Current status and challenges in uterine myometrial tissue engineering

The uterus undergoes significant modifications throughout pregnancy to support embryo development and fetal growth. However, conditions like fibroids, adenomyosis, cysts, and C-section scarring can cause myometrial damage. The importance of the uterus and the challenges associated with myometrial damage, and the need for alternative approaches are discussed in this review. The review also explores the recent studies in tissue engineering, which involve principles of combining cells, scaffolds, and signaling molecules to create functional uterine tissues. It focuses on two key approaches in uterine tissue engineering: scaffold technique using decellularized, natural, and synthetic polymer and 3D bioprinting. These techniques create supportive structures for cell growth and tissue formation. Current treatment options for myometrial damage have limitations, leading to the exploration of regenerative medicine and integrative therapies. The review emphasizes the potential benefits of tissue engineering, including more effective and less invasive treatment options for myometrial damage. The challenges of developing biocompatible materials and optimizing cell growth and differentiation are discussed. In conclusion, uterine tissue engineering holds promise for myometrial regeneration and the treatment of related conditions. This review highlights the scientific advancements in the field and underscores the potential of tissue engineering as a viable approach. By addressing the limitations of current treatments, tissue engineering offers new possibilities for improving reproductive health and restoring uterine functionality. Future research shall focus on overcoming challenges and refining tissue engineering strategies to advance the field and provide effective solutions for myometrial damage and associated disorders.

Long-term and non-invasive in vivo tracking of DiD dye-labeled human hepatic progenitors in chronic liver disease models

BACKGROUND

Chronic liver diseases (CLD) are the major public health burden due to the continuous increasing rate of global morbidity and mortality. The inherent limitations of organ transplantation have led to the development of stem cell-based therapy as a supportive and promising therapeutic option. However, identifying the fate of transplanted cells in vivo represents a crucial obstacle.

AIM

To evaluate the potential applicability of DiD dye as a cell labeling agent for long-term, and non-invasive in vivo tracking of transplanted cells in the liver.

METHODS

Magnetically sorted, epithelial cell adhesion molecule positive (1 × 10⁶ cells/mL) fetal hepatic progenitor cells were labeled with DiD dye and transplanted into the livers of CLD-severe combined immunodeficiency (SCID) mice. Near-infrared (NIR) imaging was performed for in vivo tracking of the DiD-labeled transplanted cells along with colocalization of hepatic markers for up to 80 d. The existence of human cells within mouse livers was identified using Alu polymerase chain reaction and sequencing.

RESULTS

NIR fluorescence imaging of CLD-SCID mice showed a positive fluorescence signal of DiD at days 7, 15, 30, 45, 60, and 80 post-transplantation. Furthermore, positive staining of cytokeratin, c-Met, and albumin colocalizing with DiD fluorescence clearly demonstrated that the fluorescent signal of hepatic markers emerged from the DiD-labeled transplanted cells. Recovery of liver function was also observed with serum levels of glutamic-oxaloacetic transaminase, glutamate-pyruvate transaminase, and bilirubin. The detection of human-specific Alu sequence from the transplanted mouse livers provided evidence for the survival of transplanted cells at day 80.

CONCLUSION

DiD-labeling is promising for long-term and non-invasive in vivo cell tracking, and understanding the regenerative mechanisms incurred by the transplanted cells.

Expansion of Human Hematopoietic Stem/Progenitor Cells on Decellularized Matrix Scaffolds

Umbilical cord blood (UCB) is one of the richest sources for hematopoietic stem/progenitor cells (HSPCs), with more than 3000 transplantations performed each year for the treatment of leukemia and other bone marrow, immunological, and hereditary diseases. However, transplantation of single cord blood units is mostly restricted to children, due to the limited number of HSPC per unit. This unit develops a method to increase the number of HSPCs in laboratory conditions by using cell-free matrices from bone marrow cells that mimic 'human-body-niche-like' conditions as biological scaffolds to support the ex vivo expansion of HSPCs. In this unit, we describe protocols for the isolation and characterization of HSPCs from UCB and their serum-free expansion on decellularized matrices. This method may also help to provide understanding of the biochemical organization of hematopoietic niches and lead to suggestions regarding the design of tissue engineering-based biomimetic scaffolds for HSPC expansion for clinical applications.

Propagation of pure fetal and maternal mesenchymal stromal cells from terminal chorionic villi of human term placenta

Long term propagation of human fetal mesenchymal stromal cells (MSC) in vitro has proven elusive due to limited availability of fetal tissue sources and lack of appropriate methodologies. Here, we have demonstrated the presence of fetal and maternal cells within the tips of terminal chorionic villi (TCV) of normal human term placenta, and we have exploited inherent differences in the adhesive and migratory properties of maternal vs. fetal cells, to establish pure MSC cultures of both cell types. The origin and purity of each culture was confirmed by X-Y chromosome-specific fluorescence in situ hybridization (FISH) and short tandem repeat (STR) genotyping. This is the first demonstration of fetal and maternal cells in the TCV of human term placenta and also of deriving pure fetal MSC cultures from them. The concomitant availability of pure cultures of adult and fetal MSC from one tissue provides a good system to compare genetic and epigenetic differences between adult and fetal MSCs; and also to generate new models of cell based therapies in regenerative medicine.

Synthesis and functional characterization of a fluorescent peptide probe for non invasive imaging of collagen in live tissues

Targeted molecular imaging to detect changes in the structural and functional organization of tissues, at the molecular level, is a promising approach for effective and early diagnosis of diseases. Quantitative and qualitative changes in type I collagen, which is a major component in the extra cellular matrix (ECM) of skin and other vital organs like lung, liver, heart and kidneys, are often associated with the pathophysiology of these organs. We have synthesized a fluorescent probe that comprises collagelin, a specific collagen binding peptide, coupled to fluorescent porphyrin that can effectively detect abnormal deposition of collagen in live tissues by emitting fluorescence in the near infra red (NIR) region. In this report we have presented the methodology for coupling of 5-(4-carboxy phenyl)-10, 15, 20-triphenyl porphyrin (C-TPP) to the N-terminal of collagelin or to another mutant peptide (used as a control). We have evaluated the efficacy of these fluorescent peptides to detect collagen deposition in live normal and abnormal tissues. Our results strongly suggest that porphyrin-tagged collagelin can be used as an effective probe for the non invasive in vivo detection of tissue fibrosis, especially in the liver.

