Xeno-free culture and proliferation of hPSCs on 2D biomaterials.

Human pluripotent stem cells (human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs)) have unlimited proliferative potential, whereas adult stem cells such as bone marrow-derived stem cells and adipose-derived stem cells have problems with aging. When hPSCs are intended to be cultured on feeder-free or xeno-free conditions without utilizing mouse embryonic fibroblasts or human fibroblasts, they cannot be cultured on conventional tissue culture polystyrene dishes, as adult stem cells can be cultured but should be cultivated on material surfaces grafted or coated with (a) natural or recombinant extracellular matrix (ECM) proteins, (b) ECM protein-derived peptides and specific synthetic polymer surfaces in xeno-free and/or chemically defined conditions. This review describes current developing cell culture biomaterials for the proliferation of hPSCs while maintaining the pluripotency and differentiation potential of the cells into 3 germ layers. Biomaterials for the cultivation of hPSCs without utilizing a feeder layer are essential to decrease the risk of xenogenic molecules, which contributes to the potential clinical usage of hPSCs. ECM proteins such as human recombinant vitronectin, laminin-511 and laminin-521 have been utilized instead of Matrigel for the feeder-free cultivation of hPSCs. The following biomaterials are also discussed for hPSC cultivation: (a) decellularized ECM, (b) peptide-grafted biomaterials derived from ECM proteins, (c) recombinant E-cadherin-coated surface, (d) polysaccharide-immobilized surface, (e) synthetic polymer surfaces with and without bioactive sites, (f) thermoresponsive polymer surfaces with and without bioactive sites, and (g) synthetic microfibrous scaffolds.

Cell-binding peptides on the material surface guide stem cell fate of adhesion, proliferation and differentiation.

Human cells, especially stem cells, need to communicate and interact with extracellular matrix (ECM) proteins, which not only serve as structural components but also guide and support cell fate and properties such as cell adhesion, proliferation, survival and differentiation. The binding of the cells with ECM proteins or ECM-derived peptides via cell adhesion receptors such as integrins activates several signaling pathways that determine the cell fate, morphological change, proliferation and differentiation. The development of synthetic ECM protein-derived peptides that mimic the biological and biochemical functions of natural ECM proteins will benefit academic and clinical application. Peptides derived from or inspired by specific ECM proteins can act as agonists of each ECM protein receptor. Given that most ECM proteins function in cell adhesion via integrin receptors, many peptides have been developed that bind to specific integrin receptors. In this review, we discuss the peptide sequence, immobilization design, reaction method, and functions of several ECM protein-derived peptides. Various peptide sequences derived from mainly ECM proteins, which are used for coating or grafting on dishes, scaffolds, hydrogels, implants or nanofibers, have been developed to improve the adhesion, proliferation or differentiation of stem cells and to culture differentiated cells. This review article will help to inform the optimal choice of ECM protein-derived peptides for the development of scaffolds, implants, hydrogels, nanofibers and 2D cell culture dishes to regulate the proliferation and direct the differentiation of stem cells into specific lineages.

Histomorphological Evaluation of Non-Neoplastic Lesions of Uterine Cervix and a Correlation of the Lesion with the Clinical Factors.

AIM: This study investigates the prevalence of non-malignant lesions of the cervix among various biopsy samples. METHODS: This case study consists of 50 cases of cervical biopsy over almost two years. The case history and clinical details of the patients were obtained. RESULTS: 60% of the cases that participated in this study reported white discharge per vaginum as a common clinical symptom. 4 cases (8%) showed koilocytic changes specific to the human papillomavirus during the study. Only 2% of the non-specific cervicitis showed lymphoid aggregates. Endocervical changes projected papillary endocervicitis with 9 cases (18%), squamous metaplasia with 7 cases (14%), and nabothian follicle cyst with 3 cases (6%). CONCLUSION: It has been concluded that 50 cases were studied histologically, which had adequate representation of both ecto and endocervical tissue. Moreover, 31-40 years of age of patients showed the highest percentage of non-neoplastic lesions of the cervix when compared to other age groups.

