Protoporphyrin Concentrations Research Articles

A Low-Cost, Portable, Multi-Cancer Screening Device Based on a Ratio Fluorometry and Signal Correlation Technique.

The autofluorescence of erythrocyte porphyrins has emerged as a potential method for multi-cancer early detection (MCED). With this method's dependence on research-grade spectrofluorometers, significant improvements in instrumentation are necessary to translate its potential into clinical practice, as with any promising medical technology. To fill this gap, in this paper, we present an automated ratio porphyrin analyzer for cancer screening (ARPA-CS), a low-cost, portable, and automated instrument for MCED via the ratio fluorometry of porphyrins. The ARPA-CS aims to facilitate cancer screening in an inexpensive, rapid, non-invasive, and reasonably accurate manner for use in primary clinics or at point of care. To accomplish this, the ARPA-CS uses an ultraviolet-excited optical apparatus for ratio fluorometry that features two photodetectors for detection at 590 and 630 nm. Additionally, it incorporates a synchronous detector for the precision measurement of signals based on the Walsh-ordered Walsh-Hadamard transform (WHT)w and circular shift. To estimate its single-photodetector capability, we established a linear calibration curve for the ARBA-CS exceeding four orders of magnitude with a linearity of up to 0.992 and a low detection limit of 0.296 µg/mL for riboflavin. The ARPA-CS also exhibited excellent repeatability (0.21%) and stability (0.60%). Moreover, the ratio fluorometry of three serially diluted standard solutions of riboflavin yielded a ratio of 0.4, which agrees with that expected based on the known emission spectra of riboflavin. Additionally, the ratio fluorometry of the porphyrin solution yielded a ratio of 49.82, which was ascribed to the predominant concentration of protoporphyrin IX in the brown eggshells, as confirmed in several studies. This study validates this instrument for the ratio fluorometry of porphyrins as a biomarker for MCED. Nevertheless, large and well-designed clinical trials are necessary to further elaborate more on this matter.

Carboxymethyl chitosan-based nanoparticles of acid response for the synergistic anti-tumor effect of PDT and chemotherapy

The combination of multiple anti-tumor methods has shown significant application potential in overcoming the limitations of monotherapy. Photodynamic therapy (PDT) and chemotherapy combination is a promising strategy for reducing drug resistance and side effects. Here, inspired by the acidic environment of tumors, carboxymethyl chitosan-based pH-responsive nanovesicles were developed to co-deliver the chemotherapeutic drug doxorubicin (DOX) and photosensitizer 5-aminolevulinic acid (5-ALA). The in vitro drug release studies revealed that drugs could be responsively released when nanoparticles were triggered by the acidic environment. The controlled-release behavior improved drug retention and reduced the administration time. Our nanoparticles could significantly enhance the killing effect of drugs on tumor cells and increase intracellular levels of reactive oxygen species (ROS) compared to monotherapy, effectively achieving the effects of combined chemotherapy and PDT. The loaded DOX could kill tumor cells and the loaded 5-ALA could enhance the content of protoporphyrin IX (PpIX), resulting in excess ROS production to improve the effects of PDT. In summary, our nanoparticles could co-deliver the drugs and exert synergistical anti-tumor of PDT and chemotherapy by suppressing tumor cell proliferation and facilitating cell apoptosis.

Fluorescence-Guided Surgical Techniques in Adult Diffuse Low-Grade Gliomas: State-of-the-Art and Emerging Techniques: A Systematic Review.

