Corm Research Articles

Carbon monoxide-releasing molecule-2 ameliorates postresuscitation myocardial dysfunction in rat via mitochondrial-mediated apoptosis pathway and the regulation of mitochondrial dynamics

Mitochondrial dysfunction plays a significant role in the development of postresuscitation myocardial dysfunction (PRMD). Endogenous carbon monoxide (CO) has obvious protective effects on cardiomyocytes and that mitochondria are considered to be the main targets of CO action. This study aimed to investigate whether exogenous CO (carbon monoxide releasing molecule 2, CORM-2) could protect against PRMD, and improve cardiac function in rats via the mitochondria pathway. Forty male Sprague-Dawley rats were randomly divided into five groups: sham group, model cardiopulmonary resuscitation (CPR) group, CORM-2 treatment group, inactivated CORM-2 group, and DMSO (Dimethyl sulfoxide, CORM-2 vehicle) group. Excluding the sham group, all groups underwent CPR 4 min after cardiac arrest (CA), animals in every group underwent surgery for catheter insertion before the CA-CPR. In the treatment groups, CORM-2 and inactivated CORM-2 (both 4 mg/kg, dissolved in 2% dimethyl sulfoxide and diluted in normal saline) were intraperitoneally injected 12 h before CPR was started. In the sham, model CPR, and vehicle groups, animals were administered normal saline or vehicle as appropriate. The results demonstrated that the mitochondrial ultrastructure abnormalities in CORM-2 group was less severe than CPR rats. CORM-2 alleviated myocardial contractile and diastolic dysfunction after CPR, decreased caspase-3 and caspase-9 expression in myocardial tissues, and meanwhile suppressed cytochrome c release from mitochondria. Furthermore, CORM-2 lessen the production of reactive oxygen species (ROS) and increased myocardial mitochondrial respiratory complex IV enzyme activity after CPR. Dynamin-related protein 1（Drp1) was significantly less expressed in CORM-2 group with high expression of mitofusion-2 (Mfn2), suggesting that CORM-2 can promote mitochondrial fusion and reduce mitochondrial fission. Collectively, we provide the evidence that CORM-2 effectively relieved myocardial injury after CPR in rats, protected myocardial mitochondria, and preserved cardiac function after resuscitation. The proposed mechanisms of action were improved mitochondrial respiratory function, maintained mitochondrial dynamics balance, and suppressed the mitochondrial-mediated apoptosis.

An all-in-one CO gas therapy-based hydrogel dressing with sustained insulin release, anti-oxidative stress, antibacterial, and anti-inflammatory capabilities for infected diabetic wounds

To effectively treat diabetic wounds, the development of versatile medical dressings that can long-term regulate blood glucose and highly effective anti-oxidative stress, antibacterial and anti-inflammatory are critical. Here, an all-in-one CO gas-therapy-based versatile hydrogel dressing (ICOQF) was developed via the dynamic Schiff base reaction between the amino groups on quaternized chitosan (QCS) and the aldehyde groups on benzaldehyde-terminated F108 (F108-CHO) micelles. CORM-401 (an oxidant-sensitive CO-releasing molecules) was encapsulated in the hydrophobic core of F108-CHO micelles and insulin was loaded in the three-dimensional network structure of ICOQF. The dynamic Schiff base bonds not only endowed ICOQF with good tissue adhesion, injectability and self-healing, but also gave it sustained and controllable insulin release ability. In addition, ICOQF could quickly generate CO in inflamed wound tissue by consuming reactive oxygen species. The generated CO could effectively anti-oxidative stress by activating the expression of heme oxygenase; antibacterial by inducing the rupture of bacterial cell membranes and mitochondrial dysfunction and inhibiting the synthesis of adenosine triphosphate; and anti-inflammatory by inhibiting the proliferation of activated macrophages and promoting the polarization of the M1 phenotype to the M2 phenotype. Due to these outstanding properties, ICOQF significantly promoted the healing of STZ-induced MRSA-infected diabetic wounds accompanied by good biocompatibility. This study clearly shows that ICOQF is a versatile hydrogel dressing with great application potential for the management of diabetic wounds. Statement of significanceThe development of some versatile hydrogel dressings that can not only provide a prolonged and controlled insulin release property but also utilize a non-antibiotic treatment modality for highly effective antibacterial, anti-inflammatory, and anti-oxidative stress effects is vital for the successful treatment of diabetic wounds. Herein, we developed an all-in-one CO gas-therapy-based versatile hydrogel dressing (ICOQF) with sustained and controllable insulin release abilities. Moreover, ICOQF could not only quickly release CO in the inflamed wound tissue by consumption of reactive oxygen species but also utilize the generated CO to highly effectively anti-oxidative stress, antibacterial, and anti-inflammatory. ICOQF therapy substantially promoted the healing of STZ-induced MRSA-infected diabetic wounds. Overall, this work provides a multifunctional hydrogel dressing for the management of diabetic wounds.

