Ayato Hayashi

The differential effects of pathway- versus target-derived glial cell line–derived neurotrophic factor on peripheral nerve regeneration

OBJECT Glial cell line-derived neurotrophic factor (GDNF) has potent survival effects on central and peripheral nerve populations. The authors examined the differential effects of GDNF following either a sciatic nerve crush injury in mice that overexpressed GDNF in the central or peripheral nervous systems (glial fibrillary acidic protein [GFAP]-GDNF) or in the muscle target (Myo-GDNF). METHODS Adult mice (GFAP-GDNF, Myo-GDNF, or wild-type [WT] animals) underwent sciatic nerve crush and were evaluated using histomorphometry and muscle force and power testing. Uninjured WT animals served as controls. RESULTS In the sciatic nerve crush, the Myo-GDNF mice demonstrated a higher number of nerve fibers, fiber density, and nerve percentage (p < 0.05) at 2 weeks. The early regenerative response did not result in superlative functional recovery. At 3 weeks, GFAP-GDNF animals exhibit fewer nerve fibers, decreased fiber width, and decreased nerve percentage compared with WT and Myo-GDNF mice (p < 0.05). By 6 weeks, there were no significant differences between groups. CONCLUSIONS Peripheral delivery of GDNF resulted in earlier regeneration following sciatic nerve crush injuries than that with central GDNF delivery. Treatment with neurotrophic factors such as GDNF may offer new possibilities for the treatment of peripheral nerve injury.

Treatment of unilateral lambdoid synostosis with cranial distraction.

The accurate diagnosis and treatment of posterior plagiocephaly have been a source of controversy. The unilateral lambdoid synostosis that is characterized by flattening of ipsilateral occipital bone is a rare type of craniosynostosis. An 8-month-old infant with unilateral lambdoid synostosis is reported. The patient exhibited right occipital flattening, mastoid bulge, and right frontal bone prominence, with the right auricle displaced anteroinferiorly on gross examination. A Towne projection radiograph of the skull and three-dimensional computed tomography scans revealed that the right lambdoid suture was prematurely fused. Correction of the cranial shape was performed using distraction osteogenesis combined with a barrel stave osteotomy. Significant improvement in the skull was observed 1 year after surgery.

Hemihypoglossal nerve transfer for acute facial paralysis

OBJECT The authors have developed a technique for the treatment of facial paralysis that utilizes anastomosis of the split hypoglossal and facial nerve. Here, they document improvements in the procedure and experimental evidence supporting the approach. METHODS They analyzed outcomes in 36 patients who underwent the procedure, all of whom had suffered from facial paralysis following the removal of large vestibular schwannomas. The average period of paralysis was 6.2 months. The authors used 5 different variations of a procedure for selecting the split nerve, including evaluation of the split nerve using recordings of evoked potentials in the tongue. RESULTS Successful facial reanimation was achieved in 16 of 17 patients using the cephalad side of the split hypoglossal nerve and in 15 of 15 patients using the caudal side. The single unsuccessful case using the cephalad side of the split nerve resulted from severe infection of the cheek. Procedures using the ansa cervicalis branch yielded poor success rates (2 of 4 cases). Some tongue atrophy was observed in all variants of the procedure, with 17 cases of minimal atrophy and 14 cases of moderate atrophy. No procedure led to severe atrophy causing functional deficits of the tongue. CONCLUSIONS The split hypoglossal-facial nerve anastomosis procedure consistently leads to good facial reanimation, and the use of either half of the split hypoglossal nerve results in facial reanimation and moderate tongue atrophy.

The role of Notch signaling in diabetic endothelial progenitor cells dysfunction

AIMS To investigate the role of Notch signaling pathway in vasculogenic dysfunction of diabetic EPCs (DM-EPCs). METHODS The study was performed in mice and diabetes was induced with Streptozotocin. The functional consequences of Notch pathway modulation were studied by assessment of colony forming capacity (EPC colony forming assay), EPC differentiation capacity (% of definitive EPC-CFU (dEPC-CFU)), circulating EPCs (EPC culture assay) and migrated cells (migration assay); in the presence of Notch inhibitor (γ-secretase inhibitors (GSI)) compared to control. Notch pathway and VEGF involvement in DM- EPCs were assessed by gene expression (RT-qPCR). RESULTS DM demonstrated to increase Notch pathway expression in bone marrow (BM) EPCs followed by lower EPC-CFU number, EPCs differentiation capacity, number of circulating EPCs, migrated cells and VEGF expression compared to control (p<0.05). Inhibition of Notch pathway by GSI rescued vasculogenic dysfunction in DM-EPCs as represented by increase in EPC-CFU number, differentiation capacity and number of circulating EPCs (p<0.05). CONCLUSION Our findings indicate the involvement of Notch pathway in mediating DM-EPCs dysfunction including less number of EPC-CFU, circulating EPCs and migrated cell number compared to control. Further in vitro inhibition of Notch pathway by GSI rescued DM-EPC dysfunction. Therefore targeting Notch pathway in DM may provide a target to restore DM-EPC dysfunction.

