Positive impact of dynamic seeding of mesenchymal stem cells on bone-like biodegradable scaffolds with increased content of calcium phosphate nanoparticles.

One of the main aims of bone tissue engineering, regenerative medicine and cell therapy is development of an optimal artificial environment (scaffold) that can trigger a favorable response within the host tissue, it is well colonized by resident cells of organism and ideally, it can be in vitro pre-colonized by cells of interest to intensify the process of tissue regeneration. The aim of this study was to develop an effective tool for regenerative medicine, which combines the optimal bone-like scaffold and colonization technique suitable for cell application. Accordingly, this study includes material (physical, chemical and structural) and in vitro biological evaluation of scaffolds prior to in vivo study. Thus, porosity, permeability or elasticity of two types of bone-like scaffolds differing in the ratio of collagen type I and natural calcium phosphate nanoparticles (bCaP) were determined, then analyzes of scaffold interaction with mesenchymal stem cells (MSCs) were performed. Simultaneously, dynamic seeding using a perfusion bioreactor followed by static cultivation was compared with standard static cultivation for the whole period of cultivation. In summary, cell colonization ability was estimated by determination of cell distribution within the scaffold (number, depth and homogeneity), matrix metalloproteinase activity and gene expression analysis of signaling molecules and differentiation markers. Results showed, the used dynamic colonization technique together with the newly-developed collagen-based scaffold with high content of bCaP to be an effective combined tool for producing bone grafts for bone implantology and regenerative medicine.

Mechanical and structural properties of human aortic and pulmonary allografts do not deteriorate in the first 10 years of cryopreservation and storage in nitrogen.

The aortic and pulmonary allograft heart valves (AHV) are used in the cardiac surgery for replacing the impaired semilunar valves. They are harvested from donor hearts and cryostored in tissue banks. The expiration period was set to 5 years arbitrarily. We hypothesized that their mechanical and structural properties do not deteriorate after this period. A total of 64 human AHV (31 aortic and 33 pulmonary) of different length of cryopreservation (fresh, 0-5, 5-10, over 10 years) were sampled to different tissue strips (artery, leaflet, ventriculo-arterial junction) and tested by tensile test with loading velocity 10 mm/min until tissue rupture. Neighbouring regions of tissue were processed histologically and evaluated for elastin and collagen area fraction. The results were evaluated statistically. In aortic AHV, the physical deformation response of wall samples to stress did not changed significantly neither during the process of cryopreservation nor during the first 10 years of storage. In pulmonary AHV, the ultimate strain dropped after 5 years of cryopreservation indicating that pulmonary artery was significantly less deformable at the time of rupture. On the other hand, the ultimate stress was equal during the first 10 years of cryostorage. The changes in collagen and elastin amount in the tissue samples were not associated with mechanical impairment. Neither elasticity, stiffness and solidity nor morphology of aortic and pulmonary AHV did not change reasonably with cryopreservation and in the first 10 years of cryostorage. This evidence suggests that the expiration period might be extended in the future.

IDH1 mutation is associated with lower expression of VEGF but not microvessel formation in glioblastoma multiforme.

INTRODUCTION: Glioblastoma multiforme (GBM) represents the most malignant primary brain tumor characterized by pathological vascularization. Mutations in isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) were observed in GBM. We aimed to assess the intra-tumor hypoxia, angiogenesis and microvessel formation in GBM and to find their associations with IDH1 mutation status and patients prognosis. METHODS: 52 patients with a diagnosis of GBM were included into the study. IDH1 R132H mutation was assessed by RT-PCR from FFPE tumor samples obtained during surgery. The expression of markers of hypoxia (HIF2α), angiogenesis (VEGF), tumor microvascularity (CD31, CD34, vWF, CD105), and proliferation (Ki-67) were assessed immunohistochemically (IHC). IDH1 mutation and IHC markers were correlated with the patient survival. RESULTS: 20 from 52 GBM tumor samples comprised IDH1 R132H mutation (38.5%). The majority of mutated tumors were classified as secondary glioblastomas (89.9%). Patients with IDH1 mutated tumors experienced better progression-free survival (P = 0.037) as well as overall survival (P = 0.035) compared with wild type tumors. The significantly lower expression of VEGF was observed in GBM with IDH1 mutation than in wild type tumors (P = 0.01). No such association was found for microvascular markers. The increased expression of newly-formed microvessels (ratio CD105/CD31) in tumor samples was associated with worse patient's progression-free survival (P = 0.026). SUMMARY: No increase in HIF/VEGF-mediated angiogenesis was observed in IDH1-mutated GBM compared with IDH1 wild type tumors. The histological assessment of the portion of newly-formed microvessels in tumor tissue can be used for the prediction of GBM patient's prognosis.

