Intestinal stents: Structure, functionalization and advanced engineering innovation

Construction of PVA/OHA-Gs@PTMC/PHA double-layer nanofiber flexible scaffold with antibacterial function for tension free rectal in-situ reconstruction

The effective prevention and treatment of anastomotic leakage after intestinal anastomosis for colorectal diseases is still a major clinical challenge. In order to assist intestinal anastomosis healing and avoid anastomotic leakage caused by high tension, low blood supply or infection, we designed a double-layer nanofiber intestinal anastomosis scaffold, which was composed of electrospun PTMC/PHA nanofibers as the main layer, and electrospun PVA/OHA-Gs nanofibers with antibacterial properties as the antibacterial surface layer. This double-layer scaffold has good toughness, its maximum tensile force value could reach 8 N, elongation could reach 400 %, and it has hydrophilic properties, and its contact angle was about 60°. On the basis of reducing anastomotic tension and isolating intestinal contents, this double-layer nanofiber anastomotic scaffold not only played an antibacterial effect in the short term after surgery to reduce inflammatory response, but also had the characteristics of multiple three-dimensional network structure like extracellular matrix which could promote tissue healing. The PVA/OHA-Gs@PTMC/PHA scaffold was implanted into a rabbit model simulating mechanical intestinal obstruction, and the results showed that the nanofibers of the scaffold could be degraded in vivo while maintaining a certain stability, that is, the overall structure of the PVA/OHA-Gs@PTMC/PHA scaffold would not shrink and deform due to degradation in a certain period of time. Therefore, the treatment with this scaffold showed better healing at the anastomotic site. Compared to the direct anastomosis group and pure PTMC scaffold group, the double-layer scaffold group promoted a faster return to normal anastomotic strength within 7 days. This PVA/OHA-Gs@PTMC/PHA double-layer nanofiber flexible scaffold appears to be a promising therapeutic strategy to prevent anastomotic leakage after intestinal anastomosis.

Reduction of amylose/amylopectin ratio improves the molecular orientation and performance of three-dimensional-printed thermoplastic starch/polylactic acid intestinal stents

Three-dimensional (3D)-printed intestinal stents based on thermoplastic starch (TPS)/polylactic acid (PLA) are a promising biodegradable alternative to conventional metal stents. However, the influence of the structure and conformation of starch on the properties of 3D-printed TPS/PLA intestinal stents requires clarification. This study evaluated the effects of the amylose/amylopectin ratio of starch on the molecular orientation, molecular interactions, crystallization behavior, microstructure, and thermodynamic, mechanical and hydrolysis performance of 3D-printed TPS/PLA intestinal stents. The molecular orientation of starch was determined during the preparation of the filaments for 3D printing. The 3D printing process promoted intermolecular interactions by further improving the molecular orientation, and enhanced the short-range order and crystallinity of the starch molecules. Decreasing the amylose/amylopectin ratio enhanced the short-range order of the starch molecules by increasing molecular orientation, which improved the circumferential compression performance of the 3D-printed intestinal stents but not the axial compression performance. However, the reduction in plasticized starch particles and improved PLA continuity caused by decreasing the amylose/amylopectin ratio contributed to improving the circumferential and axial compression performance as well as the anti-hydrolysis performance. These findings highlight the potential of starch to replace PLA as an inexpensive raw material for the development of high-performance biodegradable 3D-printed intestinal stents.

5-Fluorouracil/curcumin loaded silk fibroin hydrogel for the adjuvant therapy in colorectal cancer