Reconstruction of Hyaline Cartilage Deep Layer Properties in 3-Dimensional Cultures of Human Articular Chondrocytes

Background:

Articular cartilage (AC) injuries and malformations are commonly noticed because of trauma or age-related degeneration. Many methods have been adopted for replacing or repairing the damaged tissue. Currently available AC repair methods, in several cases, fail to yield good-quality long-lasting results, perhaps because the reconstructed tissue lacks the cellular and matrix properties seen in hyaline cartilage (HC).

Purpose:

To reconstruct HC tissue from 2-dimensional (2D) and 3-dimensional (3D) cultures of AC-derived human chondrocytes that would specifically exhibit the cellular and biochemical properties of the deep layer of HC.

Study Design:

Descriptive laboratory study.

Methods:

Two-dimensional cultures of human AC–derived chondrocytes were established in classical medium (CM) and newly defined medium (NDM) and maintained for a period of 6 weeks. These cells were suspended in 2 mm–thick collagen I gels, placed in 24-well culture inserts, and further cultured up to 30 days. Properties of chondrocytes, grown in 2D cultures and the reconstructed 3D cartilage tissue, were studied by optical and scanning electron microscopic techniques, immunohistochemistry, and cartilage-specific gene expression profiling by reverse transcription polymerase chain reaction and were compared with those of the deep layer of native human AC.

Results:

Two-dimensional chondrocyte cultures grown in NDM, in comparison with those grown in CM, showed more chondrocyte-specific gene activity and matrix properties. The NDM-grown chondrocytes in 3D cultures also showed better reproduction of deep layer properties of HC, as confirmed by microscopic and gene expression analysis. The method used in this study can yield cartilage tissue up to approximately 1.6 cm in diameter and 2 mm in thickness that satisfies the very low cell density and matrix composition properties present in the deep layer of normal HC.

Conclusion:

This study presents a novel and reproducible method for long-term culture of AC-derived chondrocytes and reconstruction of cartilage tissue with properties similar to the deep layer of HC in vitro.

Clinical Relevance:

The HC tissue obtained by the method described can be used to develop an implantable product for the replacement of damaged or malformed AC, especially in younger patients where the lesions are caused by trauma or mechanical stress.

Expansion of human hematopoietic stem/progenitor cells on decellularized matrix scaffolds

Umbilical cord blood (UCB) is one of the richest sources for hematopoietic stem/progenitor cells (HSPCs), with more than 3000 transplantations performed each year for the treatment of leukemia and other bone marrow, immunological, and hereditary diseases. However, transplantation of single cord blood units is mostly restricted to children, due to the limited number of HSPC per unit. This unit develops a method to increase the number of HSPCs in laboratory conditions by using cell-free matrices from bone marrow cells that mimic 'human-body niche-like' conditions as biological scaffolds to support the ex vivo expansion of HSPCs. In this unit, we describe protocols for the isolation and characterization of HSPCs from UCB and their serum-free expansion on decellularized matrices. This method may also help to provide understanding of the biochemical organization of hematopoietic niches and lead to suggestions regarding the design of tissue engineering-based biomimetic scaffolds for HSPC expansion for clinical applications.

In vitro quantitative and relative gene expression analysis of pancreatic transcription factors Pdx-1, Ngn-3, Isl-1, Pax-4, Pax-6 and Nkx-6.1 in trans-differentiated human hepatic progenitors

Aims/Introduction

Diabetes is a major health concern throughout the world because of its increasing prevalence in epidemic proportions. β‐Cell deterioration in the pancreas is a crucial factor for the progression of diabetes mellitus. Therefore, the restoration of β‐cell mass and its function is of vital importance for the development of effective therapeutic strategies and most accessible cell sources for the treatment of diabetes mellitus.

Materials and Methods

Human fetuses (12–20 weeks gestation age) were used to isolate human hepatic progenitor cells (hHPCs) from fetal liver using a two‐step collagenase digestion method. Epithelial cell adhesion molecule‐positive (EpCAM+ve)‐enriched hHPCs were cultured in vitro and induced with 5–30 mmol/L concentration of glucose for 0–32 h. Pdx‐1 expression and insulin secretion was analyzed using immunophenotypic and chemifluorescence assays, respectively. Relative gene expression was quantified in induced hHPCs, and compared with uninduced and pancreatic cells to identify the activated transcription factors (Pdx‐1, Ngn‐3, Isl‐1, Pax‐4, Pax‐6 and Nkx‐6.1) involved in β‐cell production.

Results

EpCAM+ve cells derived from human fetal liver showed high in vitro trans‐differentiation potential towards the β‐cell phenotype with 23 mmol/L glucose induction after 24 h. The transcription factors showed eminent expression in induced cells. The expression level of transcription factors was found significantly high in 23 mmol/L‐induced hHPCs as compared with the uninduced cells.

Conclusions

The present study has shown an exciting new insight into β‐cell development from hHPCs trans‐differentiation. Relative quantification of gene expression in trans‐differentiated cells offers vast possibility for the production of a maximum number of functionally active pancreatic β‐cells for a future cure of diabetes.

