Transfection of nuclear factor-kappaB decoy oligodeoxynucleotide protects against ischemia/reperfusion injury in a rat epigastric flap model

VEGF and Other Gene Therapies Improve Flap Survival-A Systematic Review and Meta-Analysis of Preclinical Studies

Surgical flaps are basic tools in reconstructive surgery. Their use may be limited by ischemia and necrosis. Few therapies address or prevent them. Genetic therapy could improve flap outcomes, but primary studies in this field present conflicting results. This systematic review and meta-analysis aimed to appraise the efficacy of external gene delivery to the flap for its survival in preclinical models. This review was registered with PROSPERO (CRD42022359982). PubMed, Embase, Web of Science, and Scopus were searched to identify studies using animal models reporting flap survival outcomes following any genetic modifications. Random-effects meta-analysis was used to calculate mean differences in flap survival with accompanying 95% CI. The risk of bias was assessed using the SYRCLE tool. Subgroup and sensitivity analyses were performed to ascertain the robustness of primary analyses, and the evidence was assessed using the GRADE approach. The initial search yielded 690 articles; 51 were eventually included, 36 of which with 1576 rats were meta-analyzed. VEGF gene delivery to different flap types significantly improved flap survival area by 15.66% (95% CI 11.80-19.52). Other interventions had smaller or less precise effects: PDGF-13.44% (95% CI 3.53-23.35); VEGF + FGF-8.64% (95% CI 6.94-10.34); HGF-5.61% (95% CI 0.43-10.78); FGF 3.84% (95% CI 1.13-6.55). Despite considerable heterogeneity, moderate risk of bias, and low quality of evidence, the efficacy of VEGF gene therapy remained significant in all sensitivity analyses. Preclinical data indicate that gene therapy is effective for increasing flap survival, but further animal studies are required for successful clinical translation.

Nuclear Factor-κB Decoy Oligodeoxynucleotide Attenuates Cartilage Resorption In Vitro

BACKGROUND

Cartilage harvest and transplantation is a common surgery using costal, auricular, and septal cartilage for craniofacial reconstruction. However, absorption and warping of the cartilage grafts can occur due to inflammatory factors associated with wound healing. Transcription factor nuclear factor-κB (NF-κB) is activated by the various stimulation such as interleukin-1 (IL-1), and plays a central role in the transactivation of this inflammatory cytokine gene. Inhibition of NF-κB may have anti-inflammatory effects. The aim of this study was to explore the potential of an NF-κB decoy oligodeoxynucleotide (Decoy) as a chondroprotective agent.

MATERIALS AND METHODS

Safe and efficacious concentrations of Decoy were assessed using rabbit nasal septal chondrocytes (rNSChs) and assays for cytotoxicity, proteoglycan (PG) synthesis, and PG turnover were carried out. The efficacious concentration of Decoy determined from the rNSChs was then applied to human nasal septal cartilage (hNSC) in vitro and analyzed for PG turnover, the levels of inflammatory markers, and catabolic enzymes in explant-conditioned culture medium.

RESULTS

Over the range of Decoy conditions and concentrations, no inhibition of PG synthesis or cytotoxicity was observed. Decoy at 10 μM effectively inhibited PG degradation in the hNSC explant, prolonging PG half-life by 63% and decreasing matrix metalloprotease 3 (MMP-3) by 70.7% (p = 0.027).

CONCLUSIONS

Decoy may be considered a novel chondroprotective therapeutic agent in cartilage transplantation due to its ability to inhibit cartilage degradation due to inflammation cytokines.

Febuxostat treatment attenuates oxidative stress and inflammation due to ischemia-reperfusion injury through the necrotic pathway in skin flap of animal model

BACKGROUND

Ischemia-reperfusion (I/R) injury is a major contributor to skin flap necrosis, which is a serious complication of reconstructive surgery. The purpose of this study was to evaluate the protective effect of treatment with febuxostat, a selective xanthine oxidase inhibitor, on I/R injury in the skin flap of an animal (rat) model.

METHODS

Superficial epigastric flaps were raised in Sprague-Dawley rats and subjected to ischemia for 3 h. Febuxostat at a dose of 10 mg/kg/day was administered to rats in drinking water from 1 week before the surgery (Feb group). Control animals received no drugs (Con group). The mean ratio of flap survival and contraction was evaluated and compared between animals with and without administration of febuxostat on day 5 after the surgery. In addition, infiltration by polymorphonuclear leukocytes and muscles of the panniculus carnosus in the flap were histologically evaluated using hematoxylin-eosin staining. Furthermore, xanthine oxidase activity, ATP levels, superoxide dismutase activity, and expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), tumor necrosis factor-α, and interleukin-1β were quantitatively assessed in the skin flap 24 h after the surgery.

RESULTS

In the Feb group, the survival and contraction rates at the 5 d timepoint post-surgery were significantly higher and lower than those in the Con group, respectively. Histological analysis showed significant reduction in polymorphonuclear leukocyte infiltration and muscle injury scores due to I/R injury in the Feb group. The expression of 8-OHdG was also significantly inhibited in animals administered febuxostat. Biochemical analysis showed a significant reduction in xanthine oxidase activity and significant increases in ATP levels and superoxide dismutase activity in the Feb group. Furthermore, the expression of interleukin-1β was significantly lower in the Feb group than in the Con group.

CONCLUSION

Febuxostat, which is clinically used for the treatment of hyperuricemia, was effective against necrosis of the skin flap via inhibition of oxidative stress and inflammation caused by I/R injury.