This study employed silk fibroin (SF) as a carrier material to encapsulate curcumin (CUR) and 5-fluorouracil (5-FU), forming a highly effective drug-loaded hydrogel. The process involved mixing SF solution containing 5-FU with curcumin solution dissolved in acetone (AC), leading to the formation of composite drug-loaded nanospheres with particle sizes ranging from 77.87 nm to 299.22 nm, demonstrated enhanced permeability and retention (EPR) effects, enabling passive targeting of solid tumors. After the formation of the nanospheres, they were dispersed into a solution containing SF and polyethylene glycol (PEG). Following gelation and PEG removal, a SF hydrogel loaded with 5-FU and CUR (5-FU/CUR@SF hydrogel) was obtained. Results indicated that the 5-FU/CUR@SF hydrogel exhibited excellent drug release properties, with 5-FU and CUR achieving sustained release of 59.66 ± 3.76 % and 47.94 ± 5.03 %, respectively, over a 400-h of sustainable releasing period. Human colorectal cancer cell line (HT-29) and normal human colon epithelial cell line (NCM-460) were cultured with the 5-FU/CUR@SF hydrogel, resulting an apoptosis rate of only 17.38 ± 1.98 % for NCM-460 cells, whereas the apoptosis rate for HT-29 cells significantly increased to 72.31 ± 2.18 %, and its cell viability dropped to 59.77 ± 0.55 %. These findings suggest that the 5-FU/CUR@SF hydrogel exhibits low cytotoxicity toward normal NCM-460 cells, while exerting significant and sustained inhibitory effects on HT-29 cancer cells. In conclusion, the SF-based drug-loaded composite hydrogel holds great potential as a novel adjuvant therapeutic strategy for the treatment of CRC.

Past and Recent Progress on Metallic Digestive Tract Stents

The implantation of digestive tract stents at various lesion sites can effectively improve digestive tract patency, opening up an excellent treatment method for diseases that are currently incurable or resistant to conventional surgery. Digestive tract stents have been extensively studied and widely used worldwide due to their unique advantages of simple implantation, low trauma, satisfactory effect, and low complication rate. Among the various types of stents, metallic stents have been developed to improve surgical efficacy due to their excellent mechanical properties and are constantly being improved. This review provides an overview of the design and development of conventional nonbiodegradable metallic digestive tract stents such as nitinol (NiTi alloy), stainless steel, and cobalt-based alloy stents. Furthermore, biodegradable metallic stents for the digestive tract, such as magnesium-based, iron-based, and zinc-based stents, are described. This paper also evaluates the advantages and disadvantages of existing metallic digestive stents as well as future research directions and challenges in the development of metallic digestive tract stents.

Palliative procedures for advanced obstructive colorectal cancer: a systematic review and meta-analysis

PURPOSE

Advanced obstructive colorectal cancer (AOCC) presents surgical challenges. Consideration must be given to alleviating symptoms and also quality of life and survival time. This study compared prognostic efficacies of palliative self-expanding metal stents (SEMSs) and surgery to provide insights into AOCC treatment.

METHODS

PubMed, Web of Science, MEDLINE, and Cochrane Library were searched for studies that met inclusion criteria. Using a meta-analysis approach, postoperative complications, survival rates, and other prognostic indicators were compared between patients treated with SEMSs and those treated surgically. Network meta-analysis was performed to compare prognoses between SEMS, primary tumor resection (PTR), and stoma/bypass (S/B).

RESULTS

Twenty-one studies were selected (1754 patients). The odds ratio (OR) of SEMS for clinical success compared with surgery was 0.32 (95% confidence interval [CI] 0.15, 0.65). The ORs for early and late complications were 0.34 (95% CI 0.19, 0.59) and 2.30 (95% CI 1.22, 4.36), respectively. The ORs for 30-day mortality and stoma formation were 0.65 (95% CI 0.42, 1.01) and 0.11 (95% CI 0.05, 0.22), respectively. Standardized mean difference in hospital stay was - 2.08 (95% CI - 3.56, 0.59). The hazard ratio for overall survival was 1.24 (95% CI 1.08, 1.42). Network meta-analysis revealed that SEMS had the lowest incidence of early complications and rate of stoma formation and the shortest hospital stay. PTR ranked first in clinical success rate and had the lowest late-complication rate. The S/B group exhibited the lowest 30-day mortality rate.

CONCLUSION

Among palliative treatments for AOCC, SEMSs had lower early complication, stoma formation, and 30-day mortality rates and shorter hospital stays. Surgery had higher clinical success and overall survival rates and lower incidence of late complications. Patient condition/preferences should be considered when selecting AOCC treatment.

