Spermatogenesis generates mature male gametes and is critical for the proper transmission of genetic information between generations. However, the developmental landscapes of human spermatogenesis remain unknown. Here, we performed single-cell RNA sequencing (scRNA-seq) analysis for 2,854 testicular cells from donors with normal spermatogenesis and 174 testicular cells from one nonobstructive azoospermia (NOA) donor. A hierarchical model was established, which was characterized by the sequential and stepwise development of three spermatogonia subtypes, seven spermatocyte subtypes, and four spermatid subtypes. Further analysis identified several stage-specific marker genes of human germ cells, such as HMGA1, PIWIL4, TEX29, SCML1, and CCDC112. Moreover, we identified altered gene expression patterns in the testicular somatic cells of one NOA patient via scRNA-seq analysis, paving the way for further diagnosis of male infertility. Our work allows for the reconstruction of transcriptional programs inherent to sequential cell fate transition during human spermatogenesis and has implications for deciphering male-related reproductive disorders.

Objective. To observe redifferentiation of dedifferentiated chondrocytes after transplantation into the joint, and to evaluate the ability of dedifferentiated chondrocytes transduced with adenovirus containing bone morphogenetic protein 4 (BMP-4) to redifferentiate in vitro and in vivo in a rabbit model of articular cartilage defects.Methods. Monolayer and pellet culture systems were used to evaluate the redifferentiation of dedifferentiated chondrocytes transduced with BMP-4. A rabbit model of partial-thickness articular cartilage defects was used to evaluate cartilage repair macroscopically and histologically, 6 and 12 weeks after transplantation with first-passage, fifth-passage, or transduced fifthpassage chondrocytes. Histologic grading of the repaired tissue was performed. Expression of BMP-4 and the ability of transplanted cells to recover a chondrocytic phenotype were also assessed. Conclusion. Some dedifferentiated chondrocytes can redifferentiate after transplantation into the loadbearing joint. BMP-4 can be used to induce redifferentiation of dedifferentiated chondrocytes in vitro and in vivo, which could help enhance articular cartilage repair. Results. BMP-4-expressing dedifferentiated

The expression pattern of sNHE suggested that this protein may be involved in the regulation of sperm motility, and aberration of its expression in sperm may contribute to the pathogenesis of asthenozoospermia.

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Vasoepididymostomy (VE), as the most challenging procedure in microsurgeries, is often carried out with a double-armed two-suture technique. In this study, we evaluated the efficacy and safety of the single-armed two-suture VEs on humans and studied the factors that could possibly affect the patency rates. From July 2012 to July 2013, we reviewed 81 patients with consecutive primary epididymal obstruction who underwent single-armed two-suture longitudinal intussusception microsurgical VEs by a single surgeon, Kai Hong (KH). At the same time, we analyzed seven factors that possibly related to the patency rates. With the single-armed technique, a total of 81 men underwent the microsurgical VEs. Data on 62 patients were completely recorded. 19 patients were lost to follow-up. Mean age was 31 years old. Mean follow-up time was 8.8 (2-17) months. The patency rate was 66.1% (41/62). Natural pregnancy rate was 34.1% (14/41). Overall pregnancy rate was 22.6% (14/62). No severe surgical complications were noted. With logistic regression test analysis, there were two factors related to a higher patency rate: anastomosis sites (P = 0.035) and motile sperm found in the epididymal fluid (P = 0.006). Motile sperm found in the epididymal fluid were associated with a higher patency rate (OR = 11.80, 95% CI = 1.79, 77.65). The single-armed two-suture longitudinal VE technique is feasible for microsurgical practice. The patency and pregnancy rates are comparable to the doubled-armed technique. Anastomosis sites and motile sperm found in the epididymal fluid were the most two important factors related to higher patency.

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The aim of our study was to compare the sperm retrieval rates (SRRs) and clinical outcomes of patients with different causes of azoospermia who underwent microdissection testicular sperm extraction-intracytoplasmic sperm injection (micro-TESE-ICSI). We conducted a retrospective study at the Reproductive Medicine Center of Peking University Third Hospital in Beijing, China, from January 2014 to December 2017. This study examined 769 patients with nonobstructive azoospermia who underwent 347 cycles of micro-TESE-ICSI. Patients with azoospermia were classified into Group A (Klinefelter syndrome, n = 284, 125 cycles), Group B (azoospermia Y chromosome factor c [ AZFc ] microdeletion, n = 91, 64 cycles), Group C (cryptorchidism, n = 52, 39 cycles), Group D (previous mumps and bilateral orchitis, n = 23, 23 cycles), and Group E (idiopathic azoospermia, n = 319, 96 cycles). Clinical characteristics, SRR, embryonic development, and pregnancy outcomes of the patients were compared between all groups. Patients in Group D had the highest and most successful SRR. The average SRR for all patients was 46.0%. The rates of clinical pregnancy, implantation, and live birth in Group D were 78.3%, 65.0%, and 74.0%, respectively, which were higher than those in all other groups ( P < 0.05). Group B patients had the lowest clinical pregnancy, implantation, and live birth rates of all groups ( P < 0.05). No differences were found in the miscarriage rate or birth defects among the groups ( P > 0.05). Patients with orchitis had the highest SRR and best clinical outcomes. Although AZFc microdeletion patients had a higher SRR, their clinical outcomes were worse.