Low, medium, and high molecular weight hyaluronic acid effects on human dental pulp stem cells in vitro.

Hyaluronic acid (HA), an extracellular biopolymer found throughout the human body, holds promise as a biocompatible and biodegradable scaffold material. High molecular weight (HMW) HA degrades, generating low molecular weight (LMW) fragments with distinct properties. These fragments can influence the behaviour of cells, including human dental pulp stem cells (hDPSCs) incorporated into HA-containing hydrogels or scaffolds. Therefore, a comprehensive examination of the impact of a range of HA molecular weights on hDPSCs is essential before designing HA-based scaffolds for these cells. hDPSC lines were cultured with LMW HA (800 Da, 1600 Da, 15 kDa), medium molecular weight HA (237 kDa), or HMW HA (1500 kDa) over six passages. The various molecular weights had negligible effects on hDPSCs viability, morphology, adhesion, or relative telomere length. Furthermore, the expression of key surface stemness markers (CD29, CD44, CD73, CD90) remained unaltered. HA did not induce osteogenic, chondrogenic, or adipogenic differentiation. Moreover, the potential for chondrogenic and osteogenic differentiation was not adversely affected by LMW or HMW HA. Various molecular weights of HA seem safe, biocompatible and therefore suitable components for hDPSCs-containing scaffolds. These findings affirm that the hDPCSs will not be negatively affected by HA fragments resulting from scaffold degradation.

Comparison of COVID-19 epidemic among Czech dentists and the Czech general population.

Dentists are one of the professional groups most at risk for COVID-19 infection. Enhanced protective measures in dentistry have been adopted worldwide; however, it is unclear to what extent they were sufficient. To assess whether the protective measures outweighed the high infection risk, we compared COVID-19-related data between Czech dentists and the general Czech population. The data was obtained through a survey study attended by 15.8% of Czech Dental Chamber members. Data of the general population were acquired from the Czech Ministry of Health database. By the end of May 2022, COVID-19 full vaccination and 1st booster dose rates among study participants were 85.8% and 70.1%, respectively, which is significantly higher (p < 0.0001) compared to the Czech general population aged over 24 years (74.9% and 49.4%, respectively). To the same date, PCR/Antigen test verified COVID-19 prevalence among participants was 41.7%, and 49.9% among the general population (p < 0.0001). Prevalence and reinfection rates among individuals who received the 1st booster were significantly lower than among individuals without the booster or full vaccination (p < 0.0001). Persons who received the booster showed a faster return to work, shorter and different types of complications. Willingness to future vaccination was positive among 79.7% of respondents. Mandatory vaccination for healthcare workers and the general population was supported by 62.0% and 49.0%, respectively. The results showed that the high risk of COVID-19 infection associated with dentistry did not lead to higher COVID-19 prevalence among respondents compared to the general population.

COVID-19 among Czech Dentistry Students: Higher Vaccination and Lower Prevalence Compared to General Population Counterparts.

The restrictions on medical students' clinical education during the COVID-19 pandemic has affected their professional readiness and often lengthened their training. These negative impacts are often considered a necessary price as clinical education is hypothesized to be associated with a high risk of pandemic spread. This work assesses this hypothesis based on COVID-19 epidemiological data among Czech dentistry students and their comparison to data of the Czech general population of similar age. We addressed two of the five Czech medical faculties (Charles University, Faculty of Medicine in Hradec Kralove and in Pilsen) providing dentistry study program with a survey. A total of 240 students participated, representing a 66.9% response rate. Over 75% of respondents participated in clinical education during the pandemic. The school environment was identified as a place of infection by only 9.8% of respondents who were aware of where they were infected. Overall, 100% of students used FFP2 respirators, and 75.3% used face shields or protective glasses while working with patients. By the end of May 2022, COVID-19 full vaccination and 1st booster rates among students were 93.8% and 54.6%, respectively, which is significantly higher (p < 0.0001, OR 7.3, 95% CI 4.4−12; p < 0.0001, OR 3.7, 95% CI 2.9−4.8, respectively) compared to their peers from the general population (67.1% and 24.4%, respectively). A total of 75.4% of respondents supported mandatory COVID-19 vaccination for healthcare professionals. To the same date, PCR and/or antigen test verified COVID-19 prevalence among students was 37.1%, while among peers from the general population, it was 45.1% (p = 0.015, OR 1.2, 95% CI 1.0−1.5). The combination of extensive protective measures and high vaccination against COVID-19 led to significantly lower COVID-19 prevalence among the students compared to their general population counterparts.