The Effectiveness of Febrile Neutropenia Prophylaxis with Lipegfilgrastim in Routine Clinical Practice.

Febrile neutropenia (FN) is a common and potentially fatal complication of anticancer treatment, particularly in patients receiving myelosuppressive chemotherapy. It has been shown that prophylaxis with granulocyte colony-stimulating factor (G-CSF), especially its pegylated forms, significantly reduces the incidence of FN, the likelihood of chemotherapy dose intensity reduction and, also, the number of hospitalizations due to FN. This review discusses currently published results from clinical trials dealing with FN prophylaxis in routine clinical practice in patients with solid tumors and myeloproliferative malignancies with a focus on lipegfilgrastim, which is the newest modification of the original molecule filgrastim. The discussed results proved that prophylactic administration of lipegfilgrastim can almost eliminate the risk of FN and significantly reduce the risk of chemotherapy (CHT) dose reduction in routine clinical practice in cases of a clear high-risk chemotherapy regimen or in the presence of risk factors (such as age, comorbidities, performance status, etc.) in patients who received chemotherapy with medium risk of FN.

Stereological analysis of size and density of hepatocytes in the porcine liver.

The porcine liver is frequently used as a large animal model for verification of surgical techniques, as well as experimental therapies. Often, a histological evaluation is required that include measurements of the size, nuclearity or density of hepatocytes. Our aims were to assess the mean number-weighted volume of hepatocytes, the numerical density of hepatocytes, and the fraction of binuclear hepatocytes (BnHEP) in the porcine liver, and compare the distribution of these parameters among hepatic lobes and macroscopic regions of interest (ROIs) with different positions related to the liver vasculature. Using disector and nucleator as design-based stereological methods, the morphometry of hepatocytes was quantified in seven healthy piglets. The samples were obtained from all six hepatic lobes and three ROIs (peripheral, paracaval and paraportal) within each lobe. Histological sections (thickness 16 µm) of formalin-fixed paraffin-embedded material were stained with the periodic acid-Schiff reaction to indicate the cell outlines and were assessed in a series of 3-µm-thick optical sections. The mean number-weighted volume of mononuclear hepatocytes (MnHEP) in all samples was 3670 ± 805 µm3 (mean ± SD). The mean number-weighted volume of BnHEP was 7050 ± 2550 µm3 . The fraction of BnHEP was 4 ± 2%. The numerical density of all hepatocytes was 146 997 ± 15 738 cells mm-3 of liver parenchyma. The porcine hepatic lobes contained hepatocytes of a comparable size, nuclearity and density. No significant differences were identified between the lobes. The peripheral ROIs of the hepatic lobes contained the largest MnHEP with the smallest numerical density. The distribution of a larger MnHEP was correlated with a larger volume of BnHEP and a smaller numerical density of all hepatocytes. Practical recommendations for designing studies that involve stereological evaluations of the size, nuclearity and density of hepatocytes in porcine liver are provided.

