Prevention of pleural adhesions by bioactive polypeptides - a pilot study

Heparin-grafted PVA hydrogels: a material for the optical part of artificial cornea

Heparin (Hep) was grafted to a poly(vinyl alcohol) (PVA) hydrogel surface by using the covalent grafting method. The structure of the modified hydrogel was determined from Fourier transform infrared attenuated total reflection and X-ray photoelectron spectroscopy. The thermal stability of the samples was investigated by thermogravimetry–differential thermal analysis. The effects of the concentration of (3-aminopropyl)triethoxysilane (kh550) and Hep on visible light transmittance, moisture content, equilibrium swelling, hydrophilicity and percentage of Hep sodium release of the composite hydrogel were studied. The visible light transmittance of the modified PVA hydrogel was above 94%. The time of swelling equilibrium was about 60 min and the equilibrium swelling ratio ranged from 3·0 to 3·5. The hydrophilicity was enhanced, and the static water contact angle decreased from 41 to 28°. The bioeffects of the PVA–kh550–Hep hydrogel were evaluated by studying cell adhesion and proliferation. During the adhesion assay in vitro, cell adhesion significantly decreased after the interfaces had been modified with Hep. The Cell Counting Kit-8 assay showed that the biocompatibility of the PVA–kh550–Hep hydrogel improved obviously compared to that of pure PVA. The experimental results demonstrated that the PVA–kh550–Hep hydrogel had good stability, bioactivity and biocompatibility, suggesting its potential applications in artificial corneas.

Suppressive Effects of Aspirin for Postthoracotomy Pleural Adhesion in Rats

BACKGROUND

Postoperative adhesion is one of major concerns at re-thoracotomy. Aspirin has both the anti-platelet and anti-inflammatory effects, and decreases several cytokines production.

OBJECTIVE

We investigated that aspirin could reduce postoperative adhesion formation in a rat model.

METHODS

We cauterised the lung visceral pleural to make postoperative adhesion in rats. The animals were allocated to a control group and an aspirin administration group (100 mg/kg/day for 14 days). We performed re-thoracotomy and evaluated the adhesion lengths on day 14. We also investigated the cytokine expression in the adhesion region and the peripheral tissue with platelet-derived growth factor (PDGF), platelet-derived growth factor receptor (PDGFR), alpha smooth muscle actin (α-SMA), transforming growth factor beta 1 (TGF-β1), and vascular endothelial growth factor-A (VEGF-A), sequentially.

RESULTS

The adhesion lengths were significantly shorter in the aspirin group than that in the control group (8.7±2.0 mm vs 11.2±1.1 mm, p=0.024). The expressions of PDGF and PDGFR were lower in the aspirin group than that in the control group on day 3. The expression of α-SMA on fibroblasts decreased in the aspirin group on day 3. There was no significant difference in the expressions of TGF-β1 and VEGF-A with administration of aspirin.

CONCLUSIONS

Aspirin could reduce postoperative pleural adhesion by inhibiting the expression of PDGF.

Nuss procedure for patients with pectus excavatum with a history of intrathoracic surgery

BACKGROUND

The aim of this study was to demonstrate the feasibility and safety of the Nuss procedure for patients with pectus excavatum (PE) with a history of intrathoracic surgery.

PATIENTS

From April 2010 to December 2013, we performed 6 cases of PE repair in patients with a history of intrathoracic surgery. The causes of previous operations were congenital cystic adenomatoid malformation in 4 patients and congenital diaphragmatic hernia in 2. The patients' median age was 5 years (range, 4-9 years) and median preoperative pectus severity index was 4.63 (range, 3.42-10.03). Their intraoperative and postoperative courses were reviewed retrospectively.

RESULTS

The mean overall operation time was 127.5 ± 17.0 minutes, and the mean operation time for endoscopic pneumolysis was 28.8 ± 12.3 minutes. Intraoperative exploration for pleural adhesion revealed that the endoscopic approach in the previous operation was associated with low pleural adhesion, and the open thoracotomy or laparotomy approach was associated with low to high pleural adhesion. One patient developed a pneumothorax on the first postoperative day. All the other patients had uneventful postoperative courses. All the patients received bar removal 2-3 years after bar insertion. One patient developed atelectasis after bar removal. All the other patients had an uneventful postoperative course. The mean postoperative follow-up time after bar removal was 20.1 ± 14.7 months.

CONCLUSIONS

History of intrathoracic surgery seems not a contraindication for the Nuss procedure. However, perioperative complications should be carefully monitored in both the bar insertion and removal operations.

Development of an Anti-Adhesive Membrane for Use in Video-Assisted Thoracic Surgery

Background: The need to prevent postoperative adhesions after surgery has been considered a significant challenge in thoracic surgery, especially with the advent of video-assisted thoracic surgery (VATS). While preventive materials for postoperative adhesions have been studied for many years, they are all still in the development phases. Methods: In this animal study, an insoluble hyaluronic acid membrane was used in VATS for wedge resection to test its operability and to examine the body's response to the membrane. Ten beagles were divided into two groups, an experimental group and a negative control group. In the experimental group, an insoluble hyaluronic acid membrane containing glycerol was used as the test membrane (10 x 10 x 0.1 cm³). The test membrane was implanted in the left thoracic cavity of the animal under VATS following wedge resection. The animals were observed for two weeks and then euthanized for examination. Results: Macroscopically, the median adhesion score was lower in the experimental group (0) than in the control group (2.5). On histopathological examination, the test membrane elicited only a minor inflammatory response and foreign body reaction. Conclusion: The test membrane showed satisfactory operability and appears to be a practical material to prevent postoperative adhesions after thoracic surgery in VATS.