Editorial of Special Issue "Hyaluronic Acid in Human Medicine".

Hyaluronic acid (HA) is an acidic, non-sulfated glycosaminoglycan that is intensively studied as a biodegradable and biocompatible material for scaffolding, regenerative medicine, and clinical applications [...].

Effect of Human Platelet Lysate as Cultivation Nutrient Supplement on Human Natal Dental Pulp Stem Cell In Vitro Expansion.

Despite several scientific or ethical issues, fetal bovine serum (FBS) remains the standard nutrient supplement in the mesenchymal stem cell cultivation medium. Cell amplification plays an important role in human stem cell therapies. Increasing interest in this field has supported attempts to find suitable human alternatives to FBS for in vitro cell propagation. Human platelet lysate (hPL) has recently been determined as one of them. Our study aimed to evaluate the influence of 2% hPL in the growth medium for in vitro expansion of human natal dental pulp stem cells (hNDP-SCs). The effect was determined on proliferation rate, viability, phenotype profile, expression of several markers, relative telomere length change, and differentiation potential of four lineages of hNDP-SCs. As a control, hNDP-SCs were simultaneously cultivated in 2% FBS. hNDP-SCs cultivated in hPL showed a statistically significantly higher proliferation rate in initial passages. We did not observe a statistically significant effect on mesenchymal stem cell marker (CD29, CD44, CD73, CD90) or stromal-associated marker (CD13, CD166) expression. The cell viability, relative telomere length, or multipotency remained unaffected in hNDP-SCs cultivated in hPL-medium. In conclusion, hPL produced under controlled and standardized conditions is an efficient serum supplement for in vitro expansion of hNDP-SCs.

Innovative Approach in the Cryogenic Freezing Medium for Mesenchymal Stem Cells.

The physical stresses during cryopreservation affect stem cell survival and further proliferation. To minimize or prevent cryoinjury, cryoprotective agents (CPAs) are indispensable. Despite the widespread use of 10% dimethyl sulfoxide (DMSO), there are concerns about its potential adverse effects. To bypass those effects, combinations of CPAs have been investigated. This study aimed to verify whether high-molecular-hyaluronic acid (HMW-HA) serves as a cryoprotectant when preserving human mesenchymal stem cells (hMSCs) to reduce the DMSO concentration in the cryopreservation medium. We studied how 0.1% or 0.2% HMW-HA combined with reduced DMSO concentrations (from 10% to 5%, and 3%) affected total cell count, viability, immunophenotype, and differentiation potential post-cryopreservation. Immediately after cell revival, the highest total cell count was observed in 10% DMSO-stored hMSC. However, two weeks after cell cultivation an increased cell count was seen in the HMW-HA-stored groups along with a continued increase in hMSCs stored using 3% DMSO and 0.1% HMW-HA. The increased total cell count corresponded to elevated expression of stemness marker CD49f. The HA-supplemented cryomedium did not affect the differential potential of hMSC. Our results will participate in producing a ready-to-use product for cryopreservation of mesenchymal stem cells.

COVID-19 Vaccination among Czech Dentists.