Applications of human hematopoietic stem cells isolated and expanded from different tissues in regenerative medicine

Bone marrow transplantation is a well-established stem cell-based therapy for the management of malignant and nonmalignant hematological disorders. In addition to the bone marrow, therapeutic hematopoietic stem cells (HSCs) can also be obtained from umbilical cord blood and mobilized peripheral blood. Transplantation of HSCs isolated from these tissues can be carried out with or without prior enrichment of specific cell types. New methodologies have been developed for lineage-specific HSC expansion and their transplantation as a supplementary treatment to whole bone marrow transplantation. In this review we have described the current methodologies for isolating and processing HSCs from various tissues, and discussed strategies to generate sufficient and functional HSCs for clinical and preclinical applications by expansion ex vivo. The various disease conditions in which these cells could be used, and the methods for delivering the cells into patients, are also discussed.

Histological analysis of cells and matrix mineralization of new bone tissue induced in rabbit femur bones by Mg-Zr based biodegradable implants

The biological efficacy of bone inducing implant materials in situ can be assessed effectively by performing histological analysis. We studied the peri-implant bone regeneration around two types of biodegradable magnesium-zirconium alloys, Mg-5Zr and Mg-Zr-2Sr, using histological, histochemical and immunohistochemical methods in the femur of New Zealand White strain rabbits. Our study includes three animal groups: (a) Mg-5Zr, (b) Mg-Zr-2Sr and (c) control. In each group three animals were used and in groups 'a' and 'b' the respective alloys were implanted in cavities made at the distal ends of the femur; control animals were left without implants to observe natural bone healing. Qualitative assessment of the cellularity and matrix mineralization events of the newly formed bone tissue was done at three months after implantation by histological methods in methyl methacrylate embedded tissue without decalcifying the bone. Quantitative mineral content and density of the new bone (NB) were evaluated by the statistical analysis of dual energy X-ray absorptiometry (DXA) data obtained from three animals in each experimental group. Based on our analysis we conclude that Mg-Zr-2Sr alloy showed better osseointegration of the newly formed bone with the implant surface. Our methodology of studying peri-implant osteoinduction of degradable implants using low temperature methyl methacrylate embedding resin can be useful as a general method for determining the bio-efficacy of implant materials.

Zirconium, calcium, and strontium contents in magnesium based biodegradable alloys modulate the efficiency of implant-induced osseointegration

Development of new biodegradable implants and devices is necessary to meet the increasing needs of regenerative orthopedic procedures. An important consideration while formulating new implant materials is that they should physicochemically and biologically mimic bone-like properties. In earlier studies, we have developed and characterized magnesium based biodegradable alloys, in particular magnesium-zirconium (Mg-Zr) alloys. Here we have reported the biological properties of four Mg-Zr alloys containing different quantities of strontium or calcium. The alloys were implanted in small cavities made in femur bones of New Zealand White rabbits, and the quantitative and qualitative assessments of newly induced bone tissue were carried out. A total of 30 experimental animals, three for each implant type, were studied, and bone induction was assessed by histological, immunohistochemical and radiological methods; cavities in the femurs with no implants and observed for the same period of time were kept as controls. Our results showed that Mg-Zr alloys containing appropriate quantities of strontium were more efficient in inducing good quality mineralized bone than other alloys. Our results have been discussed in the context of physicochemical and biological properties of the alloys, and they could be very useful in determining the nature of future generations of biodegradable orthopedic implants.

Cell biological responses of osteoblasts on anodized nanotubular surface of a titanium-zirconium alloy

Anodization of titanium and its alloys, under controlled conditions, generates a nanotubular architecture on the material surface. The biological consequences of such changes are poorly understood, and therefore, we have analyzed the cellular and molecular responses of osteoblasts that were plated on nanotubular anodized surface of a titanium-zirconium (TiZr) alloy. Upon comparing these results with those obtained on acid etched and polished surfaces of the same alloy, we observed a significant increase in adhesion and proliferation of cells on anodized surfaces as compared to acid etched or polished surface. The expression of genes related to cell adhesion was high only on anodized TiZr, but that of genes related to osteoblast differentiation and osteocalcin protein and extracellular matrix secretion were higher on both anodized and acid etched surfaces. Examination of surface morphology, topography, roughness, surface area and wettability using scanning electron microscopy, atomic force microscopy, and contact angle goniometry, showed that higher surface area, hydrophilicity, and nanoscale roughness of nanotubular TiZr surfaces, which were generated specifically by the anodization process, could strongly enhance the adhesion and proliferation of osteoblasts. We propose that biological properties of known bioactive titanium alloys can be further enhanced by generating nanotubular surfaces using anodization.

Cholesterol biosynthesis and homeostasis in regulation of the cell cycle

The cell cycle is a ubiquitous, multi-step process that is essential for growth and proliferation of cells. The role of membrane lipids in cell cycle regulation is not explored well, although a large number of cytoplasmic and nuclear regulators have been identified. We focus in this work on the role of membrane cholesterol in cell cycle regulation. In particular, we have explored the stringency of the requirement of cholesterol in the regulation of cell cycle progression. For this purpose, we utilized distal and proximal inhibitors of cholesterol biosynthesis, and monitored their effect on cell cycle progression. We show that cholesterol content increases in S phase and inhibition of cholesterol biosynthesis results in cell cycle arrest in G1 phase under certain conditions. Interestingly, G1 arrest mediated by cholesterol biosynthesis inhibitors could be reversed upon metabolic replenishment of cholesterol. Importantly, our results show that the requirement of cholesterol for G1 to S transition is absolute, and even immediate biosynthetic precursors of cholesterol, differing with cholesterol merely in a double bond, could not replace cholesterol for reversing the cell cycle arrest. These results are useful in the context of diseases, such as cancer and Alzheimer’s disease, that are associated with impaired cholesterol biosynthesis and homeostasis.

