A Genetically Encoded Fluorescent Heme Sensor Detects Free Heme in Plants.

Heme is produced in plants via a plastid-localized metabolic pathway and is subsequently distributed to all cellular compartments. In addition to covalently and non-covalently bound heme, a comparatively small amount of free heme that is not associated with protein is available for incorporation into heme-dependent proteins in all subcellular compartments and for regulatory purposes. This "labile" fraction may also be toxic. To date, the distribution of the free heme pool in plant cells remains poorly understood. Several fluorescence-based methods for the quantification of intracellular free heme have been described. For this study, we used the previously described genetically encoded heme sensor 1 (HS1) to measure the relative amounts of heme in different plant subcellular compartments. In a proof of concept, we manipulated heme content using a range of biochemical and genetic approaches and verified the utility of HS1 in different cellular compartments of Arabidopsis (Arabidopsis thaliana) and tobacco (N. tabacum and N. benthamiana) plants transformed either transiently or stably with HS1 and HS1(M7A), a variant with lower affinity for heme. This approach makes it possible to trace the distribution and dynamics of free heme and provides relevant information about its mobilization. The application of these heme sensors will create opportunities to explore and validate the importance of free heme in plant cells and to identify mutants that alter the subcellular allocation of free heme.

Succinyl-CoA-based energy metabolism dysfunction in chronic heart failure.

Heart failure (HF) is a leading cause of death and repeated hospitalizations and often involves cardiac mitochondrial dysfunction. However, the underlying mechanisms largely remain elusive. Here, using a mouse model in which myocardial infarction (MI) was induced by coronary artery ligation, we show the metabolic basis of mitochondrial dysfunction in chronic HF. Four weeks after ligation, MI mice showed a significant decrease in myocardial succinyl-CoA levels, and this decrease impaired the mitochondrial oxidative phosphorylation (OXPHOS) capacity. Heme synthesis and ketolysis, and protein levels of several enzymes consuming succinyl-CoA in these events, were increased in MI mice, while enzymes synthesizing succinyl-CoA from α-ketoglutarate and glutamate were also increased. Furthermore, the ADP-specific subunit of succinyl-CoA synthase was reduced, while its GDP-specific subunit was almost unchanged. Administration of 5-aminolevulinic acid, an intermediate in the pathway from succinyl-CoA to heme synthesis, appreciably restored succinyl-CoA levels and OXPHOS capacity and prevented HF progression in MI mice. Previous reports also suggested the presence of succinyl-CoA metabolism abnormalities in cardiac muscles of HF patients. Our results identified that changes in succinyl-CoA usage in different metabolisms of the mitochondrial energy production system is characteristic to chronic HF, and although similar alterations are known to occur in healthy conditions, such as during strenuous exercise, they may often occur irreversibly in chronic HF leading to a decrease in succinyl-CoA. Consequently, nutritional interventions compensating the succinyl-CoA consumption are expected to be promising strategies to treat HF.

ALA Promotes Sucrose Accumulation in Early Peach Fruit by Regulating SPS Activity.

5-Aminolevulinic acid (ALA), as a novel plant growth regulator, is a critical precursor for the biosynthesis of porphyrin compounds in all organisms. Many studies have reported that exogenous ALA treatment could improve fruit sweetness. However, the mechanism by which ALA promotes the increase in sugar content in fruit remains unclear. In this study, we found that ALA significantly promoted sucrose accumulation and SPS (sucrose phosphate synthase) activity in peach fruit. At 14, 28, 42, 50 and 60 days after ALA treatment, sucrose content of fruit was increased by 23%, 43%, 37%, 40% and 16%, respectively, compared with control treatment, and SPS enzyme activity was increased by 21%, 28%, 47%, 37% and 29%, respectively. Correlation analysis showed that the sucrose content of peach fruit under ALA treatment was significantly positively correlated with SPS activity. Subsequently, bioinformatics was used to identify SPS gene family members in peach fruit, and it was found that there were four members of the PpSPS gene family, distributed on chromosomes 1, 7 and 8, named PpSPS1, PpSPS2, PpSPS3 and PpSPS4, respectively. The results of qRT-PCR showed that PpSPS2 and PpSPS3 were highly expressed in response to ALA during fruit development, and the expression of PpSPS2 was positively correlated with SPS activity and sucrose accumulation in peach fruit. The results of tobacco subcellular localization showed that PpSPS2 was mainly distributed in the cytoplasm and nucleus, while PpSPS3 was mainly distributed in the nucleus. The results of this study will lay the foundation for further study on the functions of PpSPS and the regulation of sugar metabolism during the development and ripening of peach fruit by ALA.

