Daniel Böhmer

The tissue engineering of articular cartilage: cells, scaffolds and stimulating factors:

Damage or loss of articular cartilage as a consequence of congenital anomaly, degenerative joint disease or injury leads to progressive debilitation, which has a negative impact on the quality of life of affected individuals in all age groups. Classical surgical techniques for hyaline cartilage reparation are frequently insufficient and in many cases it is not possible to obtain the expected results. For this reason, researchers and surgeons are forced to find a method to induce complete cartilage repair. Recently, the advent of tissue engineering has provided alternative possibilities for the treatment of these patients by application of cell-based therapy (e.g. chondrocytes and adult stem cells) combined with synthetic substitutes of the extracellular matrix and bioactive factors to prepare functional replacement of hyaline cartilage. This communication is aimed at a brief review of the current status of cartilage tissue engineering and recent advances in the field.

Morphological characterization of in vitro expanded human dental pulp-derived stem cells

Stem cells play pivotal role in the development of tissues and organs, as well as they maintain homeostasis and integrity of multicellular organisms. Human dental pulp-derived stem cells are capable of differentiation into osteoblasts, odontoblasts, adipocytes and neuronal-like cells and can have potential use in tissue regeneration. The aim of this study was a detailed description of human dental pulp-derived stem cells (HDPSCs) cultivated in vitro ultrastructural morphology. HDPSCs were isolated from the dental pulp of impacted third molars from healthy donors. Transmission electron microscopic analysis showed typical ultrastructural morphology similar to mesenchymal stem cells from other organs. The morphology of HDPSCs cells reflects their proteosynthetic and metabolic activity. Each cell contained spherical or irregularly-shaped large pale nucleus with a large amount of euchromatine. Nuclei had noticeable nucleolus (or two nucleoli) located nearby the nuclear envelope. Abundant cisterns of rough endoplasmic reticulum and numerous coated matrix vesicles as well as granules of glycogen were present in their cytoplasm. Nearby the nucleus small, elongated mitochondria were placed. Most of HDPSCs created and secreted vesicles; in plasmalemma bounded amorphous electron-lucide granules and also few glycogen granules. These secretory vesicles had around 0.5 μm in diameter. We assume that it can be a special type of communication between cells, probably paracrine type of cell signalling, but its real function is still unknown.

In vitro cytotoxicity testing of coladerm membrane

Atpresent, biodegradable and biocompatible membranes based on collagen andglycosaminoglycans play an important role in substitutive medicine. Modernbiomaterials use a chemically modified collagen-based matrix for implants withprogrammable biodegradability as a substitute of buccal mucosa, skin,cartilage,etc. Besides the requirements for biocompatibility and biodegradability, themembranes must be also non-toxic. Therefore, cytotoxicity testing of thesematerials in vitro is an integral part of introducingnewlydeveloped types of membranes into clinical practice. As a biological model forthe tested COLADERM membrane, cell cultures from human embryonic fibroblasts(B-HEF-2) were used for both cytotoxicity testing as well as in tests to assessthe ability of cells to proliferate on this membrane. Along with the ability ofcells to grow on the surface and inside the membrane, immunohistochemicalexamination and scanning electron microscopy (SEM) were performed as well. Theobtained results have shown that the COLADERM membrane is non-toxic withsuitable structural and biological properties for clinical application as asubstitute of buccal mucosa following surgical ablation of malignant tissuesfrom the oral cavity.

Gestational choriocarcinoma analyzed by polymerase chain reaction amplification of polymorphic VNTR and human leukocyte antigen regions

[1] Uharcek P, Mlyncek M, Ravinger J. Surgical management of endometrial cancer in Slovak Republic. Eur J Surg Oncol 2006;32(1):94–7. [2] Fujimoto T, Nanjyo H, Fukuda J, Nakamura A, Mizunuma H, Yaegashi N, et al. Endometrioid uterine cancer: histopathological risk factors of local and distant recurrence. Gynecol Oncol 2009;112(2):342–7. [3] Boronow RC, Morrow CP, Creasman WT, Disaia PJ, Silverberg SG, Miller A, et al. Surgical staging in endometrial cancer: clinical-pathologic findings of a prospective study. Obstet Gynecol 1984;63(6):825–32. [4] Ayhan A, Tuncer R, Tuncer ZS, Yüce K, Küçükali T. Correlation between clinical and histopathologic risk factors and lymph nodemetastases in early endometrial cancer (a multivariate analysis of 183 cases). Int J Gynecol Cancer 1994;4(5):306–9.

