In this review, we describe the structure and function of the alveolar-capillary membrane and the identification of a novel potential marker of its integrity in the context of heart failure (HF). The alveolar-capillary membrane is indeed a crucial structure for the maintenance of the lung parenchyma gas exchange capacity, and the occurrence of pathological conditions determining lung fluids accumulation, such as HF, might significantly impair lung diffusion capacity altering the alveolar-capillary membrane protective functions. In the years, we found that the presence of immature forms of the surfactant protein-type B (proSP-B) in the circulation reflects alterations in the alveolar-capillary membrane integrity. We discussed our main achievements showing that proSP-B, due to its chemical properties, specifically binds to high-density lipoprotein, impairing their antioxidant activity, and likely contributing to the progression of the disease. Further, we found that immature proSP-B, not the mature protein, is related to lung abnormalities, more precisely than the lung function parameters. Thus, to the list of the potential proposed markers of HF, we add proSP-B, which represents a precise marker of alveolar-capillary membrane dysfunction in HF, correlates with prognosis, and represents a precocious marker of drug therapy.

中文翻译：

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心力衰竭病理生理条件下的肺泡毛细血管单位：潜在标记物的识别。

在这篇综述中，我们描述了肺泡毛细血管膜的结构和功能，以及在心力衰竭（HF）的情况下鉴定其完整性的新型潜在标志物。肺泡毛细血管膜确实是维持肺实质气体交换能力的关键结构，决定肺液积聚的病理条件（例如心力衰竭）的发生可能会显着损害肺的扩散能力，从而改变肺泡毛细血管膜的保护功能。多年来，我们发现循环系统中未成熟形式的 B 型表面活性剂蛋白 (proSP-B) 的存在反映了肺泡毛细血管膜完整性的变化。我们讨论了我们的主要成果，表明 proSP-B 由于其化学特性，可以特异性地与高密度脂蛋白结合，损害其抗氧化活性，并可能导致疾病的进展。此外，我们发现未成熟的proSP-B（而不是成熟的蛋白质）与肺异常相关，比肺功能参数更精确。因此，在潜在的心力衰竭标记物列表中，我们添加了 proSP-B，它代表了心力衰竭肺泡毛细血管膜功能障碍的精确标记物，与预后相关，并且代表了药物治疗的早熟标记物。