Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5T 3L9, Canada.
Sci Transl Med. 2013 Nov 20;5(212):212ra160. doi: 10.1126/scitranslmed.3006260.
Male fertility problems range from diminished production of sperm, or oligozoospermia, to nonmeasurable levels of sperm in semen, or azoospermia, which is diagnosed in nearly 2% of men in the general population. Testicular biopsy is the only definitive diagnostic method to distinguish between obstructive (OA) and nonobstructive (NOA) azoospermia and to identify the NOA subtypes of hypospermatogenesis, maturation arrest and Sertoli cell-only syndrome. We measured by selected reaction monitoring assay 18 biomarker candidates in 119 seminal plasma samples from men with normal spermatogenesis and azoospermia, and identified two proteins, epididymis-expressed ECM1 and testis-expressed TEX101, which differentiated OA and NOA with high specificities and sensitivities. The performance of ECM1 was confirmed by enzyme-linked immunosorbent assay. On the basis of a cutoff level of 2.3 μg/ml derived from the current data, we could distinguish OA from normal spermatogenesis with 100% specificity, and OA from NOA with 73% specificity, at 100% sensitivity. Immunohistochemistry and an immunoenrichment mass spectrometry-based assay revealed the differential expression of TEX101 in distinct NOA subtypes. TEX101 semen concentrations differentiated Sertoli cell-only syndrome from the other categories of NOA. As a result, we propose a simple two-biomarker decision tree for the differential diagnosis of OA and NOA and, in addition, for the differentiation of NOA subtypes. Clinical assays for ECM1 and TEX101 have the potential to replace most of the diagnostic testicular biopsies and facilitate the prediction of outcome of sperm retrieval procedures, thus increasing the reliability and success of assisted reproduction techniques.
男性生育力问题范围从精子产生减少（少精子症）到精液中精子无法测量（无精子症），在普通人群中，近 2%的男性被诊断为无精子症。睾丸活检是区分梗阻性（OA）和非梗阻性（NOA）无精子症以及识别低精子发生、成熟阻滞和唯支持细胞综合征等 NOA 亚型的唯一明确诊断方法。我们通过选择反应监测测定法，对 119 份来自正常精子发生和无精子症男性的精浆样本中的 18 种生物标志物候选物进行了测量，并鉴定出两种蛋白质，即附睾表达 ECM1 和睾丸表达 TEX101，它们具有较高的特异性和敏感性，可区分 OA 和 NOA。ECM1 的性能通过酶联免疫吸附测定得到了证实。基于当前数据得出的 2.3μg/ml 截断值，我们可以在 100%敏感性下，以 100%特异性区分 OA 与正常精子发生，以 73%特异性区分 OA 与 NOA。免疫组织化学和基于免疫富集的质谱分析显示 TEX101 在不同的 NOA 亚型中表达差异。TEX101 精液浓度可区分唯支持细胞综合征与其他类型的 NOA。因此，我们提出了一个简单的二标志物决策树，用于 OA 和 NOA 的鉴别诊断，以及 NOA 亚型的鉴别。ECM1 和 TEX101 的临床检测有可能取代大多数诊断性睾丸活检，并有助于预测精子提取程序的结果，从而提高辅助生殖技术的可靠性和成功率。
