Native venous valves enable proper return of blood to the heart. Under pathological conditions (e.g., chronic venous insufficiency), venous valves malfunction and fail to prevent backward flow. Clinically, this can result in painful swelling, varicose veins, edema, and skin ulcerations leading to a chronic wound situation. Surgical correction of venous valves has proven to drastically reduce these symptoms. However, the absence of intact leaflets in many patients limits the applicability of this strategy. In this context, the development of venous valve replacements represents an appealing approach. Despite acceptable results in animal models, no venous valve has succeeded in clinical trials, and so far no single prosthetic venous valve is commercially available. This calls for advanced materials and fabrication approaches to develop clinically relevant venous valves able to restore natural flow conditions in the venous circulation. In this study, we critically discuss the approaches attempted in the last years, and we highlight the potential of tissue engineering to offer new avenues for valve fabrication.

中文翻译：

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工程静脉瓣膜的进展：寻求慢性静脉疾病的明确解决方案

天然静脉瓣能够使血液正确返回心脏。在病理条件下（例如，慢性静脉功能不全），静脉瓣功能失常并且无法防止回流。在临床上，这会导致疼痛性肿胀、静脉曲张、水肿和皮肤溃疡，从而导致慢性伤口情况。静脉瓣的手术矫正已被证明可以大大减少这些症状。然而，许多患者没有完整的传单限制了这种策略的适用性。在这种情况下，静脉瓣置换术的发展代表了一种有吸引力的方法。尽管在动物模型中获得了可接受的结果，但没有静脉瓣膜在临床试验中取得成功，并且迄今为止还没有一种人工静脉瓣膜可商用。这需要先进的材料和制造方法来开发临床相关的静脉瓣膜，能够恢复静脉循环中的自然流动条件。在这项研究中，我们批判性地讨论了过去几年尝试的方法，并强调了组织工程为瓣膜制造提供新途径的潜力。