Carbon Monoxide May Reduce Ischemia Reperfusion Injury: A Case Report of Complicated Kidney Transplantation From a Carbon Monoxide Poisoned Donor

Evaluation of the Neuroprotective Effects of Idebenone in an Experimental Carbon Monoxide Poisoning Model

Carbon monoxide (CO) poisoning is among the main causes of poisoning-related mortality and morbidity, primarily affecting the central nervous system and leading to delayed neurological sequelae. Idebenone exerts antioxidant and neuroprotective effects. In this study, we aimed to evaluate the specific neuroprotective effects of idebenone against CO poisoning. Forty female Wistar Albino rats were used in this study. Except the controls, the other rats inhaled 5000 ppm CO until a change in consciousness was observed. Rats with carboxyhemoglobin concentrations over 20% in blood samples collected from the tail vein were considered successful acute CO poisoning models. The rats were divided into five groups: healthy control (HC; group 1), CO + saline (CO-S; group 2), CO + 100 mg/kg idebenone (CO-I100; group 3), CO + 200 mg/kg idebenone (CO-I200; group 4), and CO + 300 mg/kg idebenone (CO-I300; group 5). Pre-determined doses of idebenon were orally administered to the rats at 24-h intervals for 5 days. The rats were anesthetized and sacrificed 24 h after the last drug dose. Histopathological and biochemical parameters were examined in the blood and hippocampus samples of the rats. Histopathological grading of neurons in the hippocampus revealed that the CO-S group exhibited the highest number of grade 1, 2, and 3 degenerative cells (all p = 0.001). Apoptotic index was the highest in the CO-S group and significantly low in the idebenone-treated groups (p = 0.001). Neuron-specific enolase and malondialdehyde levels and oxidative stress index were significantly lower in both the hippocampus and serum samples of the idebenone-treated groups than in those of the CO-S group (all p values = 0.001). Overall, idebenone inhibited degeneration due to CO-induced brain damage and exerted neuroprotective effects against oxidative stress in rats.

Water-Soluble Carbon Monoxide-Releasing Molecules (CORMs)

Carbon monoxide-releasing molecules (CORMs) are promising candidates for producing carbon monoxide in the mammalian body for therapeutic purposes. At higher concentrations, CO has a harmful effect on the mammalian organism. However, lower doses at a controlled rate can provide cellular signaling for mandatory pharmacokinetic and pathological activities. To date, exploring the therapeutic implications of CO dose as a prodrug has attracted much attention due to its therapeutic significance. There are two different methods of CO insertion, i.e., indirect and direct exogenous insertion. Indirect exogenous insertion of CO suggests an advantage of reduced toxicity over direct exogenous insertion. For indirect exogenous insertion, researchers are facing the issue of tissue selectivity. To solve this issue, developers have considered the newly produced CORMs. Herein, metal carbonyl complexes (MCCs) are covalently linked with CO molecules to produce different CORMs such as CORM-1, CORM-2, and CORM-3, etc. All these CORMs required exogenous CO insertion to achieve the therapeutic targets at the optimized rate under peculiar conditions or/and triggering. Meanwhile, the metal residue was generated from i-CORMs, which can propagate toxicity. Herein, we explain CO administration, water-soluble CORMs, tissue accumulation, and cytotoxicity of depleted CORMs and the kinetic profile of CO release.

Successful Liver Transplantation from a Deceased Donor After Ethylene Glycol Ingestion: A Case Report and Review of the Literature of Organ Donation from Poisoned Donors

Despite the increase in deceased organ donation over the past ten years, the gap between patients awaiting transplant and available organs continues to widen. Deceased donors secondary to acute fatal poisonings represent less than 1% of all organ donors. Organs from poisoned donors have largely been discarded due to concerns of toxin transmission and poor organ function as well as the paucity of data that exists regarding this donor population. Here, we report a case of a 40-year-old male who underwent successful liver re-transplantation from a donor who died following ethylene glycol ingestion. To our knowledge this case report is the first to describe successful re-transplantation from an ethylene glycol-poisoned donor. We also provide a comprehensive review of the literature describing organ donation from poisoned donors.

CO as a therapeutic agent: discovery and delivery forms

Carbon monoxide (CO) as one of the three important endogenously produced signaling molecules, termed as "gasotransmitter," has emerged as a promising therapeutic agent for treating various inflammation and cellular-stress related diseases. In this review, we discussed CO's evolution from a well-recognized toxic gas to a signaling molecule, and the effort to develop different approaches to deliver it for therapeutic application. We also summarize recently reported chemistry towards different CO delivery forms.

