Frostbite: Current status and advancements in therapeutics

Skin organoid transplantation promotes tissue repair with scarless in frostbite

Frostbite is the most common cold injury and is caused by both immediate cold-induced cell death and the gradual development of localized inflammation and tissue ischemia. Delayed healing of frostbite often leads to scar formation, which not only causes psychological distress but also tends to result in the development of secondary malignant tumors. Therefore, a rapid healing method for frostbite wounds is urgently needed. Herein, we used a mouse skin model of frostbite injury to evaluate the recovery process after frostbite. Moreover, single-cell transcriptomics was used to determine the patterns of changes in monocytes, macrophages, epidermal cells, and fibroblasts during frostbite. Most importantly, human-induced pluripotent stem cell (hiPSC)-derived skin organoids combined with gelatin-hydrogel were constructed for the treatment of frostbite. The results showed that skin organoid treatment significantly accelerated wound healing by reducing early inflammation after frostbite and increasing the proportions of epidermal stem cells. Moreover, in the later stage of wound healing, skin organoids reduced the overall proportions of fibroblasts, significantly reduced fibroblast-to-myofibroblast transition by regulating the integrin α5β1-FAK pathway, and remodeled the extracellular matrix (ECM) through degradation and reassembly mechanisms, facilitating the restoration of physiological ECM and reducing the abundance of ECM associated with abnormal scar formation. These results highlight the potential application of organoids for promoting the reversal of frostbite-related injury and the recovery of skin functions. This study provides a new therapeutic alternative for patients suffering from disfigurement and skin dysfunction caused by frostbite.

Polydopamine Nanoparticle-Loaded Antifreezing and Photothermal Organohydrogel Based on Pullulan for Frostbite Therapy

Rapid rewarming is the standard and most common strategy for treating frostbite. Due to freezing susceptibility and lack of thermal effects, traditional therapeutic hydrogels are not suitable for being directly applied to frostbite therapy in cold conditions. Contrastively, antifreezing and photothermal hydrogels that are not apt to freeze and capable of rewarming frostbite wounds are deemed to hold great application potential in such therapy. Nevertheless, these hydrogels have rarely been researched. Herein, using glycerol as the cryoprotectant and polydopamine nanoparticles (PDA NPs) as the photothermal agent, a novel pullulan-based antifreezing and photothermal organohydrogel (CPG-PDA organohydrogel) was successfully developed to treat frostbite for the first time. The CPG-PDA organohydrogel formed through 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC·HCl)-mediated esterification reactions was found to possess certain mechanical stability, shear-thinning behaviors (injectability), excellent antifreezing properties, superb in vitro and in vivo photothermal performances, and outstanding cytocompatibility and hemocompatibility. Most noticeably, the photothermal rewarming and coating therapy using the CPG-PDA organohydrogel was observed to significantly accelerate the frostbite healing of rats. The CPG-PDA organohydrogel was opined to be a promising platform for the direct treatment of frostbite in a cold environment and would open a new avenue for the design of therapeutic strategies for frostbite.

Topical frankincense treatment for frostbite based on microcirculation improvements

ETHNOPHARMACOLOGICAL RELEVANCE

The Chinese traditional medicine frankincense, which can promote blood circulation, is often used to treat skin lesions, including frostbite.

AIM OF THE STUDY

To explore the properties of frankincense oil extract (FOE) and its active ingredients and their effect on frostbite wound recovery as an approach to understand the mechanism associated with microcirculation-improvement therapy.

MATERIALS AND METHODS

The microcirculation-improving effects of FOE and its active ingredients were evaluated using liquid nitrogen-induced frostbite animal models. The rewarming capacity of FOE on the skin was determined through infrared detection, and frostbite wound healing was evaluated following haematoxylin and eosin (H&E) staining and fibre analysis. Moreover, related factors were examined to determine the anti-apoptotic, anti-inflammatory, and microcirculatory properties of FOE and its active ingredients on affected tissue in the context of frostbite.

RESULTS

FOE and its active ingredients rapidly rewarmed wound tissue after frostbite by increasing the temperature. Moreover, these treatments improved wound healing and restored skin structure through collagen and elastin fibre remodelling. In addition, they exerted anti-apoptotic effects by decreasing the number of apoptotic cells, reducing caspase-3 expression, and eliciting anti-inflammatory effects by decreasing COX-2 and β-catenin expression. They also improved microcirculatory disorders by decreasing HIF-1α expression and increasing CD31 expression.