Bimodal distribution of motility and cell fate in Dictyostelium discoideum

Pre-starvation amoebae of Dictyostelium discoideum exhibit random movements. Starved cells aggregate by directed movements (chemotaxis) towards cyclic AMP and differentiate into live spores or dead stalk cells. Many differences between presumptive spore and stalk cells precede differentiation. We have examined whether cell motility-related factors are also among them. Cell speeds and localisation of motility-related signalling molecules were monitored by live cell imaging and immunostaining (a) in nutrient medium during growth, (b) immediately following transfer to starvation medium and (c) in nutrient medium that was re-introduced after a brief period of starvation. Cells moved randomly under all three conditions but mean speeds increased following transfer from nutrient medium to starvation medium; the transition occurred within 15 min. The distribution of speeds in starvation medium was bimodal: about 20% of the cells moved significantly faster than the remaining 80%. The motility-related molecules F-actin, PTEN and PI3 kinase were distributed differently in slow and fast cells. Among starved cells, the calcium content of slower cells was lower than that of the faster cells. All differences reverted within 15 min after restoration of the nutrient medium. The slow/fast distinction was missing in Polysphondylium pallidum, a cellular slime mould that lacks the presumptive stalk and spore cell classes, and in the trishanku (triA(-)) mutant of D. discoideum, in which the classes exist but are unstable. The transition from growth to starvation triggers a spontaneous and reversible switch in the distribution of D. discoideum cell speeds. Cells whose calcium content is relatively low (known to be presumptive spore cells) move slower than those whose calcium levels are higher (known to be presumptive stalk cells). Slow and fast cells show different distributions of motility-related proteins. The switch is indicative of a bistable mechanism underlying cell motility.

Ex vivo expansion of haematopoietic stem/progenitor cells from human umbilical cord blood on acellular scaffolds prepared from MS-5 stromal cell line

Lineage-specific expansion of haematopoietic stem/progenitor cells (HSPCs) from human umbilical cord blood (UCB) is desirable because of their several applications in translational medicine, e.g. treatment of cancer, bone marrow failure and immunodeficiencies. The current methods for HSPC expansion use either cellular feeder layers and/or soluble growth factors and selected matrix components coated on different surfaces. The use of cell-free extracellular matrices from bone marrow cells for this purpose has not previously been reported. We have prepared insoluble, cell-free matrices from a murine bone marrow stromal cell line (MS-5) grown under four different conditions, i.e. in presence or absence of osteogenic medium, each incubated under 5% and 20% O₂ tensions. These acellular matrices were used as biological scaffolds for the lineage-specific expansion of magnetically sorted CD34⁺ cells and the results were evaluated by flow cytometry and colony-forming assays. We could get up to 80-fold expansion of some HSPCs on one of the matrices and our results indicated that oxygen tension played a significant role in determining the expansion capacity of the matrices. A comparative proteomic analysis of the matrices indicated differential expression of proteins, such as aldehyde dehydrogenase and gelsolin, which have previously been identified as playing a role in HSPC maintenance and expansion. Our approach may be of value in identifying factors relevant to tissue engineering-based ex vivo HSPC expansion, and it may also provide insights into the constitution of the niche in which these cells reside in the bone marrow.

The influence of surface energy of titanium-zirconium alloy on osteoblast cell functions in vitro

The success of an implant used for bone regeneration and repair is determined by the events that take place at the cell-material interface. An understanding of these interactions in vitro gives insights into the formulation of ideal conditions for their effective functioning in vivo. Thus, it is not only important to understand the physico-chemical properties of the materials but, also necessary to assess the cellular responses to them to determine their long-term stability and efficacy as implants. In the present study, we have compared the physico-chemical and biological properties of titanium (Ti) and two Ti-based alloys, namely: Ti- Zirconium (TiZr) and Ti-Niobium (TiNb). The morphology, chemical analysis, surface roughness, and contact angle measurements of the alloys were assessed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), profilometer, and contact angle goniometer, respectively whereas the biological properties of the materials were evaluated by measuring the adhesion, proliferation, and differentiation of MC3T3-E1 osteoblast cells on the surfaces of these alloys. Our results indicate that the biological properties of osteoblasts were better on TiZr surface than on TiNb surface. Furthermore, the surface energy and substrate composition influenced the superior biological activity of the TiZr alloy.

Comparative assessment of structural and biological properties of biomimetically coated hydroxyapatite on alumina (alpha-Al2O3) and titanium (Ti-6Al-4V) alloy substrates

Previous reports have shown the use of hydroxyapatite (HAp) and related calcium phosphate coatings on metal and nonmetal substrates for preparing tissue-engineering scaffolds, especially for osteogenic differentiation. These studies have revealed that the structural properties of coated substrates are dependent significantly on the method and conditions used for coating and also whether the substrates had been modified prior to the coating. In this article, we have done a comparative evaluation of the structural features of the HAp coatings, prepared by using simulated body fluid (SBF) at 25 degrees C for various time periods, on a nonporous metal substrate titanium-aluminium-vanadium (Ti-6Al-4V) alloy and a bioinert ceramic substrate alpha-alumina (alpha-Al(2)O(3)), with and without their prior treatment with the globular protein bovine serum albumin (BSA). Our analysis of these substrates by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry showed significant and consistent differences in the quantitative and qualitative properties of the coatings. Interestingly, the bioactivity of these substrates in terms of supporting in vitro cell adhesion and spreading, and in vivo effects of implanted substrates, showed a predictable pattern, thus indicating that some coated substrates prepared under our conditions could be more suitable for biological/biomedical applications.

Differential gene expression and clonal selection during cellular transformation induced by adhesion deprivation

Background

Anchorage independent growth is an important hallmark of oncogenic transformation. Previous studies have shown that when adhesion dependent fibroblasts were prevented from adhering to a substrate they underwent anoikis. In the present study we have demonstrated how anoikis resistant cells gain the transformation related properties with sequential selection of genes. We have proposed this process as a model system for selection of transformed cells from normal cells.

Results

This report demonstrates that some fibroblasts can survive during late stages of anoikis, at which time they exhibit transformation-associated properties such as in vitro colony formation in soft agar and in vivo subcutaneous tumour formation in nude mice. Cytogenetic characterisation of these cells revealed that they contained a t (2; 2) derivative chromosome and they have a selective survival advantage in non adherent conditions. Gene expression profile indicated that these cells over expressed genes related to hypoxia, glycolysis and tumor suppression/metastasis which could be helpful in their retaining a transformed phenotype.

