Dressing and undressing MOF nanophotosensitizers to manipulate phototoxicity for precise therapy of tumors.

Photodynamic therapy (PDT) is a clinically approved treatment for tumors, and it relies on the phototoxicity of photosensitizers by producing reactive oxygen species (ROS) to destroy cancer cells under light irradiation. However, such phototoxicity is a double-edged sword, which is also harmful to normal tissues. To manipulate phototoxicity and improve the therapy effect, herein we have proposed a dressing-undressing strategy for de-activating and re-activating therapy functions of photosensitizer nanoparticles. One kind of metal organic framework (PCN-224), which is composed of Zr(IV) cation and tetrakis (4-carboxyphenyl) porphyrin (TCPP), has been prepared as a model of photosensitizer, and it has size of ∼70 nm. These PCN-224 nanoparticles are subsequently coated with a mesoporous organic silica (MOS) shell containing tetrasulfide bonds (-S-S-S-S-), realizing the dressing of PCN-224. MOS shell has the thickness of ∼20 nm and thus can block 1O2 (diffusion distance: <10 nm), deactivating the phototoxicity and preventing the damage to skin and eyes. Furthermore, PCN-224@MOS can be used to load chemotherapy drug (DOX·HCl). When PCN-224@MOS-DOX are mixed with glutathione (GSH), MOS shell with -S-S-S-S- bonds can be reduced by GSH and then be decomposed, which results in the undressing and then confers the exposure of PCN-224 with good PDT function as well as the release of DOX. When PCN-224@MOS-DOX dispersion is injected into the mice and accumulated in the tumor, endogenous GSH also confers the undressing of PCN-224@MOS-DOX, realizing the in-situ activation of PDT and chemotherapy for tumor. Therefore, the present study not only demonstrates a general dressing-undressing strategy for manipulating phototoxicity of photosensitizers, but also provide some insights for precise therapy of tumors without side-effects. STATEMENT OF SIGNIFICANCE: Photosensitizers can generate reactive oxygen species (ROS) under light radiation to destroy cancer cells. However, this phototoxicity is a double-edged sword and also harmful to normal tissues such as the skin and eyes. To control phototoxicity and improve therapeutic efficacy, we prepared a PCN-224@MOS-DOX nanoplatform and proposed a dressing and undressing strategy to deactivate and reactivate the therapeutic function of the photosensitizer nanoparticles. The MOS shell can block the diffusion of 1O2, eliminate phototoxicity, and prevent damage to the skin and eyes. When injected into mice and accumulated in tumors, PCN-224@MOS-DOX dispersions are endowed with an endogenous GSH-driven undressing effect, achieving in situ activation of PDT and tumor chemotherapy.

Light/glutathione-ignited nanobombs integrating azo and tetrasulfide bonds for multimodal therapy of colorectal cancer.

Reactive chemical bonds are associated with the generation of therapeutic radicals and gases under internal-external stimuli, which are highly attractive for cancer treatments. However, designing multifunctional nanostructures that incorporate multiple chemical bonds remains a significant challenge. Herein, novel core-shell nanobombs integrating azo (NN) and tetrasulfide bonds (SSSS) have been constructed with sensitive ignition by both near-infrared (NIR) laser and tumor microenvironments (TME) for treating colorectal tumors. The nanobombs (GNR/AIPH@MON@PVP, GAMP) were prepared by the in-situ growth of tetrasulfide-contained mesoporous organosilica nanoshell (MON) on gold nanorods (GNR) as the photothermal initiator, the load of azo compound (AIPH) as the radical producer and polymer modification. Upon NIR irradiation, the GNR core exhibits stable and high photothermal effects because of the passivation of the MON shell, leading to the thermal ablation of cancer cells. Simultaneously, the local hyperthermia ignites AIPH to release alkyl radicals to cause extensive oxidative stress without oxygen dependence. Moreover, the MON shell can be gradually decomposed in a reduced environment and release therapeutic H2S gas because of the cleavage of SSSS bonds by the glutathione (GSH) overexpressed in TME, causing mitochondrial injury. Owing to multifunctional functions, the GAMP significantly inhibits the growth rate of tumors upon NIR irradiation and achieves the highest efficacy among treatments. Therefore, this study presents activatable nanoagents containing multiple chemical bonds and provides insights into developing comprehensive antitumor strategies.