5-Aminolevulinic acid-mediated photodynamic therapy in combination with kinase inhibitor lapatinib enhances glioblastoma cell death.

5-Aminolevulinic acid (ALA) is an intraoperative imaging agent approved for protoporphyrin IX (PpIX) fluorescence-guided resection of glioblastoma (GBM). It is currently under clinical evaluation for photodynamic therapy (PDT) after the completion of GBM surgery. We previously showed that lapatinib, a clinical kinase inhibitor of epidermal growth factor receptor 1 & 2 (EGFR and HER2), enhanced PpIX fluorescence in a panel of GBM cell lines by blocking ABCG2 (ATP-binding cassette super-family G member 2)-mediated PpIX efflux, which suggests its potential for improving ALA for GBM surgery and PDT. Here we show that lapatinib enhanced PDT-induced cytotoxicity by promoting GBM cell death with the induction of apoptosis followed by necrosis. While the induction of tumor cell apoptosis was massive and rapid in the H4 cell line with no detectable Bcl-2 and a low level of Bcl-xL, it was delayed and much less in extent in A172, U-87 and U-118 cell lines with higher levels of pro-survival Bcl-2 family proteins. Lapatinib treatment alone neither reduced GBM cell viability nor had any significant effect on EGFR downstream signaling. Its enhancement of ALA-PDT was largely due to the increase of intracellular PpIX particularly in the mitochondria, resulting in the activation of mitochondria-mediated apoptosis in H4 cells. Our present study demonstrates that lapatinib inhibits ABCG2-mediated PpIX efflux and sensitizes GBM cells to ALA-PDT by inducing tumor cell death.

AGA Clinical Practice Update on Diagnosis and Management of Acute Hepatic Porphyrias: Expert Review.

