Protective effects of tiopronin against oxidative stress in severely burned patients

The effect of topical magnesium on healing of pre-clinical burn wounds

BACKGROUND

Magnesium (Mg) is an essential factor in the healing process. This study aimed to evaluate the effect of Mg creams on healing burn wounds in the rat model.

METHODS

To induce burns under general anaesthesia, a 2 × 2 cm2, 100 °C plate was placed for 12 s between the scapulas in 100 male adult Sprague Dawley rats. Animals were divided into five groups (n = 20); positive control (induced burn without treatment); vehicle control (received daily Eucerin cream base topically); comparative control (induced burn and treated daily with Alpha burn cream topically); Treatment 1 and 2 (received daily Mg cream 2% and 4% topically, respectively). All animals were bled for hematological assessment of malondialdehyde (MDA) and TNF-α and sacrificed on days 0, 1, 7, 14, and 21 after interventions for biomechanical, histological, and stereological studies.

RESULTS

Stereologically speaking, in treatment groups an increase in dermal collagen volume and fibroblasts was noticed. In treatment groups, the length of vessels, angiogenesis, and skin stretch increased, but the wound area, MDA, and TNF-α level decreased.

CONCLUSION

Mg cream was effective in healing burns.

Carbon monoxide combined with artificial blood cells acts as an antioxidant for tissues thermally-damaged by dye laser irradiation

Artificial red blood cells [i.e., hemoglobin vesicles (HbVs)] can be used as photosensitizers in pulsed-dye laser (PDL) treatment for port wine stains in animal models. Small HbVs are distributed in the vicinity of the endothelial cells of the blood vessels. In our previous in vivo experiments, both HbVs and red blood cells absorbed photons of the laser and generated heat, contributing to removal of very small blood vessels and large deeper subcutaneous blood vessels with PDL irradiation. Herein, we tested carbon monoxide-bound HbVs (CO-HbVs) that would produce heat energy while releasing CO in vessels after dye laser irradiation in a rabbit auricle model. We conducted this experiment to confirm secondary progression of thermal injury being reduced with the antioxidative property of CO. We histopathologically evaluated the damages to the large vessels and surrounding dermal tissue following PDL irradiation alone or subsequent to the intravenous injection of the qualified HbVs. The soft tissue damages were graded on a five-point scale and compared statistically. Intravenous CO-HbVs significantly reduced damage to the surrounding tissue after subsequent PDL irradiation; however, the degree of damage to the larger vessel wall resulted in a variety of changes, including a slight increase in our histopathological grades. This beneficial effect in dye laser treatment for port wine stains may be the result of the antioxidative property of CO against free radicals in the zone of stasis that may still be theoretically viable in burns. This effect of CO protecting tissues from thermal damage is consistent with previous reports of CO as a reducing agent. If the reducing agent can be delivered directly to the affected area immediately after the burn injury, even in a small amount, the complex inflammatory cascade may be reduced and unnecessary inflammation after laser treatment that lowers the patient's quality of life can be avoided.

Burn Wound Healing: Clinical Complications, Medical Care, Treatment, and Dressing Types: The Current State of Knowledge for Clinical Practice

According to the World Health Organization (WHO), it is estimated that each year approximately 11 million people suffer from burn wounds, 180,000 of whom die because of such injuries. Regardless of the factors causing burns, these are complicated wounds that are difficult to heal and are associated with high mortality rates. Medical care of a burn patient requires a lot of commitment, experience, and multidirectional management, including surgical activities and widely understood pharmacological approaches. This paper aims to comprehensively review the current literature concerning burn wounds, including classification of burns, complications, medical care, and pharmacological treatment. We also overviewed the dressings (with an emphasis on the newest innovations in this field) that are currently used in medical practice to heal wounds.

Hepatic functional pathophysiology and morphological damage following severe burns: a systematic review and meta-analysis

INTRODUCTION

Severe burns are devastating injuries affecting multiple organ systems. Little is known about the influence on the hepatic system and its physiology. This systematic review aimed to assess the current state of research on morphologic liver damage following severe burns.