This work describes and evaluates vaccination against COVID-19 among members of the Czech Dental Chamber during the pre-booster vaccination phase. A cross-sectional online survey was conducted between 23 June and 4 September 2021, among 2716 participants, representing 24.3% of all chamber members. A total of 89.5% of respondents stated that they were registered for vaccination against COVID-19, their vaccination had started or been completed, or had a medically relevant reason to avoid vaccination. A total of 79.6% of respondents stated that they were fully vaccinated, most of them with the Comirnaty (Pfizer−BioNTech) vaccine (88.3%). The vaccination rate among males was significantly higher than among females (p = 0.001, OR 1.48). The main reasons for vaccination were professional (91.5%). The share of fully vaccinated participants was significantly higher (p < 0.0001, OR = 8.17) compared to the Czech general population (30.8%). A COVID-19 vaccine breakthrough infection rate was 0.42%. The study shows that both the willingness to vaccinate and the proportion of fully vaccinated individuals among Czech dentists are high, and only about 10% of them refused vaccination based on reasons classified as not medically relevant.

COVID-19 Prevalence among Czech Dentists.

This work evaluates the prevalence of coronavirus disease (COVID-19), a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), among members of the Czech Dental Chamber. The assessment was based on an online questionnaire filled out by 2716 participants, representing 24.3% of all chamber members. Overall, 25.4% of the participants admitted they were diagnosed with COVID-19 by 30 June 2021, with no statistical differences between the sexes. While in the age groups under 50 the reported prevalence was around 30%, with increasing age, it gradually decreased to 15.2% in the group over 70 years. The work environment was identified as a place of contagion by 38.4% of the respondents. The total COVID-19 PCR-verified positivity was 13.9%, revealing a statistically lower prevalence (p = 0.0180) compared with the Czech general population, in which the COVID-19 PCR-verified positivity was ~15.6% (fourth highest rank in the world). The total infection-hospitalization ratio (IHR) was 2.8%, and the median age group of hospitalized individuals was 60-70 years. For respondents older than 60 years, the IHR was 8.7%, and for those under 40 years, it was 0%. Of the respondents, 37.7% admitted that another team member was diagnosed with COVID-19, of which the most frequently mentioned profession was a nurse/dental assistant (81.2%). The results indicate that although the dentist profession is associated with a high occupational risk of SARS-CoV-2 infection, well-chosen antiepidemic measures adopted by dental professionals may outweigh it.

Intra-Individual Variability of Human Dental Pulp Stem Cell Features Isolated from the Same Donor.

It is primarily important to define the standard features and factors that affect dental pulp stem cells (DPSCs) for their broader use in tissue engineering. This study aimed to verify whether DPSCs isolated from various teeth extracted from the same donor exhibit intra-individual variability and what the consequences are for their differentiation potential. The heterogeneity determination was based on studying the proliferative capacity, viability, expression of phenotypic markers, and relative length of telomere chromosomes. The study included 14 teeth (6 molars and 8 premolars) from six different individuals ages 12 to 16. We did not observe any significant intra-individual variability in DPSC size, proliferation rate, viability, or relative telomere length change within lineages isolated from different teeth but the same donor. The minor non-significant variances in phenotype were probably mainly because DPSC cell lines comprised heterogeneous groups of undifferentiated cells independent of the donor. The other variances were seen in DPSC lineages isolated from the same donor, but the teeth were in different stages of root development. We also did not observe any changes in the ability of cells to differentiate into mature cell lines-chondrocytes, osteocytes, and adipocytes. This study is the first to analyze the heterogeneity of DPSC dependent on a donor.

Impact of COVID-19 on Czech Dentistry: A Nationwide Cross-Sectional Preliminary Study among Dentists in the Czech Republic.

