Oral keratinocyte stem cells reside in the basal layers of the oral epithelium, representing a minor population of cells with a great potential to self‐renew and proliferate over the course of their ...lifetime. As a result of the potential uses of oral keratinocyte stem cells in regenerative medicine and the key roles they play in tissue homeostasis, inflammatory conditions, wound healing and tumor initiation and progression, intense scientific efforts are currently being undertaken to identify, separate and reprogram these cells. Although currently there is no specific marker that can characterize and isolate oral keratinocyte stem cells, several suggestions have been made. Thus, different stem/progenitor‐cell subpopulations have been categorized based on combinations of positive and/or negative membrane‐surface markers, which include integrins, clusters of differentiation and cytokeratins. Important advances have also been made in understanding the molecular pathways that govern processes such as self‐renewal, differentiation, proliferation, wound healing and programmed cell death. A thorough understanding of stem‐cell biology and the molecular players that govern cellular fate is paramount in the quest for using stem‐cell‐derived therapies in the treatment of various oral pathologies. The current review focuses on recent advances in understanding the molecular signaling pathways coordinating the behavior of these cells and in identifying suitable markers used for their isolation and characterization. Special emphasis will also be placed on the roles played by oral keratinocyte stem and progenitor cells in normal and diseased oral tissues and on their potential uses in the fields of general medicine and dentistry.
There is a growing interest in the development of organic nanomaterials for biomedical applications. An increasing number of studies focus on the uses of nanomaterials with organic structure for ...regeneration of bone, cartilage, skin or dental tissues. Solid evidence has been found for several advantages of using natural or synthetic organic nanostructures in a wide variety of dental fields, from implantology, endodontics, and periodontics, to regenerative dentistry and wound healing. Most of the research is concentrated on nanoforms of chitosan, silk fibroin, synthetic polymers or their combinations, but new nanocomposites are constantly being developed. The present work reviews in detail current research on organic nanoparticles and their potential applications in the dental field.
Oxidative stress is implicated in the pathogenesis of many systemic and oral diseases such as periodontal disease. The main aim of this study is to explore a possible association between salivary ...markers of OS and alveolar bone loss.
The study included 20 patients with chronic periodontitis and 20 controls. Salivary OS biomarkers 8-hidroxy-desoxguanosine (8-HOdG), malondialdehyde (MDA), uric acid, total antioxidant capacity (TAC) and glutathione peroxidase (GPx) were evaluated. Bone loss markers such as C-terminal telopeptide of type I collagen (CTX I), matrix metalloproteinases-8 (MMP-8), osteocalcin and 25-hydroxy vitamin D3 (25- OH D) were detected in this study. The methods included general biochemical tests and ELISA.
Salivary 8-OHdG, MDA levels were significantly higher in the chronic periodontitis group compared with controls (p < 0.05). Salivary activities for uric acid, TAC and GPx were significantly decreased in patients with chronic periodontitis vs controls (p < 0.05). Salivary levels for CTX I, MMP-8, 25-OH D and Osteocalcin were significantly higher in the chronic periodontitis group compared to the controls (p < 0.05). A significant positive correlation was observed between salivary levels of MDA and CTX I. Significant negative correlations between uric acid and CTX I and between MMP-8 and uric acid have been found. Significant positive correlations were observed between CTX I, MMP-8, 25-OH D, osteocalcin and clinical parameters of periodontal disease.
Important oxidative stress associated with alveolar bone loss biomarkers can be detected in saliva of patients with periodontal disease.
Hepatitis B, a persistent inflammatory liver condition, stands as a significant global health issue. In Romania, the prevalence of chronic hepatitis B virus (CHB) infection ranks among the highest in ...the European Union. The HLA genotype significantly impacts hepatitis B virus infection progression, indicating that certain HLA variants can affect the infection's outcome. The primary goal of the present work is to identify HLA alleles and specific amino acid residues linked to hepatitis B within the Romanian population. The study enrolled 247 patients with chronic hepatitis B; HLA typing was performed using next-generation sequencing. This study's main findings include the identification of certain HLA alleles, such as DQB1*06:03:01, DRB1*13:01:01, DQB1*06:02:01, DQA1*01:03:01, DRB5*01:01:01, and DRB1*15:01:01, which exhibit a significant protective effect against HBV. Additionally, the amino acid residue alanine at DQB1_38 is associated with a protective role, while valine presence may signal an increased risk of hepatitis B. The present findings are important in addressing the urgent need for improved methods of diagnosing and managing CHB, particularly when considering the disease's presence in diverse population groups and geographical regions.
Polymeric nanoparticles have been introduced as a delivery vehicle for active compounds in a broad range of medical applications due to their biocompatibility, stability, controlled release of active ...compounds, and reduced toxicity. The oral route is the most used approach for delivery of biologics to the body. The homeostasis and function of oral cavity tissues are dependent on the activity of stem cells. The present work focuses, for the first time, on the interaction between two types of polymeric nanoparticles, poly (lactic-co-glycolic acid) or PLGA and PLGA/chitosan, and two stem cell populations, oral keratinocyte stem cells (OKSCs) and stem cells from human exfoliated deciduous teeth (SHEDs). The main results show that statistical significance was observed in OKSCs uptake when compared with normal keratinocytes and transit amplifying cells after 24 h of incubation with 5 and 10 µg/mL PLGA/chitosan. The CD117+ SHED subpopulation incorporated more PLGA/chitosan nanoparticles than nonseparated SHED. The uptake for PLGA/chitosan particles was better than for PLGA particles with longer incubation times, yielding better results in both cell types. The present results demonstrate that nanoparticle uptake depends on stem cell type, incubation time, particle concentration, and surface properties.