Diffuse low-grade gliomas are infiltrative tumors whose margins are not distinguishable from the adjacent healthy brain parenchyma. The aim was to precisely examine the results provided by the intraoperative use of macroscopic fluorescence in diffuse low-grade gliomas and to describe the new fluorescence-based techniques capable of guiding the resection of low-grade gliomas. Only about 20% and 50% of low-grade gliomas are macroscopically fluorescent after 5-amino-levulinic acid (5-ALA) or fluorescein sodium intake, respectively. However, 5-ALA is helpful for detecting anaplastic foci, and thus choosing the best biopsy targets in diffuse gliomas. Spectroscopic detection of 5-ALA-induced fluorescence can detect very low and non-macroscopically visible concentrations of protoporphyrin IX, a 5-ALA metabolite, and, consequently, has excellent performances for the detection of low-grade gliomas. Moreover, these tumors have a specific spectroscopic signature with two fluorescence emission peaks, which is useful for distinguishing them not only from healthy brain but also from high-grade gliomas. Confocal laser endomicroscopy can generate intraoperative optic biopsies, but its sensitivity remains limited. In the future, the coupled measurement of autofluorescence and induced fluorescence, and the introduction of fluorescence detection technologies providing a wider field of view could result in the development of operator-friendly tools implementable in the operative routine.

Physicochemical, structural and functional properties of low methoxyl pectin‑iron (III) complex and its effect on rats with iron deficiency anemia

Iron deficiency anemia (IDA) is the most common nutritional disease worldwide. In this study, a low methoxyl pectin (LMP)‑iron(III) complex was prepared. The physicochemical and structural properties were characterized by HPSEC, HPIC, CV, FTIR, 1H NMR, XRD, SEM and CD. The results showed that iron increased the molecular weight of the LMP‑iron(III) from 11.50 ± 0.32 to 12.70 ± 0.45 kDa and improved its crystallinity. Moreover, the findings demonstrated that -OH and -COOH groups in LMP coordinate with Fe3+ to form β-FeOOH. The water-holding capacity, emulsion stability, and antioxidant activities of the LMP‑iron(III) were lower than those of LMP. Furthermore, the therapeutic effects of LMP‑iron(III) on IDA were investigated in rats. Following LMP‑iron(III) supplementation, compared with the model group, the administration of LMP‑iron(III) significantly increased the body weight, hemoglobin concentration, and serum iron concentration as well as decreased free erythrocyte protoporphyrin concentration. Therefore, the LMP‑iron(III) can potentially treat IDA in rats experiments, providing a theoretical basis for the development of a promising iron supplement.

Prevalence and predictors of anemia among six-week-old infants in Kwale County, Kenya: A cross-sectional study.

Anemia is a significant public health problem among children worldwide. The etiology of anemia is multifactorial but iron deficiency (ID) is the most common cause of anemia in low- and middle-income countries. ID and anemia in infancy can impair growth and cognitive development. The aim of this study was to determine the prevalence and predictors of anemia among six-week-old infants in Kwale County, Kenya. This cross-sectional study included 424 mother-infant pairs. Structured questionnaires were administered to the mothers to obtain information on socio-demographic variables, maternal characteristics and birth information. Anthropometric data was collected for each child. A heel prick was done to measure hemoglobin and zinc protoporphyrin concentration levels. Chi-square test, bivariate and multivariate regression analyses were done to determine factors associated with anemia. The prevalence of ID, anemia and IDA was 60.4% (95%CI: 55.9-65.2), 21.0% (95%CI: 17.5-25.2) and 15.8% (95%CI: 12.7-19.7) respectively. Bivariate analysis showed that the risk of anemia was significantly higher among male infants (odds ratio (OR) = 2.20 (95%CI: 1.33-3.63), p = 0.002), iron deficient infants (OR = 2.35 (95%CI: 1.39-3.99), p = 0.001) and infants from Msambweni Sub-County (OR = 2.80 (95%CI: 1.40-4.62), p<0.001). Multivariate analysis revealed that odds of anemia were significantly higher in infants born to mothers who did not use iron supplements during pregnancy (adjusted odds ratio (aOR) = 74.01 (95%CI: 2.45-2238.21), p = 0.013 and significantly lower in infants born to mothers with parity ≥ 4 (aOR = 0.05 ((95%CI: 0.00-0.77), p = 0.024). In six-week-old infants in rural Kenya, anemia prevalence was 21.0% with ID accounting for 75.3% of anemia cases. Given the physical and cognitive impairments associated with ID and anemia in early infancy, it may be prudent to re-evaluate the current Kenyan pediatric protocols to include anemia screening and potential treatment of infants less than 6-months of age.