DESCRIPTION: The acute hepatic porphyrias (AHP) are rare, inborn errors of heme-metabolism and include acute intermittent porphyria, hereditary coproporphyria, variegate porphyria, and porphyria due to severe deficiency of 5-aminolevulinic acid dehydratase. Acute intermittent porphyria is the most common type of AHP, with an estimated prevalence of patients with symptoms of approximately 1 in 100,000. The major clinical presentation involves attacks of severe pain, usually abdominal and generalized, without peritoneal signs or abnormalities on cross-sectional imaging. Acute attacks occur mainly in women in their childbearing years. AHP should be considered in the evaluation of all patients, and especially women aged 15-50 years with recurrent severe abdominal pain not ascribable to common causes. The screening tests of choice include random urine porphobilinogen and δ-aminolevulinic acid corrected to creatinine. All patients with elevations in urinary porphobilinogen and/or δ-aminolevulinic acid should initially be presumed to have AHP. The cornerstones of management include discontinuation of porphyrinogenic drugs and chemicals, administration of oral or intravenous dextrose and intravenous hemin, and use of analgesics and antiemetics. Diagnosis of AHP type can be confirmed after initial treatment by genetic testing for pathogenic variants in HMBS, CPOX, PPOX, and ALAD genes. AHP is also associated with chronic symptoms and long-term risk of systemic arterial hypertension, chronic renal and liver disease, and hepatocellular carcinoma. Patients who have recurrent acute attacks (4 or more per year) should be considered for prophylactic therapy with intravenous hemin or subcutaneous givosiran. Liver transplantation is curative and reserved for patients with intractable symptoms who have failed other treatment options. METHODS: This expert review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. These Best Practice Advice (BPA) statements were drawn from a review of the published literature and from expert opinion. Because systematic reviews were not performed, these BPA statements do not carry formal ratings of the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Women aged 15-50 years with unexplained, recurrent severe abdominal pain without a clear etiology after an initial workup should be considered for screening for an AHP. BEST PRACTICE ADVICE 2: Initial diagnosis of AHP should be made by biochemical testing measuring δ-aminolevulinic acid, porphobilinogen, and creatinine on a random urine sample. BEST PRACTICE ADVICE 3: Genetic testing should be used to confirm the diagnosis of AHP in patients with positive biochemical testing. BEST PRACTICE ADVICE 4: Acute attacks of AHP that are severe enough to require hospital admission should be treated with intravenous hemin, given daily, preferably into a high-flow central vein. BEST PRACTICE ADVICE 5: In addition to intravenous hemin, management of acute attacks of AHP should include pain control, antiemetics, management of systemic arterial hypertension, tachycardia, and hyponatremia, and hypomagnesemia, if present. BEST PRACTICE ADVICE 6: Patients should be counseled to avoid identifiable triggers that may precipitate acute attacks, such as alcohol and porphyrinogenic medications. BEST PRACTICE ADVICE 7: Prophylactic heme therapy or givosiran, administered in an outpatient setting, should be considered in patients with recurrent attacks (4 or more per year). BEST PRACTICE ADVICE 8: Liver transplantation for AHP should be limited to patients with intractable symptoms and significantly decreased quality of life who are refractory to pharmacotherapy. BEST PRACTICE ADVICE 9: Patients with AHP should be monitored annually for liver disease. BEST PRACTICE ADVICE 10: Patients with AHP, regardless of the severity of symptoms, should undergo surveillance for hepatocellular carcinoma, beginning at age 50 years, with liver ultrasound every 6 months. BEST PRACTICE ADVICE 11: Patients with AHP on treatment should undergo surveillance for chronic kidney disease annually with serum creatinine and estimated glomerular filtration rate. BEST PRACTICE ADVICE 12: Patients should be counseled on the chronic and long-term complications of AHP, including neuropathy, chronic kidney disease, hypertension, and hepatocellular carcinoma, and need for long-term monitoring.

Modularized Engineering of Shewanella oneidensis MR-1 for Efficient and Directional Synthesis of 5-Aminolevulinic Acid.

Shewanella oneidensis MR-1 has found widespread applications in pollutant transformation and bioenergy production, closely tied to its outstanding heme synthesis capabilities. However, this significant biosynthetic potential is still unexploited so far. Here, we turned this bacterium into a highly-efficient bio-factory for green synthesis of 5-Aminolevulinic Acid (5-ALA), an important chemical for broad applications in agriculture, medicine, and the food industries. The native C5 pathway genes of S. oneidensis was employed, together with the introduction of foreign anti-oxidation module, to establish the 5-ALA production module, resulting 87-fold higher 5-ALA yield and drastically enhanced tolerance than the wild type. Furthermore, the metabolic flux was regulated by using CRISPR interference and base editing techniques to suppress the competitive pathways to further improve the 5-ALA titer. The engineered strain exhibited 123-fold higher 5-ALA production capability than the wild type. This study not only provides an appealing new route for 5-ALA biosynthesis, but also presents a multi-dimensional modularized engineering strategy to broaden the application scope of S. oneidensis.

A novel tetratricopeptide-repeat protein, TTP1, forms complexes with glutamyl-tRNA reductase and protochlorophyllide oxidoreductase during tetrapyrrole biosynthesis.

