A review: progress in preventing tissue adhesions from a biomaterial perspective

Postoperative adhesions (POA) are one of the main problems suffered by patients and are a common complaint. It is considered to be closely associated with the healing mechanism of damaged tissues. Tissue adhesions accompany other symptoms such as inflammation, pain, and even dyskinesia under certain conditions, compromising the patients' quality of life. On the other hand, common treatments involve high costs, re-surgery or long-term hospital stays. Therefore, alternative approaches need to be formulated so that aforementioned problems can be resolved. To this end, a review of recent advances in this context is imperative. In this review, we have highlighted the mechanism of adhesion formation, advances in common therapeutic approaches, and prospective treatments in preventing tissue adhesions. Based on the literature, it can be determined that the disadvantages of available commercial products in the treatment of tissue adhesion have led researchers to utilize alternative methods for designing anti-adhesive products with different structures such as electrospun fibrous mats, hydrogels, and nanospheres. These studies are on the fast track in producing optimal anti-adhesion materials. We hope that this article can attract attention by showing various mechanisms and solutions involved in adhesion problems and inspire the further development of anti-adhesion biomaterials.

Diltiazem suppresses collagen synthesis and IL-1beta-induced TGF-beta1 production on human peritoneal mesothelial cells

BACKGROUND

After long-term treatment with continuous ambulatory peritoneal dialysis (CAPD), some patients may develop peritoneal fibrosis. Peritoneal mesothelial cells (PMCs) participate in the inflammatory reactions in the peritoneal cavity, and transforming growth factor-beta1 (TGF-beta1) and interleukin-1beta (IL-1beta) are involved in peritoneal fibrosis. Diltiazem is used frequently in patients with CAPD to treat hypertension. The objectives of this study were to examine the effects of diltiazem on collagen- and IL-1beta-induced TGF-beta1 production on human PMCs and the signalling pathway of diltiazem in this induction.

METHODS

Human PMCs were cultured from the enzymatic disaggregation of human omentum. Collagen synthesis was measured by [3H]proline incorporation into pepsin-resistant, salt-precipitated collagen. The expression of collagen I and III, and TGF-beta1 mRNA was evaluated by northern blotting. The production of TGF-beta1 by human PMCs was measured by immunoassay. The changes of intracellular calcium level after adding Fura-2-AM were measured by fluorescence spectrophotometry. Western blotting was used to assess mitogen-activated protein kinase (MAPK) signalling proteins.

RESULTS

We found that diltiazem (<0.2 mM) inhibited collagen I and III mRNA expression and collagen syntheses on a dose-dependent basis. Diltiazem (0.2 mM) suppressed IL-1beta- (5 ng/ml) induced TGF-beta1 production on human PMCs at both the protein and mRNA levels. Diltiazem (0.2 mM) also inhibited IL-1beta- (5 ng/ml) induced collagen I and III mRNA expression. Intracellular calcium levels did not change after the treatment with diltiazem, IL-1beta or both. The IL-1beta-treated human PMCs increased phospho-JNK (stress-activated c-Jun N-terminal kinase) and phospho-p38 MAPK expression, while diltiazem could suppress this phenomenon.

CONCLUSIONS

Diltiazem suppressed collagen synthesis of human PMCs and inhibited IL-1beta-induced TGF-beta1 production on human PMCs. This signalling transduction may be through p38 MAPK and JNK pathways instead of intracellular calcium. These results suggest diltiazem to be a potential therapeutic regimen in preventing peritoneal fibrosis and support further in vivo studies.