Trends in Blood Lead Levels Quantified by ICP-MS: A Reference Laboratory Retrospective Study.

Exposure to lead may cause severe adverse effects such as anemia, neurologic damage, developmental disorders, and reproductive disorders. Consequently, in 2021, the Centers for Disease Control and Prevention (CDC) reduced its blood lead reference value from 5 µg/dL to 3.5 µg/dL in pediatric patients, 1 to 5 years old. The objective of this study was to perform a retrospective analysis of patient blood lead concentrations reported by ARUP Laboratories to evaluate the frequency of blood lead concentrations greater than 3.5 µg/dL. The analysis of blood lead concentration was performed in venous whole blood specimens using inductively coupled plasma mass spectrometry (ICP-MS). In addition, retrospective data analysis was performed to evaluate zinc protoporphyrin (ZPP) concentrations in adult patients with corresponding lead results, using the lead industrial exposure panel. The analysis for ZPP was performed using quantitative hematofluorometry. Retrospective data analysis identified a decline in blood lead concentrations from 2012 to 2021 for pediatric and adult patients. The calculated nonparametric 95% range for ZPP blood was 15 to 43 μg/dL and the ZPP heme ratio 26 to 74 μmol ZPP/mol heme. Lowering the blood lead reference value (BLRV) to 3.5 μg/dL presents an opportunity for healthcare providers and public health agencies to extend medical or environmental interventions for lead exposure in pediatric patients.

Effect of light intensity in the nest site on eggshell pigmentation in a hole-nesting passerine

Daylight is an important factor necessary for the proper embryonic development of birds, which raises the question, what happens when birds nest in relatively dim sites? The study experimentally tested whether there is a relationship between light conditions at the nesting site and the protoporphyrin-based pigmentation in the eggshell of the Great Tit (Parus major). We hypothesised that at lower light levels, eggs are less pigmented to increase the amount of light reaching the embryo. Our study system consisted of two types of nest boxes: "dark", in which the only source of light was the entrance hole, and "bright", which had two additional side windows. Photographs of clutches taken during the incubation period were used to quantify eggshell pigmentation. Multispectral image analyses were performed to measure variables correlating with protoporphyrin content, such as spot brightness, average spot size, spotting coverage, and spot red chroma. Repeatability analysis indicated that eggshell colouration characteristics were significantly and moderately repeatable between eggs from a single clutch, which suggests that they are under genetic and environmental control. However, none of the pigmentation traits differed significantly between the two types of nest boxes. We speculate about other ecological aspects that might have influenced the observed variability in eggshell pigmentation.

Highly sensitive measurement method for photosensitizers based on dual-excitation laser modulation technique

A dual-excitation laser modulation technique for the sensitive measurement of photosensitizers in tumor is proposed. The technique is based on the difference in optical absorption properties of photosensitizers and biological tissues at 405 nm and 450 nm. The 405 nm and 450 nm laser beams, with the same modulation frequency and 180° phase difference, were coupled into a single fiber simultaneously. A periodic signal with a frequency of 1 kHz was generated in alternating excitation, and was processed by phase sensitive detectors. The weak photosensitizer fluorescence masked by tissue autofluorescence can be effectively separated through the proposed method, so that the final signal intensity is only related to the concentration of photosensitizer. The method with a sensitivity of 0.22 mL/ng was determined by measuring the low concentration of protoporphyrin IX (PpIX) solution, and the detection limit of instrument reached 0.5 ng/mL. The puncturable optical probe with a diameter of 675 µm ensures that PpIX in can be detected with spatial resolution, which was performed in the measurement of PpIX in tumor bearing nude mice.