Conclusion

Our results reveal some new links between anoikis and cell transformation and they provide a reproducible model system which can potentially be useful to study multistage cancer and to identify new targets for drug development.

Human fetal liver-derived stem cell transplantation as supportive modality in the management of end-stage decompensated liver cirrhosis

Liver transplantation is the only existing modality for treating decompensated liver cirrhosis. Several factors, such as nonavailability of donors, combined with operative risks, complications associated with rejection, usage of immunosuppressive agents, and cost intensiveness, make this strategy available to only a few people. With a tremendous upsurge in the mortality rate of patients with liver disorders worldwide, there is a need to search for an alternative therapeutic tool that can combat the above limitations and serve as a supportive therapy in the management of liver diseases. Cell therapy using human fetal liver-derived stem cells can provide great potential to conservatively manage end-stage liver diseases. Therefore, the present investigation aimed to study and prove the safety and efficacy of human fetal liver-derived stem cell transplantation in patients with end-stage liver cirrhosis. Twenty-five patients with liver cirrhosis of different etiologies were infused with human fetal liver-derived stem cells (EpCAM+ve) labeled with Tc-HMPAO through hepatic artery. Our high throughput analysis using flow cytometry, RT-PCR, and cellular characterization exemplifies fetal liver cells with their high proliferation rate could be the best source for rejuvenating the diseased liver. Further, no episodes related to hepatic encephalopathy recurred in any of the subjects following hepatic stem cell transplantation. There was marked clinical improvement observed in terms of all clinical and biochemical parameters. Further, there was decrease in mean MELD score (p < 0.01) observed in 6 months follow-up in all patients. Therapy using human fetal liver stem/progenitor cells offers a potentially supportive modality to organ transplantation in the management of liver diseases.

Human fetal liver-derived stem cell transplantation as supportive modality in the management of end-stage decompensated liver cirrhosis

Liver transplantation is the only existing modality for treating decompensated liver cirrhosis. Several factors, such as nonavailability of donors, combined with operative risks, complications associated with rejection, usage of immunosuppressive agents, and cost intensiveness, make this strategy available to only a few people. With a tremendous upsurge in the mortality rate of patients with liver disorders worldwide, there is a need to search for an alternative therapeutic tool that can combat the above limitations and serve as a supportive therapy in the management of liver diseases. Cell therapy using human fetal liver-derived stem cells can provide great potential to conservatively manage end-stage liver diseases. Therefore, the present investigation aimed to study and prove the safety and efficacy of human fetal liver-derived stem cell transplantation in patients with end-stage liver cirrhosis. Twenty-five patients with liver cirrhosis of different etiologies were infused with human fetal liver-derived stem cells (EpCAM+ve) labeled with Tc-HMPAO through hepatic artery. Our high throughput analysis using flow cytometry, RT-PCR, and cellular characterization exemplifies fetal liver cells with their high proliferation rate could be the best source for rejuvenating the diseased liver. Further, no episodes related to hepatic encephalopathy recurred in any of the subjects following hepatic stem cell transplantation. There was marked clinical improvement observed in terms of all clinical and biochemical parameters. Further, there was decrease in mean MELD score (p < 0.01) observed in 6 months follow-up in all patients. Therapy using human fetal liver stem/progenitor cells offers a potentially supportive modality to organ transplantation in the management of liver diseases.

In vitro insulin production and analysis of pancreatic transcription factors in induced human hepatic progenitor cells

BACKGROUND

beta-Cell destruction and/or insufficient insulin production are the hallmarks of diabetes mellitus (type 1 diabetes). A hepatic progenitor from developing liver is sought to be one of the surrogate sources of insulin production as the pancreas and the liver share a common precursor and signals from the cardiac mesoderm. Production of insulin is possible by transfecting pancreatic transcription factors that play important roles in development of the pancreatic beta-cell. But, there is always the fear of using genetically manipulated cells for therapeutics. Hence, the present study was designed to analyze the feasibility of using primary human fetal hepatic progenitors as a potential source for insulin production.

METHODS

Human fetal hepatic progenitors were enriched using CD-326 magnetic cell sorting. The sorted cells were cultured with different concentrations of glucose (5-30 mM) in Dulbecco's modified Eagle's medium. The amount of insulin production was estimated in the cultured cells by the chemiluminescence method. Total RNA isolated from sorted epithelial cell adhesion molecule (EpCAM)-positive cells was reverse-transcribed, and the expression of different beta-cell-producing transcriptions factors was analyzed by polymerase chain reaction (PCR). Immunocytochemical analysis was performed in cultured cells using specific insulin antibodies.

RESULTS

The viability of the total liver cells isolated was found to be 95%. The average number of EpCAM-positive cells in the total liver was found to be approximately 15%. An insulin kinetics study using glucose induction with different concentrations showed increased insulin secretion in response to glucose concentrations up to 20 mM. Furthermore, results of immunocytochemical analysis demonstrated intense insulin expression in EpCAM-positive cultured cells. Expression studies of the cultured EpCAM-positive cells using reverse transcription-PCR showed positive expression of the pancreatic transcription factors essential for insulin production.

CONCLUSIONS

The present study demonstrates that in vitro differentiation of induced human hepatic progenitors into insulin-producing cells without genetic manipulations may promote strategies for the treatment of type 1 diabetes.