The biosynthesis of the tetrapyrrole end-products chlorophyll and heme depends on a multifaceted control mechanism that acts primarily at the post-translational level upon the rate-limiting step of 5-aminolevulinic acid synthesis and upon light-dependent protochlorophyllide oxidoreductase (POR). These regulatory processes require auxiliary factors that modulate the activity, stability, complex formation, and subplastidal localization of the relevant proteins. Together, they ensure optimal metabolic flow during the day and at night. As an Arabidopsis homolog of the POR-interacting tetratricopeptide-repeat protein (Pitt) first reported in Synechocystis, we characterize tetrapyrrole biosynthesis-regulating tetratricopeptide-repeat protein1 (TTP1). TTP1 is a plastid-localized, membrane-bound factor that interacts with POR, the Mg protoporphyrin monomethylester cyclase CHL27, glutamyl-tRNA reductase (GluTR), GluTR-binding protein, and FLUORESCENCE IN BLUE LIGHT. Lack of TTP1 leads to accumulation of GluTR, enhanced 5-aminolevulinic acid synthesis and lower levels of POR. Knockout mutants show enhanced sensitivity to reactive oxygen species and a slower greening of etiolated seedlings. Based on our studies, the interaction of TTP1 with GluTR and POR does not directly inhibit their enzymatic activity and contribute to the control of 5-aminolevulinic acid synthesis. Instead, we propose that TTP1 sequesters a fraction of these proteins on the thylakoid membrane, and contributes to their stability.

Evaluation of ALA-capped silver, copper, and silver-copper nanoparticles for controlling fungal plant pathogens.

Phytopathogenic fungi significantly threaten global food security, causing substantial yield and quality losses. Sustainable solutions are urgently needed to combat these agricultural pathogens. This study explored the potential of silver (Ag), copper (Cu), and combined Ag/Cu nanoparticles capped with aminolevulinic acid (ALA) as antifungal agents. The nanoparticles (ALAAg, ALACu, and ALAAgCu) were synthesized via photoreduction and characterized using various techniques (UV-Vis, TEM, XRD, Zeta potential). Their antifungal activity against four key plant pathogens (Alternaria grandis, Colletotrichum truncatum, Corynespora cassiicola, and Fusarium oxysporum) was evaluated using poisoned food techniques. Notably, ALAAgCuNPs demonstrated superior antifungal activity compared to a conventional fungicide against two fungal strains. Even at lower concentrations, ALAAgCuNPs exhibited fungistatic effects comparable to those of the control. These promising results suggest the potential of ALAAgCu NPs as a broad-spectrum, potentially eco-friendly alternative for fungal control in plants and seeds. This approach is crucial for ensuring crop health, harvest quality, and food safety.

A comprehensive review on the recent advances for 5-aminolevulinic acid production by the engineered bacteria.

5-Aminolevulinic acid (5-ALA) is a non-proteinogenic amino acid essential for synthesizing tetrapyrrole compounds, including heme, chlorophyll, cytochrome, and vitamin B12. As a plant growth regulator, 5-ALA is extensively used in agriculture to enhance crop yield and quality. The complexity and low yield of chemical synthesis methods have led to significant interest in the microbial synthesis of 5-ALA. Advanced strategies, including the: enhancement of precursor and cofactor supply, compartmentalization of key enzymes, product transporters engineering, by-product formation reduction, and biosensor-based dynamic regulation, have been implemented in bacteria for 5-ALA production, significantly advancing its industrialization. This article offers a comprehensive review of recent developments in 5-ALA production using engineered bacteria and presents new insights to propel the field forward.

Tumor Cell Membrane-Encapsulated MLA Solid Lipid Nanoparticles for Targeted Diagnosis and Radiosensitization Therapy of Cutaneous Squamous Cell Carcinoma.

Squamous cell carcinoma (SCC) is a common nonmelanoma skin cancer. Radiotherapy plays an integral role in treating SCC due to its characteristics, such as diminished intercellular adhesion, heightened cell migration and invasion capabilities, and immune evasion. These problems lead to inaccurate tumor boundary positioning and radiotherapy tolerance in SCC treatment. Thus, accurate localization and enhanced radiotherapy sensitivity are imperative for effective SCC treatment. To address the existing limitations in SCC therapy, we developed monoglyceride solid lipid nanoparticles (MG SLNs) and enveloped them with the A431 cell membrane (A431 CM) to create A431@MG. The characterization results showed that A431@MG was spherical. Furthermore, A431@MG had specific targeting for A431 cells. In A431 tumor-bearing mice, A431@MG demonstrated prolonged accumulation within tumors, ensuring precise boundary localization of SCC. We further advanced the approach by preparing MG SLNs encapsulating 5-aminolevulinic acid methyl ester (MLA) and desferrioxamine (DFO) with an A431 CM coating to yield A431@MG-MLA/DFO. Several studies have revealed that DFO effectively reduced iron content, impeding protoporphyrin IX (PpIX) biotransformation and promoting PpIX accumulation. Simultaneously, MLA was metabolized into PpIX upon cellular entry. During radiotherapy, the heightened PpIX levels enhanced reactive oxygen species (ROS) generation, inducing DNA and mitochondrial damage and leading to cell apoptosis. In A431 tumor-bearing mice, the A431@MG-MLA/DFO group exhibited notable radiotherapy sensitization, displaying superior tumor growth inhibition. Combining A431@MG-MLA/DFO with radiotherapy significantly improved anticancer efficacy, highlighting its potential to serve as an integrated diagnostic and therapeutic strategy for SCC.