Vastus lateralis myocutaneous flap for ischial skin wound following the treatment of epithelioid sarcoma using pazopanib

Pazopanib, a targeted molecular drug, has been proposed as an effective treatment for soft tissue tumour and as a novel adjuvant therapy. There has been a paradoxical concern that wound healing could be inhibited by its anti-angiogenic properties, especially in reconstructive surgery. This paper reports on a 28-year-old woman who underwent flap surgery due to a skin and soft tissue injury after an effective treatment with pazopanib for refractory epithelioid sarcoma. The flap survived without any complication in off-periods of pazopanib for four weeks before and after the surgery, although it is only recommended that the washout periods of pazopanib commence at least seven days before scheduled surgery.

Effects of SB202190 on expression levels of IL-6 and NF-κB in flap ischemia-reperfusion injury

The aim of the current study was to investigate the effect of SB202190, a specific inhibitor of p38 MAPK signaling pathway, on the expression levels of IL-6 and NF-κB in flap ischemia-reperfusion injury. Healthy Sprague-Dawley rats were randomly divided into four groups of 12 each. For the ischemia-reperfusion group, the flap was constructed and then sutured after 8 h of ischemia. For the saline group, rats were intraperitoneally infused with saline at regular intervals after flap ischemia-reperfusion. For the inhibitor group, rats were intraperitoneally infused with SB202190 at regular intervals after flap ischemia-reperfusion. For the control group, the flap was constructed and then sutured immediately. The flap survival rate of each group was measured after 7 days. The concentration of IL-6 in serum was measured by ELISA kit. The mRNA and protein expression levels of IL-6 and NF-κB in the flap were measured using RT-PCR and western blot analysis, respectively. In the ischemia-reperfusion group and the saline group, the flap survival rates were much lower than that in the control group (P<0.05). By contrast, the mRNA and protein expression levels of IL-6 and NF-κB in the flap and the concentration of IL-6 in serum were much higher (P<0.05). In the inhibitor group, the flap survival rate was significantly higher than those in the ischemia-reperfusion and saline groups (P<0.05). By contrast, the concentration of IL-6 in serum and the mRNA and protein expression levels of NF-κB and IL-6 in the flap were significantly decreased (P<0.05). The results show that, SB202190 played a role in the protection of the flap by reducing the inflammatory response in flap ischemia-reperfusion injury.

The Effect of Botulinum Toxin A on Ischemia-Reperfusion Injury in a Rat Model

Introduction

While studies using various materials to overcome ischemia-reperfusion (IR) injury are becoming increasingly common, studies on the effects of botulinum toxin A (BoTA) on IR injury in musculocutaneous flaps are still limited. The purpose of this study was to examine our hypotheses that BoTA provide protection of musculocutaneous flap from ischemia-reperfusion injury.

Method

Five days after pretreatment injection (BoTA versus normal saline), a right superior musculocutaneous flap (6 × 1.5 cm in size) was made. Ischemia was created by a tourniquet strictly wrapping the pedicle containing skin and muscle for 8 h. After ischemia, the tourniquet was cut, and the musculocutaneous flap was reperfused.

Results

The overall survival percentage of flap after 8 h of pedicle clamping followed by reperfusion was 87.32 ± 3.67% in the control group versus 95.64 ± 3.25% in the BoTA group (p < 0.001). The BoTA group had higher expression of CD34, HIF-1α, VEGF, and NF-kB comparing to control group in qRT-PCR analysis.

Conclusions

In this study, we found that local BoTA preconditioning yielded significant protection against IR injury in a rat musculocutaneous flap model.

Role of the p38 mitogen-activated protein kinase signaling pathway in estrogen-mediated protection following flap ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury often occurs during skin flap transplantation and results in tissue damage. Although estrogen treatment significantly alleviates this I/R injury-induced damage, the detailed molecular mechanism is not clear. In this study, a superficial epigastric artery flap I/R injury model was created in adult Wistar rats. Severe necrosis was observed in skin tissue after I/R injury. Histological examination of skin tissue revealed that I/R injury damages skin structure and results in neutrophil infiltration. Inflammation-related parameters, including neutrophil count, tumor necrosis factor-α, and interleukin-10 levels, were increased due to I/R injury. These pathological phenomena were reduced by estradiol treatment. Further investigation found that I/R injury triggers the p38 mitogen-activated protein kinase (p38-MAPK) pathway. The expression levels of p38-MAPK and phosphorylated p38-MAPK were increased after I/R injury. Estradiol increased the expression level of MAPK phosphatase-2, a putative phosphatase of p38, and reduced the levels of p38-MAPK and phosphorylated p38-MAPK. These results suggest that estradiol can improve skin flap survival, possibly by inhibiting neutrophil infiltration and the expression of p38-MAPK. This study provides an explanation for how estrogen alleviates I/R injury-induced damage that occurs during skin flap transplantation. In a rat pathological model, I/R injury leads to skin necrosis, skin structure damage, neutrophil infiltration, and inflammatory cytokine secretion, which are probably downstream effects of activation of the p38-MAPK pathway. On the other hand, estradiol treatment triggers the expression of MAPK phosphatase-2, a putative phosphatase of p38-MAPK, and reduced all examined pathological phenomena. Therefore, estrogen may reduce the deleterious effect of I/R injury on skin flap transplantation through modulating the p38-MAPK pathway.