Human Fetal Liver-Derived Stem Cell Transplantation as Supportive Modality in the Management of End-Stage Decompensated Liver Cirrhosis

Liver transplantation is the only existing modality for treating decompensated liver cirrhosis. Several factors, such as nonavailability of donors, combined with operative risks, complications associated with rejection, usage of immunosuppressive agents, and cost intensiveness, make this strategy available to only a few people. With a tremendous upsurge in the mortality rate of patients with liver disorders worldwide, there is a need to search for an alternative therapeutic tool that can combat the above limitations and serve as a supportive therapy in the management of liver diseases. Cell therapy using human fetal liver-derived stem cells can provide great potential to conservatively manage end-stage liver diseases. Therefore, the present investigation aimed to study and prove the safety and efficacy of human fetal liver-derived stem cell transplantation in patients with end-stage liver cirrhosis. Twenty-five patients with liver cirrhosis of different etiologies were infused with human fetal liver-derived stem cells (EpCAM+ve) labeled with Tc-HMPAO through hepatic artery. Our high throughput analysis using flow cytometry, RT-PCR, and cellular characterization exemplifies fetal liver cells with their high proliferation rate could be the best source for rejuvenating the diseased liver. Further, no episodes related to hepatic encephalopathy recurred in any of the subjects following hepatic stem cell transplantation. There was marked clinical improvement observed in terms of all clinical and biochemical parameters. Further, there was decrease in mean MELD score ( p < 0.01) observed in 6 months follow-up in all patients. Therapy using human fetal liver stem/progenitor cells offers a potentially supportive modality to organ transplantation in the management of liver diseases.

Lipopeptide with a RGDK tetrapeptide sequence can selectively target genes to proangiogenic alpha5beta1 integrin receptor and mouse tumor vasculature

Integrins, the major class of alphabeta heterodimeric transmembrane glycoprotein receptors, play crucial roles in mediating tumor angiogenesis. Genetic ablation experiments combined with use of antibodies/peptide ligands for blocking either alpha(5) or beta(1) integrins have convincingly demonstrated alpha(5)beta(1) integrin to be unquestionably proangiogenic among the 24 known integrin receptors. Herein, we report on a novel RGDK-lipopeptide 1 that targets selectively alpha(5)beta(1) integrin and is capable of targeting genes to mouse tumor vasculatures.

Characterization of hepatic progenitors from human fetal liver during second trimester

AIM: To enrich hepatic progenitors using epithelial cell adhesion molecule (EpCAM) as a marker from human fetal liver and investigate the expression of human leukocyte antigen (HLA) and their markers associated with hepatic progenitor cells.

METHODS: EpCAM +ve cells were isolated using magnetic cell sorting (MACS) from human fetuses (n = 10) at 15-25 wk gestation. Expression of markers for hepatic progenitors such as albumin, alpha-fetoprotein (AFP), CD29 (integrin β1), CD49f (integrin α6) and CD90 (Thy 1) was studied by using flow cytometry, immunocytochemistry and RT-PCR; HLA class I (A, B, C) and class II (DR) expression was studied by flow cytometry only.

RESULTS: FACS analysis indicated that EpCAM +ve cells were positive for CD29, CD49f, CD90, CD34, HLA class I, albumin and AFP but negative for HLA class II (DR) and CD45. RT PCR showed that EpCAM +ve cells expressed liver epithelial markers (CK18), biliary specific marker (CK19) and hepatic markers (albumin, AFP). On immunocytochemical staining, EpCAM +ve cells were shown positive signals for CK18 and albumin.

CONCLUSION: Our study suggests that these EpCAM +ve cells can be used as hepatic progenitors for cell transplantation with a minimum risk of alloreactivity and these cells may serve as a potential source for enrichment of hepatic progenitor.

Management of hyperbilirubinemia in biliary atresia by hepatic progenitor cell transplantation through hepatic artery: a case report

Cholangiodestruction of bile ducts leads to biliary atresia, a rare disease characterized by intrahepatic and extrahepatic biliary inflammation. If the intrahepatic biliary tree is unaffected, surgical reconstruction by the Kasai procedure of hepatoportoenterostomy of the extra hepatic biliary tract is possible. Untreated, this condition leads to cirrhosis and death within the first year of the life. If the atresia is complete, liver transplantation is the only option. As a result of the shortage of donor livers, hepatocytes have been infused over the past two decades, providing proof of the concept that cell therapy can be effective for the treatment of liver diseases. In the present study, we report a confirmed case of a girl of 1 year of age with increased bilirubin of 28.5 mg/dL and pediatric end-stage liver disease score 20. Biochemical liver function tests showed cholestasis (elevated cholesterol and gamma-GTs) and increased ALT, total bilirubin, conjugated bilirubin, and ALP. The patient was treated with hepatic progenitor cell infusion through the hepatic artery. The total bilirubin and conjugated bilirubin started decreasing during the first month after cell infusion. The level of total bilirubin maintained a threefold decrease after months of cell infusion. The conjugated bilirubin was 16.35 mg/dL before cell infusion, decreasing to eightfold after cell infusion. After 2 months of cell infusion, hepatobiliary scintigraphy showed increased liver cell function. This case demonstrated the efficacy and functionality of hepatic progenitor cells for the management of biliary atresia. Further, as there was a decrease in serum bilirubin, it showed that there was some percentage of the engraftment of the infused cells. As the procedure is simple and the patient has tolerated the infusion therapy, it might be repeated to manage biliary atresia.

p53 target gene SMAR1 is dysregulated in breast cancer: its role in cancer cell migration and invasion

Tumor suppressor SMAR1 interacts and stabilizes p53 through phosphorylation at its serine-15 residue. We show that SMAR1 transcription is regulated by p53 through its response element present in the SMAR1 promoter. Upon Doxorubicin induced DNA damage, acetylated p53 is recruited on SMAR1 promoter that allows activation of its transcription. Once SMAR1 is induced, cell cycle arrest is observed that is correlated to increased phospho-ser-15-p53 and decreased p53 acetylation. Further we demonstrate that SMAR1 expression is drastically reduced during advancement of human breast cancer. This was correlated with defective p53 expression in breast cancer where acetylated p53 is sequestered into the heterochromatin region and become inaccessible to activate SMAR1 promoter. In a recent report we have shown that SMAR1 represses Cyclin D1 transcription through recruitment of HDAC1 dependent repressor complex at the MAR site of Cyclin D1 promoter. Here we show that downmodulation of SMAR1 in high grade breast carcinoma is correlated with upregulated Cyclin D1 expression. We also established that SMAR1 inhibits tumor cell migration and metastases through inhibition of TGFβ signaling and its downstream target genes including cutl1 and various focal adhesion molecules. Thus, we report that SMAR1 plays a central role in coordinating p53 and TGFβ pathways in human breast cancer.