Biological and morphological characterization of human neonatal fibroblast cell culture B-HNF-1

In the present study, human neonatal fibroblasts were isolated from a two-month-old human male. The purpose of the present investigation was the analysis of the morphology (light and transmission electron microscopy), karyotype and growth characteristics of the human neonatal fibroblast cell culture B-HNF-1. Moreover, STR typing and mitochondrial DNA amplification and sequencing was also performed. Analysis of chromosomes count showed that B-HNF-1 cell culture is diploid and has normal male karyotype 46, XY, which was stable during cultivation. The transmission electron microscopy demonstrated the ultra-structure of the B-HNF-1 cells; they have typical morphological features of proteosynthesis-active cells. Large number of fibroblasts bearing different shapes and surface characteristics adhered to the substrate with microvilli and filopodia. Our in vitro expanded fibroblasts have a large and irregular nucleus with prevalence of euchromatin. One to three nucleoli are present in each nucleus. The cytoplasm contains a richly developed rough endoplasmic reticulum and prominent Golgi apparatus cisterns. The result of the fragment analysis is a DNA profile defined as multiplex of STR markers and sex determining system. Sequencing analysis of hypervariable segments of control region of mitochondrial DNA showed haplotype that belongs to haplogroup W. In this study, we complexly characterized a new cell culture of human neonatal fibroblasts B-HNF-1 from different points of view. This culture should be used for further biomedical experiments.

Inhibitors in Severe Hemophilia A: 25-Year Experience in Slovakia.

UNLABELLED We present 25-year experience with inhibitors in previously untreated patients (PUPs) with severe hemophilia A in Slovakia, where safe factor VIII (FVIII) concentrates have been used since 1990. A prospective study focused on inhibitor incidence in PUPs was established in 1997. Out of a total 61 PUPs born between January 1997 and October 2015, 59 were eligible for evaluation; 50 and 9 were treated with > 20 exposure days (ED) of plasma-derived FVIII (pdFVIII) and recombinant FVIII (rFVIII) products, respectively. In the entire group 13/59 (22%) PUPs developed inhibitors; i.e. 7/50 (14%) and 6/9 (67%) treated with pdFVIII and rFVIII, respectively. Univariate analysis of inhibitor risk factors in patient groups with and without inhibitors showed the rFVIII and serious/recurrent infections within the first 50 EDs to be associated with inhibitor development (OR of 12.3 [95% CI 2.48-60.83; p = 0.002] and 5.0; [95% CI 1.16-21.9; p = 0.03), respectively]). Also, in multivariate Cox regression analysis, peak treatment ≥ 5 EDs reached statistical significance. The hazard ratio (HR) was 7.15 (95% CI 1.65-31.36) p = 0.0086 for rFVIII and 4.38 (95% CI 1.02-18.67) p = 0.046 for intensive treatment. Between 1993 and 2015, 21 immune tolerance inductions (ITIs) in 19 inhibitor patients were performed in the two largest hemophilia centers in Slovakia. In all but one ITI courses pdFVIII containing von Willebrand factor (FVIII/VWF) was used with preferred use of high-dose ITI (HD ITI) in high responders (HRs). Complete or partial success was achieved in 17/19 (89.5%) patients. Evaluating only the patients who already completed ITI, the success rate was even higher (15/16; 94%), including 7/7 low responders and 8/9 HR. CONCLUSION Our national prospective study comprising entire group of PUPs with severe hemophilia A showed higher incidence of inhibitors in patients treated with rFVIII and those with intensive therapy within first 50 EDs. However, our experience is limited to small numbers of patients; thus, our results must be interpreted cautiously. High success rate of the ITI in our inhibitor patients has been achieved with FVIII/VWF concentrates and preferred use of HD ITI in HR patients.

PTEN sequence analysis in endometrial hyperplasia and endometrial carcinoma in Slovak women.

