Dietary Nitrate Protects Against Skin Flap Ischemia-Reperfusion Injury in Rats via Modulation of Antioxidative Action and Reduction of Inflammatory Responses

Quercetin activates autophagy in the distal ischemic area of random skin flaps through Beclin1 to enhance the adaptability to energy deficiency

Random flaps are frequently employed in treating substantial skin abnormalities and in surgical tissue-rebuilding interventions. The random flap technique provides flaps of specific dimensions and contours to fit the surgical incision. However, blood supply deficiency and subsequent ischemia-reperfusion injury can cause severe oxidative stress and apoptosis, eventually leading to distal necrosis, which limits the clinical application of the flap. Quercetin (QUE) is primarily found in the glycoside form in many plant parts, such as stem bark, flowers, leaves, buds, seeds, and fruits. Cellular, animal, and clinical studies have demonstrated the antioxidant, anti-apoptosis, anti-inflammatory, and activation of autophagy properties of QUE. In previous studies, high doses of QUE effectively suppressed the survival of human umbilical vein endothelial cells (HUVECs) stimulated by hydrogen peroxide. However, different concentration gradients of QUE on HUVECs revealed a significant protective effect at a concentration of 10 mM. The protective impact of QUE on HUVECs was evaluated using scratch tests, CCK-8 assays, and EDU assays. Simultaneously, a mouse model of random skin flap was created, and the impact of QUE on skin flap survival was examined by intragastric injection. The QUE group showed a significantly larger survival area of the random flap and higher blood flow intensity compared to the control group. Furthermore, the beneficial effects of QUE were reversed by the autophagy inhibitor 3-MA. Therefore, autophagy plays a significant role in the therapeutic benefits of QUE on flap survival.

Dietary nitrate maintains homeostasis of oxidative stress and gut microbiota to promote flap survival in type 2 diabetes mellitus rats

BACKGROUND

Random-pattern skin flaps are commonly used to repair skin tissue defects in surgical tissue reconstruction. However, flap necrosis in the distal area due to ischemia injury is still challenging for its applications in plastic surgery. The complications of diabetes will further increase the risk of infection and necrosis.

METHODS

This study induced type 2 diabetes mellitus (T2DM) rats with a high-fat diet and STZ. The survival rate of the skin flap was observed by adding inorganic sodium nitrate to drinking water. Histology and immunohistochemistry were used to detect the damage to the skin flap. The nitrate content was measured by total nitric oxide and nitrate/nitrite parameter assay. Dihydroethidium and malondialdehyde (MDA) assays were used to value oxidative stress. Rat colon feces were collected for 16s rRNA gene sequence.

RESULTS

Our studies showed that nitrate administration leads to anti-obesity and anti-diabetic effects. Nitrate directly increased the survival area of skin flaps in diabetic rats and mean blood vessel density by enhancing angiogenesis, inhibiting apoptosis, and reducing oxidative stress. The 16s rRNA sequence revealed that nitrate may regulate the homeostasis of the gut microbiota and re-store energy metabolism.

CONCLUSION

Dietary nitrate has been shown to maintain the homeostasis of oxidative stress and gut microbiota to promote flap survival in rats with T2DM.

Nontopical Nitrates in Flap Perfusion and Delay Phenomenon

Background

Topical nitrates have demonstrated efficacy in improving flap perfusion. However, evidence for nontopical nitrates in modulation of flap perfusion dynamics has yet to be consolidated. Here, we review evidence regarding the use of intravascular, sublingual, and oral nitrates in modulating flap perfusion.

Methods

We performed a review of the literature for evidence linking nontopical nitrates and flap perfusion, and included clinical studies, animal studies, and in vitro studies.

Results

Evidence suggests that intravascular, sublingual, and oral nitrates exert vasodilatory properties, which may be harnessed for identification of perforators and improved flap perfusion. We also found evidence suggesting nitrates may facilitate ischemic preconditioning while reducing ischemia-reperfusion injury.

Conclusions

Nitrates delivered intravascularly, sublingually, or orally may increase flap perfusion and serve as a method for ischemic preconditioning, particularly in the intraoperative setting.