Changes in cholesterol levels in the plasma membrane modulate cell signaling and regulate cell adhesion and migration on fibronectin

The number and distribution of lipid molecules, including cholesterol in particular, in the plasma membrane, may play a key role in regulating several physiological processes in cells. We investigated the role of membrane cholesterol in regulating cell shape, adhesion and motility. The acute depletion of cholesterol from the plasma membrane of cells that were well spread and motile on fibronectin caused the rounding of these cells and decreased their adhesion to and motility on fibronectin. These modifications were less pronounced in cells plated on laminin, vitronectin or plastic, indicating that cholesterol-mediated changes in adhesion and motility are more specific for adhesion mediated by fibronectin-specific integrins, such as alpha5beta1. These changes were accompanied by remodeling of the actin cytoskeleton, the spatial reorganization of paxillin in the membrane, and changes to the dynamics of alpha5 integrin and paxillin-rich focal adhesions. Levels of tyrosine phosphorylation at position 576/577 of FAK and Erk1/Erk2 MAP-kinase activity levels were both lower in cholesterol-depleted than in control cells. These levels normalized only on fibronectin when cholesterol was reincorporated into the cell membrane. Thus, membrane cholesterol content has a specific effect on certain signaling pathways specifically involved in regulating cell motility on fibronectin and organization of the actin cytoskeleton.

Direct association between caspase 3 and α5β1 integrin and its role during anoikis of rat fibroblasts

We have demonstrated a direct association between alpha5beta1 integrin and caspase 3, both pro- and mature enzyme, in various sub-cellular compartments of rat fibroblasts undergoing anoikis. Integrin associated caspase 3 showed high activity in the plasma membranes, whereas in the cytosol and microsomal fraction it showed little or no activity. Our results suggest a possible role for recycled un-ligated alpha5beta1 integrin molecules between cytosol and plasma membrane, in regulation of caspase-3 activity and induction of cell death in adhesion-deprived cells.

Cholesterol alters the interaction of glycosphingolipid GM3 with alpha5beta1 integrin and increases integrin-mediated cell adhesion to fibronectin

Integrins bind to their ligand in the extracellular matrix (ECM), such as fibronectin (FN), through a specific interaction between the amino acid motifs in the ligand, and binding sites in the extracellular domains of the integrin molecule generated jointly by its alpha and beta subunits. It has been proposed that membrane cholesterol and glycosphingolipids (GSLs) can regulate integrin-ECM interactions and it has been demonstrated that increased membrane cholesterol leads to increased cell adhesion to FN. Here, we have shown that a specific glycosphingolipid GM3 binds directly to alpha5beta1 integrin and an increase in membrane cholesterol results in the redistribution of GM3-associated alpha5beta1 integrin molecules specifically on the surface that is in contact with the substratum. Our results suggest that GM3-associated alpha5beta1 integrins bind less avidly to FN than GM3-free integrins and that cholesterol and GM3 play an interdependent role in the distribution of alpha5beta1integrin molecules in the membrane and regulation of cell adhesion.

A correlation between membrane cholesterol level, cell adhesion and tumourigenicity of polyoma virus transformed cells

We have investigated the implications of the rise in membrane cholesterol levels on several in vitro and in vivo properties of polyoma virus transformed rat fibroblasts (PyF), with a special emphasis on alpha5beta1 integrin functions. We show that increased membrane cholesterol causes the PyF cells to change their shape and become more bipolar in appearance. These cells also show significantly higher adhesion to the cell-binding domain of fibronectin, increased localization of alpha5beta1 integrin and talin molecules in focal adhesions and a more robust actin cytoskeleton organization. PyF cells with increased membrane cholesterol show reduced growth in vitro and tumours caused by these cells in nude mice are slow growing. These changes in the growth properties of PyF cells are reversible when the cholesterol levels of PyF cells become normal. Our results suggest that changes in membrane cholesterol levels influence the growth and morphological properties of transformed cells, which can be exploited in controlling the growth of tumours in vivo.

Variation of mitochondrial size during the cell cycle: A multiparameter flow cytometric and microscopic study

BACKGROUND

Changes in mitochondrial structure and size are observed in response to alterations in cell physiology. Flow cytometry provides a useful tool to study these changes in intact cells. We have used flow cytometry and digital fluorescence microscopy to analyze the variations in mitochondrial size in relation to specific phases of the cell cycle.

METHODS

Supravital staining of rat fibroblasts was done with Hoechst 33342 and rhodamine 123, and cells were analyzed in a dual-laser flow cytometer. Synchronized cells at various stages of the cell cycle were analyzed for changes in mitochondrial size. These cells were also examined by electron microscopy, digital fluorescence microscopy and computerized image analysis to compare the lengths of the mitochondria.

RESULTS

By using fluorescence pulse width analysis, we observed two populations of mitochondria in intact cells. The percentage of cells with small and large mitochondria at specific stages of the cell cycle indicated that mitochondrial size increases during the cell cycle; early G1 phase cells had the smallest mitochondria and the mitotic phase cells had the largest mitochondria. These results were confirmed by microscopic analysis of cells.

CONCLUSIONS

Flow cytometry can distinguish the relative mitochondrial size in intact cells, and in combination with digital microscopy it can be used to study mitochondrial variation during the cell cycle.