This work evaluates the impact of the COVID-19 pandemic on Czech dentistry from March 2020 to March 2021. The assessment was based on questionnaires filled out by 3674 Czech dentists representing 42.6% of practicing dentists in the country. During March-May, 2020 (the first COVID-19 wave), 90.7% of dental practices remained open; however, only 22.8% of the practices continued to operate with no changes, 46.5% had fewer patients, 21.4% treated only acute cases, and 3.8% were closed. During September 2020-May 2021 (the second wave of COVID-19), 96.1% of dental practices remained open, 60.8% operated with no changes, 34.5% had fewer patients, 0.8% treated only acute cases, and 0.5% were closed. The reasons leading to the closure of Czech dental practices during the whole pandemic were a shortage of personal protective equipment (50.5%), a COVID-19 outbreak in the workplace (24.5%), fear of a possible self-infection (24.0%), and quarantine (20.5%). The time range of Czech dental practices closure during the whole pandemic was: 1-2 weeks (49.9%), 2-4 weeks (21.2%), and >1 month (0.8%). The greatest professional difficulties of Czech dentists during the pandemic were crisis operating management (55%), health safety and hygiene concerns (21%), shortage of personal protective equipment (21%), and difficulty working with the protective equipment (15%). In addition, 47.3% of dentists also observed a declining interest in preventive dental care, and 16.9% of them observed worse oral care of patients. These results show that despite the lack of protective equipment, dental care was maintained throughout the pandemic. Additionally, the pandemic negatively affected the patients' approach to dental care, indicating a deterioration in oral health as a possible delayed outcome of the COVID-19 pandemic.

The Effects of Cryogenic Storage on Human Dental Pulp Stem Cells.

Dental pulp stem cells (DPSCs) are a type of easily accessible adult mesenchymal stem cell. Due to their ease of access, DPSCs show great promise in regenerative medicine. However, the tooth extractions from which DPSCs can be obtained are usually performed at a period of life when donors would have no therapeutic need of them. For this reason, it is imperative that successful stem cell storage techniques are employed so that these cells remain viable for future use. Any such techniques must result in high post-thaw stem cell recovery without compromising stemness, proliferation, or multipotency. Uncontrolled-rate freezing is not a technically or financially demanding technique compared to expensive and laborious controlled-rate freezing techniques. This study was aimed at observing the effect of uncontrolled-rate freezing on DPSCs stored for 6 and 12 months. Dimethyl sulfoxide at a concentration of 10% was used as a cryoprotective agent. Various features such as shape, proliferation capacity, phenotype, and multipotency were studied after DPSC thawing. The DPSCs did not compromise their stemness, viability, proliferation, or differentiating capabilities, even after one year of cryopreservation at -80 °C. After thawing, they retained their stemness markers and low-level expression of hematopoietic markers. We observed a size reduction in recovery DPSCs after one year of storage. This observation indicates that DPSCs can be successfully used in potential clinical applications, even after a year of uncontrolled cryopreservation.

The Effect of Cultivation Passaging on the Relative Telomere Length and Proliferation Capacity of Dental Pulp Stem Cells.

Telomeres are repetitive nucleoprotein DNA sequences that shorten with each cell division. The stem cells activate telomerase to compensate for the telomere loss. This study aimed to evaluate the effect of cultivation passaging on the relative telomere length and proliferation capacity of dental pulp stem cells. We used ten dental pulp stem cell (DPSC) lineages stored for 12 months using uncontrolled-rate freezing to reach the study's goal. We analyzed their proliferation rate, phenotype using flow cytometry, multipotency, and relative telomere length using a qPCR analysis. We determined the relative telomere length in the added study by performing analysis after one, two, and three weeks of cultivation with no passaging. We documented the telomere attrition with increasing passaging. The shorter the relative telomere length, the lower reached population doublings, and longer population doubling time were observed at the end of the cultivation. We observed the telomere prolongation in DPSCs cultivated for two weeks with no passaging in the added subsequent study. We concluded that excessive proliferation demands on DPSCs during in vitro cultivation result in telomere attrition. We opened the theory that the telomerase might be more efficient during cell cultivation with no passaging. This observation could help in preserving the telomere length during ex vivo DPSC expansion.

Low Molecular Weight Hyaluronic Acid Effect on Dental Pulp Stem Cells In Vitro.