CONCLUSIONS

FOE and its active components can effectively treat frostbite by enhancing microcirculation, inhibiting the infiltration of inflammatory cells, decreasing cell apoptosis, and exerting antinociceptive effects. These findings highlight FOE as a new treatment option for frostbite, providing patients with an effective therapeutic strategy.

Frostbite on Denali: a case series and review of treatment options

Frostbite, defined as tissue freezing due to cold weather exposure, is a major risk associated with mountaineering in cold climates. It represents a significant source of morbidity in the climbing population. In 2021, three individuals were evaluated at a single institution after developing frostbite while climbing Denali, Alaska, US. The affected patients were healthy men in the third to sixth decade of their lives, and all experienced frostbite injuries involving the fingers. Among the patients, one individual was unable to descend from the mountain due to the severity of his condition and required medical evacuation. The other men were able to descend without significant difficulty. After leaving the mountain, the patients were treated with thrombolysis, pentoxifylline, hyperbaric oxygen therapy, and/or regional sympathetic blockade. Exposure to cold weather, ascent to high altitudes, and increased mechanisms of heat loss were likely potential risk factors for frostbite injury in these patients. Psychological factors related to the COVID-19 pandemic may have also impacted these individuals' risk for frostbite injury. Prevention is the most effective way to avoid frostbite, and knowledge and understanding of the risks associated with the development of this condition may reduce future occurrences among mountaineers. Since frostbite is not a common diagnosis encountered in patients treated in outpatient wound centres, physicians should maintain awareness of the pathophysiology and treatment options for this condition.

Construction and validation of a risk prediction model for soldiers with frostbite in northeast China: a cross-sectional study

BACKGROUND

One of the challenges of physical training in extreme condition is frostbite, especially in Northeast China. In this study, we aimed to construct a risk prediction model for frostbite among soldiers in Northeast China, and verify its effect.

METHODS

698 participants were selected via convenience sampling from Northeast China from December 2021 to January 2022 (winter). They were randomly divided into a training set (N = 479) and a testing set (N = 202) in a ratio of 7:3. All participants completed a researcher-made questionnaire on frostbite. The prediction model was constructed through the use of Logistic regression analysis, which was used to predict the independent risk factors for frostbite formation and screen significant indicators. The model's performance was assessed using the receiver operating characteristic (ROC) curve and decision curve analysis (DCA) to evaluate the prediction efficiency and goodness of fit.

RESULTS

The incidence of frostbite in the training set was 19.83% (95 people), all of which were first-degree frostbite. Among them, frostbite in multiple parts was the most common (58.95%), followed by singular body parts like hands (24.21%), ears (11.58%) and feet (5.26%). Single factor logistic regression analyses showed that ambient temperature, ambient wind speed, outdoor stationary time, stationary status, and history of frostbite are independent risk factors that affect the occurrence of frostbite. Furthermore, we constructed the frostbite risk prediction model for soldiers in the northeastern region of China. The area under the receiver operating characteristic curve (AUC) for the risk of frostbite in the training set and testing set was 0.816 (95% CI, 0.770 ~ 0.862) and 0.787 (95% CI, 0.713 ~ 0.860), respectively. The Hosmer-Lemeshow test of the model showed χ2 = 11.328 and P = 0.184 (> 0.05). The DCA curve indicated that most of the clinical net benefits of the model are greater than 0, demonstrating good clinical usefulness.

CONCLUSION

The constructed frostbite prediction model can effectively identify soldiers with a higher risk of frostbite. It provided theoretical support for commanders to take preventive measures to reduce the incidence of frostbite among soldiers and was of great clinical guiding significance.