The Nitrate-Nitrite-Nitric Oxide Pathway: Potential Role in Mitigating Oxidative Stress in Hypertensive Disorders of Pregnancy

Hypertensive diseases of pregnancy (HDPs) represent a global clinical challenge, affecting 5-10% of women and leading to complications for both maternal well-being and fetal development. At the heart of these complications is endothelial dysfunction, with oxidative stress emerging as a pivotal causative factor. The reduction in nitric oxide (NO) bioavailability is a vital indicator of this dysfunction, culminating in blood pressure dysregulation. In the therapeutic context, although antihypertensive medications are commonly used, they come with inherent concerns related to maternal-fetal safety, and a percentage of women do not respond to these therapies. Therefore, alternative strategies that directly address the pathophysiology of HDPs are required. This article focuses on the potential of the nitrate-nitrite-NO pathway, abundantly present in dark leafy greens and beetroot, as an alternative approach to treating HDPs. The objective of this review is to discuss the prospective antioxidant role of nitrate. We hope our discussion paves the way for using nitrate to improve endothelial dysfunction and control oxidative stress, offering a potential therapy for managing HDPs.

Pretreatment with platelet-rich plasma protects against ischemia-reperfusion induced flap injury by deactivating the JAK/STAT pathway in mice

BACKGROUND

Ischemia-reperfusion (I/R) injury is a major cause of surgical skin flap compromise and organ dysfunction. Platelet-rich plasma (PRP) is an autologous product rich in growth factors, with tissue regenerative potential. PRP has shown promise in multiple I/R-induced tissue injuries, but its effects on skin flap injury remain unexplored.

METHODS

We evaluated the effects of PRP on I/R-injured skin flaps, optimal timing of PRP administration, and the involved mechanisms.

RESULTS

PRP protected against I/R-induced skin flap injury by improving flap survival, promoting blood perfusion and angiogenesis, suppressing oxidative stress and inflammatory response, and reducing apoptosis, at least partly via deactivating Janus kinase (JAK)-signal transducers and activators of transcription (STAT) signalling pathway. PRP given before ischemia displayed overall advantages over that given before reperfusion or during reperfusion. In addition, PRP pretreatment had a stronger ability to reverse I/R-induced JAK/STAT activation and apoptosis than AG490, a specific inhibitor of JAK/STAT signalling.

CONCLUSIONS

This study firstly demonstrates the protective role of PRP against I/R-injured skin flaps through negative regulation of JAK/STAT activation, with PRP pretreatment showing optimal therapeutic effects.

Systematic review of pathologic markers in skin ischemia with and without reperfusion injury in microsurgical reconstruction: Biomarker alterations precede histological structure changes

BACKGROUND

Ischemia and ischemia-reperfusion injury contribute to partial or complete flap necrosis. Traditionally, skin histology has been used to evaluate morphological and structural changes, however histology does not detect early changes. We hypothesize that morphological and structural skin changes in response to ischemia and IRI occur late, and modification of gene and protein expression are the earliest changes in ischemia and IRI.

METHODS

A systematic review was performed in accordance with PRISMA guidelines. Studies reporting skin histology or gene/protein expression changes following ischemia with or without reperfusion injury published between 2002 and 2022 were included. The primary outcomes were descriptive and semi-quantitative histological structural changes, leukocyte infiltration, edema, vessel density; secondary outcomes were quantitative gene and protein expression intensity (PCR and western blot). Model type, experimental intervention, ischemia method and duration, reperfusion duration, biopsy location and time point were collected.

RESULTS

One hundred and one articles were included. Hematoxylin and eosin (H&E) showed inflammatory infiltration in early responses (12-24 h), with structural modifications (3-14 days) and neovascularization (5-14 days) as delayed responses. Immunohistochemistry (IHC) identified angiogenesis (CD31, CD34), apoptosis (TUNEL, caspase-3, Bax/Bcl-2), and protein localization (NF-κB). Gene (PCR) and protein expression (western blot) detected inflammation and apoptosis; endoplasmic reticulum stress/oxidative stress and hypoxia; and neovascularization. The most common markers were TNF-α, IL-6 and IL-1β (inflammation), caspase-3 (apoptosis), VEGF (neovascularization), and HIF-1α (hypoxia).

CONCLUSION

There is no consensus or standard for reporting skin injury during ischemia and IRI. H&E histology is most frequently performed but is primarily descriptive and lacks sensitivity for early skin injury. Immunohistochemistry and gene/protein expression reveal immediate and quantitative cellular responses to skin ischemia and IRI. Future research is needed towards a universally-accepted skin injury scoring system.