METHODS

A search was conducted in Pubmed, Web of Science and Cochrane databases using PRISMA guidelines. Outcomes included serum levels of transaminases, fatty infiltration and necrosis. Weighted individual study estimates were used to calculate pooled transaminase levels and necrosis/fatty infiltration rates using a random-effects approach. Risk ratios (RRs) or Odds ratios (ORs) and 95% confidence intervals (CIs) were used to describe pooled estimates for risk factors.

RESULTS

The literature search retrieved 2548 hits, of which 59 studies were included into qualitative synthesis, and finally ten studies were included into meta-analysis. Studies were divided into those reporting autopsies and those reporting changes of serum transaminase levels. The majority of liver autopsies showed fatty infiltration 82% (95% CI39%-97%) or necrosis of the liver 18% (95% CI13%-24%).

DISCUSSION

Heterogeneity in studies on hepatic functional damage following severe burns was high. Only few were well-designed and published in recent years. Many studies could not be included because of insufficient numerical data. There is a high number of patients deceasing from burns that present with fatty infiltration or necrosis of hepatic tissue. Transaminases were elevated during the first days after burn. Further research on how severe burns affect the hepatic function and outcome, especially long-term, is necessary.

The antioxidant N-(2-mercaptopropionyl)-glycine (tiopronin) attenuates expression of neuropathic allodynia and hyperalgesia

The current pharmacotherapy of neuropathic pain is inadequate as neuropathic pain involves varied clinical manifestations with multifactorial etiology, modulated by a cascade of physical and molecular events leading to different clinical presentations of pain. There is an accumulating evidence of the involvement of oxidative stress in neuropathy, and antioxidants have shown promise in mitigating neuropathic pain syndromes. To explore the evidence supporting this beneficial proclivity of antioxidants, this study investigated the antinociceptive effectiveness of N-(2-mercaptopropionyl)glycine or tiopronin, a well-recognized aminothiol antioxidant, in a refined chronic constriction injury (CCI) rat model of neuropathic pain. Tiopronin (10, 30, and 90 mg/kg, i.p.) and pregabalin (30 mg/kg, i.p.) were administered daily after CCI surgery. The neuropathic paradigms of mechanical/cold allodynia and mechanical/heat hyperalgesia were assessed on days 3, 7, 14, and 21 post-nerve ligation. At the end of study, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels were estimated in the sciatic nerve, dorsal root ganglion, and spinal cord for assessing the extent of oxidative stress. The expression of neuropathic nociception was attenuated by tiopronin which was observed as a significant attenuation of CCI-induced allodynia and hyperalgesia. Tiopronin reversed the neuronal oxidative stress by significantly reducing MDA, and increasing SOD, CAT, and GSH levels. Pregabalin also showed similar beneficial propensity on CCI-induced neuropathic aberrations. These findings suggest prospective neuropathic pain attenuating efficacy of tiopronin and further corroborated the notion that antioxidants are effective in mitigating the development and expression of neuropathic pain and underlying neuronal oxidative stress.

Skin wound healing with composite biomembranes loaded by tiopronin or captopril

Novel wound dressings composed of chitosan (Ch) and hyaluronan (HA) loaded with tiopronin or captopril as antiinflammatory drugs were prepared. Composite biomembranes were examined in skin wounds of ischemic rabbits with the aim to accelerate the process of healing. The results proved that the biomembranes composed of Ch/HA/tiopronin or Ch/HA/captopril facilitated healing of skin wounds compared to untreated animals and animals treated with Ch/HA membranes. These results were confirmed by histology. Cu(II) ions and ascorbate-induced high-molar-mass HA degradation by means of rotational viscometry was performed and the ability of the both drugs to scavenge reactive oxygen species was evaluated. The results showed that captopril as well as tiopronin decreased the rate of HA degradation exclusively at higher concentrations.