Phosphatase and tensin homolog (PTEN) is a protein that acts as a tumor suppressor by dephosphorylating the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate. Loss of PTEN function has been implicated in the pathogenesis of a number of different tumors, particularly endometrial carcinoma (ECa). ECa is the most common neoplasia of the female genital tract. Our study evaluates an association between the morphological appearance of endometrial hyperplasia and endometrial carcinoma and the degree of PTEN alterations. A total of 45 endometrial biopsies from Slovak women were included in present study. Formalin-fixed and paraffin-embedded tissue samples with simple hyperplasia (3), complex hyperplasia (5), atypical complex hyperplasia (7), endometrioid carcinomas G1 (20) and G3 (5), and serous carcinoma (5) were evaluated for the presence of mutations in coding regions of PTEN gene, the most frequently mutated tumor suppressor gene in endometrial carcinoma. 75% of the detected mutations were clustered in exons 5 and 8. Out of the 39 mutations detected in 24 cases, 20 were frameshifts and 19 were nonsense, missense, or silent mutations. Some specimens harboured more than one mutation. The results of current study on Slovak women were compared to a previous study performed on Polish population. The two sets of results were similar.

Mouth cavity base defect treated with biosynthetic graft

The use of in vitro prepared biosynthetic grafts can considerably improve the patient’s quality of life. This work reports on the use of an autologous graft prepared from a patient’s preputial cells cultivated on biodegradable polymeric membrane. Coladerm membrane is based on the chemically modified polyelectrolyte complex of atelocollagen and hyaluronan. The graft was used to cover a defect in the mouth cavity base and tongue after reconstruction surgery performed at this site in the past. The presented clinical case showed that the autologous biosynthetic graft prepared from foreskin cells can be successfully used for covering of medium-size defects in mouth cavity base resulting in the regeneration of target mouth structures with significant improvement of patient’s quality of life.

Comprehensive characterization of human adipose tissue-derived stem cells expanded in vitro

Adipose tissue seems to be a rich and safe source of mesenchymal stem cells (MSCs). The present study was aimed to investigate the biological and morphological characteristics of human adipose tissue-derived stem cells (ATSCs). Light and transmission electron microscopy were used. Course of proliferation was analyzed by growth curve. Expression of surface antigens was assessed by flow cytometry. Chondrogenic potential was assessed by immunohistochemistry. Obtained results showed morphology typical of fibroblastoid cells. TEM analysis proved ultrastructural morphology similar to MSCs from other sources. ATSCs reflected their proteosynthetic and metabolic activity. Each cell had irregular shape of nucleus with noticeable nucleoli. Abundant cisterns of rough endoplasmic reticulum were present in their cytoplasm. Karyotype mapping showed normal count of human chromosomes (46,XX). The growth curve revealed high capability for proliferation and population doubling time was 27.36 hours. ATSCs were positive for CD13, CD29, CD44, CD73, CD90, CD105 and CD106, but did not express CD14, CD34, CD45 and HLA-DR. It was also proved that ATSCs underwent chondrogenic differentiation in vitro. On the basis of obtained results it should be emphasized that ATSCs are typical MSCs and after further investigations they may be used in tissue engineering and regenerative medicine.

ERVW-1 gene polymorphisms related to preeclampsia.

OBJECTIVES Identification of genetic association between the gene ERVW-1 and preeclampsia. BACKGROUND Preeclampsia is a multifactorial disease affecting women during pregnancy and it is one of the main causes of perinatal and maternal morbidity and mortality. The pathophysiology of preeclampsia is very complex and several aspects of the disease have not been elucidated yet. Abnormal placentation frequently occurs during severe preeclampsia. Protein syncytin 1, a product of the ERVW-1 gene, plays a crucial role in the syncytiotrophoblast differentiation and optimal placentation. The syncytin 1 expression is disturbed during preeclampsia. The main focus of this study was the analysis of the ERVW-1 regulatory regions and identification of DNA polymorphisms associated with preeclamptic cases in Slovak population. METHODS Regulatory region of gene ERVW-1 was analyzed by sequencing to identify genetic variants. RESULTS We identified four DNA variants, namely rs4727276, rs148592540, rs569899772 and rs555416193, in samples of Slovak population. CONCLUSION No relation between polymorphisms and preeclampsia was observed, indicating that further investigations with a larger sampling are still required. However, our work represents new original approach in genetic differential diagnosis of preeclampsia with possible useful findings in the future (Tab. 3, Fig. 1, Ref. 34).