentiodynamically in physiological medium has been determined, and the corrosion potentials and intensities have been determined. Tests have been carried out to determine ion release by ICP-MS at different immersion times. The results show that the corrosion resistance and the release of titanium ions into the medium are related to the accumulated energy or the degree of deformation. The titanium debris exhibit compressive residual stresses of −202 MPa, the implant treated with implantoplasty −120 MPa, and as-received −77 MPa, with their corrosion behavior resulting in corrosion rates of 0.501, 0.77, and 0.444 mm/year, respectively. Debris is the material with the worst corrosion resistance and the one that releases the most titanium ions to the physiological medium (15.3 ppb after 21 days vs. 7 ppb for as-received samples). Pitting has been observed on the surface of the debris released into the physiological environment. This behavior should be taken into account by clinicians for the good long-term behavior of implants with implantoplasty.     

Effect of glucagon-like peptide-1 receptor agonists on cardiovascular events in overweight or obese adults without diabetes: A meta-analysis of placebo-controlled randomized trials

Our aim was to study the effect of glucagon-like peptide-1 receptor agonists (GLP-1 RA) on the risk of any cardiovascular event in adults with overweight or obesity and without diabetes. We conducted a random-effects meta-analysis of placebo-controlled randomized controlled trials. Nine trials were eligible and, in total, 11 430 patients were included, of which 7702 (67%) were submitted to treatment with GLP-1 RA. During follow-up, 673 participants receiving GLP-1 RA treatment (8.7%) and 416 participants receiving placebo (11.2%) had a cardiovascular event. Treatment with GLP-1 RA versus placebo resulted in a reduction in the risk of any cardiovascular event (RR = 0.81, CI 0.70-0.92; p = .001). In overweight or obese adults without diabetes, treatment with GLP-1 RA reduced the risk of cardiovascular events. Our findings support the use of GLP-1 RA for reducing the cardiovascular risk of these patients.     

Estimation of COVID-19 vaccine effectiveness against hospitalisation in individuals aged ≥ 65 years using electronic health registries; a pilot study in four EU/EEA countries,October 2021 to March 2022

By employing a common protocol and data from electronic health registries in Denmark, Navarre (Spain), Norway and Portugal, we estimated vaccine effectiveness (VE) against hospitalisation due to COVID-19 in individuals aged ≥ 65 years old, without previous documented infection, between October 2021 and March 2022. VE was higher in 65–79-year-olds compared with ≥ 80-year-olds and in those who received a booster compared with those who were primary vaccinated. VE remained high (ca 80%) between ≥ 12 and < 24 weeks after the first booster administration, and after Omicron became dominant.     

Platelet-derived growth factor-D enables liver myofibroblasts to promote tumor lymphangiogenesis in cholangiocarcinoma

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Identical COL71A1 heterozygous mutations resulting in different dystrophic epidermolysis bullosa phenotypes

Dystrophic epidermolysis bullosa is a rare blistering condition caused by mutations in the COL7A1 gene. Different clinical variants have been described, with dominant and recessive inheritance, but no consistent findings have been elucidated to establish a genotype–phenotype correlation. We present three unrelated patients with two identical pathogenic compound heterozygous mutations in the COL7A1 gene that developed different clinical forms of dystrophic epidermolysis bullosa—epidermolysis bullosa pruriginosa and mild recessive non‐Hallopeau–Siemens—raising the possibility of other genetic or environmental modifying factors responsible for the phenotype of the disease.     

Nocardiosis: an overview and additional report of 28 cases in cattle and dogs

Phenotypic characteristics, antimicrobial susceptibility profile, and clinical-epidemiological features of 28 Nocardia strains isolated from 19 cases of bovine mastitis, eight cutaneous-subcutaneous lesions and one case of pneumonia in dogs were evaluated. Microbiological, biochemical, cytological and scanning electron microscopy methods were used in diagnosis. Nocardia asteroides type IV, Nocardia otitidiscaviarum,Nocardia nova (type III) and Nocardia farcinica (type V) were isolated from bovine milk, bronchial lavage and/or cutaneous-subcutaneous abscesses in dogs. Nocardial bovine mastitis was diagnosed predominantly in clinical cases, in dairy herds with poor environmental hygienic conditions between milking and inappropriate intramammary therapy. Canine nocardiosis was observed commonly in animals co-infected with distemper virus. Sulphamethoxazole-trimethoprim (92.8%), amikacin (92.8%) and ceftiofur (92.8%) were the most effective drugs in 28 isolates. Multiple drug resistance to three or more and five or more antimicrobials was observed in ten (35.7%) and three (10.7%) strains, respectively, predominantly with use of cloxaxillin, cefoperazone and ampicillin. The species (type) classification, clinical-epidemiological characteristics, diagnosis, multiple-drug resistance and public health considerations in Nocardia strains isolated from cattle and dogs in Brazil are discussed, with special reference to report of bovine mastitis by N. otitidiscaviarum by first time in Brazil and the similarity between Nocardia species isolated from human and animal origin.     

Evaluation of hepatic resection for hepatocellular carcinoma on cirrhotic livers

BACKGROUND: The hepatocellular carcinoma is a disorder that affects patients suffering from cirrhosis. Liver resection, orthotopic liver transplantation and percutaneous ablation are some forms of therapy currently used to provide a cure for this disease. AIM: To assess the results achieved through liver resection for the treatment of the hepatocellular carcinoma in patients with cirrhosis being under treatment in a general hospital. METHODS: Clinical observation, laboratory test results, endoscopic and histopathologic analysis were taken into consideration in the case of 22 patients who underwent liver resection between 1996 and 2005. To verify the survival rates, identify the prognostic factors and determine the risk of recurrence, special attention was given to the serologic levels of bilirubins and alpha-fetoprotein, and to the level of the hepatocellular dysfunction (classified according to the Child-Pugh-Turcotte and the Model for End-Stage Liver Disease parameters). The size and number of tumours, microvascular invasion and the presence of satellite lesions were also taken into consideration. The level of statistic significance employed was of 95%. RESULTS: In the cases studied, patients had an average age of 62.09 years, being 17 of them male. In 10 cases the liver cirrhosis was associated to the hepatitis C chronic infection; in 4 cases there was a combination of chronic ingestion of ethanol and the hepatitis C virus; in 3 cases there was an association with the hepatitis B virus chronic infection. Two cases were related to the chronic ingestion of ethanol alone and in one case the use of medications was reported. It was not possible to establish the etiology in two of the cases studied. Eighteen patients had a single tumour, 11 of them smaller than 5 cm. The survival rate varied between 10 days and 120 months, being of 33.5 months on average. At the end of the 1st, 3rd and 5th year, the survival rates were 61.90%, 16.67% and 11.11%, respectively. Three patients died within the first 3 months after the liver resection. Thirteen patients died after the first 3 months, 12 of the cases associated to tumour recurrence and tumour progression. There was one death in the immediate post-operative period of a second operation carried out to remove a recurrent tumour. When it comes to the survival rate and the identification of prognostic factors, a relationship between patients survival and microvascular invasion was observed. No statically significant relationship was established between the survival rate and the serologic levels of bilirubins and alpha-fetoprotein or the level of hepatocellular dysfunction, size or number of tumours. However, a more significant incidence of tumour recurrence was observed in patients with microvascular invasion in the histopathologic study. CONCLUSION: In spite of the reduced number of cases studied, the surgical treatment of the hepatocellular carcinoma produced bad results. A careful selection of cases where surgery could be an option may be a decisive factor to improve such results. A careful selection of cases might be a decisive factor in order to improve such results.