Quantitative assessment of neural elements in a rat model using nerve growth factor after remnant-preserving anterior cruciate ligament reconstruction: a histological and immunofluorescence pilot study.

BACKGROUND: Immunofluorescence analyses of anterior cruciate ligament (ACL) allografts following remnant-preserving ACL reconstruction using Achilles tendon allografts have provided evidence for the presence of neural elements. In this study, we aimed to examine the expression of neural elements and quantify the presence of neural cells in ACL remnants and Achilles allografts using nerve growth factor (NGF) therapy after remnant-preserving ACL reconstruction. METHODS: Experiments were conducted on 5 pairs of rats (approximately 8 weeks old and weighing 320 g at the time of surgery). Longitudinally, split Achilles tendons from the paired rats were freshly frozen and later defrosted with warm saline and allografted onto the right ACL of the other rat that was partially detached at the femoral attachment site. A sham operation was conducted on the left knee to be used as a control. NGF was injected into both knee joints every week for 6 weeks after surgery. The presence of neural cells in the ACL of the sham-operated knee, allografted Achilles tendon, and ACL remnant was examined 6 weeks post-surgery using H and E and immunofluorescent staining. RESULTS: H and E staining did not reveal neural cells in any of the three groups. However, immunofluorescence analysis showed the presence of nestin-positive neural elements in the normal ACL tissues as well as ACL remnants. Additionally, neural elements were examined in 7 of the 8 (87.5%) allograft tissues. Quantitative analysis showed no difference in the number or area of nuclei among the three groups. However, the number and area of neural cells in the Achilles allografts were significantly lower than those in the other two groups (p = 0.000 and p = 0.001, respectively). CONCLUSION: Our observations indicate that ACL remnants promote the new ingrowth and persistence of neural cells. We suggest that the ingrowth of neural elements can support the persistence and new ingrowth of mechanoreceptors, thereby enhancing the functional stability of knee joints. Moreover, the expression of neural cells in the Achilles allografts was lower than that in normal ACL tissues and ACL remnants in the quantitative evaluation, thereby confirming the essential role of ACL remnants in knee joint functionalization.

Seeding decellularized nerve allografts with adipose-derived mesenchymal stromal cells: An in vitro analysis of the gene expression and growth factors produced.

Mesenchymal stromal cells (MSCs) secrete many soluble growth factors and have previously been shown to stimulate nerve regeneration. MSC-seeded processed nerve allografts could potentially be a promising method for large segmental motor nerve injuries. Further progress in our understanding of how the functions of MSCs can be leveraged for peripheral nerve repair is required before making clinical translation. The present study, therefore, investigated whether interactions of adipose-derived MSCs with decellularized nerve allografts can improve gene and protein expression of growth factors that may support nerve regeneration. Human nerve allografts (n = 30) were decellularized and seeded with undifferentiated human adipose-derived MSCs. Subsequently, the MSCs and MSC-seeded grafts were isolated on days 3, 7, 14, and 21 in culture for RNA expression analysis by qRT-PCR. Evaluated genes included NGF, BDNF, PTN, GAP43, MBP, PMP22, VEGF, and CD31. Growth factor production was evaluated and quantified using enzyme-linked immunosorbent assay (ELISA). On day 21, semi-quantitative RT-PCR analysis showed that adherence of MSCs to nerve allografts significantly enhances mRNA expression of neurotrophic, angiogenic, endothelial, and myelination markers (e.g., BDNF, VEGF, CD31, and MBP). ELISA results revealed an upregulation of BDNF and reduction of both VEGF and NGF protein levels. This study demonstrates that seeding of undifferentiated adipose-derived MSCs onto processed nerve allografts permits the secretion of neurotrophic and angiogenic factors that can stimulate nerve regeneration. These favorable molecular changes suggest that MSC supplementation of nerve allografts may have potential in improving nerve regeneration.

Reinnervation of rat endometrium in the anterior eye chamber model of experimental endometriosis: Old methods for new questions.

Endometriosis is a benign estrogen-dependent chronic gynecological disease characterized by the presence of endometrial-like tissue outside the uterine cavity. In both women and experimental endometriotic rats, endometriosis lesions endow autonomic and sensory nerves, which are thought to contribute to the disease-associated pain. Some evidence indicates that the reinnervation of lesions is regulated by factors produced by the endometrial tissue as well as by environmental factors from the peritoneum. In this study, we examined the reinnervation of the rat endometrial tissue in an ectopic environment different from the peritoneum employing the anterior eye chamber model of experimental endometriosis. At 3 and 6weeks following transplantation, endometrial grafts retained many histological features of the eutopic tissue. Both sympathetic and sensory nerves reinnervated endometrial grafts and distributed in the stroma-like tissue, around blood vessels and in close proximity to the glands and lining epithelium. Sympathetic innervation was more robust than sensory innervation. No significant topographical relationship between sympathetic nerves and macrophages was observed. These results suggest that the rat endometrium possesses intrinsic neuritogenic capacities and can be reinnervated by sympathetic and sensory nerves in ectopic sites different from the peritoneum.

Dehydrated Human Amnion/Chorion Membrane Allograft Nerve Wrap Around the Prostatic Neurovascular Bundle Accelerates Early Return to Continence and Potency Following Robot-assisted Radical Prostatectomy: Propensity Score-matched Analysis.

We present a propensity-matched analysis of patients undergoing placement of dehydrated human amnion/chorion membrane (dHACM) around the neurovascular bundle (NVB) during nerve-sparing (NS) robot-assisted laparoscopic prostatectomy (RARP). From March 2013 to July 2014, 58 patients who were preoperatively potent (Sexual Health Inventory for Men [SHIM] score >19) and continent (no pads) underwent full NS RARP. Postoperative outcomes were analyzed between propensity-matched graft and no-graft groups, including time to return to continence, potency, and biochemical recurrence. dHACM use was not associated with increased operative time or blood loss or negative oncologic outcomes (p>0.500). Continence at 8 wk returned in 81.0% of the dHACM group and 74.1% of the no-dHACM group (p=0.373). Mean time to continence was enhanced in group 1 patients (1.21 mo) versus (1.83 mo; p=0.033). Potency at 8 wk returned in 65.5% of the dHACM patients and 51.7% of the no-dHACM group (p=0.132). Mean time to potency was enhanced in group 1, (1.34 mo), compared to group 2 (3.39 mo; p=0.007). Graft placement enhanced mean time to continence and potency. Postoperative SHIM scores were higher in the dHACM group at maximal follow-up (mean score 16.2 vs 9.1). dHACM allograft use appears to hasten the early return of continence and potency in patients following RARP.