A comparative study on egg cholesterol contents and eggshell protoporphyrin and biliverdin pigments of different poultry species

This study compared the cholesterol levels and shell pigments (protoporphyrin and biliverdin) of chicken (conventional and organic), quail, pheasant, and goose eggs. The material for the study was chicken (organic system - Lohmann Brown and conventional system - HyLine Brown) eggs, quail (Coturnix coturnix japonica), goose (local), and pheasant (Phasianus colchicus) eggs homogeneously selected with a subjective scoring. High-performance liquid chromatography with photodiode array detection was used to analyze the samples (HPLC-PDA). There were no significant differences in the yolk cholesterol content of eggs between species. Based on mg/g of yolk, different poultry species had comparable amounts of cholesterol. Quail eggshells contained significantly more protoporphyrin (81.92 M/g) than chicken (conventional-organic) and pheasant eggshells (P&amp;lt;0.01), but conventional chicken eggshells contained less protoporphyrin (10.73 M/g) than other species (P&amp;lt;0.01). Biliverdin was found only in the eggshells of quail (2.83 M/g) and pheasant (1.02 M/g) (P&amp;lt;0.01). It was observed that white shelled goose eggs had no detectable pigment. Research is required to elucidate the role of diet, age, stressor, strain, and housing systems on protoporphyrin and biliverdin pigment concentrations and cholesterol in table eggs and breeder eggs production.

Functional Characterization of the Co2+ Transporter AitP in Sinorhizobium meliloti: A New Player in Fe2+ Homeostasis.

Co2+ induces the increase of the labile-Fe pool (LIP) by Fe-S cluster damage, heme synthesis inhibition, and "free" iron import, which affects cell viability. The N2-fixing bacteria, Sinorhizobium meliloti, is a suitable model to determine the roles of Co2+-transporting cation diffusion facilitator exporters (Co-eCDF) in Fe2+ homeostasis because it has a putative member of this subfamily, AitP, and two specific Fe2+-export systems. An insertional mutant of AitP showed Co2+ sensitivity and accumulation, Fe accumulation and hydrogen peroxide sensitivity, but not Fe2+ sensitivity, despite AitP being a bona fide low affinity Fe2+ exporter as demonstrated by the kinetic analyses of Fe2+ uptake into everted membrane vesicles. Suggesting concomitant Fe2+-dependent induced stress, Co2+ sensitivity was increased in strains carrying mutations in AitP and Fe2+ exporters which did not correlate with the Co2+ accumulation. Growth in the presence of sublethal Fe2+ and Co2+ concentrations suggested that free Fe-import might contribute to Co2+ toxicity. Supporting this, Co2+ induced transcription of Fe-import system and genes associated with Fe homeostasis. Analyses of total protoporphyrin content indicates Fe-S cluster attack as the major source for LIP. AitP-mediated Fe2+-export is likely counterbalanced via a nonfutile Fe2+-import pathway. Two lines of evidence support this: (i) an increased hemin uptake in the presence of Co2+ was observed in wild-type (WT) versus AitP mutant, and (ii) hemin reversed the Co2+ sensitivity in the AitP mutant. Thus, the simultaneous detoxification mediated by AitP aids cells to orchestrate an Fe-S cluster salvage response, avoiding the increase in the LIP caused by the disassembly of Fe-S clusters or free iron uptake. IMPORTANCE Cross-talk between iron and cobalt has been long recognized in biological systems. This is due to the capacity of cobalt to interfere with proper iron utilization. Cells can detoxify cobalt by exporting mechanisms involving membrane proteins known as exporters. Highlighting the cross-talk, the capacity of several cobalt exporters to also export iron is emerging. Although biologically less important than Fe2+, Co2+ induces toxicity by promoting intracellular Fe release, which ultimately causes additional toxic effects. In this work, we describe how the rhizobia cells solve this perturbation by clearing Fe through a Co2+ exporter, in order to reestablish intracellular Fe levels by importing nonfree Fe, heme. This piggyback-ride type of transport may aid bacterial cells to survive in free-living conditions where high anthropogenic Co2+ content may be encountered.

