[Islet biomimetic microenvironment constructed by chitosan oligosaccharide protects islets from hypoxia-induced damage by reducing intracellular reactive oxygen species]

Objective

Gelatin methacryloyl (GelMA)/hyaluronic acid methacryloyl (HAMA)/chitosan oligosaccharide (COS) hydrogel was used to construct islet biomimetic microenvironment, and to explore the improvement effect of GelMA/HAMA/COS on islet activity and function under hypoxia.

Methods

Islets cultured on the tissue culture plate was set as the control group, on the GelMA/HAMA/COS hydrogel with COS concentrations of 0, 1, 5, 10, and 20 mg/mL respectively as the experimental groups. Scanning electron microscopy was used to observe the microscopic morphology, rheometer test to evaluate the gel-forming properties, contact angle to detect the hydrophilicity, and the biocompatibility was evaluated by the scaffold extract to L929 cells [using cell counting kit 8 (CCK-8) assay]. The islets were extracted from the pancreas of 8-week-old Sprague Dawley rats and the islet purity and function were identified by dithizone staining and glucose-stimulated insulin secretion (GSIS) assays, respectively. Islets were cultured under hypoxia (1%O 2) for 24, 48, and 72 hours, respectively. Calcein-acetyl methyl/propidium iodide (Calcein-AM/PI) staining was used to evaluate the effect of hypoxia on islet viability. Islets were cultured in GelMA/HAMA/COS hydrogels with different COS concentrations for 48 hours, and the reactive oxygen species kits were used to evaluate the antagonism of COS against islet reactive oxygen species production under normoxia (20%O 2) and hypoxia (1%O 2) conditions. Calcein-AM/PI staining was used to evaluate the effect of COS on islet activity under hypoxia (1%O 2) conditions. Islets were cultured in tissue culture plates (group A), GelMA/HAMA hydrogels (group B), and GelMA/HAMA/COS hydrogels (group C) for 48 hours, respectively. Immunofluorescence and GSIS assays were used to evaluate the effect of COS on islet activity under hypoxia (1%O 2) conditions, respectively.

Results

GelMA/HAMA/COS hydrogel had a porous structure, the rheometer test showed that it had good gel-forming properties, and the contact angle test showed good hydrophilicity. CCK-8 assay showed that the hydrogel in each group had good biocompatibility. The isolated rat islets were almost round, with high islet purity and insulin secretion ability. Islets were treated with hypoxia for 24, 48, and 72 hours, Calcein-AM/PI staining showed that the number of dead cells gradually increased with time, which were significantly higher than those in the non-hypoxia-treated group ( P<0.001). Reactive oxygen staining showed that GelMA/HAMA/COS hydrogels with different COS concentrations could antagonize the production of reactive oxygen under normal oxygen and hypoxia conditions, and this ability was positively correlated with COS concentration. Calcein-AM/PI staining indicated that GelMA/HAMA/COS hydrogels with different COS concentrations could improve islet viability under hypoxia conditions, and cell viability was positively correlated with COS concentration. Immunofluorescence staining showed that GelMA/HAMA/COS hydrogel could promote the expression of islet function-related genes under hypoxia conditions. GSIS assay results showed that the insulin secretion of islets in hypoxia condition of group C was significantly higher than that of groups B and C ( P<0.05).

Conclusion

GelMA/HAMA/COS hydrogel has good biocompatibility, promotes islet survival and function by inhibiting reactive oxygen species, and is an ideal carrier for building islet biomimetic microenvironment for islet culture and transplantation.

[Effects of ulnar styloid and sigmoid notch fractures on postoperative wrist function of patients with distal radius fracture]

OBJECTIVE

To study the effects of ulnar styloid and sigmoid notch fractures on postoperative wrist function in patients with distal radius fracture.

METHODS

In total, 139 patients treated for distal radius fracture in the Department of Orthopedic Trauma at Peking University People's Hospital from Jan. 2006 to June 2016 were selected for outpatient follow-ups. Evaluation was based on Sartiento's modification of the Gartland and Werley scores. Efficacy was assessed with wrist pain as the focus.

RESULTS

The excellent and good efficacy rate was 97.1% (excellent: n=107, 77.0%; good: n=28, 19.4%; and fair: n=4, 2.9%). Gender, age, and whether the ulnar styloid fracture achieved union did not significantly impact the scores (P>0.05). The scores of the basal fracture group were significantly different (P=0.001). Internal fixation of ulnar styloid fracture was associated with a significant difference in scores (P=0.005). The effect of sigmoid notch fracture was also associated with a significant difference in scores (P=0.024). This study included 22 cases of ulnar wrist pain, and the overall incidence of ulnar wrist pain was 15.8%. Gender, age, whether the ulnar styloid fracture achieved union, and whether internal fixation was conducted for ulnar styloid fracture and sigmoid notch fracture had no significant effect on the occurrence of ulnar wrist pain (P>0.05). The incidence of ulnar wrist pain was higher in basal fractures than that in tip fractures. Among ulnar styloid fractures, the union rate of basal fracture was higher than that of tip fractures. The union rates of basal fracture and tip fracture were significantly different (P<0.001). Basal fractures were significant risk factors for ulnar wrist pain (P=0.028). Basal fracture of the ulnar styloid group and sigmoid notch fracture group had poor wrist function scores. Wrist function score improved significantly after internal fixation of ulnar styloid fracture. The incidence of ulnar wrist pain was higher in basal fracture group. The union rate in basal fracture group was higher than in tip fracture group.

