Effects of sildenafil and tadalafil on skin flap viability

Exploring the Multifaceted Potential of Sildenafil in Medicine

Phosphodiesterase type 5 (PDE5) is pivotal in cellular signalling, regulating cyclic guanosine monophosphate (cGMP) levels crucial for smooth muscle relaxation and vasodilation. By targeting cGMP for degradation, PDE5 inhibits sustained vasodilation. PDE5 operates in diverse anatomical regions, with its upregulation linked to various pathologies, including cancer and neurodegenerative diseases. Sildenafil, a selective PDE5 inhibitor, is prescribed for erectile dysfunction and pulmonary arterial hypertension. However, considering the extensive roles of PDE5, sildenafil might be useful in other pathologies. This review aims to comprehensively explore sildenafil's therapeutic potential across medicine, addressing a gap in the current literature. Recognising sildenafil's broader potential may unveil new treatment avenues, optimising existing approaches and broadening its clinical application.

Itaconic acid induces angiogenesis and suppresses apoptosis via Nrf2/autophagy to prolong the survival of multi-territory perforator flaps

Background

Perforator flaps are widely used in hand microsurgery to reconstruct and repair soft tissue injuries. However, ischemia and subsequent ischemia-reperfusion injury may cause distal necrosis of the flap. Itaconic acid (IA) is a modulator of macrophage function, which exerts anti-inflammatory effects in macrophage activation.

Methods

The necrotic area of the flap was detected by measuring the flap temperature with an infrared thermometer. Flap cell apoptosis was detected by TUNEL staining and Western blot analysis of the apoptosis-associated proteins Bcl-2 and Bax. HE staining was used to detect angiogenesis of the skin flaps. CD31 was detected to identify positive vascular expression, and the survival of choke vessels in different areas of the skin flap was assessed by arteriography. In addition, Western blot was performed to quantify the expressions of VEGF, Nrf2, LC3II, SQSTM1, and CTSD.

Results

Itaconic acid raises VEGF protein levels in skin flaps and the number of CD31-positive vessels. The skin flaps in the IA treatment group exhibited higher neovascularization and less necrosis than those in the control group. The results of TUNEL staining and Western blot revealed that Itaconic acid attenuated apoptosis in the ischemic area of flap. The combination of itaconic acid and Nrf2 inhibitor ML385 reversed this beneficial effect. The results revealed that itaconic acid attenuated apoptosis, enhanced angiogenesis, and enhanced autophagy.

Conclusion

In summary, our findings indicate that itaconic acid might be an effective treatment to reduce flap necrosis. Additionally, this study identified a novel mechanism for the effects of itaconic acid on flap survival.

Use of Phosphodiesterase Inhibitors in the Postoperative Period of Skin Flaps: A Systematic Review

Ischemia-reperfusion injury can occur in several clinical conditions, and it has been widely studied in the context of skin flaps. Vascular distress results in an imbalance between the supply and demand of oxygen to living tissues, and the result of this process is tissue necrosis. Several drugs have been studied to reduce vascular distress of skin flaps and tissue loss.

Methods

The present study performed a systematic review of literature in the main databases (PubMed, Web of Science, LILACS, SciELO, and Cochrane), including articles published in the last 10 years.

Results

It was observed that phosphodiesterase inhibitors, mainly types III and V, have shown promising results in terms of vascularization of the postoperative skin flap, especially when started on the first postoperative day and maintained for 7 days.

Conclusion

New studies with different posology, duration of use, and new drugs are needed to better elucidate the use of this substance to optimize the circulation of skin flaps.

Deep Eutectic Liquids as a Topical Vehicle for Tadalafil: Characterisation and Potential Wound Healing and Antimicrobial Activity

Deep eutectic solvents (DESs) and ionic liquids (ILs) offer novel opportunities for several pharmaceutical applications. Their tunable properties offer control over their design and applications. Choline chloride (CC)-based DESs (referred to as Type III eutectics) offer superior advantages for various pharmaceutical and therapeutic applications. Here, CC-based DESs of tadalafil (TDF), a selective phosphodiesterase type 5 (PDE-5) enzyme inhibitor, were designed for implementation in wound healing. The adopted approach provides formulations for the topical application of TDF, hence avoiding systemic exposure. To this end, the DESs were chosen based on their suitability for topical application. Then, DES formulations of TDF were prepared, yielding a tremendous increase in the equilibrium solubility of TDF. Lidocaine (LDC) was included in the formulation with TDF to provide a local anaesthetic effect, forming F01. The addition of propylene glycol (PG) to the formulation was attempted to reduce the viscosity, forming F02. The formulations were fully characterised using NMR, FTIR and DCS techniques. According to the obtained characterisation results, the drugs were soluble in the DES with no detectable degradation. Our results demonstrated the utility of F01 in wound healing in vivo using cut wound and burn wound models. Significant retraction of the cut wound area was observed within three weeks of the application of F01 when compared with DES. Furthermore, the utilisation of F01 resulted in less scarring of the burn wounds than any other group including the positive control, thus rendering it a candidate formula for burn dressing formulations. We demonstrated that the slower healing process associated with F01 resulted in less scarring potential. Lastly, the antimicrobial activity of the DES formulations was demonstrated against a panel of fungi and bacterial strains, thus providing a unique wound healing process via simultaneous prevention of wound infection. In conclusion, this work presents the design and application of a topical vehicle for TDF with novel biomedical applications.

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.

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