Dietary nitrate accelerates the healing of infected skin wounds in mice by increasing microvascular density

As skin injuries resulting from acute trauma, burns, and chronic diseases present significant challenges to healthcare systems worldwide, the promotion of skin wound healing remains an unmet therapeutic area. Dietary nitrate serves as a crucial pathway for the production of nitric oxide, which plays various physiological roles in the body, including vasodilation, increased blood flow, and antioxidant activity. However, the impact of dietary nitrate on skin wound healing remains uncertain. This study aimed to investigate the role of dietary nitrate in infected skin wound healing using a mouse model. We created a full-thickness wound infection model in mice and examine the effects of dietary nitrate (0.5 mmol/kg/d and 1 mmol/kg/d) on wound healing. The results demonstrated that dietary nitrate significantly increased serum nitrate and nitrite levels, leading to accelerated wound healing by increasing microvascular density, promoting collagen deposition and re-epithelialization. Moreover, nitrate supplementation exhibited a certain degree of reduction in inflammatory factors within the body. Our study also found that 1 mmol/kg/d nitrate has a more effective therapeutic effect and can increase blood perfusion and expedite the formation of new blood vessels, thereby promoting skin wound healing. These results indicate that dietary nitrate presents a novel therapeutic approach for infected skin wound healing.

Nesfatin-1 regulates the HMGB1-TLR4-NF-κB signaling pathway to inhibit inflammation and its effects on the random skin flap survival in rats

OBJECTIVE

Random skin flaps are often placed by plastic surgeons to treat limb deformities and dysfunction. Nesfatin-1 (NES) is a peptide that exerts angiogenic, anti-inflammatory, and anti-oxidant effects. We assessed the impact of NES on flap survival and the underlying mechanism.

METHODS

We modified the McFarlane random skin flap rat model. Thirty-six male Sprague-Dawley rats were randomly divided into a control group (corn oil solution with DMSO), low-dose group (NES-L at 10 µg/kg/day), and high-dose group (NES-H at 20 µg/kg/day). On day 7 after surgery, average flap survival areas were calculated. Laser Doppler blood flow monitoring and lead oxide/gelatin angiography were used to evaluate blood perfusion and neovascularization, respectively. Flap histopathological status was evaluated by hematoxylin and eosin (H&E) staining. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were determined. Immunohistochemical techniques were used to evaluate the expression of angiogenetic and inflammatory factors.

RESULTS

In the experimental groups, the mean skin flap survival areas and blood perfusion increased considerably. The SOD activities in the experimental groups increased and the MDA contents decreased. Immunohistochemically, VEGF expression was upregulated in the experimental groups and the expression levels of inflammatory factors decreased markedly.

CONCLUSION

NES inhibited ischemic skin flap necrosis, promoted angiogenesis, and reduced ischemia-reperfusion injury and inflammation. Inhibition of the inflammatory HMGB1-TLR4-NF-κB signal pathway, which reduced flap inflammation and oxidative stress, may explain the enhanced flap survival.

Mini Review of Biochemical Basis, Diagnosis and Management of Crush Syndrome

Crush syndrome (CS) is a metabolic disorder whose victims are individuals suffered from natural disasters such as earthquake or man-made conflicts. CS complications include acute kidney injury and cardiac arrhythmia that collectively end with death if untreated immediately. These complications are accounted for the liberation of damaged muscle tissues contents, primarily myoglobin and potassium. The present mini review discusses the biochemical basis of the development of CS. In addition, diagnosis and management and the application of novel experimental therapeutics of CS are also highlighted.

The current state of knowledge on how to improve skin flap survival: A review

The incorporation of skin flaps in wound closure management with its cosmetic implications has appeared as a gleam of hope in providing desirable outcomes. Given the influence of extrinsic and intrinsic factors, skin flaps are prone to several complications, including ischemia-reperfusion injury (IRI). Numerous attempts have been undertaken to enhance the survival rate of skin flaps entailing pre/post-conditioning with surgical and pharmacological modalities. Various cellular and molecular mechanisms are employed in these approaches in order to reduce inflammation, promote angiogenesis and blood perfusion, and induce apoptosis and autophagy. With the emerging role of multiple stem cell lineages and their ability to improve skin flap viability, these approaches are increasingly being used to develop even more translationally applicable methods. Therefore, this review aims at providing current evidence around pharmacological interventions for improving skin flap survival and discussing their underlying mechanism of action.