Cleistanthin B causes G1 arrest and induces apoptosis in mammalian cells

Cleistanthin B is a potential anticancer agent isolated from the tropical plant Cleistanthus collinus. We have previously shown that cleistanthin B is clastogenic and induces micronuclei formation and chromosomal aberrations. We now show that this compound inhibits DNA synthesis in Chinese hamster ovary (CHO) cells and induces apoptosis in cervical carcinoma (SiHa) cells. Flow cytometric analysis of cleistanthin treated CHO cells revealed that they were blocked in G1. Cervical carcinoma (SiHa) cells exposed to cleistanthin B shrank, rounded up and had condensed chromatin and fragmented nuclei. DNA isolated from cleistanthin treated cells exhibited the characteristic apoptotic ladder when electrophoresed in agarose gels. These results were confirmed by flow cytometry. Etoposide, a structurally similar compound also induced apoptosis in these cells although with a difference. Etoposide induced apoptosis after permitting cells to enter into S phase, while cleistanthin B stopped entry of cells into S phase and subsequently drove them to apoptosis.

The significance of alpha 5 beta 1 integrin dependent and independent actin cytoskelton organization in cell transformation and survival

Cell-matrix and cell-cell interactions are important physiological determinants of cell growth, survival and transformation. Cell adhesion to the extra cellular matrix (ECM) via integrins also crucially influences the organization of the cytoskeleton. It triggers a cascade of intracellular biochemical events, which regulate cell viability and growth. We have studied the relationship between cell attachment to the substratum and cytoskeletal organization and cell survival and transformation. Our results demonstrate that in the absence of attachment to the substratum, adhesion-dependent fibroblasts exhibit rapid loss of viability. However, a small percentage of cells survive even after remaining non-adherent for 16h. The adherent and non-adherent cells differ from one another both morphologically and physiologically. The latter show a loss of alpha5beta1 integrin expression on their surface and bind non-specifically to the substratum and ECM, thereby activating certain pathways more efficiently than adherent cells. We have also shown that non-adherent cells grow faster and have worse cytoskeletal organization after attachment to the substratum, and do not form focal adhesions or actin stress fibres. Hence, our data suggests that rat fibroblasts in prolonged suspension exhibit some properties that are comparable to cells undergoing transformation, by adapting integrin-dependent or independent signalling pathways for their survival.

Correlates of developmental cell death in Dictyostelium discoideum

We have studied the correlates of cell death during stalk cell differentiation in Dictyostelium discoideum. Our main findings are four. (i) There is a gradual increase in the number of cells with exposed phosphatidyl serine residues, an indicator of membrane asymmetry loss and increased permeability. Only presumptive stalk cells show this change in membrane asymmetry. Cells also show an increase in cell membrane permeability under conditions of calcium-induced stalk cell differentiation in cell monolayers. (ii) There is a gradual fall in mitochondrial membrane potential during development, again restricted to the presumptive stalk cells. (iii) The fraction of cells showing caspase-3 activity increases as development proceeds and then declines in the terminally differentiated fruiting body. (iv) There is no internucleosomal cleavage of DNA, or DNA fragmentation, in D. discoideum nor is there any calcium- and magnesium-dependent endonucleolytic activity in nuclear extracts from various developmental stages. However, nuclear condensation and peripheralization does occur in stalk cells. Thus, cell death in D. discoideum shows some, but not all, features of apoptotic cell death as recognized in other multicellular systems. These findings argue against the emergence of a single mechanism of 'programmed cell death (PCD)' before multicellularity arose during evolution.

Cell cycle phase, cellular Ca2+ and development in Dictyostelium discoideum

In Dictyostelium discoideum, the initial differentiation of cells is regulated by the phase of the cell cycle at starvation. Cells in S and early G2 (or with a low DNA content) have relatively high levels of cellular Ca2+ and display a prestalk tendency after starvation, whereas cells in mid to late G2 (or with a high DNA content) have relatively low levels of Ca2+ and display a prespore tendency. We found that there is a correlation between cytosolic Ca2+ and cell cycle phase, with high Ca2+ levels being restricted to cells in the S and early G2 phases. As expected on the basis of this correlation, cell cycle inhibitors influence the proportions of amoebae containing high or low Ca2+. However, it has been reported that in the rtoA mutant, which upon differentiation gives rise to many more stalk cells than spores (compared to the wild type), initial cell-type choice is independent of cell cycle phase at starvation. In contrast to the wild type, a disproportionately large fraction of rtoA amoebae fall into the high Ca2+ class, possibly due to an altered ability of this mutant to transport Ca2+.

The role of membrane lipids in regulation of integrin functions

Recent evidence suggests that the biochemical and physical organization of lipid molecules in the plasma membrane can affect integrin-mediated cellular functions. The nature and mechanism of integrin-lipid interactions are unknown, but it is clear that they play specific roles in modulating the properties of integrins and integrin-associated proteins. A better knowledge of integrin functions, especially in the lipid milieu of plasma membranes, is necessary for the understanding of the phenomena that are regulated by integrins.

Modulation of alpha5beta1 integrin functions by the phospholipid and cholesterol contents of cell membranes

Several modifications of the alpha5beta1 integrin, which alter its intracellular and extracellular interaction with fibronectin and other proteins, have been reported. However, the significance of the lateral mobility of integrin molecules in the plasma membrane, as a regulator of their distribution and function, is poorly understood. We examined this problem by increasing the cholesterol content of plasma membranes, and consequently modifying the fluidity of membrane phospholipids, in rat fibroblasts. Under these conditions, the clustering of alpha5beta1 integrin molecules in focal adhesions, their adhesion to the cell-binding domain of fibronectin, and their association with the cytoskeletal protein talin were significantly enhanced as compared to control cells. However, the activation of MAP-kinase pathways by the association of fibronectin with alpha5beta1 integrin, and its association with integrin-linked kinase (ilk), were suppressed. The treated cells also showed distinct changes in shape, and their actin stress fiber network was more dense and thick as compared to control cells. The changes in fluidity of phospholipids occurred differentially and fluidity of phosphatidyl-ethanolamine increased, while that of phosphatidyl-choline was reduced. Our results suggest that proteins in focal adhesions could be partitioned in specific lipid domains, which regulate specific aspects of alpha5beta1 integrin functions.