Is the Intensity of 5-Aminolevulinic Acid–Derived Fluorescence Related to the Light Source?

Kamp, Marcel A.; Knipps, Johannes; Neumann, Lisa Margarete; Mijderwijk, Hendrik-Jan; Dibué-Adjei, Maxine; Steiger, Hans‐Jakob; Slotty, Philipp J.; Rapp, Marion; Cornelius, J.F.; Sabel, Michael

doi:10.1016/j.wneu.2019.07.136

Cited by 12 publications

(5 citation statements)

References 18 publications

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“…5-ALA-induced PpIX is more often detected intracellularly, and to a lesser extent in extracellular fluorescence of metabolically active pathological tissue, as well as in some normal brain areas. This study, along with previous reports, demonstrates that there are multiple variables that affect detection of PpIX and FNa fluorescence intensities, including biological and optical variables (52)(53)(54)(55) that result in the absence of fluorescence in some tumor areas as well as FP staining of the normal brain tissue with both fluorophores.…”

Section: Existing Literature On Combined Use Of 5-ala and Fnasupporting

confidence: 75%

5-aminolevulinic acid, fluorescein sodium, and indocyanine green for glioma margin detection: analysis of operating wide-field and confocal microscopy in glioma models of various grades

Belykh,

Bardonova,

Abramov

et al. 2023

Front. Oncol.

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IntroductionSurgical resection remains the first-line treatment for gliomas. Several fluorescent dyes are currently in use to augment intraoperative tumor visualization, but information on their comparative effectiveness is lacking. We performed systematic assessment of fluorescein sodium (FNa), 5-aminolevulinic acid (5-ALA)–induced protoporphyrin IX (PpIX), and indocyanine green (ICG) fluorescence in various glioma models using advanced fluorescence imaging techniques.MethodsFour glioma models were used: GL261 (high-grade model), GB3 (low-grade model), and an in utero electroporation model with and without red fluorescence protein (IUE +RFP and IUE -RFP, respectively) (intermediate-to-low-grade model). Animals underwent 5-ALA, FNa, and ICG injections and craniectomy. Brain tissue samples underwent fluorescent imaging using a wide-field operative microscope and a benchtop confocal microscope and were submitted for histologic analysis.ResultsOur systematic analysis showed that wide-field imaging of highly malignant gliomas is equally efficient with 5-ALA, FNa, and ICG, although FNa is associated with more false-positive staining of the normal brain. In low-grade gliomas, wide-field imaging cannot detect ICG staining, can detect FNa in only 50% of specimens, and is not sensitive enough for PpIX detection. With confocal imaging of low-intermediate grade glioma models, PpIX outperformed FNa.DiscussionOverall, compared to wide-field imaging, confocal microscopy significantly improved diagnostic accuracy and was better at detecting low concentrations of PpIX and FNa, resulting in improved tumor delineation. Neither PpIX, FNa, nor ICG delineated all tumor boundaries in studied tumor models, which emphasizes the need for novel visualization technologies and molecular probes to guide glioma resection. Simultaneous administration of 5-ALA and FNa with use of cellular-resolution imaging modalities may provide additional information for margin detection and may facilitate maximal glioma resection.

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Section: Existing Literature On Combined Use Of 5-ala and Fnasupporting

confidence: 75%

5-aminolevulinic acid, fluorescein sodium, and indocyanine green for glioma margin detection: analysis of operating wide-field and confocal microscopy in glioma models of various grades

Belykh,

Bardonova,

Abramov

et al. 2023

Front. Oncol.