CORM-401, an orally active carbon monoxide-releasing molecule, increases body temperature by activating non-shivering thermogenesis in rats

ABSTRACT Thermoregulation is critical in health and disease and is tightly controlled to maintain body temperature homeostasis. Carbon monoxide (CO), an endogenous gasotransmitter produced during heme degradation by heme oxygenases, has been suggested to play a role in body core temperature (Tb) regulation. However, a direct involvement of CO in thermoregulation has not been confirmed and its mechanism(s) of action remain largely unknown. In the present study we characterized the effects of systemic delivery of CO by administration of an orally active CO-releasing molecule (CORM-401) on Tb regulation in conscious freely moving rats. Specifically, we evaluated the main thermo effectors in rats treated with CORM-401 by assessing: (i) non-shivering thermogenesis, i.e. the increased metabolism of brown fat measured through oxygen consumption and (ii) the rate of heat loss from the tail through calculations of heat loss index. We found that oral administration of CORM-401 (30 mg/kg) resulted in augmented CO delivery into the blood circulation as evidenced a by significant increase in carbon monoxy hemoglobin levels(COHb). In addition, treatment with CORM-401 increased Tb, which was caused by an elevated non-shivering thermogenesis indicated by increased oxygen consumption without significant changes in the tail heat loss. On the other hand, CORM-401 did not affect blood pressure, but significantly decreased heart rate. In summary, the findings of the present study reveal that increased circulating CO levels lead to a rise in Tb, which could have important implications in the emerging role of CO in the modulation of energetic metabolism.

Carbon monoxide and β-cell function: Implications for type 2 diabetes mellitus

Carbon monoxide (CO), a member of the multifunctional gasotransmitters family produced by heme oxygenases (i.e., HO-1 and HO-2), has received significant attention because of its involvement in carbohydrate metabolism. Experimental evidence indicates that both HO-2- and HO-1-derived CO stimulate insulin secretion, but the latter mainly acts as a compensatory response in pre-diabetes conditions. CO protects pancreatic β-cell against cytokine- and hypoxia-induced apoptosis and promotes β-cell regeneration. CO cross-talks with nitric oxide (NO) and hydrogen sulfide (H2S), other important gasotransmitters in carbohydrate metabolism, in regulating β-cell function and insulin secretion. These data speak in favor of the potential therapeutic application of CO in type 2 diabetes mellitus (T2DM) and preventing the progression of pre-diabetes to diabetes. Either CO (as both gaseous form and CO-releasing molecule) or pharmacological formulations made of natural HO inducers (i.e., bioactive components originating from plant-based foods) are potential candidates for developing CO-based therapeutics in T2DM. Future studies are needed to assess the safety/efficacy and potential therapeutic applications of CO in T2DM.

Synergetic Antimicrobial Activity and Mechanism of Clotrimazole-Linked CO-Releasing Molecules.