Dermorphin [D-Arg2, Lys4] (1-4) Amide Alleviates Frostbite-Induced Pain by Regulating TRP Channel-Mediated Microglial Activation and Neuroinflammation

Cold injury or frostbite is a common medical condition that causes serious clinical complications including sensory abnormalities and chronic pain ultimately affecting overall well-being. Opioids are the first-choice drug for the treatment of frostbite-induced chronic pain; however, their notable side effects, including sedation, motor incoordination, respiratory depression, and drug addiction, present substantial obstacle to their clinical utility. To address this challenge, we have exploited peripheral mu-opioid receptors as potential target for the treatment of frostbite-induced chronic pain. In this study, we investigated the effect of dermorphin [D-Arg2, Lys4] (1-4) amide (DALDA), a peripheral mu-opioid receptor agonist, on frostbite injury and hypersensitivity induced by deep freeze magnet exposure in rats. Animals with frostbite injury displayed significant hypersensitivity to mechanical, thermal, and cold stimuli which was significant ameliorated on treatment with different doses of DALDA (1, 3, and 10 mg/kg) and ibuprofen (100 mg/kg). Further, molecular biology investigations unveiled heightened oxido-nitrosative stress, coupled with a notable upregulation in the expression of TRP channels (TRPA1, TRPV1, and TRPM8), glial cell activation, and neuroinflammation (TNF-α, IL-1β) in the sciatic nerve, dorsal root ganglion (DRG), and spinal cord of frostbite-injured rats. Treatment with DALDA leads to substantial reduction in TRP channels, microglial activation, and suppression of the inflammatory cascade in the ipsilateral L4-L5 DRG and spinal cord of rats. Overall, findings from the present study suggest that activation of peripheral mu-opioid receptors mitigates chronic pain in rats by modulating the expression of TRP channels and suppressing glial cell activation and neuroinflammation.

In situ forming Hydrogel with adding ZnO Nano-particle for effectively methicillin-resistant Staphylococcus aureus infected frostbite injury

Hydrogel has emerged as a promising wound dressing material, and in situ forming hydrogel has emerged as a promising wound dressing recently. But most in situ forming hydrogel are normally unstable. Herein, we report an in-situ forming hydrogel synthesized from poly(Nisopropylacrylamide166-co-n-butyl acrylate9)-poly(ethyleneglycol)-poly(N-isopropylacrylamide166-co-n-butyl acrylate9) copolymer (P(NIPAM166-co-nBA9)-PEG-P(NIPAM166-conBA9), denoted as PEP) and zinc oxide nano-particle(ZnO nano-particle) in response to skin temperature. This thermoresponsive hydrogel exhibits sol-gel reversibility at high temperatures, which is closed to the temperature of human skin. To investigate its healing effects, we used the Hydrogel dressing® in an SD rat model. The biocompatibility and antibacterial ability against methicillin-resistant Staphylococcus aureus(MRSA) of this PEP-ZnO hydrogel wound dressing are confirmed in vitro and in vivo, which could transparently promote the healing of a MRSA-infected frostbitten skin Injury.

Materials and methods

Thirty rats were randomly divided into two groups. The treatment group received hydrogel and transparent film dressing 30 min to 1 h post-burn, while the control group received only cotton dressing. The wound area was measured, and the wound closure rate was calculated on days 3, 7, and 14 post-surgery. Tissue samples were collected from each rat on these days and stored at -80 °C for histological analysis using H&E, Masson and immunohistochemical staining. This analysis assessed factors such as granulation tissue length, re-epithelialization, re-angiogenesis, collagen deposition, inflammatory cell infiltration, and collagen production. Clinical and histological assessments at 14 days showed more rapid healing in the hydrogel dressing group compared to the control group.

Conclusion

Our results indicate that the design of our hydrogel for cooling injury wounds effectively improves healing and mitigates the damage from low temperatures.

Tat-CIRP Peptide Facilitates Frozen Wound Healing by Ameliorating Inflammation and Promoting Angiogenesis

Background

Frostbite is a chemia resulting from cold-induced skin damage. The process of frostbite is often accompanied by inflammation, and the therapeutic strategies focusing on anti-inflammation are the main direction to data. Tat-CIRP is a 15 amino acid peptide containing HIV protein and cold-inducible RNA-binding protein (CIRP), which is believed to compete with endogenous CIRP for myeloid differentiation 2 (MD2) binding. This study aims to investigate the efficacy of Tat-CIRP in the treatment of frostbite.

