Abstract Background Cerebral venous thrombosis is a rare form of stroke predominantly affecting young women and is associated with a 6–15% risk of death or long-term dependency. We investigated the impact of age, sex, and genetic risk factors on cerebral venous thrombosis onset, clinical severity, and long-term outcomes among individuals of European ancestry. Methods The BEAST (Biorepository to Establish the Aetiology of Sinovenous Thrombosis) study is an international, prospective, observational cohort that enrolled 1309 adult cerebral venous thrombosis patients from 11 countries (United Kingdom, United States of America, Mexico, and European nations). Genetic analyses assessed associations with factor VIII concentrations and cerebral venous thrombosis risk. Clinical predictors of coma and poor long-term outcomes were identified using logistic regression and non-parametric neural network models. Additionally, a meta-analysis of 25 studies comprising 2301 patients was conducted to compare the long-term (≥ 6 months) safety and efficacy of direct oral anticoagulants and warfarin in cerebral venous thrombosis management. Results Women developed cerebral venous thrombosis ~9 years earlier than men, whilst individuals with ≥2 identifiable risk factor experienced cerebral venous thrombosis onset ~12 years earlier than those without risk factors. Amongst patients aged 45 years or older, malignancy was associated with a 3.6-fold increased risk of cerebral venous thrombosis (OR 3.6; 95% CI: 1.4–9.0; P = 0.006). Genetic analyses identified five PROC (protein C) single nucleotide polymorphisms (rs1799810, rs41280570, rs1158867, rs2069919, rs5937) as novel genetic determinants, each conferring an approximately 1.3-fold increased risk of cerebral venous thrombosis in individuals of European ancestry. Strong linkage disequilibrium amongst these variants implicated rs1799810 in the 5’ UTR promoter region as a functional single nucleotide polymorphisms. Elevated factor VIII concentrations (≥150 IU/dL), an X-linked inherited trait, were associated with an approximately 8-fold increased risk of superior sagittal sinus thrombosis in men and a 2-fold increased risk in women. Although cerebral venous thrombosis was more prevalent in women, men exhibited a 2-fold higher risk of coma. The meta-analysis demonstrated comparable safety and efficacy between direct oral anticoagulants and warfarin, with similar rates of favourable clinical outcomes, intracranial haemorrhage, all-cause mortality, non-recanalisation, and recurrent venous thrombosis. Conclusions Protein C variants, particularly rs1799810, and elevated factor VIII concentrations are significant genetic determinants of cerebral venous thrombosis risk amongst Europeans, with distinct sex-specific effects. Whilst direct oral anticoagulants and warfarin demonstrate equivalent long-term efficacy and safety, direct oral anticoagulants offer practical advantages through simplified clinical management.

Nitrogen-containing heterocycles including a huge number of organic substances are widely used as dyes and catalysts, efficient antimicrobial, inflammatory and antitumoral agents as well as photosensitizers for antimicrobial and antitumor photodynamic therapy. In this paper, we focus on the behavior of the well-known drug “Prospidium chloride” (PC) in the methanol (MeOH)-water mixtures. This water-soluble cytostatic is used to treat many malignant neoplasms, precancerous lesions and autoimmune diseases. The antitumor activity of PC is mediated by two distinct mechanisms. The first mechanism includes ion channel blocking in the membrane leading to the tumor cell death induced by apoptosis, while the second one is associated with the alkylating effect due to the drug's side chains binding to one or two molecules of deoxyribonucleic acid (DNA). The second mechanism suggests the high reactivity of covalently bonded chlorine atoms in nucleophilic substitution reactions and, consequently, the possibility of hydroxyl-substituted products formation in aqueous PC solutions. In this regard, it is important to analyze the behavior of PC in solvent media that do or do not favor hydrolysis, as well as in their mixtures. Our results show that the drug is more exothermically solvated in water than in the alcohol, and the PC-water pair interaction in MeOH is strongly enthalpically attractive. However, solute-water attraction does not induce drug hydrolysis in the mixed solvent at least at a low water content. The 1H NMR studies do not confirm the formation of hydroxyl-substituted products and demonstrate high stability of PC in a liquid phase both at the standard and elevated (338 K) temperatures. For citation: Kustov A.V., Smirnova N.L., Berezin D.B., Kladiev A.A., Aleksandriiskiy V.V., Kladiev A.A. Interaction of prospidium chloride with water in methanol – results of calorimetric and NMR studies. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 6. P. 44-51. DOI: 10.6060/ivkkt.20266906.7009.

