Photodynamic therapy and endoscopic mucosal resection as minimally invasive approaches for the treatment of early esophageal tumors: Pre-clinical and clinical experience in Lausanne

Lead Structures for Applications in Photodynamic Therapy. 6. Temoporfin Anti-Inflammatory Conjugates to Target the Tumor Microenvironment for In Vitro PDT

Due to the ongoing development of clinical photodynamic therapy (PDT), the search continues for optimized photosensitizers that can overcome some of the side effects associated with this type of treatment modality. The main protagonists being: post-treatment photosensitivity, due to only limited cellular selectivity and post-treatment tumor regrowth, due to the up-regulation of pro-inflammatory agents within the tumor microenvironment. A photosensitizer that could overcome one or both of these drawbacks would be highly attractive to those engaged in clinical PDT. Certain non-steroidal anti-inflammatory drugs (NSAIDs) when used in combination with PDT have shown to increase the cytotoxicity of the treatment modality by targeting the tumor microenvironment. Temoporfin (m-THPC), the gold standard chlorin-based photosensitizer (PS) since its discovery in the 1980's, has successfully been conjugated to non-steroidal anti-inflammatory compounds, in an attempt to address the issue of post-treatment tumor regrowth. Using a modified Steglich esterification reaction, a library of "iPorphyrins" was successfully synthesized and evaluated for their PDT efficacy.

Temoporfin (Foscan®, 5,10,15,20-tetra(m-hydroxyphenyl)chlorin)--a second-generation photosensitizer

This review traces the development and study of the second-generation photosensitizer 5,10,15,20-tetra(m-hydroxyphenyl)chlorin through to its acceptance and clinical use in modern photodynamic (cancer) therapy. The literature has been covered up to early 2011.

Strength of Esophageal Closure Techniques With and Without Tissue Reinforcement

OBJECTIVES

The purpose of this study was to investigate the effects of esophagotomy closure techniques on the esophageal bursting pressure.

MATERIALS AND METHODS

Altogether, 122 freshly dead sheep esophagi received from the local slaughterhouse were prepared for manual closure. After esophagotomy, the specimens were divided into four groups. An interrupted mucosal suture pattern (n = 30), an interrupted mucosal-submucosal suture pattern (n = 30), an interrupted mucosal-submucosal + over-over continuous muscular suture pattern (n = 32), and an interrupted mucosal-submucosal + reinforcement with a diaphragmatic part with full-thickness interrupted U suture pattern (n = 30) were used for esophagotomy closure; 4-0 silk was used in all specimens. Bursting pressures were measured with a sphygmomanometer.

RESULTS

We found a statistically significant difference among the bursting pressures of all groups (p < 0.001). The bursting pressure values gradually increased from group 1 to group 4 (47.6 +/- 22.7, 86.2 +/- 49.5, 185.4 +/- 53.5, and 226.8 +/- 62.4 mmHg, respectively). Reinforcing the esophageal suture line with tissue significantly increased the bursting pressure compared to the other groups.

CONCLUSIONS

Each layer of the esophagus significantly contributes to strengthening esophageal wall tension with primary esophageal closure, and reinforcement of the esophageal suture with tissue provides an additional significant increase in the bursting pressure of the esophagus.