Structural characteristics of speckled chicken eggshells and their effect on reproductive performance

Speckles are common on the brown eggshells of chicken eggs, especially for aged hens. They are important as they affect the consumer preference and economic value of eggs. The cause of speckles in eggshells is still unclear. In this study, we verified the difference of eggshell quality between speckled eggs and normal eggs. Structural characteristics of speckled eggshells were investigated using a scanning electron microscope. Results showed no significant difference in the eggshell quality between normal eggs and speckled eggs, except for a lower eggshell color-L value in the latter. More materials deposited between vertical crystal layer and cuticle layer in the speckled shell region, leading to the thicker eggshell than adjacent normal area. The relative content of protoporphyrin IX was significantly higher in the speckled area than in the adjacent normal area of the eggshells. In addition, there was no significant differences in productive and reproductive performance between hens that laid normal eggs or speckled eggs, except for a lower hatchability of the speckled eggs. In conclusion, we infer that the uneven distribution of eggshell pigment protoporphyrin IX leads to the formation of speckled eggs. This is the first study to establish the characteristics and causes of speckled eggshells. Moreover, this study provides novel insights into external egg quality and a foundation for the in-depth study of speckled eggshells.

Fortification of salt with iron and iodine versus fortification of salt with iodine alone for improving iron and iodine status.

Fortification of salt with iron and iodine versus fortification of salt with iodine alone for improving iron and iodine status.

Avian eggshell coloration predicts shell-matrix protoporphyrin content.

Avian eggshell pigmentation may provide information about a female's physiological condition, in particular her state of oxidative balance. Previously we found that female house wrens (Troglodytes aedon Vieillot, 1809) with lighter, less-maculated, and redder ground-colored shells were older and produced heavier offspring than females laying darker, browner eggs. The strong pro-oxidant protoporphyrin is responsible for this species' eggshell pigmentation, so differences in pigmentary coloration may be related to eggshell protoporphyrin content and reflect female oxidative balance and condition during egg-formation. Therefore, we tested the assumption that egg-surface coloration is related to the amount of protoporphyrin in the shell matrix. We analyzed digital photographs of eggs to determine maculation coverage as a measure of the overall ground coloration of the egg and its red-, green-, and blue-channel pixel values. Pigments were then extracted from these same eggs and analyzed using high-performance liquid chromatography. There was a strong, positive relationship between eggshell redness and protoporphyrin content of eggshells, but no relationship between percent maculation and protoporphyrin content. Thus, when older, larger females deposit more protoporphyrin in their eggshells, this may reflect a tolerance for high levels of circulating protoporphyrin or an effective mechanism for off-loading protoporphyrin into the eggshell matrix.

The effect of photobiomodulation therapy of some indices of rats’ blood cells functional state under experimental diabetes mellitus