Methods

A mouse model of frostbite was established, and on the first day after frostbite occurrence, Tat-CIRP peptide was administered intravenously via the tail with a dosage interval of one day for a total of three doses. Frozen mouse skin sections were subjected to histological analysis, including hematoxylin-eosin (HE) staining, Masson staining, and immunohistochemical examination. Western blotting was performed to detect the expression level of Ki-67 in mouse skin tissue.

Results

One day after frostbite, mice exhibited skin swelling and a solid appearance. From day 1 to 5 after frostbite, MD2 expression was significantly upregulated, while CIRP expression was downregulated. Compared to the frostbite group, mice treated with Tat-CIRP showed accelerated frostbite recovery, reduced levels of inflammatory factors and MD2. Furthermore, the expression of cell proliferation-associated protein Ki-67 and angiogenesis-related protein CD31 was upregulated.

Conclusion

Tat-CIRP promotes frozen wound healing via inhibiting inflammation and promoting angiogenesis in frostbitten mice.

Feet Salvage Using Anterolateral Thigh Flaps after Severe Frostbite Injury: A Case Report

BACKGROUND

Frostbite is a severe injury characterized by tissue damage due to exposure to freezing temperatures. It often necessitates prompt medical intervention to prevent further complications such as necrosis and amputation. This case report explores the successful use of bilateral anterolateral thigh (ALT) free flaps for feet salvage in a 19-year-old male refugee from Gambia who suffered severe frostbite injuries.

CASE REPORT

The patient, found after six days in freezing conditions, exhibited necrosis on multiple toes. Initial management included stabilization, intravenous fluids, and rewarming. Subsequent necrectomy and amputation revealed exposed metatarsal bones, necessitating a meticulous reconstructive strategy. Bilateral ALT flaps were chosen to preserve walking function, with a staged reconstruction involving multiple operations. The patient's progress, from inpatient care to outpatient follow-ups, is detailed, emphasizing the challenges and decisions in managing severe frostbite injuries.

RESULTS

The surgical intervention utilizing bilateral ALT flaps successfully salvaged the patient's feet. Throughout the postoperative period, wound care, rehabilitation, and outpatient monitoring contributed to positive outcomes. Despite challenges associated with the patient's ethnic background and nutritional status, the staged reconstruction facilitated effective healing and functional recovery. The use of ALT flaps provided a reliable solution with minimal donor site morbidity.

CONCLUSION

This case highlights the efficacy of bilateral ALT flap reconstruction in salvaging feet following severe frostbite injury. The successful restoration of foot function underscores the importance of early intervention and tailored reconstructive approaches in frostbite management. Despite patient-specific challenges, including nutritional status and limited healthcare resources, the use of ALT flaps facilitated optimal recovery and functional outcomes. Importantly, this report is unique as it describes a novel case of feet salvage using bilateral ALT flaps in severe frostbite injury, with only one similar case previously reported in the literature. This emphasizes the rarity and significance of this specific surgical approach in frostbite management.

Cold burn injuries in the United Kingdom: retain-->A 5-year cohort study of patients presenting to a regional burn unit

AIMS

To assess the aetiology, management and outcomes of cold burn injuries presenting to a regional burn unit in the United Kingdom.

METHODS

Retrospective cohort study of consecutive patients over a 5-year period (2018-2022).

RESULTS

Sixty-two patients (M:F 34:38; median age 23.5 years) were identified. The most common aetiology was aerosol (n = 28, 45.2%). Seven (11.5%) injuries were sustained during a social media or peer 'challenge' and 19 (31.2%) were self-harm, of whom 5 (26.3%) were inpatients on a mental health ward at the time of injury. All 'challenge' and self-harm injuries were caused by aerosol. Patients with 'challenge' injury were younger than those with self-harm (p = .007) and non-intentional injuries (p < .001). A greater proportion of self-harm injuries were in female patients compared with non-intentional injuries (p < .001). Median total body surface area (TBSA) was 0.35% (IQR: 0.3). Most burns were superficial partial thickness (n = 35, 56.5%), followed by deep dermal (n = 18, 29.0%), full-thickness (n = 8, 12.9%), and superficial (n = 1, 1.6%). The upper limb was most frequently affected (n = 35, 56.5%). Aetiology and a non-intentional, 'challenge' or self-harm injury did not affect TBSA (p = 0.776 and p = 0.364) or depth (p = 0.353 and p = 0.381). Five (8.1%) patients underwent autografting. The median time to healing was 17 days (range: 7-45, IQR: 22.75). Follow-up ranged from 1 to 173 weeks.