Application of a modified lateral thoracic artery perforator flap in partial breast defects.

Background: Breast cancer has become the most frequently diagnosed cancer in the world. Detection at an early stage, frequently allows women to benefit from breast conserving surgery. However, some patients are not satisfied with the breast shape after breast-conserving surgery, and autologous tissue flaps are needed to fill the defect in the resection area. The modified lateral thoracic artery perforator (LTAP) flap isn't one of the commonly used flaps in breast surgery and has the advantages of a reliable blood supply, simple operation and few postoperative complications. In this study, we aimed to evaluate the feasibility and effectiveness of a modified LTAP flap for repairing partial breast defects after breast-conserving surgery. Methods: In this study, we retrospectively analyzed the clinical data of 126 patients treated with LTAP flaps to repair local breast defects at Affiliated Hospital of Guangdong Medical University between January 2020 and June 2021. Data were collected on the demographic characteristics of these patients, tumor size and location, type of axillary lymph node surgery, availability of adjuvant chemotherapy and radiotherapy, and postoperative complications. Results: The median weight of the tumor specimen was 185 g (range, 170-320 g), and this glandular tissue accounted for 30% to 40% of the total breast volume. The average flap size was 10.5 cm ×2.5 cm (length range, 8-15 cm, width range: 2-4 cm). The minimum follow-up time was 6 months, with an average of 10 months (range, 6-22 months). The mean operative time was 130 minutes (range: 90-180 minutes), and the mean hospital stay was 3 days (range, 2-5 days). All modified LTAP flaps survived completely without donor site complications. None of the patients required revision surgery on the postoperative breast. Conclusions: The modified LTAP flap is a reliable method for repairing partial breast defects after breast-conserving surgery. It has the advantages of a simple operation, a reliable blood supply, fewer postoperative complications, and a high flap survival rate. It is especially suitable for Asian women with small breast volumes and can achieve good breast contouring effects.

Efficacy of Dexamethasone intravitreal implant in treating non-arteritic anterior ischemic optic neuropathy / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To explore the therapeutic effects and safety of dexamethasone intravitreal implant(DEX)on non-arteritic anterior ischemic optic neuropathy(NAION), and responses to the different course of disease.<p>METHODS: Totally 70 patients(70 eyes)in the First Affiliated Hospital of Zhengzhou University diagnosed with NAION from January 2018 to December 2020 were obtained retrospectively as combination treatment group and routine treatment group. 35 patients(35 eyes)in each group received usual care(methylprednisolne pluse therapy, microcirculation improvement and neurotrophic treatment), and combination treatment group also received a dexamethasone intravitreal implant. The best corrected visual acuity(BCVA), mean damage(MD)and pattern standard deviation(PSD)of the visual field, mean thickness of the retinal nerve fiber layer(RNFL)and intraocular pressure(IOP)were compared between the two groups, and two groups with a different course of disease before and 3mo after treatment.<p>RESULTS: BCVA and MD improved in both groups at 3mo after treatment(<i>P</i><0.05). The PSD in the combination treatment group was not significantly different before and after treatment(<i>P</i>>0.05). The PSD at 3mo after treatment in the routine treatment group was worse than before treatment(<i>P</i><0.05). BCVA, MD, and PSD in the combination treatment group had better improvement than in the routine treatment group at 3mo after treatment(<i>P</i><0.05). Visual acuity improvement rate in the combination treatment group was higher than in the routine treatment group at 3mo after treatment(<i>P</i><0.05). There was no obvious difference in RNFL thickness between the two groups(<i>P</i>>0.05). BCVA, PSD and effective rate in the combination treatment group had better improvement than in the routine treatment group in disease course ≤ 15d at 3mo after treatment(<i>P</i><0.05), and no apparent difference in the group of disease course > 15d(<i>P</i>>0.05). There was a mild and controllable increase in IOP in the combination treatment group compared to routine treatment group.<p>CONCLUSION: Dexamethasone intravitreal implant can promote BCVA and the recovery of visual function for the long term. It is deemed safe and effective in treating NAION, with better therapeutic effects within 2wk after onset.