Hybrid films loaded with 5-fluorouracil and Reglan for synergistic treatment of colon cancer via asynchronous dual-drug delivery

Combination therapy with oral administration of several active ingredients is a popular clinical treatment for cancer. However, the traditional method has poor convenience, less safety, and low efficiency for patients. The combination of traditional pharmaceutical techniques and advanced material conversion methods can provide new solutions to this issue. In this research, a new kind of hybrid film was created via coaxial electrospraying, followed by a casting process. The films were composed of Reglan and 5-fluorouracil (5-FU)-loaded cellulose acetate (CA) core-shell particles in a polyvinylpyrrolidone (PVP) film matrix. Microscopic observations of these films demonstrated a solid cross section loaded with core-shell particles. X-ray diffraction and Fourier-transform infrared tests verified that the Reglan and 5-FU loaded in the films showed amorphous states and fine compatibilities with the polymeric matrices, i.e., PVP and CA, respectively. In vitro dissolution tests indicated that the films were able to provide the desired asynchronous dual-drug delivery, fast release of Reglan, and sustained release of 5-FU. The controlled release mechanisms were shown to be an erosion mechanism for Reglan and a typical Fickian diffusion mechanism for 5-FU. The protocols reported herein pioneer a new approach for fabricating biomaterials loaded with multiple drugs, each with its own controlled release behavior, for synergistic cancer treatment.

Artificial heart valve reinforced with silk woven fabric and poly (ethylene glycol) diacrylate hydrogels composite

The present study describes the preparation of woven silk fabric (WSF) and poly(ethylene glycol) diacrylate (PEGDA) hydrogel composite reinforced artificial heart valve (SPAHV). Interestingly, the longitudinal and latitudinal elastic modulus of the SPAHV composite can achieve at 54.08 ± 3.29 MPa and 23.96 ± 2.18 MPa, respectively, while its volume/mass swelling ratio and water permeability was 1.9 %/2.8 % and 3 mL/(cm2∙min), respectively, revealing remarkable anisotropic mechanical properties, low water swelling property and water permeability. The in vitro & in vivo biocompatibility and anti-calcification ability of SPAHV were further examined using L929 mouse fibroblasts and Sprague Dawley (SD) male rat model under 8 weeks of subcutaneous implantation. The expression of pro-inflammatory cytokine TNF-α and anti-inflammatory cytokine IL-10 was determined by immunohistochemical staining, as well as the H&E staining and alizarin red staining were accessed. The results showed that the composites possess better biocompatibility, resistance to degradation and anti-calcification ability compared to the control group (p < 0.05). Thus, the SPAHV composite with robust mechanical properties and biocompatibility has potential application for artificial heart valves.

Psoralea corylifolia formula extract-loaded silk fibroin/polycaprolactone fibrous membrane for the treatment of colorectal cancer

Intestinal obstructions caused by intestinal tumors pose life-threatening risks to patients. Adjuvant treatment using intestinal stents carrying drug loaded membranes has the advantages of timely relief of intestinal obstruction, as well as effective inhibition of tumor progression. The present work is to develop an intestinal stent loaded with a combination of traditional Chinese medicines capable of good biocompatibility, degradability, sustained drug release and anti-tumor properties. The drug combination extract was obtained from Psoralea corylifolia formula (PCF) and then was loaded into silk fibroin (SF)/polycaprolactone (PCL) fibrous membranes using emulsion electrospinning technology. Results showed that the membrane prepared by emulsion electrospinning technology has apparent core-shell structure, and the mechanical property and hydrophilicity of the membrane are gradually improved with the addition of PCF. Drug sustained release results demonstrated that there were no bursting phenomena, and showed a gradual sustained release up to 400 h. The antitumor efficacy was assessed in vitro using a human colorectal cancer cell line HCT-116 and an epithelial cell line NCM-460. Results showed that this drug-loaded membrane sustained antitumor cell growth performance, indicating its great potential for clinical treatment for intestinal cancer in the near future.