Biodistribution and toxicity assessment of intratumorally injected arginine-glycine-aspartic acid peptide conjugated to CdSe/ZnS quantum dots in mice bearing pancreatic neoplasm.
Chem Biol Interact. 2018 Jun 14;:
Authors: Li MM, Cao J, Yang JC, Shen YJ, Cai XL, Chen YW, Qu CY, Zhang Y, Shen F, Zhou M, Xu LM
Quantum dots (QDs) conjugated with arginine-glycine-aspartic acid (RGD) peptides (which are integrin antagonists) are novel nanomaterials with the unique optical property of high molar extinction coefficient, and they have potential utility as photosensitizers in photodynamic therapy (PDT). Our group previously demonstrated significant benefits of using PDT with QD-RGD on pancreatic tumor cells. This study aimed to evaluate the biodistribution and toxicity of QD-RGD in mice prior to in vivo application. Mice with pancreatic neoplasms were intratumorally injected with varying doses of QD-RGD, and the biodistribution 0-24 h post injection was compared to that in control mice (intravenously injected with unconjugated QD). Various tissue samples were collected for toxicity analyses, which included inductively coupled plasma mass spectrometry (ICP-MS) to assess Cd2+ concentrations and hematoxylin-eosin staining for histopathological examination. Fluorescent imaging revealed relatively sufficient radiant efficiency in mice under specific conditions. The ICP-MS and HE data showed no significant signs of necrosis due to Cd2+ release by QDs. The mice survived well and had no apparent weakness or weight loss during the 4 weeks post injection. These findings provide novel insights into the biodistribution of QD-RGD and encourage profound in vivo studies regardless of safety concerns. These findings alleviate safety concerns and provide novel insights into the biodistribution of QD-RGD, offering a solid foundation for comprehensive in vivo studies.
PMID: 29908985 [PubMed - as supplied by publisher]
Effects of Methylene Blue-mediated Photodynamic Therapy on a Mouse Model of Squamous Cell Carcinoma and Normal Skin.
Photodiagnosis Photodyn Ther. 2018 Jun 14;:
Authors: da Silva AP, Neves CL, Dos Anjos Silva E, Portela TCL, Iunes RS, Cogliati B, Severino D, da Silva Baptista M, Dagli MLZ, Blazquez FJH, da Silva JRMC
BACKGROUND: Photodynamic therapy is used to treat a variety of cancers and skin diseases by inducing apoptosis, necrosis, immune system activation, and/or vascular damage. Here, we describe the effects of a single photodynamic therapy session using methylene blue on a mouse model of squamous cell carcinoma and normal skin.
METHODS: The photodynamic therapy protocol comprised application of a 1% methylene blue solution, followed by irradiation with a diode laser for 15 min at 74 mW/cm2, for a total dose of 100 J/cm2. Morphological changes, cell proliferation, apoptosis, collagen quantity, immune system activity, and blood vessel number were analyzed 24 h and 15 days after photodynamic therapy.
RESULTS: In the squamous cell carcinoma group, photodynamic therapy reduced tumor size and cell proliferation and raised cytokine levels. In normal skin, it decreased cell proliferation and collagen quantity and increased apoptosis and blood vessel numbers.
CONCLUSIONS: The effects of photodynamic therapy were greater on normal skin than squamous cell carcinoma tissues. The reduced epithelial thickness and keratinization of the former are factors that contribute to the efficacy of this treatment. Adjustments to the treatment protocol are necessary to potentiate the effects for squamous cell carcinoma therapy.
PMID: 29908976 [PubMed - as supplied by publisher]
Herbal sun protection agents: Human studies.
Clin Dermatol. 2018 May - Jun;36(3):369-375
Authors: Rabinovich L, Kazlouskaya V
Topical sunscreens are the mainstay for protection from ultraviolet (UV) radiation. With skin cancer rates on the rise and great interest in reversing or preventing the effects of photoaging, new molecules with potential to defend against UV damage have received a great deal of attention. Specifically, there is a growing interest in herbal substances that offer protection against the damaging effects of UV rays. Herbal substances may work as adsorbents of the UV rays and antioxidants and potentially have few side effects. Many of them have shown the potential to protect from UV rays in in vitro studies and animal models; however, only a limited number of human studies were conducted which we discuss in the current review. Among the most studied herbal substances that have proven photoprotective activity are green tea extract, carotenoids, and Polypodium leucotomos extract (PLE). They have been shown to increase minimal erythema dose and improve signs of photodamage. PLE has been shown to be helpful in holistic treatment of several conditions, including polymorphous light eruption, solar urticaria, and melasma; it also may be used as an adjuvant to the UVB treatment of vitiligo and photodynamic therapy of actinic keratosis.
PMID: 29908579 [PubMed - in process]