Several metal-based carbon monoxide-releasing molecules (CORMs) are active CO donors with established antibacterial activity. Among them, CORM conjugates with azole antibiotics of type [Mn(CO)3(2,2′-bipyridyl)(azole)]+ display important synergies against several microbes. We carried out a structure–activity relationship study based upon the lead structure of [Mn(CO)3(Bpy)(Ctz)]+ by producing clotrimazole (Ctz) conjugates with varying metal and ligands. We concluded that the nature of the bidentate ligand strongly influences the bactericidal activity, with the substitution of bipyridyl by small bicyclic ligands leading to highly active clotrimazole conjugates. On the contrary, the metal did not influence the activity. We found that conjugate [Re(CO)3(Bpy)(Ctz)]+ is more than the sum of its parts: while precursor [Re(CO)3(Bpy)Br] has no antibacterial activity and clotrimazole shows only moderate minimal inhibitory concentrations, the potency of [Re(CO)3(Bpy)(Ctz)]+ is one order of magnitude higher than that of clotrimazole, and the spectrum of bacterial target species includes Gram-positive and Gram-negative bacteria. The addition of [Re(CO)3(Bpy)(Ctz)]+ to Staphylococcus aureus causes a general impact on the membrane topology, has inhibitory effects on peptidoglycan biosynthesis, and affects energy functions. The mechanism of action of this kind of CORM conjugates involves a sequence of events initiated by membrane insertion, followed by membrane disorganization, inhibition of peptidoglycan synthesis, CO release, and break down of the membrane potential. These results suggest that conjugation of CORMs to known antibiotics may produce useful structures with synergistic effects that increase the conjugate’s activity relative to that of the antibiotic alone.

Construction of a unique two-photon fluorescent probe and the application for endogenous CO detection in live organisms.

Carbon monoxide (CO) is one of the most significant signal molecules and plays an important role in regulating human physiological and pathological processes. In this study, a novel Pd-based complex (Pd-BNP-OH) was developed for endogenous CO detection. The structure and morphology of Pd-BNP-OH was characterized by SEM, XPS, and NMR analyses. When Pd-BNP-OH was reacted with CO, a strong fluorescence enhancement at 510nm was observed. In addition, Pd-BNP-OH exhibited high stability and selectivity toward CO in PBS buffer. In biological experiments, Pd-BNP-OH exhibited little cytotoxicity in cellular environment, and a bright fluorescence turn on was observed in the presence of exogenous CO and endogenous generated CO. The probe was then applied for CO detection in live zebrafish by both one-photon and two-photon excitation. Significantly, Pd-BNP-OH has excellent two-photon property, controllable structure and high biocompatibility. These features enable the probe to detect endogenously generated carbon monoxide in live organisms successfully.

Group 6 photo-activable carbon monoxide-releasing molecules (PhotoCORMs) with 1’10-phenanthroline based ligand as potential anti-proliferative and anti-microbial agents

A new series of group 6 UV activable photoCORMs were synthesized by reacting the ligand (((1,10-phenanthroline-5-yl)imino)methyl)naphthalen-2-ol (1) with group 6 (Cr, Mo, and W) hexacarbonyl to form 2, 3, and 4, respectively. The structural elucidations of all compounds were conducted via IR, NMR, and CHN elemental analyses. The crystal structures of all the synthesized compounds were obtained and the half-life of the photoCORMs were determined by using the three-layered myoglobin solution assay. Results showed that the half-life of the compounds decreased down the group 6 in a concentration-dependent manner, with compound 2 displaying the shortest half-life (7.1 s) at 60 µM. In the absence of UV light, compounds 1 and 3 showed cytotoxicity and selectivity against human-derived colorectal adenocarcinoma HT-29 and carcinoma HCT 116, with ligand 1 being the most cytotoxic compound. Nonetheless, most compounds were inactive against bacteria and fungi when UV light is absent, while only 1 showed appreciable activity against B. cereus, B. subtilis, E. faecalis, and S. aureus. In the presence of UV light, the cytotoxicity and selectivity of photoCORMs 2, 3, and 4 were significantly elevated, with 2 and 4 demonstrating the most drastic improvement against HT-29 (from IC50 ≥ 100 to 26.03 and 38.03 µM, respectively). The growth inhibitory activity of 2, 3, and 4 were also considerably enhanced in the presence of UV illumination when tested against B. cereus, B. subtilis, S. aureus, E. coli, K. pneumoniae, and S. flexneri, with compound 2 demonstrating the biggest leap among the three photoCORMs.