Background. Diabetes mellitus is a chronic endocrine-metabolic disease caused by an absolute or relative insulin deficiency. During diabetes, there are perfect conditions for the development of oxidative stress: the content of substrates for oxidation increases, the content of natural antioxidants decreases and the activity of antioxidant systems is suppressed. It is known that photobiomodulation therapy produce antioxidant and antihyperglycemic effects. Here we investigated its influence on blood system functioning. Materials and Methods. The study was performed on male Wistar rats. Experimental diabetes mellitus was induced by the intraperitoneal injection of streptozotocin. Leukocyte formula was calculated using blood smears stained by Romanowsky–Giemsa. Catalase activity was determined spectrophotometrically. Affinity of hemoglobin to oxygen was evaluated by spectrophotometric method in Ivanov’s modification by drawing oxygenation curves. The protoporphyrin content in whole blood was measured by analyzing its fluorescence spectra. The content of NO2-, total and inducible NO synthase activity was determined spectrophotometrically. Results. Under the action of photobiomodulation therapy on healthy animals, there was a shift of oxygenation curves to the left and a decrease of P50, whereas under irradiation of rats with diabetes, there was a shift of oxygenation curves to the right and increase in P50 compared to indices in nonirradiated animals. During diabetes, there was a decrease in protoporphyrin content compared to control, but there was a tendency to increase under photobiomodulation. Photobiomodulation therapy of rats with diabetes increased catalase activity in erythrocyte hemolysates. We revealed significant changes in leukocyte formula under photobiomodulation. The total NO synthase activity in leukocytes of rats with diabetes was higher compared to healthy animals, but decreased under the action of photobiomodulation. We found an increase in inducible NO synthase activity in leukocytes of rats with diabetes and in leukocytes of irradiated healthy animals. An increase in NO2- content in leukocytes of rats with diabetes was detected. Under photobiomodulation, NO2- content was significantly lower in rats with diabetes. Conclusion. Photobiomodulation therapy produces a corrective action on blood system during diabetes, in particular, it improves oxygen release from hemoglobin and prevents hypoxia. Simultaneously with the increase in tissue oxygen saturation, a decrease in NO synthase activity and nitrite content along with an increase in catalase activity prevents the development of oxidative stress.

Beyond pigmentation: signs of liver protection during afamelanotide treatment in Swiss patients with erythropoietic protoporphyria, an observational study.

From the 47 Swiss EPP-patients treated at our center since 2006, we included those 38 patients in the current analysis who received at least one afamelanotide dose between 2016 and 2018 and underwent regular laboratory testing before and during the treatment. We compared the means of pretreatment measurements with those during the treatment. Protoporphyrin concentrations dropped from 21.39 ± 11.12 (mean ± SD) before afamelanotide to 16.83 ± 8.24 µmol/L (p < .0001) during treatment. Aspartate aminotransferase decreased from 26.67 ± 13.16 to 22.9 ± 7.76 IU/L (p = .0146). For both entities, patients with higher values showed a more progressive decrease, indicating a risk reduction of EPP-related liver disease. The pre-existing hypochromia and broad mean red-cell distribution width were further augmented under afamelanotide. This was more likely due to an influence of afamelanotide on maturating erythroblasts than due to an exacerbated iron deficiency, as mean zinc-protoporphyrin decreased significantly and ferritin remained unchanged. No serious afamelanotide-related adverse events were observed for a total of 240 treatment years. Our findings point to a protective effect of afamelanotide on erythroblast maturation and protoporphyrin-induced liver injury. Afamelanotide, a skin tanning hormone, may protect patients with erythropoietic protoporphyria not only from skin burns, but also from liver injury associated with the disease. Patients with erythropoietic protoporphyria (EPP), an inherited metabolic disease, suffer from light-induced skin burns and liver injury elicited by the accumulated light sensitizer protoporphyrin. The excess protoporphyrin is produced in red cell precursors in the bone marrow, and it is eliminated from the body via the liver and bile. A high protoporphyrin excretion burden damages the liver cells, the risk for this increases with higher protoporphyrin concentrations. About 20% of EPP patients show some sign of liver injury and 4% develop life-threatening liver dysfunction.Afamelanotide, closely related to natural α-melanocyte stimulating hormone (MSH), induces skin tanning. This effect protects EPP patients from light-induced skin burns as shown in previous studies. We have treated Swiss EPP patients with afamelanotide since 2006, and we regularly perform safety tests of this treatment.Recent in vitro and animal studies demonstrated α-MSH effects other than skin tanning, including an improved synthesis of red blood cell precursors in the bone-marrow and protection of the liver from experimentally induced damage. Until now, it is unknown whether afamelanotide has similar effects in the human organism.To study this question, we analyzed retrospectively the safety laboratory data of 38 Swiss patients, who received at least one dose of afamelanotide from 2016 to 2019. We found that both, the average protoporphyrin concentrations and aspartate aminotransferase, a test for liver function, improved during afamelanotide treatment as compared to before.We concluded that afamelanotide applied to EPP patients to protect them from light-induced skin burns also may reduce their risk of liver injury.

