Protoporphyrin IX

About: Protoporphyrin IX is a research topic. Over the lifetime, 2250 publications have been published within this topic receiving 65544 citations. The topic is also known as: PpIX.

Laser-based spectroscopic methods in tissue characterization

Abstract: Laser-based spectroscopic techniques were developed for tumor tissue characterization utilizing different tumor-localizing substances. In particular, sensitization with the heme precursor delta-amino levulinic acid (ALA) administered topically, orally or intravenously was used for the induction of protoporphyrin IX (PpIX). The autofluorescence as well as the PpIX-related fluorescence signals were monitored, and tumor demarcation functions were calculated for different human malignant tumors, such as tumors in the urinary bladder and the prostatic gland, in the head and neck region, in the breast and in the gastrointestinal tract. In the gastrointestinal tract, colon tumors were examined as well as tumors and dysplastic lesions in the esophagus, where patients with Barrett's esophagus were examined. Time-integrated laser-induced fluorescence measurements utilizing a point monitoring fluorosensor and a multicolor fluorescence imaging system were performed in vivo in patients in different clinical specialities.

Desferrioxamine shows different potentials for enhancing 5-aminolaevulinic acid-based photodynamic therapy in several cutaneous cell lines

Abstract: Protoporphyrin IX (PpIX) is the photosensitizer in 5-aminolaevulinic acid (ALA)-based photodynamic therapy (PDT). Its further bioconversion to heme requires iron and can be suppressed by iron chelators such as desferrioxamine (DFO). To investigate the effectiveness of DFO in enhancing PpIX-based PDT in skin tissue, we selected fibroblasts, HaCat cells and Hep-2 cells as targets co-cultured with ALA, that have different biological characteristics for PpIX conversion. Evaluated interventions included: (1) blank control (no ALA, no DFO); (2) DFO alone; (3) ALA alone; and (4) DFO in combination with ALA. Before photodynamic irradiation, cellular PpIX level and fluorescence were measured. After irradiation, cell death ratio was calculated and morphological changes in the cells were observed. The results showed that the content and photodynamic effects of cellular PpIX presented in the order Hep-2 cells > HaCat cells > fibroblasts, either co-cultured with ALA alone or with ALA plus DFO. DFO was found to have increasing effects on both PpIX level and cell death ratio in the same order. It was found that DFO had different potentials for augmenting ALA-PDT in these cutaneous cell lines. The cells proliferating more rapidly might be more susceptible to enhancement of DFO.

Molecular and Metabolic Mechanisms Underlying Selective 5-Aminolevulinic Acid-Induced Fluorescence in Gliomas.

Abstract: 5-aminolevulinic acid (5-ALA) is a porphyrin precursor in the heme synthesis pathway When supplied exogenously, certain cancers consume 5-ALA and convert it to the fluorogenic metabolite protoporphyrin IX (PpIX), causing tumor-specific tissue fluorescence Preoperative administration of 5-ALA is used to aid neurosurgical resection of high-grade gliomas such as glioblastoma, allowing for increased extent of resection and progression free survival for these patients A subset of gliomas, especially low-grade tumors, do not accumulate PpIX intracellularly or readily fluoresce upon 5-ALA administration, making gross total resection difficult to achieve in diffuse lesions We review existing literature on 5-ALA metabolism and PpIX accumulation to explore potential mechanisms of 5-ALA-induced glioma tissue fluorescence Targeting the heme synthesis pathway and understanding its dysregulation in malignant tissues could aid the development of adjunct therapies to increase intraoperative fluorescence after 5-ALA treatment

Protoporphyrin IX Induces a Necrotic Cell Death in Human THP-1 Macrophages through Activation of Reactive Oxygen Species/c-Jun N-Terminal Protein Kinase Pathway and Opening of Mitochondrial Permeability Transition Pore

Abstract: Background: Protoporphyrin IX (PpIX) and its derivatives are widely used in photodynamic therapy (PDT) to kill cancer cells. Studies showed that the application o