Hyaluronic acid (HA) and dental pulp stem cells (DPSCs) are attractive research topics, and their combined use in the field of tissue engineering seems to be very promising. HA is a natural extracellular biopolymer found in various tissues, including dental pulp, and due to its biocompatibility and biodegradability, it is also a suitable scaffold material. However, low molecular weight (LMW) fragments, produced by enzymatic cleavage of HA, have different bioactive properties to high molecular weight (HMW) HA. Thus, the impact of HA must be assessed separately for each molecular weight fraction. In this study, we present the effect of three LMW-HA fragments (800, 1600, and 15,000 Da) on DPSCs in vitro. Discrete biological parameters such as DPSC viability, morphology, and cell surface marker expression were determined. Following treatment with LMW-HA, DPSCs initially presented with an acute reduction in proliferation (p < 0.0016) and soon recovered in subsequent passages. They displayed significant size reduction (p = 0.0078, p = 0.0019, p = 0.0098) while maintaining high expression of DPSC markers (CD29, CD44, CD73, CD90). However, in contrast to controls, a significant phenotypic shift (p < 0.05; CD29, CD34, CD90, CD106, CD117, CD146, CD166) of surface markers was observed. These findings provide a basis for further detailed investigations and present a strong argument for the importance of HA scaffold degradation kinetics analysis.

The Association of Caries Increment Dynamics in Preschool Children with Risk Factors: The 3-Year Prospective Study.

This prospective study monitored the dental status, the presence of plaque, and cariogenic microorganism levels of identical children over three years. The aim was to determine the dynamics of caries increment as well as the relationship between risk factors and caries prevalence. A total number of 125 children (72 boys and 53 girls) was included in the study, with an average age of 3.95 ± 0.06 years at the baseline. During the clinical examination at the nursery schools, the presence of dental plaque was recorded, and saliva samples were collected from the tongue of children for the DentoCult SM test providing easy detection of mutans streptococci from saliva samples. At baseline, 65.6% of the children had no caries, 4% had restored teeth with fillings or crowns or missing teeth due to caries, and 30.4% had at least one untreated caries. The percentages of intact teeth, restored or missing teeth, and untreated caries were 52.8%, 8.8%, 38.4% in the second year and 49.1%, 13.8%, and 31.1% in the third year. The dmft index value was 1.41 ± 0.24 in the first year, 2.29 ± 0.30 in the second year, and 2.33 ± 0.31 in the third year. There was a significant correlation between plaque presence and dt and dmft values (p < 0.05; the statistical analyses were performed using the Kolmogorov-Smirnov test). This 3-year longitudinal study highlighted the importance of examining both the oral hygiene and the level of cariogenic microorganisms when undertaking the evaluation of caries risk evaluation in preschool children.

Perception of Undergraduate Students at the Faculty of Medicine in Hradec Králové Regarding Their Endodontic Education and Suggested Improvements.

AIM: The aim of this study was to assess the perception of undergraduate dentistry students at Charles University, Faculty of Medicine in Hradec Králové, the Czech Republic regarding their endodontic education within the context of the Undergraduate Curriculum Guidelines for Endodontology by the European Society of Endodontology (ESE). The secondary aim was to compare this perception among students in the Czech and English groups. METHODOLOGY: A questionnaire survey was conducted among fifth year students at the very end of their studies. RESULTS: The students returned 60 filled questionnaires, making the response rate of 75.9%. More than two thirds of the respondents declared that they were competent at or had knowledge of most of the major competencies defined by the ESE. Eighty seven percent of respondents felt competent to perform a root canal treatment on anterior teeth; 86.7% on premolars; and 48.3% on molars. Nearly all respondents (98.3%) recommended more opportunities to practice on patients. CONCLUSIONS: The overall perception of the students was that their endodontic education was sufficient and largely conformed to the guidelines. Insufficient exposure to endodontic practice on patients was identified as a deficiency. There were no significant differences in perceptions between the two study groups.

Hyaluronic Acid-Based Medical Device for Treatment of Alveolar Osteitis-Clinical Study.

