5-Aminolevulinic acid-based fluorescence diagnostics of cervical preinvasive changes

5-aminolevulinic acid combined with sodium ferrous citrate ameliorated lupus nephritis in a mouse chronic graft-versus-host disease model

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by the abnormal activation of immune cells and hypersecretion of autoantibodies and causes irreversible chronic damage, such as lupus nephritis. Chronic graft-versus-host-disease (cGvHD) in mice induced by the injection of parental mouse lymphocytes into F1 hybrids leads to a disease similar to SLE. 5-aminolevulinic acid (5-ALA) is a key progenitor of heme, and its combination with sodium ferrous citrate (SFC) can up-regulate the heme oxygenase (HO-1) expression, resulting in an anti-inflammatory effect. While HO-1 had been reported to be involved in T cell activation and can limit immune-based tissue damage through Treg suppression, which promotes effector response. Thus, we hypothesized that treatment with 5-ALA/SFC could ameliorate lupus nephritis in a mouse cGvHD model. Our results showed that 5-ALA/SFC-treatment significantly decreased the anti-double-stranded DNA (ds-DNA) autoantibodies, blood urea nitrogen (BUN) and creatinine (Cre) levels, reduced kidney inflammatory dendritic cells (DCs) and B cell activation, and increased the regulatory T cells (Tregs) at nine weeks. Furthermore, 5-ALA/SFC suppressed mRNA expression of TNF-α, IL-1β, IFN-γ and markers on DCs. In addition, we also found that 5-ALA/SFC treatment increased the HO-1 expression on donor-derived DCs and Tregs concurrently, increased the number of Tregs, and reduced the population of activated DCs, B cells and CD8+ T cells at three weeks (early stage of the disease). We thus identified a novel role of 5-ALA/SFC for therapeutically improving the symptoms of lupus nephritis in a mouse cGvHD model and expanded the current understanding of how this immunoregulatory agent can be used to generate beneficial immune responses and treat autoimmune disease.

Effects of 5-Aminolevulinic Acid as a Supplement on Animal Performance, Iron Status, and Immune Response in Farm Animals: A Review

Efforts directed toward enhancing animals' productivity are focused on evaluating the effects of non-traditional feed additives that are safer than antibiotics, which have been banned because of their health hazards. Many studies used an amino acid that contributes to heme biosynthesis, known as 5-aminolevulinic acid (5-ALA), to promote the productivity of farm animals. However, these studies demonstrate inconsistent results. In order to develop a clear understanding of the effects of 5-ALA in farm animals, we comprehensively searched PubMed and Web of Science for studies evaluating 5-ALA effects on the performance, iron status, and immune response of different farm animals. The search retrieved 1369 publications, out of which 16 trials were relevant. The 5-ALA-relevant data and methodological attributes of these trials were extracted/evaluated by two independent researchers, based on a set of defined criteria. Samples were comprised of pigs, chickens, and dairy cows. The 5-ALA doses ranged from 2 mg to 1 g/kg of feed, and treatment duration ranged from 10 to 142 days. Overall, 5-ALA improved iron status in most studies and increased white blood cells count in 3 out of 10 studies, in addition to improving animals' cell-mediated immune response following immune stimulation with lipopolysaccharide. Inconsistent findings were reported for growth performance and egg production; however, a combination of 10 mg/kg of 5-ALA with 500 mg/kg of vitamin C promoted the highest egg production. In addition, 5-ALA improved milk protein concentration. In conclusion, 5-ALA can enhance farm animals' iron status and immune response; however, the heterogeneity of the reviewed studies limits the generalizability of the findings. Standard procedures and outcome measures are needed to confirm the benefits of 5-ALA. Attention should also be paid to any adverse effects.