CONCLUSION

The overall effect of surgical treatment of distal radius fracture is satisfactory. Ulnar styloid basal fracture and sigmoid notch fracture are risk factors for postoperative wrist dysfunction in patients with distal radius fracture, and the basal fracture is one of the risk factors of ulnar wrist pain. The union rate of ulnar styloid basal fractures is better than that of tip fractures. Internal fixation of ulnar styloid fracture can improve wrist function.

[Application of multidisciplinary team (MDT) in the treatment of severe trauma]

OBJECTIVE

To explore the effect of multi-disciplinary team (MDT) in general hospitals on severe trauma patients.

METHODS

This study reviewed the treatment of patients with severe trauma in trauma center of Peking University People's Hospital from March 2017 to April 2019. The baseline information: the patients' gender, age, injury mechanism, etc.; the start indicators: the Glasgow coma scale (GCS), trauma index (TI), injury severity score (ISS); the start related indicators: time for activation, time for MDT to arrive, time for CT scan, time for damage control surgery; patient treatment and prognosis: ICU (intensive care unit) length of stay, number of cured and discharged patients, number of dead cases, number of patients transferred to rehabilitation hospital, were all analyzed. It discussed the composition of MDT, the initiation scheme, the indicators of initiation of MDT for severe trauma, and analyzed the correlation between the application of MDT and the prognosis of patients.

RESULTS

From March 2017 to April 2019, 112 trauma patients were treated by MDT in Peking University People's Hospital. There were 69 males and 43 females. The minimum age was 15 years, the maximum age was 89 years, most of them were 36-55 years old. The main injury mechanism was traffic accident injury. The GCS, TI, ISS were 13.0±2.9, 13.0±2.8, and 21.5±11.9, respectively. It took 3.7±0.8 minutes to start the call, 6.1±0.9 minutes for MDT personnel to arrive at the emergency rescue area, 23.8±3.0 minutes for fast CT and 92.6±15.4 minutes for injury control operation. All the hospitalized patients were treated effectively. ICU (Intensive care unit) hospitalization time was 12.6±6.7 days. 55 discharged patients were cured, 5 died (1 died of hemorrhagic shock, 4 died of severe brain injury) and 52 transferred to rehabilitation hospital.

CONCLUSION

The treatment of severe trauma patients by MDT in trauma center of general hospitals can greatly improve the ability and level of treatment of severe trauma patients, make up for the lack of treatment of severe trauma especially multiple trauma patients in large general hospitals, and improve the treatment effect of severe trauma patients. It provides a reference model for large general hospitals to treat patients with severe trauma and multiple trauma and for the construction of trauma centers.

[Application of multidisciplinary team (MDT) in the treatment of severe trauma]

OBJECTIVE

To explore the effect of multi-disciplinary team (MDT) in general hospitals on severe trauma patients.

METHODS

This study reviewed the treatment of patients with severe trauma in trauma center of Peking University People's Hospital from March 2017 to April 2019. The baseline information: the patients' gender, age, injury mechanism, etc.; the start indicators: the Glasgow coma scale (GCS), trauma index (TI), injury severity score (ISS); the start related indicators: time for activation, time for MDT to arrive, time for CT scan, time for damage control surgery; patient treatment and prognosis: ICU (intensive care unit) length of stay, number of cured and discharged patients, number of dead cases, number of patients transferred to rehabilitation hospital, were all analyzed. It discussed the composition of MDT, the initiation scheme, the indicators of initiation of MDT for severe trauma, and analyzed the correlation between the application of MDT and the prognosis of patients.

RESULTS

From March 2017 to April 2019, 112 trauma patients were treated by MDT in Peking University People's Hospital. There were 69 males and 43 females. The minimum age was 15 years, the maximum age was 89 years, most of them were 36-55 years old. The main injury mechanism was traffic accident injury. The GCS, TI, ISS were 13.0±2.9, 13.0±2.8, and 21.5±11.9, respectively. It took 3.7±0.8 minutes to start the call, 6.1±0.9 minutes for MDT personnel to arrive at the emergency rescue area, 23.8±3.0 minutes for fast CT and 92.6±15.4 minutes for injury control operation. All the hospitalized patients were treated effectively. ICU (Intensive care unit) hospitalization time was 12.6±6.7 days. 55 discharged patients were cured, 5 died (1 died of hemorrhagic shock, 4 died of severe brain injury) and 52 transferred to rehabilitation hospital.

CONCLUSION

The treatment of severe trauma patients by MDT in trauma center of general hospitals can greatly improve the ability and level of treatment of severe trauma patients, make up for the lack of treatment of severe trauma especially multiple trauma patients in large general hospitals, and improve the treatment effect of severe trauma patients. It provides a reference model for large general hospitals to treat patients with severe trauma and multiple trauma and for the construction of trauma centers.