Alveolar Osteitis (AO) is a complication following the extraction of a tooth. AO manifests through localized pain in, and around, the extraction site, where the post-operative blood clot has been disintegrated. The aim of this single cohort study was to evaluate the outcome of a treatment of AO, using a pharmacological device composed of hyaluronic acid and octenidine dihydrochloride. The tested device is a sponge-like material, composed solely of a fully dissoluble medicaments (hyaluronic acid, calcium chloride, and octenidine dihydrochloride). It was designed to serve as a non-toxic, slow-dissolving antiseptic, that adheres to mucosa and obturates the wound. This study includes 58 subjects who were diagnosed with AO. The tested device was administered once daily until local pain subsided to < 20 mm of the Visual Analog Scale (VAS). The treatment was considered effective when the pain subsided to < 20 mm VAS in < 8 days of treatment; as per comparative studies. Our findings provide a statistically significant success rate of 96.0% (95.0% confidence interval of 75.75% to 97.8%) after pharmacological device administrations. No adverse medical effects were detected. Acquired data confirmed that lyophilized hyaluronic acid, combined with octenidine, is effective for the treatment of AO. The results are clinically important as AO is a common complication after third molar extractions.

The Analysis of Dental Treatment under General Anaesthesia in Medically Compromised and Healthy Children.

Dental care under general anaesthesia (GA) is an option when normal treatment cannot be accomplished due to un-cooperation and systemic or cognitive/intellectual disabilities. The purpose of this retrospective cohort study was to analyse the dental treatment under GA in medically compromised and healthy children. The data were collected from the medical records of children who received their dental treatment under GA. The data regarding patient age, sex, general health, and type of treatment were analysed. This clinical trial included 229 study subjects (138 males, 91 females) with an average age of 8.34 (SD 3.78). Counts and relative counts were used for description of qualitative data. The association between the variables was analysed using contingency tables. The significance of the findings was tested by the chi-square test. Most of the children were older pre-school 63 (27.51%) and young school children 102 (44.54%). Medical disability (systemic or intellectual) was diagnosed in 142 children (62.01%); the remaining 87 (37.99%) were healthy children. Dental treatment of primary teeth was more commonly performed in healthy children (65.52%) compared to medically compromised children (58.45%) (p = 0.287). The total number of medically compromised children and the total number of healthy children were both considered to be 100% for the purpose of the following calculations. In terms of permanent dentition, medically compromised children required more extractions and fillings (38.03%, 57.04%) compared to healthy children (14.94%, 17.24%, respectively). The results of this study revealed that dental treatment under GA was more commonly performed in medically compromised children in permanent teeth only in comparison to healthy children. Based on these findings, both health professionals and state authorities should focus more on preventive care in medically compromised children in order to improve their oral health.

Characteristics of Human Natal Stem Cells Cultured in Allogeneic Medium.

Recently, human natal dental pulp stem cells (hNDP-SCs) have been characterized in vitro and it has been shown that they satisfy criteria defining human mesenchymal stromal cells (MSCs), as proposed by the International Society for Cellular Therapy. However, these results were reached in the presence of xenogeneic expansion medium, which has the potential to alter the cells' functional capacity. To determine the validity of the previously reported hNDP-SCs characteristics for human cell therapy, we have cultured hNDP-SCs in allogeneic expansion medium. Two hNDP-SC lineages were isolated from vital natal teeth, donated by a healthy newborn female and cultured in 2% platelet rich plasma (PRP). Analysis of the phenotypic expressions, proliferation rates, viability, telomerase length and in vitro adipogenic, osteogenic and chondrogenic differentiation potentials of two hNDP-SCs lineages (Zn001 and Zn002) were performed. Both lineages displayed similar morphology, proliferation rates, adipogenic, chondrogenic and osteogenic differentiation potential. Telomere shortening by 41.0% and 13.49% occurred from 3rd till 14th passage for lineages Zn001 and Zn002 respectively. Viability of both lineages was higher than 90%. Flow cytometry demonstrated that both lineages were positive to the majority of tested markers, including markers, which were negatively, expressed when hNDP-SCs were cultured previously in xenogeneic medium. Using immune-cytochemistry the cells were shown to express beta III-tubulin, nestin, neurofilaments and Nanog. PRP used as allogeneic medium is suitable for cultivation of hNDP-SCs.