Diagnostic performance of photodynamic diagnosis with oral 5-aminolevulinic acid for upper tract- and bladder urothelial carcinoma: a single-centre, retrospective analysis.

PURPOSE: To compare the diagnostic performance of photodynamic diagnosis (PDD) enhanced with oral 5-aminolaevulinic acid between the suspected upper tract urothelial carcinoma (UTUC) and bladder urothelial carcinoma (BUC) cases. METHODS: This retrospective study included 18 patients with suspected UTUC who underwent ureteroscopy (URS) with oral 5-ALA in the PDD-URS cohort between June 2018 and January 2019; and 110 patients with suspected BUC who underwent transurethral resection of bladder tumour (TURBT) in the PDD-TURBT cohort between January 2019 and March 2023. Sixty-three and 708 biopsy samples were collected during diagnostic URS and TURBT, respectively. The diagnostic accuracy of white light (WL) and PDD in the two cohorts was evaluated, and false PDD-positive samples were pathologically re-evaluated. RESULTS: The area under the receiver operating characteristic curve (AUC) of PDD was significantly superior to that of WL in both cohorts. The per biopsy sensitivity, specificity, and positive and negative predictive values of PDD in patients in the PDD-URS and PDD-TURBT cohorts were 91.2 vs. 71.4, 75.9 vs. 75.3, 81.6 vs. 66.3, and 88.0 vs. 79.4%, respectively. The PDD-URS cohort exhibited a higher AUC than did the PDD-TURBT cohort (0.84 vs. 0.73). Seven of four false PDD-positive samples (57.1%) in the PDD-URS cohort showed potential precancerous findings compared with eight of 101 (7.9%) in the PDD-TURBT cohort. CONCLUSION: The diagnostic performance of PDD in the PDD-URS cohort was at least equivalent to that in the PDD-TURBT cohort.

Effects of dietary 5-aminolevulinic acid on growth performance and nonspecific immunity of Litopenaeus vannamei, as determined by transcriptomic analysis.

5-aminolevulinic acid (5-ALA) is an endogenous non-protein amino acid that is frequently used in modern agriculture. This study set out to determine how dietary 5-ALA affected the nonspecific immunity and growth performance of Litopenaeus vannamei. The shrimp were supplemented with dietary 5-ALA at 0, 15, 30, 45, and 60 mg/kg for three months. Transcriptome data of the control group and the group supplemented with 45 mg/kg dietary 5-ALA were obtained using transcriptome sequencing. 592 DEGs were identified, of which 426 were up-regulated and 166 were down-regulated. The pathways and genes associated with growth performance and nonspecific immunity were confirmed using qRT-PCR. The highest survival rate, body length growth rate, and weight gain values were observed in shrimp fed diets containing 45 mg/kg 5-ALA. L. vannamei in this group had a significantly higher total hemocyte count, phagocytosis rate and respiratory burst value than those in the control group. High doses of dietary 5-ALA (45 mg/kg, 60 mg/kg) significantly increased the activities of catalase, superoxide dismutase, oxidized glutathione, glutathione-peroxidase, phenoloxidase, lysozyme, acid phosphatase, and alkaline phosphatase. At the transcriptional level, dietary 5-ALA significantly up-regulated the expression levels of antioxidant immune-related genes. The optimal concentration of 5-ALA supplementation was 39.43 mg/kg, as indicated by a broken line regression. Our study suggested that dietary 5-ALA positively impacts the growth and nonspecific immunity of L. vannamei, providing a novel theoretical basis for further research into 5-ALA as a dietary supplement.

