ABSTRACT
Background: Tissue-engineered periodontal ligament (PDL) around a dental implant by using PDL stem cells (PDLSCs) may be useful in periodontal regeneration and can reduce or eliminate certain shortcomings of dental implants. Materials and Methods: PDLSCs were isolated from extracted human PDL cells and cultured in a bioreactor. They were identified using markers CD45, CD73, CD90, CD105, and CD146. After the formation of multiple cellular layers, they were then attached on titanium mini dental implants and placed in rabbit tibia. The rabbits were sacrificed after 9 months, and the implants were analyzed histologically and radiographically by Cone beam computed tomography (CBCT). Results: Isolated PDLSCs obtained from human premolars showed a colony-forming ability on the 7th day and 14th day. Immunocytochemistry revealed that cells had taken up the adequate positive stains for primary antibodies CD73, CD90, CD105, and CD146 and negative staining for CD45. The histological sections obtained from sacrificed rabbits, when viewed under the light microscope, clearly showed the presence of PDL around dental implants. CBCT examination showed that the implant was well within the bone and did not migrate. The site appeared to be normal without any lytic changes in the bone. Conclusion: It can safely be postulated from the present study that tissue engineering of PDL can be achieved around dental implants using PDLSCs. Important inter-tissue interactions like the formation of a functional PDL around the implantation site, and induction of bone formation in the vicinity of the implants may be possible. Future research in humans is required for further research.
ABSTRACT
OBJECTIVE: Cancer stem cells (CSCs) belong to a subpopulation of undifferentiated cells present within tumors that have the potential to regenerate, differentiate, maintenance of pluripotency, drug resistance, and tumorigenicity when transplanted into an innate host. These can influence the growth and behavior of these tumors and are used to investigate the initiation, progression, and treatment strategies of laryngeal cancer. Research on CSC science and targeted therapies were hinge on their isolation and/or enrichment procedures. The object of the study is to isolate cancer stem cells from primary laryngeal carcinoma (CSCPLC) by tumor spheres enrichment. We checked the properties of self-renewal, stemness, clonogenicity, and chemotherapeutic resistance. MATERIALS AND METHODS: We performed tumor sphere formation assay (primary, secondary, and tertiary) chemotherapy resistance by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay were performed to evaluate the CSC cells. Immunofluorescence for stem cell markers (CD133+, CD44+) and gene expression of stem cell markers for CD133+, CD44+, OCT4, SOX2, and NANOG was done using the real-time polymerase chain reaction technique. RESULTS: We were able to isolated CSC subpopulations from PLC cell lines by the tumor sphere method. These cells exhibited good primary, secondary, and tertiary tumor sphere formation efficiency and also disclosed a resistant index of more than 2. Immunofluorescence for stem cell markers (CD133+ and CD44+) confirms the presence of CSC. There was significantly higher mRNA expression of stem cell markers in CSC enriched subpopulations compared to the parental cell lines. CONCLUSION: We conclude that tumor spheres enrichment is an efficient, economical, and reliable approach for the isolation and characterization of CSC from PLC cell lines. These cells demonstrated the properties of self-renewal, stemness, clonogenicity, and chemotherapeutic resistance.
ABSTRACT
Oral squamous cell carcinoma (OSCC) is most common oral cancer with multifactorial etiology. Surgical therapy is treatment of choice but known to have recurrence. The main reason for recurrence is associated with surgical margins which need to be tumor free. Changes at genetic level cannot be ascertained only through routine light microscopy in surgical margins, even though they are tumor free. Detection of early marker like p16 can help in predicting the risk of recurrence. Hence study aimed to detect p16 microsatellite marker (D9s1747) in surgical margins of oral squamous cell carcinoma and compare the same with p16 marker through immunohistochemistry. Total of 40 paraffin embedded tissue samples diagnosed and surgically treated cases of OSCC were included. From each sample one tumor proper and one surgical margin was obtained. From paraffin embedded tissue sample 2 sections of 4 µm thick was obtained from tumor proper and tumor margin. One section was stained with hematoxylin and eosin and other section was stained immunohistochemically using p16 antibody. DNA extraction was done for tumor proper and surgical margin tissue and PCR analysis was carried for p16 microsatellite marker (D91747). Out of 40 cases 37 cases showed positivity in tumor proper for p16 with IHC. Out of 37 cases 23 cases showed positivity for both tumor proper and surgical margin. There were 3 cases negative for tumor proper. Out of these 3 cases, 1 (33.3%) case was positive for surgical margin. Out of 40 cases 27 cases showed positivity for tumor proper with p16 microsatellite marker. Out of 27 cases 16 cases showed positivity for both tumor proper and surgical margin. There were 13 cases negative for tumor proper. However there were 8 (61.5%) cases negative which were in tumor proper but showed positivity for surgical margin. Other 5 cases were negative in both tumor proper and surgical margin. Our study reveals that surgical margins of OSCC exhibit alteration in p16 markers both by IHC and PCR techniques. p16 and p16 microsatellite marker detection in margins indicates field change. Further studies with larger sample size comparing expression with clinical and histological parameter and follow up has to be done to substantiate our findings.