Biomonitoring findings for occupational lead exposure in battery and ceramic tile workers using biochemical markers, alkaline comet assay, and micronucleus test coupled with fluorescence in situ hybridisation.

Manufacture of lead-containing products has long been associated with various health risks. To get an insight into the related genotoxic risks, we conducted a biomonitoring study in 50 exposed workers and 48 matched controls using a battery of endpoints that sensitively detect the extent of genome instability in peripheral blood lymphocytes. The levels of primary DNA damage were estimated with the alkaline comet assay, while cytogenetic abnormalities were determined with the cytokinesis-block micronucleus (CBMN) cytome assay. Additionally, CBMN slides of 20 exposed and 16 control participants were subjected to fluorescence in situ hybridisation (FISH), coupled with pancentromeric probes to establish the incidence of centromere-positive micronuclei, nuclear buds, and nucleoplasmic bridges. Blood lead levels (B-Pb) were measured with atomic absorption spectrometry. To further characterise cumulative effects of occupational exposure, we measured erythrocyte protoporphyrin (EP) concentrations and delta-aminolevulinic acid dehydratase (ALAD) activity in blood. We also assessed the influence of serum folate (S-folate) and vitamin B12 (S-B12) on genome stability. Compared to controls, occupationally exposed workers demonstrated significantly higher B-Pb (298.36±162.07 vs 41.58±23.02), MN frequency (18.71±11.06 vs 8.98±7.50), centromere positive MN (C+ MN) (8.15±1.8 vs 3.69±0.47), and centromere negative MN (C- MN) (14.55±1.80 vs 4.56±0.89). Exposed women had significantly higher comet tail intensity (TI) and length (TL) than control women. Furthermore, workers showed a positive correlation between age and nuclear buds and MN, between MN and years of exposure, and between S-B12 levels and TI and ALAD activity, while a negative correlation was found between TI and B-Pb. These findings suggest that occupational settings in the manufacture of lead-containing products pose significant genotoxic risks, which calls for developing more effective work safety programmes, including periodical monitoring of B-Pb and genetic endpoints.

An in vitro study of the effect of 5-ALA-mediated photodynamic therapy on oral squamous cell carcinoma

BackgroundThe primary aim of this study was to observe the effect of 5-ALA-mediated photodynamic therapy on oral squamous cell carcinoma in vitro.MethodsSCC25 cells were divided into the observation group and the blank control group. Different concentrations of 5-ALA and SCC25 cells were co-incubated for different times, and the concentration of protoporphyrin IX was detected by flow cytometry. SCC25 cells were divided into the 5-ALA group (100 mg/L), the laser irradiation group alone, the 5-ALA plus laser irradiation group, and the blank control group (0 mg/L 5-ALA), and the methyl thiazolyl tetrazolium (MTT) solution method was used (each group was incubated for 4, 8 and 12 h in turn). The cell survival rate was calculated. Using annexin V-fluorescein isothiocyanate/propidium iodide method, the apoptosis of SCC25 cells was detected by flow cytometry.ResultsThe level of protoporphyrin IX in SCC25 cells increased with increased concentrations of 5-ALA and length of incubation. However, after 12 h, protoporphyrin IX level in SCC25 cells was gradually stabilized, and similar effect was obtained with 100 mg/L or more 5-ALA, indicating that the level of protoporphyrin IX in SCC25 cells was determined by 5-ALA concentration and incubation time. 5-ALA plus laser irradiation exerted an inhibitory effect on the growth of SCC25 cells, which was highly associated with drug dose and incubation time. Compared with the control group, laser irradiation alone or 5-ALA alone had no effect on the apoptosis of SCC25 cells. Different concentrations of 5-ALA combined with laser irradiation showed a remarkable effect of apoptosis, and a higher apoptosis rate was seen with higher drug concentrations.Conclusion5-ALA-mediated photodynamic therapy affects the growth of SCC25 cells in vitro, which may provide a new idea for the clinical treatment of oral squamous cell carcinoma.