Characteristics of human natal stem cells cultured in allogeneic medium

Abstract Recently, human natal dental pulp stem cells (hNDP-SCs) have been characterized in vitro and it has been shown that they satisfy criteria defining human mesenchymal stromal cells (MSCs), as proposed by the International Society for Cellular Therapy. However, these results were reached in the presence of xenogeneic expansion medium, which has the potential to alter the cells' functional capacity. To determine the validity of the previously reported hNDP-SCs characteristics for human cell therapy, we have cultured hNDP-SCs in allogeneic expansion medium. Two hNDP-SC lineages were isolated from vital natal teeth, donated by a healthy newborn female and cultured in 2% platelet rich plasma (PRP). Analysis of the phenotypic expressions, proliferation rates, viability, telomerase length and in vitro adipogenic, osteogenic and chondrogenic differentiation potentials of two hNDP-SCs lineages (Zn001 and Zn002) were performed. Both lineages displayed similar morphology, proliferation rates, adipogenic, chondrogenic and osteogenic differentiation potential. Telomere shortening by 41.0% and 13.49% occurred from 3rd till 14th passage for lineages Zn001 and Zn002 respectively. Viability of both lineages was higher than 90%. Flow cytometry demonstrated that both lineages were positive to the majority of tested markers, including markers, which were negatively, expressed when hNDP-SCs were cultured previously in xenogeneic medium. Using immune-cytochemistry the cells were shown to express beta III-tubulin, nestin, neurofilaments and Nanog. PRP used as allogeneic medium is suitable for cultivation of hNDP-SCs.

Resumo Recentemente, células-tronco da polpa dental humana (hNDP-SCs) foram caracterizadas in vitro e foi demonstrado que elas satisfazem critérios que definem células mesenquimais do estroma humana (MSCs), tal como proposto pela Sociedade Internacional para Terapia Celular. No entanto, esses resultados foram alcançados na presença de meio de expansão xenogênico, que tem o potencial de alterar a capacidade funcional das células. Para determinar a validade das características das hNDP-SCs anteriormente relatadas para a terapia celular humana, cultivamos hNDP-SCs em meio de expansão alogênico. Duas linhagens hNDP-SC foram isoladas de dentes natais vitais, doadas por uma recém-nascida saudável, e cultivadas em plasma rico em plaquetas a 2% (PRP). Análises das expressões fenotípicas, taxas de proliferação, viabilidade, comprimento de telomerase e potenciais de diferenciação adipogênica, osteogênica e condrogênica in vitro das duas linhagens hNDP-SC (Zn001 e Zn002) foram realizadas. Ambas as linhagens apresentaram morfologia, taxas de proliferação, potencial de diferenciação adipogênico, condrogênico e osteogênico semelhantes. O encurtamento dos telômeros em 41,0% e 13,49% ocorreu da 3ª até a 14ª passagem para as linhagens Zn001 e Zn002, respectivamente. A viabilidade de ambas as linhagens foi superior a 90%. A citometria de fluxo demonstrou que ambas as linhagens foram positivas para a maioria dos marcadores testados, incluindo marcadores, que foram negativamente expressados quando hNDP-SCs foram previamente cultivadas em meio xenogênico. Usando análise imunocitoquímica, as células mostraram expressar a beta III-tubulina, nestina, neurofilamentos e Nanog. O PRP usado como meio alogênico mostrou-se adequado para o cultivo de hNDP-SCs.

Cryopreservation of Dental Stem Cells.

Nowadays, regenerative and reparative medicine has grown in popularity. Dental stem cells are easily accessible source of adult stem cells. They can be harvested by a tooth extraction or spontaneous deciduous tooth exfoliation. They have to be isolated, expanded and stored until time they would be needed for individual stem cell therapy. Cryopreservation is both a short-term and long-term storage of tissues or cells at sub-zero temperatures. There are several methods of cryopreservation requiring different technologies. The objective of this review is to compare them and highlight their advantages and disadvantages.