A method for removal of fibroblasts from human tissue culture systems

The phenomenon of fibroblast overgrowth is one of the major problems encountered during long-term culture of more slowly growing specialized cell types. A cell surface glycoprotein, Thy-1, which was originally found to be present on murine T-lymphocytes and brain cells, is also found to be present on only a few human cell types, mainly fibroblasts and neuronal cells. We have taken advantage of this fact, using a solid-phase immunoadsorption technique termed "panning", to rid our culture system (normal human keratinocytes) of contaminating dermal fibroblasts. A mouse monoclonal antibody raised against human brain Thy-1 was used to attach dermal fibroblasts to a goat anti-mouse immunoglobulin-coated plastic surface. By this method we were able to separate a 1:1 mixture of human dermal fibroblasts and keratinocytes with greater than 97.5% efficiency. Furthermore we have successfully removed dermal fibroblasts from naturally arising contaminated keratinocyte cultures, where the proportion of fibroblasts (less than 10%) was considerably less than that of the artificially mixed populations. These results compare favorably with those expected of the fluorescence-activated cell sorter (FACS) method of cell separation. In addition this technique is comparatively simple and inexpensive and is thought to be of use to other primary tissue culture systems (especially human) where contamination and subsequent overgrowth with fibroblasts remains a problem.     

A simplified technique for the short-term tissue culture of rabbit corneal cells

Summary A technique for the short-term culture of pure populations of rabbit corneal endothelial and epithelial cells has been developed. Rabbit corneas were placed on concave agarose surfaces, treated briefly with a solution of trypsin and ethylenediamine tetracetic acid, and transferred, either epithelial cell surface or endothelial cell surface down, to microscope slide culture chambers. Within 6 to 12 h the epithelial cells or endothelial cells attached to the slide chamber surface and the cornea was removed, leaving behind a pure population of cells which spread out and grew to fill the surface of the slide chamber. This technique provides a simple and economic means for the reproducible initiation of primary cultures of rabbit corneal epithelial and endothelial cells for us in a variety of experiments. This study was supported in part by Public Health Service grants EY03150, EY02580, and EY02377 from the National Eye Institute, National Institutes of Health, Bethesda, MD, and a Foreign Fellowship (Dr. Xie) from Research to Prevent Blindness, Inc., New York, NY.     

Rainbow trout leukocyte culture: A simplified method

Summary The addition of 10% fetal bovine serum to Leibovitz’s L-15 culture medium resulted in marked growth of peripheral blood leukocytes from rainbow trout,Salmo gairdneri. Culture medium without serum or with 20% homologous serum did not induce substantial growth. In contrast to what has been reported by others, oxygenation of the culture medium was found not to be required for excellent cell growth.     

Maintenance of fetal human pancreatic beta cells in tissue culture

Large quantities of viable human islet tissue (beta cells) are required for transplant and for investigations of the autoimmune basis of Type I diabetes. Fetal pancreas offers a potential advantage over other possible sources of beta cells in that it retains some capacity for growth in vitro. We have cultured a total of 45 human pancreata from fetuses of gestational ages from 18 to 23 weeks. Each pancreas was obtained within minutes after delivery and usually cultured within 30 minutes. Pancreata were dispersed and cultured for up to 32 days. Maintenance and growth of the beta cells was assessed by the content of insulin in extracts of cultured tissue. As has been reported by others, fetal human beta cells survived in vitro for over 4 weeks. In three experiments in which a direct comparison was made, collagenase digestion of the fetal pancreas resulted in a significantly greater loss of insulin content compared to minced tissue cultured without digestion. Storage of three pancreata in medium overnight at 4 degrees C significantly reduced the insulin content of the pancreas compared to pancreata cultured immediately. During culture, the majority of the beta cells (based on insulin content) were found in small, macroscopic clumps attached to the surface of the culture dish, and surrounded by a nearly confluent monolayer of fibroblastoid cells. There was a marked decrease in the insulin content of the tissue during culture, most of it (to less than 25% of the original) occurring over the first 4-6 days of culture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth of dissociated beating human heart cells in tissue culture

Fetal human heart cells have been dissociated by trypsinization and successfully grown in tissue culture on two occassions. The characteristics of the growth and mitotic activity were quite similar to those previously found for rodent heart cells. The maximum beating rates seen in the cultures from each specimen were 33 and 75 per minute.     

A simple and established method of tissue culture of human gingival fibroblasts for gingival augmentation

Recent advances in tissue engineering technology suggest its application in different medical fields, including periodontology. There are some reports of new non-enzymatic methods of isolating human gingival fibroblast for short-time cultivation in vitro to be used in autologous gingival augmentation. The aim of this study was to obtain a simple and established method of culturing human gingival fibroblasts. The authors developed a recurrent method that can be successfully used in autologous gingival augmentation.     