Characterization of plasma-derived protoporphyrin-IX-positive extracellular vesicles following 5-ALA use in patients with malignant glioma

BACKGROUND

Malignant gliomas are rapidly progressive brain tumors with high mortality. Fluorescence guided surgery (FGS) with 5-aminolevulinic acid (5-ALA) provides fluorescent delineation of malignant tissue, which helps achieve maximum safe resection. 5-ALA-based fluorescence is due to preferential accumulation of the fluorophore protoporphyrin-IX (PpIX) in malignant glioma tissue. Additionally, gliomas cells release extracellular vesicles (EVs) which carry biomarkers of disease. Herein, we performed animal and human studies to investigate whether 5-ALA dosed glioma cells, in vitro and in vivo, release PpIX positive EVs in circulation which can be captured and analyzed.

METHODS

We used imaging flow cytometry (IFC) to characterize PpIX-positive EVs released from 5-ALA-dosed glioma cells, glioma-bearing xenograft models, as well as patients with malignant glioma undergoing FGS.

FINDINGS

We first show that glioma cells dosed with 5-ALA release 247-fold higher PpIX positive EVs compared to mock dosed glioma cells. Second, we demonstrate that the plasma of glioma-bearing mice (n = 2) dosed with 5-ALA contain significantly higher levels of circulating PpIX-positive EVs than their pre-dosing background (p = 0.004). Lastly, we also show that the plasma of patients with avidly fluorescent tumors (n = 4) undergoing FGS contain circulating PpIX-positive EVs at levels significantly higher than their pre-dosing background (p = 0.00009) and this rise in signal correlates with enhancing tumor volumes (r 2  = 0.888).

INTERPRETATION

Our findings highlight the potential of plasma-derived PpIX-positive EV-based diagnostics for malignant gliomas, offering a novel liquid biopsy platform for confirming and monitoring tumor status.

High-Throughput Imaging of PPIX Using Confocal Microscopy

Increases in levels of protoporphyrin IX (PPIX; a heme precursor) may be driven by xenobiotic induction of aminolevulinic acid synthase 1 (ALAS1) expression. ALAS1 is the rate-limiting enzyme of heme biosynthesis and may be upregulated to satisfy the increased need for heme in CYP450 enzymes. Therefore, a high-throughput fluorescence spectroscopy method that detects PPIX would enable the screening of drugs that increase ALAS1 through nuclear hormone receptor-mediated induction of transcription that may cause toxicity or even provide utility in the diagnosis or treatment of cancers that have elevated cellular PPIX levels. This chapter describes a high-throughput plate-based imaging technique for determining cellular protoporphyrin levels by using the GE Healthcare InCell 6000 confocal imaging system to detect the presence and location of PPIX in each cell and may be adapted for use with other imaging systems. Laser excitation and a scientific-grade complementary metal oxide semiconductor (CMOS) camera generate short exposure times, decreasing photobleaching in the target cells that may result in inaccurate measurements of PPIX and increasing screening throughput. Nuclear staining was detected by using a laser with 405-nm excitation and 455-nm emission wavelengths, and the presence of PPIX was measured using 405-nm excitation and 706-nm emission wavelengths. Image analysis involving top-hat segmentation on both nuclear and PPIX staining was performed by using the InCell Analyzer Workstation software. This assay may be adapted to screen for PPIX formation, degradation, and transportation effectors. Indeed, the inclusion of PPIX transport inhibition would be expected to further widen the linear range of fluorescence and improve the method.

What should be the goal for future development of colposcopy? Cons and pros of sensitivity and specificity

PURPOSE

To discuss what features of colposcopy should be developed for the future in different settings.

RESULT

There are cons and pros of aiming sensitivity, negative predictive value and specificity and positive predictive value. In case of diagnosis and intervention, methods increasing the specificity and positive predictive value will help to decrease unnecessary interventions. Besides, HPV test is highly sensitive and has a good negative predictive value. It is usually available before colposcopy.

CONCLUSION

Colposcopy can be used in a screening or diagnostic/interventional scenario. Aims to improve sensitivity or specificity may change according to the aim of colposcopy. However, in the presence of highly sensitive tests which are performed before colposcopy, first goal to improve for colposcopy can be specificity and positive predictive value.