Spirulina extract improves age-induced vascular dysfunction

Context Vascular dysfunction is considered a hallmark of ageing that has been associated with altered vasomotor responses, in which nitric oxide (NO) and reactive oxygen species participate. The consumption of Spirulina extracts, with antioxidant properties, increased recently. Objective This study investigates the effect of Spirulina aqueous extract (SAE) on the vascular function of the aorta from aged rats. Materials and methods Aortic segments from aged male Sprague-Dawley rats (20–22 months old) were exposed to SAE (0.1% w/v, for 3 h) to analyse: (i) the vasodilator response induced by acetylcholine (ACh), by the NO donor sodium nitroprusside (SNP), by the carbon monoxide releasing molecule (CORM) and by the KATP channel opener, cromakalim (CK); (ii) the vasoconstrictor response induced by KCl and noradrenaline (NA); (iii) the production of NO and superoxide anion, and (iv) the expression of the p-eNOS and HO-1 proteins. Results Incubation with SAE increased the expression of p-eNOS (1.6-fold) and HO-1 (2.0-fold), enhanced NO release (1.4-fold in basal and 1.9-fold in ACh-stimulated conditions) while decreased the production of superoxide (0.7-fold). SAE also increased the sensitivity (measured as pEC50) to ACh (control: −7.06 ± 0.11; SAE: −8.16 ± 0.21), SNP (control: −7.96 ± 0.16; SAE: −9.11 ± 0.14) and CK (control: −7.05 ± 0.39; SAE: −8.29 ± 0.53), and potentiated the response to KCl (1.3-fold) and to NA (1.7-fold). Conclusion The antioxidant properties of SAE improved the vasomotor responses of aorta from aged rats. These results may support the use of Spirulina as a protection against vascular dysfunction.

Role and Potential Mechanism of Heme Oxygenase-1 in Intestinal Ischemia-Reperfusion Injury.

Intestinal ischemia-reperfusion (IR) injury is a complex, multifactorial, and pathophysiological condition with high morbidity and mortality, leading to serious difficulties in treatment, especially in humans. Heme oxygenase (HO) is the rate-limiting enzyme involved in heme catabolism. HO-1 (an inducible form) confers cytoprotection by inhibiting inflammation and oxidation. Furthermore, nuclear factor-erythroid 2-related factor 2 (Nrf2) positively regulates HO-1 transcription, whereas BTB and CNC homolog 1 (Bach1) competes with Nrf2 and represses its transcription. We investigated the role and potential mechanism of action of HO-1 in intestinal IR injury. Intestinal ischemia was induced for 45 min followed by 4 h of reperfusion in wild-type, Bach1-deficient, and Nrf2-deficient mice, and a carbon monoxide (CO)-releasing molecule (CORM)-3 was administered. An increase in inflammatory marker levels, nuclear factor-κB (NF-κB) activation, and morphological impairments were observed in the IR-induced intestines of wild-type mice. These inflammatory changes were significantly attenuated in Bach1-deficient mice or those treated with CORM-3, and significantly exacerbated in Nrf2-deficient mice. Treatment with an HO-1 inhibitor reversed this attenuation in IR-induced Bach1-deficient mice. Bach1 deficiency and treatment with CORM-3 resulted in the downregulation of NF-κB activation and suppression of adhesion molecules. Together, Bach1, Nrf2, and CO are valuable therapeutic targets for intestinal IR injury.

Structure-Photoreactivity Relationship of 3-Hydroxyflavone-Based CO-Releasing Molecules.

Carbon monoxide (CO) is an endogenous signaling molecule that regulates diverse physiological processes. The therapeutic potential of CO is hampered by its intrinsic toxicity, and its administration poses a significant challenge. Photoactivatable CO-releasing molecules (photoCORMs) are an excellent tool to overcome the side effects of untargeted CO administration and provide precise spatial and temporal control over its release. Here, we studied the CO release mechanism of a small library of derivatives based on 3-hydroxy-2-phenyl-4H-benzo[g]chromen-4-one (flavonol), previously developed as an efficient photoCORM, by steady-state and femto/nanosecond transient absorption spectroscopies. The main objectives of the work were to explore in detail how to enhance the efficiency of CO photorelease from flavonols, bathochromically shift their absorption bands, control their acid-base properties and solubilities in aqueous solutions, and minimize primary or secondary photochemical side-reactions, such as self-photooxygenation. The best photoCORM performance was achieved by combining substituents, which simultaneously bathochromically shift the chromophore absorption spectrum, enhance the formation of the productive triplet state, and suppress the singlet oxygen production by shortening flavonol triplet-state lifetimes. In addition, the cell toxicity of selected flavonol compounds was analyzed using in vitro hepatic HepG2 cells.

Golgi-Targeting Fluorescent Probe for Monitoring CO-Releasing Molecule-3 In Vitro and In Vivo.