Dietary nitrate supplementation increases nitrate and nitrite concentrations in human skin interstitial fluid

Acute dietary nitrate (NO₃^-) supplementation can increase [NO₃^-], but not nitrite ([NO₂^-]), in human skeletal muscle, though its effect on [NO₃^-] and [NO₂^-] in skin remains unknown. In an independent group design, 11 young adults ingested 140 mL of NO₃^--rich beetroot juice (BR; 9.6 mmol NO₃^-), and 6 young adults ingested 140 mL of a NO₃^--depleted placebo (PL). Skin dialysate, acquired through intradermal microdialysis, and venous blood samples were collected at baseline and every hour post-ingestion up to 4 h to assess dialysate and plasma [NO₃^-] and [NO₂^-]. The relative recovery rate of NO₃^- and NO₂^- through the microdialysis probe (73.1% and 62.8%), determined in a separate experiment, was used to estimate skin interstitial [NO₃^-] and [NO₂^-]. Baseline [NO₃^-] was lower, whereas baseline [NO₂^-] was higher in the skin interstitial fluid relative to plasma (both P < 0.001). Acute BR ingestion increased [NO₃^-] and [NO₂^-] in the skin interstitial fluid and plasma (all P < 0.001), with the magnitude being smaller in the skin interstitial fluid (e.g., 183 ± 54 vs. 491 ± 62 μM for Δ[NO₃^-] from baseline and 155 ± 190 vs. 217 ± 204 nM for Δ[NO₂^-] from baseline at 3 h post BR ingestion, both P ≤ 0.037). However, due to the aforementioned baseline differences, skin interstitial fluid [NO₂^-] post BR ingestion was higher, whereas [NO₃^-] was lower relative to plasma (all P < 0.001). These findings extend our understanding of NO₃^- and NO₂^- distribution at rest and indicate that acute BR supplementation increases [NO₃^-] and [NO₂^-] in human skin interstitial fluid.

Exploration of the Protective Mechanism of Bax Removal against Ischemia Reperfusion Injury of Skin Flap through the p38 Mitogen-Activated Protein Kinase Pathway

This research is aimed at exploring the influences of the Bax gene in the p38 mitogen-activated protein kinase (MAPK) pathway and its protective mechanism against ischemia-reperfusion injury (IRI) of skin flap. Forty male Sprague-Dawley (SD) rats were equally divided into the experimental group (Bax gene knockout rats) and control group. The dorsal flap model was prepared, and the survival rate of flap was observed after surgery. The rat flap tissue was cut and stained with hematoxylin-eosin (HE) and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The distribution characteristics of p38MAPK and Bax were detected to evaluate the protective mechanism of Bax gene knockout on IRI of skin flap. After surgery, the survival rate of flaps in the experimental group (82.32%, 70.28%) was significantly higher than that in the control group (57.64%, 46.14%) (P < 0.05). The results of HE staining showed that on the 1^st day after surgery, compared with those in the control group, the skin flaps of the rats in the experimental group were arranged more neatly. The results of TUNEL staining showed that compared with that of the control group, the tissue structure of the skin flap of the experimental group was normal and only a few apoptotic cells appeared. In addition, compared with that in the control group (7.14, 4.25, 3.48, 2.18/6.46, 7.12, 4.86, and 2.44), the expression of Bax and p38 MAPK in the experimental group (0.96, 0.81, 0.76, 0.55/1.63, 1.33, 1.01, and 0.56) significantly decreased (P < 0.05). In short, after the Bax gene was knocked out, injury of the flap after ischemia-reperfusion was considerably improved, which may play a protective role on the IRI of the flap by affecting the p38MAPK pathway.