CONCLUSIONS

The incidence of cold burns has increased when compared with previous literature. A disproportionate number of cold burns are self-inflicted using aerosols, either as self-harm or because of social media or peer 'challenges'. Other emerging aetiologies include non-intentional skin contact with nitrous oxide containers during its recreational use.

Comprehensive treatment of deep frostbite of multiple fingers after trauma: A case report

BACKGROUND

Frostbite is becoming increasingly common in urban environments, and severe cases can lead to tissue loss. The treatment goal is to preserve tissue and function; the sooner appropriate treatment is administered, the more tissue can be saved. However, not every patient with deep frostbite seeks medical care promptly.

CASE SUMMARY

We report the case of a 73-year-old male patient who was lost in the wilderness for 2 d due to trauma and confusion. He experienced deep frostbite on multiple fingers. Treatment should not be discontinued for patients with deep frostbite who present after the optimum treatment timing. Bullae that no longer form (bloody) blisters within 24 h of aspiration should be removed. Mucopolysaccharide polysulfate cream has clinical value in frostbite treatment. The patient was transferred to Chinese Academy of Medical Sciences and Peking Union Medical College Hospital 12 h after being rescued. The patient had contraindications for thrombolysis, the most effective treatment, due to intracranial hemorrhage and presenting past the optimum treatment timing. We devised a comprehensive treatment plan, which involved delayed use vasodilators and high-pressure oxygen therapy at day 49 post-injury. We experimented with mucopolysaccharide polysulfate cream to treat the frostbite. The aim of the treatment was to safeguard as much tissue as possible. In the end, the fingers that suffered from frostbite were able to be partially preserved.

CONCLUSION

The case indicated that patients with severe frostbite who missed the optimal treatment time and had contraindications for thrombolysis could still partially preserve the affected limbs through comprehensive treatment.

Microwave Therapy for Frostbite Management: A Case Series

Microwave body tightening and contouring is a common and efficient cosmetic medical procedure. The current study presents preliminary data about microwave treatment for body contouring where an innovative and unexpected benefit on frostbites was shown. This is a case series on two patients with frostbite treated with microwave therapy. The participants received the treatment for five sessions at 20-day intervals, including the beginning of the study. In addition to being satisfied with the treatment of their skin imperfections, the patients noticed a remarkable and progressive improvement in frostbite on their limbs. Both patients experienced a significant improvement in skin sensation and appearance and no side effects were observed. Our findings confirmed the safety and efficacy of microwave therapy in treating cellulite and skin laxity but rather a positively effect and a significant improvement in the treatment of frostbite as a secondary intention.

Effects and mechanisms of extremely cold environment on body response after trauma

With the outbreak of the Ukrainian crisis, extremely cold environment warfare has once again become the focus of international attention. People exposed to extremely cold environments may suffer from cold damage, further aggravate trauma, trigger high disability and mortality rates, and even cause serious sequelae. To declare the effects and mechanisms of the extremely cold environment on the body after trauma, this paper reviews, firstly, physiological reaction of human body in an extremely cold environment. Then, the post-traumatic body response in an extremely cold environment was introduced, and finally, the sequelae of trauma in extremely cold environment was further summarized in the paper. The results indicated that extremely cold environment can cause a series of damage to the body, especially the body after trauma. The extremely cold factor is a double-edged sword, showing a favorable and unfavorable side in different aspects. Moreover, in addition to the trauma suffered by the body, the subsequent sequelae such as cognitive dysfunction, anxiety, depression and even post-traumatic stress disorder may also be induced. The paper summarizes the human body's physiological response in an extremely cold environment, and declares the effects and mechanisms of the extremely cold environment on the body after trauma, which may provide a theoretical basis for effectively improving the level of combat trauma treatment in extremely cold regions.