CO-releasing molecule-3 (CORM-3), mainly metal carbonyl compounds, is widely used as experimental tools to deliver CO, a biological “gasotransmitter”, in mammalian systems. CORM-3 is also proposed as a potential new antimicrobial agent, which kills bacteria effectively and rapidly in vitro and in animal models. Organelle-targeting therapy, as a highly effective therapeutic strategy with little toxic and side effects, has important research significance and development prospects. Therefore, the development of effective methods for detecting and tracking CORM-3 at the subcellular level has important implications. In this paper, an easily available Golgi-targetable fluorescent probe (Golgi-Nap-CORM-3) was proposed for CORM-3 detection. In the probe Golgi-Nap-CORM-3, the phenyl sulfonamide group was selected as the Golgi-targetable unit, naphthalimide dye was chosen as a fluorophore, and the nitro group was selected as a CORM-3-responsive unit. Golgi-Nap-CORM-3 shows a CORM-3-reponsive increase of fluorescence emission at 520 nm. Using the excellent probe, the change of CORM-3 in HeLa cells, HepG2 cells, and zebrafish is successfully monitored. This study demonstrates very important information for the study of CORM-3 in vivo systems.

Carbon monoxide-releasing molecule-2 protects intestinal mucosal barrier function by reducing epithelial tight-junction damage in rats undergoing cardiopulmonary resuscitation

BackgroundIschemia-reperfusion injury (IRI) to the small intestine is associated with the development of systemic inflammation and multiple organ failure after cardiopulmonary resuscitation (CPR). It has been reported that exogenous carbon monoxide (CO) reduces IRI. This study aimed to assess the effects of carbon monoxide-releasing molecule-2 (CORM-2) on intestinal mucosal barrier function in rats undergoing CPR. MethodsWe established a rat model of asphyxiation-induced cardiac arrest (CA) and resuscitation to study intestinal IRI, and measured the serum levels of intestinal fatty acid-binding protein. Morphological changes were investigated using light and electron microscopes. The expression levels of claudin 3 (CLDN3), occludin (OCLN), zonula occludens 1 (ZO-1), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), and nuclear factor kappa B (NF-κB) p65 were detected by western blotting. ResultsCompared with the sham-operated group, histological changes and transmission electron microscopy revealed severe intestinal mucosal injury in the CPR and inactive CORM-2 (iCORM-2) groups. In contrast, CORM-2 alleviated intestinal IRI. CORM-2, unlike iCORM-2, markedly decreased the Chiu's scores (2.38 ± 0.38 vs. 4.59 ± 0.34; P < 0.05) and serum intestinal fatty acid-binding protein level (306.10 ± 19.22 vs. 585.64 ± 119.84 pg/mL; P < 0.05) compared with the CPR group. In addition, CORM-2 upregulated the expression levels of tight junction proteins (CLDN3, OCLN, and ZO-1) (P < 0.05) and downregulated those of IL-10, TNF-α, and NF-кB p65 (P < 0.05) in the ileum tissue of rats that received CPR. ConclusionsCORM-2 prevented intestinal mucosal damage as a result of IRI during CPR. The underlying protective mechanism was associated with inhibition of ischemia-reperfusion-induced changes in intestinal epithelial permeability and inflammation in intestinal tissue.

Carbon monoxide releasing molecule-2 attenuates angiotensin II-induced IL-6/Jak2/Stat3-associated inflammation by inhibiting NADPH oxidase- and mitochondria-derived ROS in human aortic smooth muscle cells