A method for obtaining a long-lived intestinal tissue culture

The interest in the studies of the intestines using the method of tissue organ culture has considerably grown in recent years. It can be explained by the great possibilities of obtaining unique data about the state of intestines in normal and pathological condition, e.g. malabsorption syndrome. The paper deals with the method modified by the authors to obtain long-living (24 hours) intestinal tissue organ culture. The investigations used bioptic sections which were obtained by jejunoscopy with spot biopsy of children suffering from intestinal malabsorption. The viability of the explants was proved by histological and histochemical tests. The promise held by the methods is emphasized.     

A simplified method for the generation of human osteoclasts in vitro

Osteoclasts are large, multinucleated cells responsible for the resorption of mineralized bone matrix. These cells are critical players in the bone turnover involved in bone homeostasis. Osteoclast activity is connected to the establishment and expansion of skeletal metastases from a number of primary neoplasms. Thus, the formation and activation of osteoclasts is an area of research with many potential avenues for clinical translation. Past studies of osteoclast biology have utilized primary murine cells cultured in vitro. Recently, techniques have been described that involve the generation of osteoclasts from human precursor cells. However, these protocols are often time-consuming and insufficient for generating large numbers of osteoclasts. We therefore developed a simplified protocol by which human osteoclasts may be easily and reliably generated in large numbers in vitro. In this study, osteoclasts were differentiated from bone marrow cells that had been aliquotted and frozen. Cells were generated by culture with recombinant macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL). Both human and murine RANKL were shown to efficiently generate osteoclasts, although higher concentrations of murine RANKL were required. Formation of osteoclasts was demonstrated qualitatively by tartrate-resistant acid phosphatase (TRAP) staining. These cells were fully functional, as confirmed by their ability to form resorption pits on cortical bone slices. Functional human osteoclasts can be difficult to generate in vitro by current protocols. We have demonstrated a simplified system for the generation of human osteoclasts in vitro that allows for large numbers of osteoclasts to be obtained from a single donor.     

A simplified method for purification of annexin V from human placenta

A simplified procedure for purification of annexin V from human placenta was developed. At first, the protein was separated from other proteins in membrane bound form in the presence of Ca2+, then was extracted with EDTA and purified by affinity chromatography on PAAG-immobilized phosphatidylserine. The purified protein gave a single band with a molecular weight of 35,000 in SDS-PAGE.     

A human neuronal tissue culture model for Lesch-Nyhan disease

Mutations in the gene encoding the purine salvage enzyme, hypoxanthine-guanine phosphoribosyltransferase (HPRT) cause Lesch-Nyhan disease, a neurodevelopmental disorder characterized by cognitive, neurological, and behavioral abnormalities. Despite detailed knowledge of the enzyme's function, the key pathophysiological changes that accompany loss of purine recycling are unclear. To facilitate delineating the consequences of HPRT deficiency, four independent HPRT-deficient sublines of the human dopaminergic neuroblastoma, SK-N-BE(2) M17, were isolated by targeted mutagenesis with triple helix-forming oligonucleotides. As a group, these HPRT-deficient cells showed several significant abnormalities: (i) impaired purine recycling with accumulation of hypoxanthine, guanine, and xanthine, (ii) reduced guanylate energy charge and GTP:GDP ratio, but normal adenylate energy charge and no changes in any adenine nucleotide ratios, (iii) increased levels of UTP and NADP+, (iv) reduced DOPA decarboxylase, but normal monoamines, and (v) reduction in cell soma size. These cells combine the analytical power of multiple lines and a human, neuronal origin to provide an important tool to investigate the pathophysiology of HPRT deficiency.     

Characterization of a simplified ice-free cryopreservation method for heart valves

The aim of the present study was to characterize the hemocompatibility of ice-free cryopreserved heart valves in anticipation of future human trials. Porcine pulmonary heart valves were infiltrated with either an 83 % cryoprotectant solution followed by rapid cooling and storage at ?80 °C or with 10 % DMSO and control rate freezing to ?80 °C and storage in vapor phase nitrogen as conventional frozen controls. Cryopreserved leaflets were compared with fresh, decellularized and glutaraldehyde-fixed control valve leaflets using a battery of coagulation protein assays after exposure to human blood. Von Willebrand Factor staining indicated that most of the endothelium was lost during valve processing prior to cryopreservation. Hemocompatibility, employing thrombin/antithrombin-III-complex, polymorphonuclear neutrophil-elastase, beta-thromboglobulin and terminal complement complex SC5b-9, was preserved compared with both fresh and frozen leaflets. Hemocompatibility differences were observed for cryopreserved leaflets versus both decellularized and glutaraldehyde fixed controls. In conclusion, the hemocompatibility results support the use of ice-free cryopreservation as a simplified preservation method because no statistically significant differences in hemocompatibility were observed between the two cryopreservation methods and fresh untreated controls.