Targeting PAR1 biased signaling with parmodulin reduces thromboinflammation and acute lung injury in sickle cell disease.

Liquid plasma (LQP) stands out as an alternative to thawed plasma (TP) for emergent transfusions due to its longer shelf-life. We aimed to measure fibrinogen, protein C (PC), protein S (PS), factor V (FV), factor VII (FVII) and factor VIII (FVIII) activity in LQP, quantify how these factors' levels change during storage and characterize how they compare in LQP and TP. Coagulation factor activities were measured on days 15, 26 and 27 for LQP (n = 26) and Day 5 for TP (n = 31). Bayesian statistics was used to compare coagulation factor activity and quantify changes in activity during storage. Fibrinogen and PC activity on Day 26 in LQP (LQP26) was comparable to that on Day 5 in TP (TP5) with posterior mean activity of 257 versus 246 mg/dL and 100.4% versus 108.7%, respectively. FV, FVII and FVIII had lower activity in LQP26 compared to TP5, with posterior mean activities of 42.6% versus 72.0%, 55.0% versus 59.7% and 48.8% versus 59.2%, respectively. PS in LQP26 was low, with posterior mean activity of 28.0%, which was less than half that of TP5 at 66.4%. From Day 15 to Day 26, FVII in LQP decreased at a rate of 3.49% per day, whereas fibrinogen, PC, PS, FV and FVIII activity in LQP remained relatively stable. LQP26 has comparable activities of fibrinogen, PC and FVII as TP5, lower activities of FV and PS and slightly lower activity of FVIII. LQP is a viable alternative for use in emergency transfusions and massive transfusion protocols.

The endothelial protein C receptor (EPCR) is an important component of the protein C (PC) system, recognised for its diverse roles in blood coagulation, inflammation, and stem cell regulation. Wound healing is a complex physiological process that can be divided into four distinct but overlapping phases: haemostasis, inflammation, proliferation and remodelling. Recently, EPCR has emerged as a key regulator in wound repair and regeneration. During haemostasis, EPCR enhances the conversion of PC to its activated form (APC) to optimise local and systemic anticoagulation. In the inflammatory phase, EPCR modulates immune cell activity, inhibits inflammatory factors, and maintains tissue barrier integrity. As the process transitions to the proliferative phase, EPCR promotes endothelial and epithelial cell proliferation, migration, neovascularisation and re-epithelization, and mediates the expression of matrix metalloproteinases to facilitate tissue reconstruction. Finally, during the remodelling phase, EPCR exerts a potential antifibrotic effect by regulating fibroblast activation and collagen deposition via the Transforming growth factor (TGF)-β1/Smad3 pathway, ensuring functional repair. While therapeutic potential has been shown in animal models, translating EPCR-mediated therapies to clinical application faces many challenges, including wound heterogeneity, dosage control, targeted delivery, and potential bleeding risks. Studies have shown that local drug delivery strategies, non-anticoagulant APC variants, and individualised treatment based on EPCR expression will be the key directions for future development. Additionally, EPCR may serve as a potential biomarker for assessing wound severity and guiding personalised interventions.

Inhibition of activated protein C anticoagulant function enhances coagulation but does not interrupt downstream mechanisms driving hemophilic arthropathy.

SUMMARYG protein-coupled receptors (GPCRs) exhibit signaling bias or preferential activation of heterotrimeric G proteins versus GPCR kinase (GRK)-mediated β-arrestin signaling. The protease-activated receptor-1 (PAR1) activates both G protein and β-arrestin in response to thrombin but only β-arrestin in response to activated protein C (APC). Thrombin-activated PAR1-G protein signaling is desensitized by β-arrestin-1, whereas APC-activated PAR1 signaling is propagated by β-arrestin-2. The mechanisms underlying PAR1 biased signaling are not known. Here, using computational modeling combined with cellular and biochemical studies, we reveal the molecular basis of signaling by thrombin- and APC-activated PAR1. Although both thrombin- and APC-induced PAR1 signaling are regulated by the same GRK, GRK5, the two types of signaling are differentially dependent on GRK5 membrane anchoring, PAR1 C-terminal phosphorylation sites, and the binding mode of β-arrestin-2. These differences translate into distinct β-arrestin-2 conformations and define the APC cytoprotective signaling signature, which contrasts with thrombin inflammatory signaling.