Frostbite of The Extremities - Recognition, Evaluation and Treatment

OBJECTIVES

Frostbite refers to the freezing of body tissue which is caused by prolonged exposure to cold temperatures and results in tissue destruction. Tissue damage is due to both immediate cold-induced cell death and the more gradual development of localized inflammatory processes and tissue ischemia. A detailed treatment plan based on the current UpToDate literature is needed to decrease morbidity and mortality rates.

METHODS

The United States National Library of Medicine (PubMed/Medline), EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews were systematically searched to identify publications relevant to this review.

CONCLUSION

In this review, we present the current knowledge on the diagnosis and treatment of frostbite injuries. We then provide an extended and detailed treatment plan, from first aid in the field to treatment of short and long-term complications .

Frostbite of the upper extremities: Hot issues in diagnosis and surgical treatment (review)

BACKGROUND

Frostbite is a severe thermal injury, which characterized by tissue necrosis with a high percentage of amputations, disability of patients.

METHODS

According to the databases Web of Science, Google Scholar, PubMed, E-library down to 2001-2021 the search for works related to the problem of diagnosis, treatment of frostbite of the upper extremities was made. Actual possibilities of diagnostics, the questions of classification, treatment of frostbite, including the features of plastic surgery operations used to close hand defects after excision of necrotic tissues have been analyzed.

RESULTS

Frostbite is more common in people with alcohol dependence, mental illness and in socially disadvantaged groups. The most informative instrumental methods of diagnosis: bone scintigraphy, magnetic resonance imaging, single-photon emission computed tomography. Thrombolytic therapy (tPA) and prostacyclin are most effective if used within the first day after tissue rewarming. With deep frostbite and late medical care surgical treatment is fundamental. Amputation and debridement are carried out after the formation of the demarcation line. To replace soft tissue defects that extend beyond the fingers, it is preferable to use fasciocutaneous flaps.

CONCLUSION

The defining moments in the treatment of deep frostbite are timely diagnosis and complex treatment. With late admission surgical treatment, including reconstructive skin plastic surgery, becomes important.

A Review of Construction Workforce Health Challenges and Strategies in Extreme Weather Conditions

AbstractConstruction sites continue to operate despite inclement weather, exposing workers to unpleasant working circumstances that can lead to various physical and mental health challenges. A thorough literature review yielded 21 challenges for hot weather conditions such as heat stroke, kidney disease, heat cramps, anxiety, depression and 20 challenges for cold weather conditions like asthma, frostbite, Musculo-Skeletal disorders, hallucination. Workers vulnerable to hot and cold weather based on demographic characteristics were identified. The study also provides 27 strategies to address the challenges experienced in hot and cold weather conditions. Some of these include ensuring that workers stay hydrated, scheduling sufficient rest periods, and allowing workers to self-pace. The results of this study will help construction decision-makers and project managers understand the difficulties faced by a field workforce who labors in extreme working conditions on construction sites and will facilitate adoption of strategies that can prevent weather-related physical and mental health problems.

Long-Term Sequelae of Frostbite-A Scoping Review

Frostbite is tissue damage caused by freezing temperatures and constitutes an important cause of morbidity in cold climate zones and high altitude. The direct effects of sub-zero temperatures lead to tissue freezing, electrolyte shifts and pH alterations, microvascular damage, and eventually to cell death. Upon rewarming, inflammatory reperfusion injury and thrombosis may lead to further tissue damage. Several studies and various case reports show that many patients suffer from long-term sequelae such as vasomotor disturbances (associated with susceptibility to refreezing), and neuropathic and nociceptive pain, as well as damage to skeletal structures. There are still many uncertainties regarding the pathophysiology of these sequelae. It has been shown that the transient receptor potential channel (TRP) family plays a role in cold allodynia. Botulinum Toxin type A (BTX-A) injections have been reported to be beneficial in vasomotor and neuropathic disturbances secondary to frostbite. Epidural sympathetic block has been used for short-term treatment of frostbite induced chronic pain. Furthermore, amitriptyline, gabapentinoids, and duloxetine may have some benefits. Frostbite arthritis clinically resembles regular osteoarthritis. In children there is a risk of epiphyseal cartilage damage leading to bone deformities. Despite some promising therapeutic concepts, the scarcity of data on frostbite long-term sequelae in the literature indicates the need of more in-depth studies of this pathology in all its aspects.