Exosomes Derived from Bone Marrow Mesenchymal Stem Cells Alleviate Ischemia-Reperfusion Injury and Promote Survival of Skin Flaps in Rats

Free tissue flap transplantation is a classic and important method for the clinical repair of tissue defects. However, ischemia-reperfusion (IR) injury can affect the success rate of skin flap transplantation. We used a free abdomen flap rat model to explore the protective effects of exosomes derived from bone marrow mesenchymal stem cells (BMSCs-exosomes) against the IR injury of the skin flap. Exosomes were injected through the tail vein and the flaps were observed and obtained on day 7. We observed that BMSCs-exosomes significantly reduced the necrotic lesions of the skin flap. Furthermore, BMSCs-exosomes relieved oxidative stress and reduced the levels of inflammatory factors. Apoptosis was evaluated via the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and Western blot analysis of Bax, Bcl-2. Simultaneously, BMSCs-exosomes promoted the formation of new blood vessels in the IR flap, as confirmed by the increased expression level of VEGFA and the fluorescence co-staining of CD31 and PCNA. Additionally, BMSCs-exosomes considerably increased proliferation and migration of human umbilical vein endothelial cells and promoted angiogenesis in vitro. BMSCs-exosomes could be a promising cell-free therapeutic candidate to reduce IR injury and promote the survival of skin flaps.

Improving the ischemia-reperfusion injury in vascularized composite allotransplantation: Clinical experience and experimental implications

Long-time ischemia worsening transplant outcomes in vascularized composite allotransplantation (VCA) is often neglected. Ischemia-reperfusion injury (IRI) is an inevitable event that follows reperfusion after a period of cold static storage. The pathophysiological mechanism activates local inflammation, which is a barrier to allograft long-term immune tolerance. The previous publications have not clearly described the relationship between the tissue damage and ischemia time, nor the rejection grade. In this review, we found that the rejection episodes and rejection grade are usually related to the ischemia time, both in clinical and experimental aspects. Moreover, we summarized the potential therapeutic measures to mitigate the ischemia-reperfusion injury. Compare to static preservation, machine perfusion is a promising method that can keep VCA tissue viability and extend preservation time, which is especially beneficial for the expansion of the donor pool and better MHC-matching.

Eicosapentaenoic acid loaded silica nanoemulsion attenuates hepatic inflammation through the enhancement of cell membrane components

Background

Liver inflammation is a multistep process that is linked with cell membrane fatty acids composition. The effectiveness of eicosapentaenoic acid (EPA) undergoes an irreversible change during processing due to their unsaturated nature; so the formation of nanocarrier for EPA is crucial for improving EPA’s bioavailability and pharmacological properties.

Objective

In this study we aimed to evaluate the efficiency of EPA alone or loaded silica nanoemulsion on the management of hepatic inflammation induced by diethyl nitrosamine (DEN) through the enhancement of the cell membrane structure and functions.

Methods

The new formula of EPA was prepared to modify the properties of EPA. Forty-eight male Wistar albino rats were classified into: control, EPA, EPA loaded silica nanoemulsion (EPA–NE), DEN induced hepatic inflammation; DEN induced hepatic inflammation treated with EPA or EPA –NE groups. Plasma tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), liver hydroxyproline (Hyp) content, and liver oxidant and anti-oxidants were estimated. Urinary 8- hydroxyguanozine (8- OHdG) and erythrocyte membrane fatty acids fractions were estimated by High-performance liquid chromatography (HPLC). Also, histopathology studies were done to verify our hypothesis.

Results

It was appeared that administration of EPA, in particular EPA loaded silica nanoemulsion, ameliorated the inflammatory response, increased the activity of the anti-oxidants, reduced levels of oxidants, and improved cell membrane structure compared to hepatic inflammation induced by DEN group. Histopathological examination confirmed these results.

Conclusion

EPA and notably EPA loaded silica nanoemulsion strongly recommended as a promising supplement in the management of hepatic inflammation.

The Promising Effect of Topiramate on Random-Pattern Skin Flap Survival in Rats

BACKGROUND

Partial necrosis of skin flaps following plastic and reconstructive surgeries is one of the major problems in these medical interventions. This study was conducted to evaluate the beneficial effects of topiramate an anti-epileptic agent on ischemic random skin flaps.

MATERIALS AND METHODS

Twenty-four Wistar rats were provided and randomly divided into four experimental groups (control group and low-, intermediate- and high-dose treatment groups). A rat random-pattern skin flap model was performed in all groups, and animals in the low-, intermediate- and high-dose experimental groups were administered topiramate intraperitoneally at doses of 25, 50 and 100 mg/kg, respectively, 1 h before raising the flap and once daily for 7 consecutive days after the initial surgical procedure. Control rats received vehicle according to the same schedule. On postoperative day 7 the flap necrotic area was measured, and tissue samples were stained with hematoxylin and eosin for histological analysis. Furthermore, the oxidative stress in flap tissue was assessed by measuring the activity of superoxide dismutase (SOD), glutathione (GSH) level and the content of malondialdehyde (MDA).