Abdominal aortic aneurysm (AAA) is a common inflammatory vascular disease. Angiotensin II (Ang II) involves in AAA progression by promoting the proliferation and migration of vascular smooth muscle cells, the degradation of extracellular matrices, and the generation of ROS to lead to vascular inflammation. Carbon monoxide releasing molecule-2 (CORM-2) is known to exert anti-inflammatory and antioxidant activities. However, it remains unclear whether CORM-2 can suppress Ang II-induced vascular inflammation to prevent AAA progression. Therefore, this study aimed to investigate the vasoprotective effects of CORM-2 against Ang II-induced inflammatory responses of human aortic smooth muscle cells (HASMCs) and the underlying mechanisms of those effects. The results showed that Ang II induced inflammatory responses of HASMCs via NADPH oxidase- and mitochondria-derived ROS/NF-κB/IL-6/Jak2/Stat3 pathway which was attenuated by the pretreatment with CORM-2. Additionally, CORM-2 further exhibited anti-inflammatory activities in Ang II-stimulated HASMCs, as indicated by the reduction of monocyte adhesion to HASMCs and migration of HASMCs via the suppression of ICAM-1 and VCAM-1 as well as MMP-2 and MMP-9 levels, respectively. Moreover, Ang II-induced COX-2-mediated PGE2 secretion was also inhibited by the pretreatment with CORM-2. Importantly, our data demonstrated that CORM-2 reversed Ang II-induced IL-6 overexpression dependent on Nrf2 activation and HO-1 expression. Taken together, the present study indicates that CORM-2-induced Nrf2/HO-1 alleviates IL-6/Jak2/Stat3-mediated inflammatory responses to Ang II by inhibiting NADPH oxidase- and mitochondria-derived ROS, suggesting that CORM-2 is a promising pharmacologic candidate to reverse the pathological changes involved in the inflammation of vessel wall for the prevention and treatment of AAA.

Manganese Carbonyl-Loaded Hollow Mesoporous Silica Nanoparticles Coated with Neutrophil Membranes for Acute Kidney Injury Therapy

Acute kidney injury (AKI) has a very high incidence in hospitalized patients, but it lacks effective therapy clinically. Its pathogenesis is associated with capillary hypoperfusion around renal tubules, production of reactive oxygen free radicals (ROS), and infiltration of inflammatory cells. Endogenous carbon monoxide (CO) can protect cells or organs by vasodilation, anti-inflammation, and reducing oxidative stress injury. However, direct exogenous CO supplementation is difficult to control the exact dose, and excessive CO has obvious toxicity, which is difficult to be applied in clinical treatment. In this study, we constructed H2O2-responsive nanomedicine for CO therapy of AKI by loading manganese carbonyl (MnCO) onto the hollow mesoporous silicon nanoparticles (hMSN), which were coated with a neutrophil membrane with the insertion of phosphatidylserine (PS) into the membrane surface (MnCO@hMSN@NM-PS). MnCO@hMSN@NM-PS was located in the renal tubules of AKI through the biomimetic chemotaxis of the neutrophil membrane to the inflammation site and the active binding of PS to kidney injury molecule-1 (KIM-1), which was overexpressed in damaged renal tubular epithelial cells. MnCO@hMSN@NM-PS had a good protective effect on oxidative damage of renal tubular cells in vitro and glycerol-induced AKI in vivo. MnCO@hMSN@NM-PS offers hope for the treatment of AKI.

Detection and imaging of Carbon monoxide releasing Molecule-2 in HeLa cells and zebrafish using a Metal-Free Near-Infrared fluorescent off–on probe

By incorporating 4-nitrobenzene as the recognition unit into a stable hemicyanine skeleton based on IR 780, a designed near-infrared fluorescent off–on probe DNXI shows excellent analytical performance in real-time monitoring of carbon monoxide releasing molecule-2 (CORM-2) in living HeLa cells and zebrafish without transition metals. The response mechanism of CORM-2 with DNXI may reduce the nitro group to an amino group, followed by 1,6-rearrangement elimination reaction, resulting in the recovery of both color and fluorescence signal. As a result, DNXI shows very low background signal, which is rather desired for achieving sensitive detection of CORM-2. Compared with the existing CORM-2 probes, DNXI shows excellent optical performance in vitro and in vivo, high selectivity and sensitivity to CORM-2, as well as near-infrared fluorescence emission 712 nm, with a low detection limit of 103 nM. More importantly, DNXI is low cytotoxic, cell membrane permeable, and its applicability has been demonstrated for monitoring CORM-2 in living HeLa cells and zebrafish. These superior properties of the probe enable it have great potential to be used in biological systems or in vivo related studies.

X-ray-Triggered CO Release Based on GdW10/MnBr(CO)5 Nanomicelles for Synergistic Radiotherapy and Gas Therapy.