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“…In a recent paper, it was shown that the intensity of the PpIX fluorescence is related to the light source used, which, according to the authors, could have implications for surgery (19). This is further highlighted by the fact that various surgical microscopes can exhibit "considerably different illumination optical power levels at identical system settings" (20).…”

Section: Discussionmentioning

confidence: 99%

5-Aminolevulinic Acid Multispectral Imaging for the Fluorescence-Guided Resection of Brain Tumors: A Prospective Observational Study

et al. 2020

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Fluorescence-guided surgery with five-aminolevulinic acid (5-ALA) is the state-of-the-art treatment of high-grade gliomas. However, intraoperative visualization of 5-ALA under blue light remains challenging, especially when blood covers the surgical field and thereby fluorescence. To overcome this problem and combine the brightness of visible light with the information delivered with fluorescence, we implemented multispectral fluorescence (MFL) in a surgical microscope, a technique that is able to project both information in real-time. We prospectively examined 25 patients with brain tumors. One patient was operated on two different lesions in the same setting. The tumors comprised: six glioblastomas, four anaplastic astrocytomas, one anaplastic oligodendroglioma, two meningiomas, 11 metastatic tumors, one acoustic neuroma, and one ependymoma. The MFL technique with a real-time overlay of fluorescence and white light was compared intraoperatively to the classic blue filter. All lesions were clearly visible and highlighted from the surrounding tissue. The pseudocolor we chose was green, representing fluorescence, with the surrounding brain tissue remaining in its original color. When blood was covering the surgical field, orientation was easy to maintain. The MFL technique opens the way for precise and clear visualization of fluorescence in real-time under white light. It can be easily used for the resection of all tumors accumulating 5-ALA. Drawbacks of classic PpIX fluorescence such as hidden fluorescence, intraoperative changes could be overcome with the presence of additional white light in MFL technique.

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“…Fermentation broth was centrifuged to obtain the supernatant. After appropriate dilution by DMSO, the fluorescence intensity (excitation at 410 nm, emission at 633 nm) was detected in 96-well plates, and the PPIX concentration was determined from the standard curve [ 38 ].…”

Section: Methodsmentioning

confidence: 99%

Heme biosensor-guided in vivo pathway optimization and directed evolution for efficient biosynthesis of heme

Zhang

Wang

et al. 2023

Biotechnol Biofuels

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Background Heme has attracted much attention because of its wide applications in medicine and food. The products of genes hemBCDEFY convert 5-aminolevulinic acid to protoporphyrin IX (PPIX; the immediate precursor of heme); protoporphyrin ferrochelatase (FECH) inserts Fe2+ into PPIX to generate heme. Biosynthesis of heme is limited by the need for optimized expression levels of multiple genes, complex regulatory mechanisms, and low enzymatic activity; these problems need to be overcome in metabolic engineering to improve heme synthesis. Results We report a heme biosensor-guided screening strategy using the heme-responsive protein HrtR to regulate tcR expression in Escherichia coli, providing a quantifiable link between the intracellular heme concentration and cell survival in selective conditions (i.e., the presence of tetracycline). This system was used for rapid enrichment screening of heme-producing strains from a library with random ribosome binding site (RBS) variants and from a FECH mutant library. Through up to four rounds of iterative evolution, strains with optimal RBS intensities for the combination of hemBCDEFY were screened; we obtained a PPIX titer of 160.8 mg/L, the highest yield yet reported in shaken-flask fermentation. A high-activity FECH variant was obtained from the saturation mutagenesis library. Fed-batch fermentation of strain SH20C, harboring the optimized hemBCDEFY and the FECH mutant, produced 127.6 mg/L of heme. Conclusion We sequentially improved the multigene biosynthesis pathway of PPIX and performed in vivo directed evolution of FECH, based on a heme biosensor, which demonstrated the effectiveness of the heme biosensor-based pathway optimization strategy and broadens our understanding of the mechanism of heme synthesis.

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Is the Intensity of 5-Aminolevulinic Acid–Derived Fluorescence Related to the Light Source?

Cited by 12 publications

References 18 publications

5-aminolevulinic acid, fluorescein sodium, and indocyanine green for glioma margin detection: analysis of operating wide-field and confocal microscopy in glioma models of various grades

5-aminolevulinic acid, fluorescein sodium, and indocyanine green for glioma margin detection: analysis of operating wide-field and confocal microscopy in glioma models of various grades

5-Aminolevulinic Acid Multispectral Imaging for the Fluorescence-Guided Resection of Brain Tumors: A Prospective Observational Study

Heme biosensor-guided in vivo pathway optimization and directed evolution for efficient biosynthesis of heme

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