Carbon monoxide: An emerging therapy for acute kidney injury

Treating acute kidney injury (AKI) represents an important unmet medical need both in terms of the seriousness of this medical problem and the number of patients. There is also a large untapped market opportunity in treating AKI. Over the years, there has been much effort in search of therapeutics with minimal success. However, over the same time period, new understanding of the underlying pathobiology and molecular mechanisms of kidney injury have undoubtedly helped the search for new therapeutics. Along this line, carbon monoxide (CO) has emerged as a promising therapeutic agent because of its demonstrated cytoprotective, and immunomodulatory effects. CO has also been shown to sensitize cancer, but not normal cells, to chemotherapy. This is particularly important in treating cisplatin-induced AKI, a common clinical problem that develops in patients receiving cisplatin therapies for a number of different solid organ malignancies. This review will examine and make the case that CO be developed into a therapeutic agent against AKI.

CO-Releasing Materials: An Emphasis on Therapeutic Implications, as Release and Subsequent Cytotoxicity Are the Part of Therapy

The CO-releasing materials (CORMats) are used as substances for producing CO molecules for therapeutic purposes. Carbon monoxide (CO) imparts toxic effects to biological organisms at higher concentration. If this characteristic is utilized in a controlled manner, it can act as a cell-signaling agent for important pathological and pharmacokinetic functions; hence offering many new applications and treatments. Recently, research on therapeutic applications using the CO treatment has gained much attention due to its nontoxic nature, and its injection into the human body using several conjugate systems. Mainly, there are two types of CO insertion techniques into the human body, i.e., direct and indirect CO insertion. Indirect CO insertion offers an advantage of avoiding toxicity as compared to direct CO insertion. For the indirect CO inhalation method, developers are facing certain problems, such as its inability to achieve the specific cellular targets and how to control the dosage of CO. To address these issues, researchers have adopted alternative strategies regarded as CO-releasing molecules (CORMs). CO is covalently attached with metal carbonyl complexes (MCCs), which generate various CORMs such as CORM-1, CORM-2, CORM-3, ALF492, CORM-A1 and ALF186. When these molecules are inserted into the human body, CO is released from these compounds at a controlled rate under certain conditions or/and triggers. Such reactions are helpful in achieving cellular level targets with a controlled release of the CO amount. However on the other hand, CORMs also produce a metal residue (termed as i-CORMs) upon degradation that can initiate harmful toxic activity inside the body. To improve the performance of the CO precursor with the restricted development of i-CORMs, several new CORMats have been developed such as micellization, peptide, vitamins, MOFs, polymerization, nanoparticles, protein, metallodendrimer, nanosheet and nanodiamond, etc. In this review article, we shall describe modern ways of CO administration; focusing primarily on exclusive features of CORM's tissue accumulations and their toxicities. This report also elaborates on the kinetic profile of the CO gas. The comprehension of developmental phases of CORMats shall be useful for exploring the ideal CO therapeutic drugs in the future of medical sciences.

Can carbon monoxide-poisoned victims be organ donors?

The increasing demand for organ allografts to treat end-stage organ failure has driven changes in traditional donor criteria. Patients who have succumbed to carbon monoxide (CO) poisoning, a common cause of toxicological mortality, are usually rejected as organ donors. To fulfill the increasing demand, selection criteria must be expanded to include CO-poisoned donors. However, the use of allografts exposed to high CO concentrations is still under debate. Basic research and literature review data suggest that patients with brain death caused by CO poisoning should be considered appropriate organ donors. Accepting organs from CO-poisoned victims could increase the number of potential donors and lower the death rate of patients on the waiting lists. This review and reported cases may increase awareness among emergency department physicians, as well as transplant teams, that patients dying of CO exposure may be acceptable organ donors.

Research of medical gases in Poland

Research of medical gases is well established in Poland and has been marked with the foundation of several professional societies. Numerous academic centers including those dealing with hyperbaric and diving medicine conduct studies of medical gases, in vast majority supported with intramural funds. In general, Polish research of medical gases is very much clinical in nature, covering new applications and safety of medical gases in medicine; on the other hand there are several academic centers pursuing preclinical studies, and elaborating basic theories of gas physiology and mathematical modeling of gas exchange. What dominates is research dealing with oxygen and ozone as well as studies of anesthetic gases and their applications. Finally, several research directions involving noble gas, hydrogen and hydrogen sulfide for cell protection, only begin to gain recognition of basic scientists and clinicians. However, further developments require more monetary spending on research and clinical testing as well as formation of new collective bodies for coordinating efforts in this matter.

The diagnostic value of serum ischemia-modified albumin levels in experimentally induced carbon monoxide poisoning and their correlation with poisoning severity

OBJECTIVES

The objectives were to determine the diagnostic value of blood ischemia-modified albumin (IMA) levels in experimentally induced carbon monoxide (CO) poisoning and to analyze their correlation with poisoning severity.