Key transporters leading to specific protoporphyrin IX accumulation in cancer cell following administration of aminolevulinic acid in photodynamic therapy/diagnosis.

The administration of aminolevulinic acid allow the formation and accumulation of protoporphyrin IX specifically in cancer cells, which then lead to photocytotoxicity following light irradiation. This compound, when accumulated at high levels, could also be used in cancer diagnosis as it would emit red fluorescence when being light irradiated. The concentration of protoporphyrin IX is pivotal in ensuring the effectiveness of the therapy. Studies have been carried out and showed the importance of various transporters in regulating the amount of these substrates by controlling the transport of various related metabolites in and out of the cell. There are many transporters involved and their expression levels are dependent on various factors, such as oxygen availability and iron ions. It is also important to note that these transporters may also have different expression levels depending on their organ. Understanding the mechanisms and the roles of these transporters are essential to ensure maximum accumulation of protoporphyrin IX, leading to higher efficiency in photodynamic therapy/diagnosis. In this review, we would like to discuss the roles of various transporters in protoporphyrin IX accumulation and how their involvement directly affect cancerous microenvironment.

Protoporphyrin IX copolymer with poly(ethylene glycol) methacrylate and its thermoresponsive properties

Porphyrins and their derivatives have been widely used in catalysis, energy conversion, photonics, and biomedicine; however, their use in biological applications is restricted by their limited solubility in aqueous systems. We have prepared a water-soluble copolymer containing moieties of naturally occurring protoporphyrin IX using direct copolymerization of a poly(ethylene glycol) (PEG) methacrylate monomer with protoporphyrin IX via free-radical polymerization. The content of protoporphyrin IX in the copolymer was determined by 1H NMR and UV–vis absorption spectroscopies. Their solution properties and the photostability of the protoporphyrin IX moiety in the copolymer provide direct evidence of the covalent incorporation of protoporphyrin IX within the copolymer. The copolymer showed a reversible phase transition in aqueous solution due to the lower critical solution temperature (LCST). The phase transition temperature varies with the pH of the solutions because of the protonation of the carboxylic acid groups. This copolymer may be useful as an alternative thermoresponsive material for biomedical applications.

Trends in erythrocyte protoporphyrin IX concentration by age, sex and season among patients with erythropoietic protoporphyria-20 years of follow-up.

Erythropoietic protoporphyria (EPP) is an inherited disorder leading to an increased concentration of the photoactive protoporphyrin IX (PpIX) in erythrocytes. Upon photoactivation in the dermal blood vessels and release to the skin, it causes painful skin symptoms when illuminated, depending on PpIX concentration. The present study aimed to investigate if erythrocyte PpIX concentration changes with age in patients with EPP. In addition, we tested gender differences and seasonal variation in erythrocyte PpIX concentration. 53 EPP patients aged 0-90 years were included in this retrospective observational study. A total of 751 blood samples were routinely analyzed for erythrocyte PpIX between 2000 and 2020. Trends in erythrocyte protoporphyrin IX concentration depending on age, sex and season were investigated. Erythrocyte PpIX levels increased during childhood and youth (median annual increase of 2.7 μmol/L) to reach a stable level in adults though, with a decrease in concentration of about 8% in summer. On average the PpIX level was higher in men (mean of 56 μmol/L, range: 6-139) than women (mean of 38 μmol/L, range: 6-82). We hope that our results can contribute to finding a physiological explanation for the changes in erythrocyte PpIX observed throughout the lives of patients with EPP.