Beyond fluorescence-guided resection: 5-ALA-based glioblastoma therapies.

Glioblastoma is the most common primary malignant brain tumor. Despite advances in multimodal concepts over the last decades, prognosis remains poor. Treatment of patients with glioblastoma remains a considerable challenge due to the infiltrative nature of the tumor, rapid growth rates, and tumor heterogeneity. Standard therapy consists of maximally safe microsurgical resection followed by adjuvant radio- and chemotherapy with temozolomide. In recent years, local therapies have been extensively investigated in experimental as well as translational levels. External stimuli-responsive therapies such as Photodynamic Therapy (PDT), Sonodynamic Therapy (SDT) and Radiodynamic Therapy (RDT) can induce cell death mechanisms via generation of reactive oxygen species (ROS) after administration of five-aminolevulinic acid (5-ALA), which induces the formation of sensitizing porphyrins within tumor tissue. Preliminary data from clinical trials are available. The aim of this review is to summarize the status of such therapeutic approaches as an adjunct to current standard therapy in glioblastoma.

A Review of the Dermatologic Clinical Applications of Topical Photodynamic Therapy.

Topical photodynamic therapy is a widely approved therapy for actinic keratoses and low-risk nonmelanoma skin cancers with a rapidly growing range of emerging indications for other cutaneous diseases. This review summarizes the best-available evidence to provide a clinical update for dermatologists on the approved and emerging indications of photodynamic therapy. The body of evidence suggests that photodynamic therapy is superior or noninferior to other available treatment modalities for actinic keratoses, low-risk basal cell carcinomas, Bowen's disease, skin field cancerization, chemoprevention of keratinocyte carcinomas in organ transplant recipients, photoaging, acne vulgaris, and cutaneous infections including verrucae, onychomycosis, and cutaneous leishmaniasis. There is emerging evidence that photodynamic therapy plays a role in the management of actinic cheilitis, early-stage mycosis fungoides, extramammary Paget disease, lichen sclerosis, and folliculitis decalvans but there are no comparative studies with other active treatment modalities. Common barriers to topical photodynamic therapy include procedural pain, costs, and the time required for treatment delivery. There is significant heterogeneity in the photodynamic therapy protocols reported in the literature, including different photosensitizers, light sources, number of treatments, time between treatments, and use of procedural analgesia. Topical photodynamic therapy should be considered in the management of a spectrum of inflammatory, neoplastic, and infectious dermatoses. However, more comparative research is required to determine its role in the treatment algorithm for these dermatologic conditions and more methodological research is required to optimize photodynamic therapy protocols to improve the tolerability of the procedure for patients.

Photodynamic therapy in management of cutaneous leishmaniasis: A systematic review.

This systematic review evaluated the efficacy and safety of photodynamic therapy (PDT) in the management of cutaneous leishmaniasis (CL). The electronic search for identification of relevant studies, adhered to the PICOS (Population, Intervention, Comparator, Outcomes and Study type) framework, was conducted through PubMed, Google scholar, Dimensions, X-mol, and Semantic Scholar till December 2023. All types of studies reporting PDT in the management of CL with no language restriction were included. Methodological quality appraised of the selected studies was performed using Jadad index. Of the 317 identified studies, 21 reported PDT for the treatment of CL lesions, consisting of two randomized controlled trials (RCTs), four single-center open study, one case series and 14 case reports. Collectively, these studies presented a total of 304 patients with ages ranging from 1 to 82 years, undergoing varying number of PDT sessions (3-28) and follow-up durations spanning 4 weeks to 24 months. The CL lesions predominantly manifested on the exposed body areas, such as face, limbs, neck, ear and nose, and characterized with the use of clinical variables, such as plaques, papules, erythema and ulceration. PDT protocols differed in the photosensitizer type, incubation time, light source characteristics (e.g., wavelength, output power, and energy density), duration of light illumination, number of PDT sessions and their respective frequencies. Treatment response was assessed through the clinical presentation (i.e., at the baseline and after PDT completion) or by the absence of Leishmania parasites. Adverse effects comprised of pain, burning and tingling sensation experienced during PDT, followed by erythema, pigmentation changes and edema post-treatment. This systematic review revealed that PDT is an efficacious and safe modality for the treatment of CL, with mild and transient side effects.