Endothelial protein C receptor-mediated endogenous and therapeutic transport of activated protein C across the blood-retina barrier protects the retina.

G-protein-coupled receptors (GPCRs) display bias toward either G proteins or GPCR kinase (GRK)-mediated β-arrestin (βarr) signaling depending on the agonist-stabilized receptor conformation. The cellular context and subcellular location of GPCRs can also influence biased signaling through mechanisms that are not well understood. The protease-activated receptor-1 (PAR1) exhibits signaling bias in response to thrombin and activated protein C (APC). APC-induced βarr2-biased signaling requires PAR1 compartmentalization in caveolae, a subtype of lipid rafts, whereas thrombin-activated PAR1 G protein signaling does not. Caveolin-1 (Cav1) is the principal structural component of caveolae and regulates protein-protein interactions. The mechanisms by which Cav1 contributes to APC-PAR1-induced βarr2-biased signaling are not known. Here, we report that a substantial population of endogenous PAR1 colocalizes with Cav1 in endothelial cells and is modulated by APC, assessed by single-molecule super-resolution stochastic optical reconstruction microscopy imaging. APC activation of PAR1 also induces Cav1 tyrosine-14 phosphorylation through a βarr2- and c-Src-dependent pathway, which disrupts PAR1-Cav1 coassociation. A smaller population of endogenous GRK5 was also found to colocalize with Cav1 in endothelial cells and was modestly altered by APC activation of PAR1. Moreover, GRK5 was found to interact with Cav1 in intact cells through an N-terminal aromatic-rich Cav1 binding motif. Mutation of this motif disrupts GRK5-Cav1 binding, shifts GRK5 predominantly to the cytoplasm rather than the plasma membrane, and perturbs GRK5-mediated βarr2 recruitment to APC-activated PAR1. Thus, beyond its structural function, Cav1 participates in protein-protein interactions with PAR1 and GRK5, two key effectors that enable APC-induced βarr2 signaling.

Protein C (PC) and its activated form, activated protein C (APC), are well-established regulators of coagulation and cytoprotection. While their systemic functions are extensively characterized, their physiological roles in the retina have only recently begun to be explored. This gap persists despite the observation that congenital PC deficiency is consistently associated with severe ocular complications. Emerging evidence, including the development of a murine model of severe protein C deficiency (SPCD), indicates that APC contributes to retinal integrity and vascular homeostasis under physiological conditions. Beyond its physiological function, APC has shown therapeutic activity in several models of retinal disease. Recent findings from our group further demonstrated that intravenously administered APC and its cytoprotective analog, 3K3A-APC, can cross the blood-retina barrier via the endothelial protein C receptor (EPCR), despite their relatively large molecular weight (~62 kDa), and induce cytoprotective activities in the retina. These findings highlight the translational potential of 3K3A-APC and support its further development as a systemically delivered therapeutic approach for retinal pathologies. This review integrates current knowledge of the molecular biology of the PC/APC pathways with its emerging physiological functions in the retina, and the accumulating preclinical and early clinical evidence that supports its therapeutic relevance.

Background: Aortic dissection (AD) is a life-threatening vascular emergency with limited effective pharmacological treatments. Recent studies have identified Src homology 2 domain-containing transforming protein C1 (p66Shc) as a crucial mediator of oxidative stress, apoptosis, and inflammation in aortic cells, thereby contributing to cellular dysfunction and vascular remodeling implicated in AD development and progression. Despite its established role in promoting vascular dysfunction and remodeling, the protective potential of targeting p66Shc in AD remains unclear.Methods: We quantified activated protein C (aPC) levels in clinical plasma samples from control subjects and AD patients using enzyme-linked immunosorbent assay (ELISA). To evaluate changes in p66Shc expression, we analyzed aortic tissues by Western blotting (WB), immunohistochemistry (IHC), and immunofluorescence (IF) staining. An in vivo AD model was established in thrombomodulin (TM)-mutant ApoE-/- mice, which display impaired TM-dependent PC activation, and exogenous PC was administered to evaluate its therapeutic effect. In parallel, mechanistic studies were performed in human endothelial cells using WB, co-immunoprecipitation (Co-IP), dual-label IF staining, chromatin immunoprecipitation (ChIP), luciferase reporter assays, and mitochondrial functional analyses.Results: In this study, we demonstrate that aPC, a coagulation protease with known cytoprotective properties, downregulates p66Shc expression through epigenetic modifications. Additionally, aPC can modulate the expression of a cold shock protein Y-box-binding protein 1 (YB1), which acts as a transcription factor, leading to elevated O-linked N-acetylglucosamine transferase (OGT) levels. This upregulation enhances the O-glycosylation of p66Shc on its 29th tyrosine residue, preventing its mitochondrial translocation, preserving mitochondrial membrane potential, and reducing reactive oxygen species (ROS) production. Consequently, these molecular mechanisms inhibit the onset and progression of AD.Conclusions: aPC epigenetically represses p66Shc transcription and promotes its O-glycosylation at Thr29 via the YB-1/OGT axis, thereby inhibiting mitochondrial ROS production and preventing vascular injury.