Designed peptide-grafted hydrogels for human pluripotent stem cell culture and differentiation.

Human pluripotent stem cells (hPSCs) have the ability to differentiate into cells derived from three germ layers and are an attractive cell source for cell therapy in regenerative medicine. However, hPSCs cannot be cultured on conventional tissue culture flasks but can be cultured on biomaterials with specific hPSC integrin interaction sites. We designed hydrogels conjugated with several designed peptides that had laminin-ß4 active sites, optimal elasticities and different zeta potentials. A higher expansion fold of hPSCs cultured on the hydrogels was found with the increasing zeta potential of the hydrogels conjugated with designed peptides, where positive amino acid (lysine) insertion into the peptides promoted higher zeta potentials of the hydrogels and higher expansion folds of hPSCs when cultured on the hydrogels using xeno-free protocols. The hPSCs cultured on hydrogels conjugated with the optimal peptides showed a higher expansion fold than those on recombinant vitronectin-coated plates, which are the gold standard of hPSC cultivation dishes. The hPSCs could differentiate into specific cell lineages, such as mesenchymal stem cells (MSCs) and MSC-derived osteoblasts, even after being cultivated on hydrogels conjugated with optimal peptides for long periods of time, such as 10 passages.

Inhibition of Aldose Reductase by Novel Phytocompounds: A Heuristic Approach to Treating Diabetic Retinopathy.

Aldose reductase (ALR2) activation in the polyol pathway has been implicated as the primary mechanism for the progression of diabetic retinopathy. Most of the aldose reductase inhibitors (ARIs), used for the treatment of diabetic complications, were withdrawn due to ineffective treatment and adverse side effects caused by nonspecificity. Epalrestat, a carboxylic acid inhibitor, is the only ARI used for the treatment of diabetic neuropathy, though associated with minor side effects to 8% of the treated population. Our study exploited the interactions of Epalrestat-ALR2 crystal structure for the identification of specific phytocompounds that could inhibit human lens ALR2. 3D structures of plant compounds possessing antidiabetic property were retrieved from PubChem database for inhibition analysis, against human lens ALR2. Among the shortlisted compounds, Agnuside and Eupalitin-3-O-galactoside inhibited lens ALR2 with IC50 values of 22.4 nM and 27.3 nM, respectively, compared to the drug Epalrestat (98 nM), indicating high potency of these compounds as ALR2 inhibitors. IC50 concentration of the identified ARIs was validated in vitro using ARPE-19 cells. The in silico and in vitro approaches employed to identify and validate specific and potent ALR2 inhibitors resulted in the identification of phytocompounds with potency equal to or better than the ALR2 inhibiting drug, Epalrestat.

Diverse nanocomposites as a potential dressing for diabetic wound healing.

Wound healing is a programmed process of continuous events which is impaired in the case of diabetic patients. This impaired process of healing in diabetics leads to amputation, longer hospitalisation, immobilisation, low self-esteem, and mortality in some patients. This problem has paved the way for several innovative strategies like the use of nanotechnology for the treatment of wounds in diabetic patients. The use of biomaterials, nanomaterials have advanced approaches in tissue engineering by designing multi-functional nanocomposite scaffolds. Stimuli-responsive scaffolds that interact with the wound microenvironment and controlled release of bioactive molecules have helped in overcoming barriers in healing. The use of different types of nanocomposite scaffolds for faster healing of diabetic wounds is constantly being studied. Nanocomposites have helped in addressing specific issues with respect to healing and improving angiogenesis. Method: A literature search was followed to retrieve the articles on strategies for wound healing in diabetes across several databases like PubMed, EMBASE, Scopus and Cochrane database. The search was performed in May 2022 by two researchers independently. They keywords used were "diabetic wounds, nanotechnology, nanocomposites, nanoparticles, chronic diabetic wounds, diabetic foot ulcer, hydrogel". Exclusion criteria included insulin resistance, burn wound, dressing material.