Pancreatic cancer is one of the most aggressive and lethal malignancies. Despite remarkable progress in understanding pancreatic carcinogenesis at the molecular level, as well as progress in new ...therapeutic approaches, pancreatic cancer remains a disease with a dismal prognosis. Among the mechanisms responsible for drug resistance, the most relevant are changes in individual genes or signaling pathways and the presence of highly resistant cancer stem cells(CSCs). In pancreatic cancer, CSCs represent 0.2%-0.8% of pancreatic cancer cells and are considered to be responsible for tumor growth, invasion, metastasis and recurrence. CSCs have been extensively studied as of late to identify specific surface markers to ensure reliable sorting and for signaling pathways identified to play a pivotal role in CSC self-renewal. Involvement of CSCs in pancreatic cancer pathogenesis has also highlighted these cells as the preferential targets for therapy. The present review is an update of the results in two main fields of research in pancreatic cancer, pathogenesis and therapy, focused on the narrow perspective of CSCs.
We propose a multistep all laser, maskless, and solvent free synthesis of micro-patterned substrates of biodegradable polymer blends, with applicability for guided cell adhesion and localized ...hyaluronic acid (HA) immobilization. The polymer blends comprised polyurethane (PU), poly(lactic-co-glycolic acid) (PLGA), and polylactide-polyethylene glycol-polylactide (PPP) in 1:1:1 blending ratios. Polymer patterning was performed by laser processing in two steps. First, the polymers were patterned with periodic micro-channels by direct femtosecond laser ablation, which provided flexibility in design and spatial accuracy for the patterns. As a second step, the micro-patterned polymers were coated with thin layers of polymer blends using matrix assisted pulsed laser evaporation (MAPLE). The resulted
sandwich
substrates were composed of a bottom, micro-patterned layer and thin, top layer which conserved the patterns from the underlying layer and preserved the polymers chemical composition. Depending on the bottom/top layers, the substrates were denominated PU/PU:PLGA:PPP and PU:PLGA:PPP/PU:PLGA:PPP, respectively. The laser generated micro-patterns were used for selective attachment of oral keratinocyte stem cells and for HA immobilization. The highest cellular density was found on the PU:PLGA:PPP/PU:PLGA:PPP substrate, where the spongy-like micro-channels provided multiple anchoring points for the cells. For both substrates, the micro-channels enabled localized immobilization of HA. The effectiveness of HA immobilization was tested against cell adhesion and protein adsorption.
Squamous cells carcinoma (SCC) is the second most frequent of the keratinocyte-derived malignancies after basal cell carcinoma and is associated with a significant psychosocial and economic burden ...for both the patient himself and society. Reported risk factors for the malignant transformation of keratinocytes and development of SCC include ultraviolet light exposure, followed by chronic scarring and inflammation, exposure to chemical compounds (arsenic, insecticides, and pesticides), and immune-suppression. Despite various available treatment methods and recent advances in noninvasive or minimal invasive diagnostic techniques, the risk recurrence and metastasis are far from being negligible, even in patients with negative histological margins and lymph nodes. Analyzing normal, dysplastic, and malignant keratinocyte proteome holds special promise for novel biomarker discovery in SCC that could be used in the future for early detection, risk assessment, tumor monitoring, and development of targeted therapeutic strategies.
Background: It is well known that hydrogen sulfide (H2S), the main substance causing physiologic halitosis, is also involved in the etiology of periodontitis. Gingival crevicular epithelium is the ...first barrier against periodontal pathogens and their products; keratinocyte stem cells play key roles in maintaining this barrier. An increased apoptotic process can affect keratinocyte stem cells, having a direct impact on oral epithelial tissue architecture. Our objective is to determine whether H2S induces apoptosis in human keratinocyte stem cells.
Methods: Apoptosis levels; p53 activity; reactive oxygen species; mitochondrial membrane depolarization; cytochrome C release; and caspase‐9, ‐8, and ‐3 were assessed using enzyme‐linked immunosorbent assay and flow cytometry. Genomic DNA damage was examined using single‐cell gel electrophoresis. Real‐time polymerase chain reaction was used for Bax detection.
Results: The percentage of apoptotic cells was significantly increased (20.5% ± 1.6% versus 4.5% ± 1.1% at 24 hours and 37.8% ± 5.4% versus 4.8% ± 0.9% at 48 hours; P <0.05, respectively; n = 5). Mitochondrial membrane potential was collapsed and reactive oxygen species levels were significantly increased compared to their control groups. At each time point the amount of released cytochrome C into the cytosol was significantly increased. Caspase‐9 and ‐3 activities were significantly increased (P <0.05), whereas caspase‐8 remained inactive. After both 24 and 48 hours, total and phosphorylated p53 levels were significantly increased.
Conclusion: We conclude that H2S can induce apoptosis in human keratinocyte stem cells, a key component of the epithelial barrier, following DNA damage and p53 activation.
In the past years, biomedical research has recognized hydrogen sulfide (H₂S) not only as an environmental pollutant but also, along with nitric oxide and carbon monoxide, as an important biological ...gastransmitter with paramount roles in health and disease. Current research focuses on several aspects of H₂S biology such as the biochemical pathways that generate the compound and its functions in human pathology or drug synthesis that block or stimulate its biosynthesis. The present work addresses the knowledge we have to date on H₂S production and its biological roles in the general human environment with a special focus on the oral cavity and its involvement in the initiation and development of periodontal diseases.
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