目的对2个抗凝血酶（AT）和蛋白C（PC）联合缺陷家系进行临床特征和基因突变分析，探讨SERPINC1基因和PROC基因联合缺陷与疾病发生的关系。方法采用常规方法检测先证者及其家系成员AT活性（ＡT∶A）、AT抗原（AT∶Ag）、PC活性（PC∶A）、PC抗原（PC∶Ag）、蛋白S活性（PS∶A）指标。采用二代测序（NGS）和CNVplex技术对筛选基因的编码区和调控区进行点突变、小缺失或插入及基因拷贝数变异的检测，并对突变位点进行Sanger法测序验证。运用ClustalX-2.1-win软件分析突变位点的保守性；使用在线生物信息学软件预测突变位点的致病性；通过CAT法检测凝血酶生成情况。结果先证者1的PROC基因第5外显子存在c.400+5G>A剪切位点突变，SERPINC1基因第5外显子存在c.883G>A（p.Val295Met）杂合错义突变；先证者2的PROC基因第9外显子存在c.811C>T（p.Arg271Trp）杂合错义突变，SERPINC1基因第5外显子存在c.880C>T（p.Arg294Cys）杂合错义突变，突变位点分别来源于患者的父亲和母亲。生物信息学分析发现以上突变位点大多数为保守位点，这些基因突变大多数被预测为“致病的、有害的”，可通过改变蛋白空间结构、破坏蛋白稳定性，引起AT和PC水平或功能异常。凝血酶生成试验结果显示，4例突变携带者均出现不同程度的内源性凝血酶生成增多呈高凝倾向，在血栓调节蛋白（sTM）的存在下，PC途径的抗凝功能明显减弱。结论在2个家系中发现AT和PC两个突变位点，可能与2例患者的反复静脉血栓发生有关；SERPINC1和PROC基因联合突变携带者具有更高的静脉血栓发生风险。

Cytosporone B ameliorates hypercoagulability in sepsis by agonizing the Nur77-thrombomodulin pathway.

This study presents an optimized protocol for measuring singlet oxygen (1O2) quantum yield using a two-component chemical trap consisting of imidazole (ImH) and 4-nitroso-N,N-dimethylaniline (RNO) for water-soluble phthalocyanines (Pcs). Deprotonation of nitrogen atoms in a cavity of metal-free Pc upon addition of ImH to aqueous solution, as well as coordination of ImH to the metal center in a Pc cavity causes changes in the spectral and photophysical properties of a Pc, which could potentially compromise the accuracy of 1O2 yield determination. Through a systematic investigation, we examined the influence of ImH concentration, solution pH, and ionic strength (adjusted using different salts) on the ImH-Pc interaction. The optimal measurement conditions were determined to be a 0.5 mM ImH concentration in neutral pH buffer solution with ionic strength exceeding 100 mM. These specific parameters were found to minimize ImH-induced alterations in Pc spectral characteristics while maintaining reliable 1O2 yield quantification. The validity of this approach was confirmed through comparative measurements in phosphate buffered saline (PBS) using both the ImH-RNO system and a reference cationic anthracene trap TMAPA, which showed consistent results. These results demonstrate the feasibility of using an optimized protocol to evaluate the photodynamic activity of different Pcs using the ImH-RNO system.