RESULTS

Treating animals with 50 and 100 mg/kg topiramate significantly decreased the necrotic flap areas as compared to the control group. Histological studies demonstrated that in intermediate and high dose topiramate groups the inflammatory cell numbers were attenuated and microvessel development were markedly increased. Furthermore, the MDA contents were significantly reduced and GSH levels were significantly increased in these groups as compared to the control group. However, the SOD activity was increased significantly only in high-dose group as compared to the control group.

CONCLUSIONS

These findings indicated that topiramate in doses of 50 and 100 mg/kg increases random skin flap survival.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Assessing non-protein nitrogen sources in commercial dry dog foods

Protein is a macronutrient required by dogs for growth and maintenance metabolism. However, a portion of the crude protein listed on pet foods may actually arise from non-digestible organic nitrogen or potentially toxic inorganic non-protein nitrogen sources. Neither non-protein source is retained or used by the animal. However, these compounds may result in adverse effects such as methemoglobin formation and increased oxidative stress or potentially beneficial effects such as improved vascular distensibility and decreased inflammation. To analyze nitrogen retention and screen for non-protein nitrogen, four commercial, dry kibble dog foods and one laboratory-made diet were evaluated and then fed to beagles during two separate feeding trials. During the first trial, dogs were randomly assigned each diet (n = 4 dogs/diet) and fed chromium oxide-coated diets for 48 h, followed by total urine and marked fecal collection, as well as plasma collection for total nitrogen, nitrate, ammonia, and urea determination. The amount of nitrogen retained (93%–96%) did not differ among commercial diets. Protein total tract apparent digestibility (TTAD) ranged from 69% to 84%, with the high protein diets significantly higher than the laboratory-made and mid-ranged diets (1-way ANOVA: P < 0.05). The high protein diet also contained the highest concentration of nitrate with subsequent elevations in plasma nitrotyrosine levels (indicator of oxidative stress). During the second trial, eight dogs (n = 8) were fed the same diets for 6 d, after which echocardiography was completed with blood, urine, and feces collected. For health end-points, methemoblobin, plasma nitrotyrosine, and C-reactive protein (CRP; indicator of inflammation) levels were measured. Methemoglobin levels were significantly lower in the high protein diet (P > 0.05), possible due to the stimulation of methemoglobin reductase while nitrotyrosine was unchanged and CRP was undetectable. Furthermore, there was a positive relationship between crude protein, crude fat (simple linear regression: P = 0.02, r² > 0.6), price (P = 0.08, r² > 0.6), and caloric density (P = 0.11, r² > 0.6). There were no significant cardiovascular differences among any of the diets (P > 0.05). Ultimately, this study shows that in commercial diets, price does reflect protein content but that feeding dogs high protein diets for a long period of time may provide an excess in calories without a change in cardiovascular function or detectable increases in inflammation.

The Novel Role of Crocus sativus L. in Enhancing Skin Flap Survival by Affecting Apoptosis Independent of mTOR: A Data-Virtualized Study

BACKGROUND

Despite the improvements to enhance skin flap viability, the effects of ischemia-reperfusion (IR), oxidative stress, necrosis, and apoptosis are still challenging. Crocus sativus L. (Saffron) is highly noticeable due to its tissue-protective and antioxidant properties. So, we aimed to investigate its effects on skin flap viability, oxidative stress, apoptosis markers, histopathological changes, and mTOR/p-mTOR expression.

MATERIALS AND METHODS

40 Sprauge-Dawley rats, weighting 200-240 g, were divided into four groups including: (1) Sham (8 × 3 cm skin cut, without elevation); (2) Flap Surgery (8 × 3 cm skin flap with elevation from its bed); (3) Saffron 40 mg/kg + Flap Surgery; and (4) Saffron 80 mg/kg + Flap Surgery. Saffron was administrated orally for 7 days. At day 7, flap necrosis percentage, histopathological changes, malondialdehyde level, Myeloperoxidase and superoxide dismutase activity, Bax, Bcl-2, mTOR, and p-mTOR expression were measured. Protein expressions were controlled by β-Actin.