Incidence and predictors of intraoperative hypotension during transurethral bladder tumor resection with oral 5-aminolevulinic acid.

OBJECTIVES: To analyze the incidence and risk factors of intraoperative hypotension related to photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT) with oral 5-aminolevulinic acid (5-ALA). METHODS: We retrospectively analyzed 487 patients with bladder tumors who underwent PDD-TURBT (n = 184) or conventional TURBT (conv-TURBT) (n = 303) between 2018 and 2021. Intraoperative hypotension was defined as hypotension requiring vasopressors during TURBT, and its incidence was compared between the two groups. Potential risk factors of intraoperative hypotension, including preoperative change in mean arterial pressure (MAP), were further investigated in patients receiving PDD-TURBT. RESULTS: The median age was 72 years, 392 patients (81%) were male, and 203 (42%) had hypertension. TURBT was performed under general and spinal anesthesia in 76 (16%) and 411 (84%) patients, respectively. The incidence of intraoperative hypotension was significantly higher in PDD-TURBT compared to conv-TURBT (43% vs. 17%, respectively). The median change in MAP until the induction of anesthesia was +6.5 mmHg (range: -29.0 to +46.3) in the PDD-TURBT group and +14.7 mmHg (range: -35.3 to +67.7) in the conv-TURBT group, showing a significantly smaller increase in the PDD-TURBT group (p < 0.001). In the multivariable analysis for PDD-TURBT patients, advanced age, general anesthesia, and lower MAP change (<+6.5 mmHg) until anesthesia induction were significantly associated with intraoperative hypotension (p = 0.0104, <0.001, and <0.001, respectively). CONCLUSIONS: Intraoperative hypotension occurred more frequently in patients who underwent PDD-TURBT than in those who underwent conv-TURBT. Using oral 5-ALA decreases preoperative blood pressure elevation and may be responsible for intraoperative hypotension.

Comprehensive analysis of perioperative hypotension in photodynamic diagnosis-assisted transurethral resection of bladder tumor with 5-aminolevulinic acid.

OBJECTIVE: Intraoperative hypotension remains a serious adverse event of photodynamic diagnosis-assisted transurethral resection of bladder tumor with oral administration of 5-aminolevulinic acid. We conducted a re-analysis of perioperative hypotension in photodynamic diagnosis-assisted transurethral resection of the bladder tumor with oral 5-aminolevulinic acid to ascertain its safety. METHODS: A total of 407 cases who underwent transurethral resection of bladder tumors in our institution were reviewed (274 cases for the PDD group with photodynamic diagnosis and 133 for the white light (WL) group without). A classification of hypotension severity was devised to identify risk factors for clinically troublesome hypotension. The distribution of hypotension severity in each of the PDD and WL groups was compared. Additionally, the patient background and perioperative data by hypotension severity were compared only in the PDD group. RESULTS: More patients with moderate and severe hypotension were noted in the PDD group. The renal function was lower with increasing hypotension severity in the PDD group. More patients on general anesthesia were included in the mild and moderate hypotension group, whereas more patients on spinal anesthesia were included in the severe hypotension group. Furthermore, the frequency of side effects other than hypotension tended to increase with hypotension severity. CONCLUSIONS: Renal function impairment and the other adverse effects of 5-aminolevulinic acid may be risk factors for severe hypotension. Mild or moderate hypotension may be caused by general anesthesia and severe hypotension may be caused by spinal anesthesia. To elucidate specific risk factors, further case-control studies are warranted.

Differences in oncological benefits from second transurethral resection between white-light initial surgery and photodynamic diagnosis-guided initial surgery for primary high-risk non-muscle invasive bladder cancer.