Diabetic cardiomyopathy (DCM) is a serious complication of end-stage diabetes that manifests as cardiac hypertrophy and heart failure. The present study performed a bioinformatics analysis to predict possible targets for aerobic exercise to improve DCM, and animal experiments were conducted to detect the relevant mechanisms. Oxidative stress (OS)-DCM-trained differentially expressed genes (DEGs) were retrieved from the GeneCards database and a Gene Expression Omnibus microarray dataset. Subsequently, a protein-protein interaction network was constructed to screen the hub genes of the OS-DCM-trained DEGs. In addition, a model of type 2 diabetes was established using streptozotocin and a high-fat diet. Rats were divided into the control, DCM and DCM plus exercise (DCME) groups. The DCME group underwent 8 weeks of moderate-intensity treadmill training. Assessment of cardiac function, myocardial enzymes and OS-related indicators in each group. Compared with the control group, the levels of BNP, CK-MB, c-TnT, LDH, MDA, LVEF, LVIDd, and LVIDs in the DCM group were significantly increased (P < 0.05), while SOD, GSH, and LVFS were significantly decreased (P < 0.05); The above indicators were significantly improved in DCME group rats (P < 0.05). In addition, the expression levels of target genes predicted to be associated with the aerobic exercise-induced improvement of DCM were detected and western blotting was used to determine the relevant signaling pathways. Bioinformatics analysis identified nine hub genes, which, according to Kyoto Encyclopedia of Genes and Genomes enrichment analysis, were mainly involved in “IL-17 signaling pathway,” “TNF signaling pathway,” “apoptosis” and “necroptosis.” Aerobic exercise improved the heart function and myocardial enzymes of the rats in the DCM group, reduced myocardial damage, and inhibited fibrosis and OS. Detection of the nine core genes revealed that only protein C (PROC) met the predicted trend; PROC expression was lower in the DCM group than that in the control group and was higher in the DCME group than that in the DCM group (P < 0.05). Further confirmation using western blotting suggested that aerobic exercise may improve DCM by activating the PROC/proteinase-activated receptor 1 (PAR1)/nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. In conclusion, aerobic exercise may mitigate DCM by activating the PROC/PAR1/Nrf2/HO-1 signaling pathway. These findings could pave the way for further investigations into how exercise might regulate OS and influences DCM progression, providing novel insights into its diagnosis and prognosis.

Antiphospholipid syndrome (APS) is an autoimmune condition with thrombotic and/or obstetric manifestations (tAPS and oAPS respectively). Impaired sensitivity to activated protein C (APC), often referred to as "acquired APC resistance," is known to be an independent risk factor for thrombosis across a variety of conditions. In particular it has been implicated in the prothrombotic phenotype of APS and may serve as a prognostic marker in tAPS. However, data on APC sensitivity in oAPS remain inconclusive.We included 60 women less than 50 years of age from two prospective French cohorts with neither overlapping manifestations nor associated autoimmune diseases. APC sensitivity was assessed using calibrated automated thrombography with platelet-rich plasma. APC sensitivity ratio (APCsr) was defined as the ratio of endogenous thrombin potential (ETP) in the presence of 25 nM APC (ETP-APC25) to ETP in its absence (ETP0).A total of 60 women was analyzed (43 tAPS and 17 oAPS); 15 tAPS women received anticoagulant treatment. No difference in APCsr was observed between tAPS and oAPS patients. In anticoagulated tAPS women, ETP0 and ETP-APC25 levels were, as expected, significantly lower than non-anticoagulated women, but APCsr remained consistent in identifying patients with high-risk serological profile.Our findings suggest that decreased APC sensitivity is shared by the two main APS clinical phenotypes, which hence must have distinct pathogenic alterations as well. APC sensitivity can be investigated with CT even if clotting times are prolonged (lupus anticoagulant effect) and if thrombin generation is decreased as a result of anticoagulant treatment.

Congenital protein C (PC) deficiency is a major thrombotic risk factor in the Japanese population that often leads to severe thrombosis and bleeding in the neonatal period. Treatment typically involves anticoagulation such as warfarin and heparin, with PC concentrates used in acute cases. Here we report the case of a 25-year-old woman diagnosed with severe congenital PC deficiency. She had recurrent episodes of purpura fulminans despite warfarin therapy. After a COVID-19 infection, she developed coagulopathy with poorly controlled thrombotic and bleeding complications, followed by DIC. Replacement therapy with protein C concentrate led to rapid improvement in DIC, thrombosis, and bleeding. The patient will continue warfarin, and regular replacement therapy with protein C concentrate is also planned. This case highlights the potential benefits of new treatment options for severe PC deficiency and underscores the importance of early and appropriate intervention in managing this rare but potentially life-threatening condition.

