Osteogenic potential of human dental pulp stem cells cultured onto poly-ε-caprolactone/poly (rotaxane) scaffolds.

BACKGROUND: Bioengineering aims to develop innovative scaffolds to improve cellular activities for tissue regeneration. OBJECTIVES: To evaluate the biological behavior of human dental pulp stem cells (hDPSCs) seeded onto an experimental polymeric-based scaffold comprising poly-ε-caprolactone/poly (rotaxane). MATERIAL AND METHODS: Adhesion, viability, and proliferation as well as alkaline phosphatase (ALP) activity, mineralized nodule formation (alizarin red assay), and expression of genes related to osteogenic differentiation, including ALP, type 1 collagen alpha 1 (COL1A1), Runt-related transcription factor (Runx-2), and osteocalcin (BGLAP/OCN), were evaluated in hDPSCs seeded onto polymeric scaffolds. RESULTS: hDPSCs expressed typical levels of mesenchymal stem cell surface markers. Cell growth increased upon cultivation on polymeric blend scaffold and the cells gained osteoblast-like appearance. Fourteen days after seeding hDPSCs on the scaffolds, irrespective to the culture medium used (clonogenic or mineralization medium), the cells presented ALP activity higher than that of control cells grown in clonogenic medium. The cells cultivated in mineralization medium on the scaffold showed significantly higher expression of all genes than the control cells, except for BGLAP gene expression. At 21 days, the group cultivated on the scaffold and mineralization medium showed maximum level of mineralization. SIGNIFICANCE: Poly-ε-caprolactone/poly (rotaxane) blend is noncytotoxic to hDPSCs and improved genomic and functional osteogenic differentiation. Thus, poly-ε-caprolactone/poly (rotaxane) blend may serve as a promising bioactive biomaterial for bone tissue bioengineering.

Effects of photobiomodulation therapy on the extracellular matrix of human dental pulp cell sheets.

Photobiomodulation therapy (PBMT) and the cell sheet (CS) technology improve processes relevant to tissue regeneration. The aim of this study was to investigate the effects of different PBMT parameters on the architecture (histology), protein composition (Western blotting and immunohistochemistry) and ultrastructure [scanning electron microscopy (SEM) and transmission electron microscopy (TEM)] of the extracellular matrix (ECM) synthesized by CSs composed by human dental pulp stem cells (hDPSCs). METHODS: Thawed cells were recharacterized by the expression profile of the surface molecules of mesenchymal stem cells (MSCs) using flow cytometry. Clonogenic medium supplemented with vitamin C (20 µg/ml) was used for obtaining the CSs. PBMT was performed with continuous-wave diode laser (660 nm, 20 mW, 0.028cm2, 0.71 W/cm2) in punctual and contact mode. The CSs were allocated in 3 experimental groups: Control: no further treatment; PBMT1 [4 s, 3 J/cm2 (lower energy density), 0.08 J/point] and PBMT2 [7 s, 5 J/cm2 (higher energy density), 0.14 J/point]. Statistical comparisons were performed (p ≤ .05). RESULTS: The cells presented the classical immunoprofile of MSCs. Type I and type III collagens and fibronectin were present in the ECM of the CSs. PBMT1 induced higher amount of fibronectin. The overall ultrastructure of the CSs in the PBMT1 was epithelial-like, whereas the PBMT2 leads to CSs with fusiform cells arranged in bundles. TEM identified a more mature ECM and signs of apoptosis and necrosis in the PBMT2 group. CONCLUSION: PBMT influence the composition and ultrastructure of the ECM of CSs of hDPSCs. Thus, PBMT, specifically when applied in the lower energy density, could be of importance in the determination of the mechanical quality of CSs, which may favor cell therapy by improving the CS transplantation approach.

Role of routine small intestinal biopsy in adult patient with irritable bowel syndrome-like symptoms.

AIM: The clinical evaluation of patients with chronic diarrhea and/or abdominal pain requires a complex work-up. The aim of the study was to evaluate whether routine duodenal biopsy sampling of macroscopically normal mucosa of patients with irritable bowel syndrome-like symptoms undergoing upper endoscopy assists in diagnosis and management. METHODS: Consecutive adults scheduled for upper endoscopy for evaluation of uninvestigated dyspepsia and abdominal pain and/or chronic diarrhea based upon the history, were enrolled. Gastric biopsies and 3 duodenal biopsies were taken for histological evaluation. RESULTS: A total of 786 sets of biopsies from 262 consecutive patients (200 females and 62 males, mean age 46 years; range: 15-82), were analyzed. Microscopic damage was observed in 212 of 262 patients (81%) with normal mucosa. Mild to moderate and severe duodenitis or villi atrophy was histologically confirmed in 65%, 26% and 8% of 212 patients respectively. The negative predictive value of a normal appearing duodenal mucosa was 19%. Additional tests confirmed celiac disease in 12 patients. Lactose malabsorption was present in 42%, bacterial overgrowth in 14%, and H. pylori infection in 28%. Colonoscopy performed in 92 patients revealed non specific colitis (25%), microscopic colitis (28%), Crohn's disease (1%), and diverticulosis (15%). CONCLUSION: Duodenal biopsies revealed abnormalities in the majority of adults with chronic diarrhea and/or abdominal pain despite macroscopically normal gross findings. These results suggest that duodenal biopsies could be helpful in patients with chronic diarrhea and/or abdominal pain for the following work up.