RESULTS

Saffron administration decreased flap necrosis percentage (p < 0.01), which was not dose-dependent. Treatment groups showed significant histological healing signs (Neovascularization, Fibroblast migration, Epithelialization, and Epithelialization thickness), decreased MDA content (p < 0.01), increased SOD (p < 0.01) and decreased MPO activity (p < 0.01). Bax and Bcl-2 expression, decreased and increased respectively in treated groups (p < 0.0001). mTOR and p-mTOR expression were not changed significantly in Saffron treated groups.

CONCLUSION

Saffron could increase skin flap viability, alleviate necrosis, decrease oxidative stress and decrease apoptotic cell death, after skin flap surgery, but it acts independent of the mTOR pathway. So, Saffron could potentially be used clinically to enhance skin flap viability.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266. https://www.springer.com/00266.

Soluble microneedle patch with photothermal and NO-release properties for painless and precise treatment of ischemic perforator flaps

Skin necrosis is the most serious complication of flap plastic surgery, which means the failure of the operation. Systemic administration rarely benefits the local area and can lead to side effects, while topical administration has poor permeability due to the skin barrier function. Currently, few of these common medical interventions can totally respond to the blood supply of the skin after surgery. Herein, a soluble microneedle (MN) patch made of hyaluronic acid was used to target the ischemic area in a painless and precise manner for transdermal drug delivery. Based on the important role of nitric oxide (NO) in angiogenesis, the thermosensitive NO donor (BNN6) and gold nanorods (GNRs) acting as photothermal agents were introduced into the microneedles (MNs). The hyperthermia induced by GNRs under near infrared (NIR, 808 nm) irradiation could enhance the penetration of drugs and facilitate NO release from BNN6. A series of corresponding experiments proved that the system played a significant promotion role in vascular regeneration, providing a painless, precise and NO-assisted treatment method for the ischemic perforator flaps.

Dietary Sodium Nitrate Activates Antioxidant and Mitochondrial Dynamics Genes after Moderate Intensity Acute Exercise in Metabolic Syndrome Patients

Exercise can induce a pro-inflammatory response in aged subjects with metabolic disorders and nitrate supplementation has shown anti-inflammatory effects. We evaluated the influence of dietary nitrate on the response of the antioxidant and mitochondrial dynamics genes to acute exercise in peripheral blood mononuclear cells (PBMCs), as well as the antioxidant and the inflammatory response of PBMCs against immune stimulation. Metabolic syndrome patients participated in a crossover study in which they consumed a beverage containing 16 mM sodium nitrate or a placebo with the same composition without nitrate before performing a submaximal test at 60–70% of their maximal heart rate for 30 min. The intake of nitrate increased the nitrate plus nitrite plasma levels about 8-fold and induced the upregulation of catalase, superoxide dismutase, glutathione peroxidase, mitofusin 2 and PGC1α in PBMCs after exercise. The gene expression of catalase and TNFα was enhanced by phorbol myristate acetate (PMA) only in the placebo group, while the glutathione peroxidase expression was enhanced by PMA only after nitrate intake. The intake of nitrate by metabolic syndrome patients induces an antioxidant and mitochondrial response to exercise at the same time that it attenuates the pro-inflammatory response to immune stimulation.

Emerging medical therapies in crush syndrome - progress report from basic sciences and potential future avenues

Crush injury is a disease that is commonly found in victims of earthquakes, debris flows, mine disasters, explosions, terrorist attacks, local wars, and other accidents. The complications that arise due to the crush injury inflicted on victims give rise to crush syndrome (CS). If not treated in time, the mortality rate of CS is very high. The most important measure that can be taken to reduce mortality in such situations is to immediately start treatment. However, the traditional treatment methods such as fluid resuscitation, diuresis, and hemodialysis are not feasible enough to be carried out at the disaster scene. So there is a need for developing new treatments that are efficient and convenient. Because it is difficult to diagnose in the disaster area and reach the treatment equipment and treat on time. It has become a new research needs to be directed into identifying new medical treatment targets and methods using the etiology and pathophysiological mechanisms of CS. In recent years, a large number of new anti-oxidant and anti-inflammatory drug therapies have been shown to be highly efficacious in CS rat/mouse models. Some of them are expected to become specific drugs for the emergency treatment of a large number of patients who may develop CS in the aftermath of earthquakes, wars, and other disasters in the future. Hence, we have reviewed the latest research on the medical therapy of CS as a source for anyone wishing to pursue research in this direction.