Carbon monoxide (CO) therapy has become a hot topic in the field of gas therapy because of its application prospect in the treatment of various diseases. Due to the high affinity for human hemoglobin, the main challenge of CO-loaded nanomedicine is the lack of selectivity and toxicity in the delivery process. Although many commercial CO-releasing molecules (CORMs) have been widely developed because of their ability to deliver CO, CORMs still have some disadvantages, including difficult on-demand controlled CO release, poor solubility, and potential toxicity, which are limiting their further application. Herein, an X-ray-triggered CO-releasing nanomicelle system (GW/MnCO@PLGA) based on GdW10 nanoparticles (NPs) (GW) and MnBr(CO)5 (MnCO) encapsulating in the poly(lactic-co-glycolic acid) (PLGA) polymer was constructed for synergistic CO radiotherapy (RT). The production of strongly oxidative superoxide anion (O2-•) active species can lead to cell apoptosis under the X-ray sensitization of GW. Moreover, strongly oxidative O2-• radicals further oxidize and compete with the Mn center, resulting in the on-demand release of CO. The radio/gas therapy synergy to enhance the efficient tumor inhibition of the nanomicelles was investigated in vivo and in vitro. Therefore, the establishment of an X-ray-triggered controlled CO release system has great application potential for further synergistic RT CO therapy in deep tumor sites.

Моніторинг вмісту в крові карбоксигемоглобіну для оцінки тяжкості травматичного шоку та реперфузійних ушкоджень (аналітичний огляд з результатами власних спостережень)

Монооксид вуглецю — природний метаболіт організму. В організмі СО утворюється в процесі роботи ферменту гемоксигенази 1 та 2 із зруйнованого гемоглобіну. Цей процес зумовлює утворення деякої кількості карбоксигемоглобіну у здорових осіб, навіть якщо СО не надходить до організму ззовні в процесі дихання. СО виконує функції сигнальної молекули, модулюючи стан тонусу серцево-судинної системи, пригнічує та сприяє зворотному розвитку порушень, що викликані запальною відповіддю, та може відігравати важливу роль як потенційний терапевтичний агент. З іншого боку, СО при взаємодії з гемоглобіном утворює карбоксигемоглобін та витісняє кисень із зв’язки з гемоглобіном, що веде до неспроможності доставки кисню тканинам. Окрім цього, СО також зв’язується із міоглобіном та мітохондріальною цитохромоксидазою. Тривала присутність у крові значної кількості СО викликає серйозні ушкодження міокарда та центральної нервової системи. Отже, надмірна ендогенна продукція СО та надмірне утворення карбоксигемоглобіну можуть відігравати значну роль у тканинному пошкодженні та формуванні поліорганної дисфункції. Окрім гему, що звільнюється при руйнуванні гемоглобіну, джерелом продукції ендогенного СО та, у свою чергу, карбоксигемоглобіну можуть бути компоненти зруйнованих клітинних мембран та мітохондріальні ферменти, що містять гем. Клітинні ушкодження, що мають місце в умовах травматичного шоку, наслідки ішемії/реперфузії, геморагічне просочення тканин, гемотрансфузії та інтенсивне утворення агресивних вільних радикалів ведуть до зазначених подій. На сьогодні більшість дослідників розглядає продукцію СО та карбоксигемоглобіну при критичних станах як компенсаторний механізм, що забезпечує цитопротекцію та зростання виживаності хворих. Ми вивчили результати досліджень, що стосуються оцінки інтенсивності продукції СО, вмісту в крові карбоксигемоглобіну та вмісту СО в повітрі, що видихається, у пацієнтів в критичних станах та порівняли ці результати із даними власних спостережень. В іноземних джерелах наведено концентрації карбоксигемоглобіну в крові, що в більшості випадків не перевищували 4 %. У нашому дослідженні вивчались пацієнти із політравмою та крововтратою на ранньому госпітальному етапі. Оцінювалися показники центральної гемодинаміки, а також сатурація капілярної крові киснем, перфузійний індекс та вміст у крові карбоксигемоглобіну за допомогою технології компанії «Masimo». Усі постраждалі надходили до клініки з нормальним вмістом карбоксигемоглобіну в крові. Патологічне зростання концентрації карбоксигемоглобіну спостерігалося в процесі реперфузії. Швидка рідинна ресусцитація, застосування гіпертонічних розчинів та адреналіну сприяли зростанню артеріального тиску, перфузійного індексу та концентрації карбоксигемоглобіну. Наступне за реперфузією зростання концентрації в крові карбоксигемоглобіну було тим більшим, чим більш тяжким був перебіг шоку. Реінфузія крові також сприяла збільшенню концентрації карбоксигемоглобіну в крові. Високі показники концентрації карбоксигемоглобіну в крові постраждалих із травматичним шоком у період реперфузії закономірно викликають питання про його роль у формуванні мітохондріальної дисфункції при травматичній хворобі.