OBJECTIVES: The aim of this study was to compare clinical outcomes between patients receiving second TUR after initial white-light transurethral resection of bladder tumor (WL-TURBT) and initial photodynamic diagnosis (PDD)-assisted TURBT. METHODS: A total of 1007 patients were divided into four groups based on the treatment pattern: WL-TURBT with second TUR (161 patients, WL-second group) or without second TUR (540 patients, WL-alone group) and PDD-TURBT with second TUR (112 patients, PDD-second group) or without second TUR (194 patients, PDD-alone group). Oncologic outcomes (bladder cancer recurrence, progression, urothelial cancer-specific mortality) and rates of residual tumor and risk stratification of non-muscle-invasive bladder cancer (NMIBC) after second TUR were evaluated. RESULTS: After propensity score-matching 121 patients were included each in the WL-alone and WL-second groups, and 63 patients each in the PDD-alone and PDD-second groups. In the WL group, the second TUR was significantly associated with improved progression-free (p = 0.012) and urothelial cancer-specific free survival (p = 0.011), but not with recurrence-free survival (p = 0.93). Patients initially treated with PDD-TURBT, and with a tumor diameter <30 mm and multifocality had a relatively high benefit from second TUR. The rates of residual tumor and risk stratification of NMIBC did not significantly differ between WL-TURBT and PDD-TURBT groups. CONCLUSIONS: Our findings suggested that a second TUR could be omitted after an initial PDD-TURBT in selected patients with high-risk NMIBC.

Photodynamic diagnosis-assisted transurethral resection of bladder tumor for high-risk non-muscle invasive bladder cancer improves intravesical recurrence-free survival (BRIGHT study).

OBJECTIVES: In a primary analysis of data from the BRIGHT study (UMIN000035712), photodynamic diagnosis-assisted transurethral resection of bladder tumor (PDD-TURBT) using oral 5-aminolevulinic acid hydrochloride reduced residual tumors in high-risk non-muscle invasive bladder cancer (NMIBC). We aimed to evaluate the effectiveness of PDD-TURBT for intravesical recurrence after a second transurethral resection for high-risk NMIBC. METHODS: High-risk NMIBC patients initially treated with PDD-TURBT (PDD group) were prospectively registered between 2018 and 2020. High-risk patients with NMIBC who were initially treated with white-light TURBT (WL group) were retrospectively registered. Intravesical recurrence-free survival after the second transurethral resection was compared between the PDD and WL groups using propensity score matching analysis. RESULTS: In total, 177 patients were enrolled in the PDD group, and 306 patients were registered in the WL group. After propensity score matching (146 cases in each group), intravesical recurrence within 1 year was significantly less frequent in the PDD group than in the WL group (p = 0.004; hazard ratio [HR] 0.44, 95% confidence interval [CI]: 0.25-0.77). In subgroup analysis, PDD-TURBT showed a particularly high efficacy in reducing intravesical recurrence within 1 year, especially in cases of tumors measuring less than 3 cm (p = 0.003; HR 0.31, 95% CI: 0.14-0.67), absence of residual tumor at second transurethral resection (p = 0.020; HR 0.37, 95% CI: 0.16-0.86), and no postoperative intravesical Bacillus Calmette-Guérin therapy (p < 0.001; HR 0.27, 95% CI: 0.13-0.58). CONCLUSIONS: PDD-TURBT may reduce short-term intravesical recurrence in patients with high-risk NMIBC.

On the Possibility of Using 5-Aminolevulinic Acid in the Light-Induced Destruction of Microorganisms.

Antimicrobial photodynamic inactivation (aPDI) is a method that specifically kills target cells by combining a photosensitizer and irradiation with light at the appropriate wavelength. The natural amino acid, 5-aminolevulinic acid (5-ALA), is the precursor of endogenous porphyrins in the heme biosynthesis pathway. This review summarizes the recent progress in understanding the biosynthetic pathways and regulatory mechanisms of 5-ALA synthesis in biological hosts. The effectiveness of 5-ALA-aPDI in destroying various groups of pathogens (viruses, fungi, yeasts, parasites) was presented, but greater attention was focused on the antibacterial activity of this technique. Finally, the clinical applications of 5-ALA in therapies using 5-ALA and visible light (treatment of ulcers and disinfection of dental canals) were described.