The maternal hemostatic shift: Understanding VTE risk in pregnancy and postpartum.

ObjectiveRecurrent spontaneous abortion (RSA) affects 0.5%–2.5% of fertile couples and arises from complex, interacting thrombotic, immune, coagulation, endocrine–metabolic, and demographic factors. However, current early risk stratification in routine practice remains insufficient for population-level screening. We aimed to develop an accurate, low-cost, and clinically feasible early screening model for identifying women at high risk of RSA using routinely available clinical biomarkers.MethodsThis retrospective study enrolled women attending Guangdong Reproductive Hospital between 1 January 2020 and 31 December 2024. Among 1226 screened individuals, 285 met eligibility criteria and were included (181 RSA patients and 104 healthy controls). Demographic and laboratory variables were extracted from electronic medical records and structured follow-up. Ten classical machine-learning algorithms and a Transformer-based tabular model (TabPFN) were trained and compared. Class imbalance was handled using the synthetic minority oversampling technique (SMOTE). Model robustness was evaluated using 5-fold cross-validation. Biological-domain contributions were quantified through ablation analysis. Feature selection was optimized using recursive feature elimination with random forest (RFE-RF), and interpretability was assessed via SHAP.ResultsThe TabPFN Multidimensional model integrating features across six clinical domains achieved the best discriminative performance for RSA risk prediction (ROC–AUC = 0.927, 95% CI 0.891–0.947), outperforming all comparator algorithms. Domain ablation showed that removing any single biological category reduced performance, supporting the complementary value of multidimensional clinical integration. Acquired thrombophilia markers provided the strongest predictive contribution, followed by hereditary thrombophilia, immune indices, coagulation parameters, endocrine–metabolic variables, and demographic factors. A parsimonious six-biomarker model—anti-phosphatidylserine/prothrombin antibodies (aPS/PT), protein C (PC), antinuclear antibodies (ANA), antithrombin III (AT-III), thrombin time (TT), and body mass index (BMI)—retained high discrimination (AUC = 0.925) with 83% accuracy, supporting a pragmatic and cost-effective screening strategy. SHAP analysis identified elevated aPS/PT, ANA positivity, reduced AT-III activity, and prolonged TT as the most influential predictors, implicating thrombo-immune dysregulation as a central mechanism associated with RSA.ConclusionA Transformer-based tabular model using six routinely measured, low-cost biomarkers enable accurate, interpretable, and scalable early screening for RSA risk, with potential utility in resource-limited settings to facilitate timely referral and targeted preventive management.

Schiff base-decorated non-ionic phthalocyanine compounds with different metals and a metal-free derivative were synthesized and characterized using different spectroscopic techniques. The influence of the central metal on the photophysicochemical properties was systematically investigated in DMSO. The obtained results reveal that the singlet oxygen quantum yield followed the order In3b > Zn3b > 3bH2Pc in DMSO. The synthesized non-ionic phthalocyanine compounds, except metal-free phthalocyanine (0.12 for 3bH2Pc), have good ΦΔ values (0.71 for Zn3b and 0.85 for In3b) compared with the unsubstituted ZnPc in DMSO (ΦΔ = 0.67). In addition to the photophysicochemical studies, in vitro PDT studies were also performed on PC3 prostate cancer cells to evaluate the biological activity of Pcs. All compounds exhibited low dark cytotoxicity at the selected concentration. Upon light irradiation, phthalocyanine-mediated PDT significantly reduced cell viability and induced apoptotic cell death. These effects were accompanied by a pronounced increase in intracellular ROS generation, particularly in the cells treated with metallophthalocyanine-mediated PDT. In particular, In3b- and Zn3b-mediated PDT exhibited markedly enhanced cytotoxic and apoptotic effects compared with metal-free 3bH2Pc. These findings demonstrate a strong correlation between improved photophysical properties, increased ROS generation, and enhanced in vitro PDT efficacy.