A new metal-free near-infrared fluorescent probe based on nitrofuran for the detection and bioimaging of carbon monoxide releasing molecule-2 in vivo.

As a stable donor for releasing controlled amounts of CO, carbon monoxide releasing molecule-2 (CORM-2) is a new type of therapeutic drug that contributes to exploring the pathophysiological effects of CO. The accurate detection of CORM-2 in biological systems is of great significance for controlling its dosage as a therapeutic drug and elucidating the reaction mechanisms of CO, but currently there is a lack of metal-free near-infrared fluorescent probes. Herein, a new metal-free near-infrared fluorescent probe based on nitrofuran which could selectively identify CORM-2 was designed and it has been successfully applied in living cells, zebrafish and mice. After reacting with CORM-2, both the color and fluorescence signal of the solution are restored, which is ascribed to the reduction of the nitro group. The spectroscopic probe DXPN shows high sensitivity to CORM-2 with a low detection limit of 87 nM and near-infrared fluorescence emission of 712 nm. Notably, this is the first time that paper chips are being used as a carrier to detect CORM-2 through fluorescence signals instead of the traditional liquid phase detection mode of fluorescent probes. These superior properties of the probe make it a promising and reliable tool for exploring the role played by CORM-2 in biological systems.

Carbon monoxide activation of delayed rectifier potassium currents of human cardiac fibroblasts through diverse pathways.

To identify the effect and mechanism of carbon monoxide (CO) on delayed rectifier K+ currents (IK) of human cardiac fibroblasts (HCFs), we used the whole-cell mode patch-clamp technique. Application of CO delivered by carbon monoxide-releasing molecule-3 (CORM3) increased the amplitude of outward K+ currents, and diphenyl phosphine oxide-1 (a specific IK blocker) inhibited the currents. CORM3-induced augmentation was blocked by pretreatment with nitric oxide synthase blockers (L-NG-monomethyl arginine citrate and L-NG-nitro arginine methyl ester). Pretreatment with KT5823 (a protein kinas G blocker), 1H-[1,-2,-4] oxadiazolo-[4,-3-a] quinoxalin-1-on (ODQ, a soluble guanylate cyclase blocker), KT5720 (a protein kinase A blocker), and SQ22536 (an adenylate cyclase blocker) blocked the CORM3 stimulating effect on IK. In addition, pretreatment with SB239063 (a p38 mitogen-activated protein kinase [MAPK] blocker) and PD98059 (a p44/42 MAPK blocker) also blocked the CORM3’s effect on the currents. When testing the involvement of S-nitrosylation, pretreatment of N-ethylmaleimide (a thiol-alkylating reagent) blocked CO-induced IK activation and DL-dithiothreitol (a reducing agent) reversed this effect. Pretreatment with 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)-21H,23H porphyrin manganese (III) pentachloride and manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (superoxide dismutase mimetics), diphenyleneiodonium chloride (an NADPH oxidase blocker), or allopurinol (a xanthine oxidase blocker) also inhibited CO-induced IK activation. These results suggest that CO enhances IK in HCFs through the nitric oxide, phosphorylation by protein kinase G, protein kinase A, and MAPK, S-nitrosylation and reduction/oxidation (redox) signaling pathways.

Devil or angel: two roles of carbon monoxide in stroke.

Stroke is one of the most important acute diseases that endanger human health and result in death, including acute cerebral hemorrhage and acute cerebral ischemia. Acute onset is its most prominent feature. Carbon monoxide (CO) is a colorless and odorless gas existing at room temperature. It is not only a common air pollutant, but also has been found to be closely related to stroke. A large amount of exogenous CO has an important impact on the incidence and prognosis of stroke, while endogenous CO as a gas signal also has an important impact on neuroprotection after stroke. Both low-dose CO inhalation and CO-releasing molecule-3 (a molecule that emits CO) treatment have shown the benefits of stroke, and perhaps the role of CO in stroke is one of the key areas for future research.