METHODS

Thirty-six female rats were randomly assigned to one of three groups: I (control group), II (low-dose CO poisoning group), and III (high-dose CO poisoning group). The control group was kept in room air, while groups II and III were exposed to 3 L/min of 3,000 ppm and 3 L/min of 5,000 ppm CO gas for 30 minutes, respectively. Serum carboxyhemoglobin (COHb), IMA, and malondialdehyde (MDA) levels; brain, heart, lung, liver, and kidney tissue MDA measurements; and histopathologic damage scores were then compared.

RESULTS

IMA levels were significantly higher in groups II and III than in group I. A moderate positive correlation was observed between COHb and IMA levels. There was a strong positive correlation between COHb levels and degree of damage in all organs, but IMA and MDA levels did not reflect a similar correlation.

CONCLUSIONS

Ischemia-modified albumin levels are higher in rats exposed to CO. This indicates that IMA levels can potentially be important in the diagnosis of exposure to CO or of CO poisoning. However, IMA levels are not a good biochemical marker in terms of determining the severity of poisoning.

Role of carbon monoxide in kidney function: is a little carbon monoxide good for the kidney?

Carbon monoxide (CO) is an endogenously produced gas resulting from the degradation of heme by heme oxygense or from fatty acid oxidation. Heme oxygenase (HO) enzymes are constitutively expressed in the kidney (HO-2) and HO-1 is induced in the kidney in response to several physiological and pathological stimuli. While the beneficial actions of HO in the kidney have been recognized for some time, the important role of CO in mediating these effects has not been fully examined. Recent studies using CO inhalation therapy and carbon monoxide releasing molecules (CORMs) have demonstrated that increases in CO alone can be beneficial to the kidney in several forms of acute renal injury by limiting oxidative injury, decreasing cell apoptosis, and promoting cell survival pathways. Renal CO is also emerging as a major regulator of renal vascular and tubular function acting to protect the renal vasculature against excessive vasoconstriction and to promote natriuresis by limiting sodium reabsorption in tubule cells. Within this review, recent studies on the physiological actions of CO in the kidney will be explored as well as the potential therapeutic avenues that are being developed targeting CO in the kidney which may be beneficial in diseases such as acute renal failure and hypertension.

Use of carbon monoxide in minimizing ischemia/reperfusion injury in transplantation

Although carbon monoxide (CO) is known to be toxic because of its ability to interfere with oxygen delivery at high concentrations, mammalian cells endogenously generate CO primarily via the catalysis of heme by heme oxygenases. Recent findings have indicated that heme oxygenases and generation of CO serve as a key mechanism to maintain the integrity of the physiological function of organs and supported the development of a new paradigm that CO, at low concentrations, functions as a signaling molecule in the body and exerts significant cytoprotection. Consequently, exogenously delivered CO has been shown to mediate potent protection in various injury models through its anti-inflammatory, vasodilating, and antiapoptotic functions. Ischemia/reperfusion (I/R) injury associated with organ transplantation is one of the major deleterious factors limiting the success of transplantation. Ischemia/reperfusion injury is a complex cascade of interconnected events involving cell damage, apoptosis, vigorous inflammatory responses, microcirculation disturbance, and thrombogenesis. Carbon monoxide has a great potential in minimizing I/R injury. This review will provide an overview of the basic physiology of CO, preclinical studies examining efficacy of CO in I/R injury models, and possible protective mechanisms. Carbon monoxide could be developed to be a valuable therapeutic molecule in minimizing I/R injury in transplantation.

Solid organ procurement from donors with carbon monoxide poisoning and/or burn--a systematic review

INTRODUCTION

Traditionally, carbon monoxide poisoning and/or burn are considered contraindications to organ procurement. Previously reported cases have shown mixed results and many have been redundantly reported in the literature.

METHODS

We performed a systematic review of all reported cases of organ transplantation procured from donors with carbon monoxide poisoning and/or burn to investigate whether these patients are suitable donors for solid organ transplantations.

RESULTS

Organ survival rates of reported organs were high (86%). All organs procured from donors with carbon monoxide poisoning and burn survived during follow-up. Mean donors' peak carbon monoxide levels were comparable for organs surviving or failing during follow-up (31 ± 2.7 vs. 29 ± 26.8; p=0.95). Eighty-seven per cent of organs procured from donors supported with inotropes or vasopressors prior to organ procurement and 91% of organs procured from donors who were cardiopulmonary resuscitated prior to organ procurement survived during follow-up.

CONCLUSIONS

Burn, carbon monoxide poisoning, high peak carbon monoxide-levels, use of inotropes or vasopressors or cardiopulmonary resuscitation prior to procurement are not contraindications for organ procurement and transplantation. New guidelines for burn units defining the special requirements for organ procurement from donors with carbon monoxide poisoning and/or burn are needed to raise the awareness for potential organ donors and to ultimately increase the donor pool and save patients' lives.