Advances in Experimental Targeted Therapy and Immunotherapy for Patients with Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) represents the most malignant primary brain tumor in adults with generally dismal prognosis, early clinical deterioration and high mortality. GBM is extremely invasive, characterized by intense and aberrant vascularization and high resistance to multimodal treatment. Standard therapy (surgery, radiotherapy and chemotherapy with temozolomide) has very limited effectiveness, with median overall survival of patients no longer than 15 months. Progress in genetics and epigenetics of GBM over the past decade has revealed various aberrations in cellular signaling pathways, the tumor microenvironment, and pathological angiogenesis. A number of targeted anticancer drugs, such as small-molecule kinase inhibitors and monoclonal antibodies, have been evaluated in clinical trials with newly-diagnosed, as well as recurrent GBM. Unfortunately, to date, only a single anti-angiogenic agent, bevacizumab, has been approved for the treatment of recurrent GBM in the USA and Canada. The novel possibilities of cancer immunotherapy, especially immune checkpoint inhibitors, are being evaluated in clinical trials of patients with GBM. The most recent clinical experiences with targeted therapy as well as immunotherapy of GBM are given in this review. The relative lack of success of some of these approaches recently revealed in well-designed randomized clinical trials is also discussed.

[Arytmogenic ventricular cardiomyopathy]. / Arytmogenní ventrikulární kardiomyopatie.

Arrhythmogenic ventricular cardiomyopathy is considered to be a primary cardiomyopathy. Over the last few decades, although being a relatively rare disease with its prevalence 1:2000 - 1:5000, there were numerous studies performed with the aim to elucidate the underlaying causes, pathogenesis, diagnostical aspects and possible treatment options of the disease. Arrhythmogenic ventricular cardiomyopathy is genetically conditioned disease where proteins of the cell-cell junctions are involved. Mutations of the myocardial intercalated dics proteins, mainly desmosomal proteins (e.g.plakoglobin), are held to be responsible for electromechanical instability of the myocardium which causes regressive changes in cardiomyocytes in most cases of arrhythmogenic ventricular cardiomyopathy. Subsequent morphological changes include fibrofatty replacement and inflammation of the myocardium. The condition results in structural changes of the heart hence arrhytmias and other signs of heart disease. There are 3 variants of this cardiomyopathy: 'classical variant with predominant right ventricular involvement, biventricular and variant with left ventricular predominance. Clinical findings in patients with arrhythmogenic ventricular cardiomyopathy suggested the most appropriate means of the diagnostics and helped to create Task Force Criteria for in vivo diagnosis of the disease. The major pitfall and significance of arrhythmogenic ventricular cardiomyopathy lies in its common presentation as sudden cardiac death affecting mostly young adults.

Segmental and age differences in the elastin network, collagen, and smooth muscle phenotype in the tunica media of the porcine aorta.

The porcine aorta is often used in studies on morphology, pathology, transplantation surgery, vascular and endovascular surgery, and biomechanics of the large arteries. Using quantitative histology and stereology, we estimated the area fraction of elastin, collagen, alpha-smooth muscle actin, vimentin, and desmin within the tunica media in 123 tissue samples collected from five segments (thoracic ascending aorta; aortic arch; thoracic descending aorta; suprarenal abdominal aorta; and infrarenal abdominal aorta) of porcine aortae from growing domestic pigs (n=25), ranging in age from 0 to 230 days. The descending thoracic aorta had the greatest elastin fraction, which decreased proximally toward the aortic arch as well as distally toward the abdominal aorta. Abdominal aortic segments had the highest fraction of actin, desmin, and vimentin positivity and all of these vascular smooth muscle markers were lower in the thoracic aortic segments. No quantitative differences were found when comparing the suprarenal abdominal segments with the infrarenal abdominal segments. The area fraction of actin within the media was comparable in all age groups and it was proportional to the postnatal growth. Thicker aortic segments had more elastin and collagen with fewer contractile cells. The collagen fraction decreased from ascending aorta and aortic arch toward the descending aorta. By revealing the variability of the quantitative composition of the porcine aorta, the results are suitable for planning experiments with the porcine aorta as a model, i.e. power test analyses and estimating the number of samples necessary to achieving a desirable level of precision. The complete primary morphometric data, in the form of continuous variables, are made publicly available for biomechanical modeling of site-dependent distensibility and compliance of the porcine aorta.