Experience and anatomical study of modified lengthening temporalis myoplasty for established facial paralysis

Lengthening temporalis myoplasty, reported by Daniel Labbé in 1997, is a unique and definite facial reanimation procedure that involves moving the whole temporal muscle anteroinferiorly and inserting its tendon directly into the nasolabial fold. In the present article, we report our experience in the use of his modified method of the procedure, which preserves the zygomatic arch by transecting the coronoid process through the nasolabial fold incision. We also describe our cadaveric study that aimed to elucidate a secure approach for coronoid process transection. We performed this procedure in five patients with permanent facial paralysis. To improve facial symmetry, we also performed several additional static reconstructions such as T-shaped double-sleeve fascia grafts for lower lip deformities. We were successful in achieving considerable static improvement at rest, immediately after the surgery, and the recovery of facial movement was apparent approximately 3 months after the surgery. With regard to the cadaveric study, we noted that the entry to the buccal fat region, which is also the pathway of the temporal fascia, was a narrow space, and a short transection of the medial upper edge of the masseter fascia would make it easy to locate the coronoid process. Therefore, for a safe and secure access to the coronoid process from the nasolabial fold, we believe that we should first expose the cranial side and continue to dissect along the side and lower edge of the maxilla to locate the medial upper edge of the masseter fascia. By transecting along its edge, we could easily access the coronoid process, located immediately behind it, and widen the pathway of the temporal fascia. This modified method is less invasive and simpler compared to the original procedure, and understanding the detailed anatomy for dissection would help surgeons perform this procedure more confidently.

The supernumerary nostril.

The supernumerary nostril is a very rare congenital nasal abnormality, and several cases have been reported in the literature since 1906 when the first case was reported by Lindsay. In the other previously reported cases, the supernumerary nostril typically could present unilaterally or bilaterally, and it was therefore called a double nose, with most reported cases being unilateral. At our institution, we encountered a patient with a supernumerary nostril that was located above the left nostril. We thus performed an operation on this supernumerary nostril and obtained good results and a successful postoperative course. We herein present our findings while also discussing the pertinent literature.

Oxidative stress tolerance of early stage diabetic endothelial progenitor cell

Introduction One of the causes for poor vasculogenesis of diabetes mellitus (DM) is known to rise from the dysfunction of bone marrow-derived endothelial progenitor cells (BM EPCs). However, the origin of its cause is less understood. We aimed to investigate the effect of oxidative stress in early stage of diabetic BM-EPC and whether its vasculogenic dysfunction is caused by oxidative stress. Methods Bone marrow c-Kit+Sca-1+Lin− (BM-KSL) cells were sorted from control and streptozotocin-induced diabetic C57BL6J mice by flow cytometry. BM-KSLs were then assessed for vasculogenic potential (colony forming assay; EPC-CFA), accumulation of intracellular ROS (CM-H2DCFDA), carbonylated protein (ELISA), anti-oxidative enzymes expression (RT-qPCR) and catalase activity (Amplex Red). Results Compared to control, DM BM-KSL had significantly lower EPC-CFUs in both definitive EPC-CFU and total EPC-CFU (p < 0.05). Interestingly, the oxidative stress level of DM BM-KSL was comparable and was not significantly different to control followed by increased in anti-oxidative enzymes expression and catalase activity. Conclusions Primitive BM-EPCs showed vasculogenic dysfunction in early diabetes. However the oxidative stress is not denoted as the major initiating factor of its cause. Our results suggest that primitive BM-KSL cell has the ability to compensate oxidative stress levels in early diabetes by increasing the expression of anti-oxidative enzymes.

Intraoperative Use of Indocyanine Green Fluorescence Angiography during Distally Based Radial Artery Perforator Flap for Squamous Cell Carcinoma of the Thumb.

Summary: Distally based radial artery perforator flap (DBRAPF) is useful for hand defects; however, the location of the perforator varies among individuals. Preoperative evaluation has been a problematic issue when performing this flap. A 64-year-old man developed squamous cell carcinoma on an old burn scar at the dorsal thumb and was referred to our clinic for further treatment. After wide resection of the tumor, including the long and short extensors of the thumb, we reconstructed the defect with DBRAPF. At that time, near-infrared fluorescence angiography with indocyanine green (ICG) was used to identify the position of the perforator. After injecting ICG intravenously, we could observe its uptake at approximately 5 cm proximal to the styloid process. We designed a 10 × 6 cm island flap with that uptake as pivot point. During flap elevation, the perforator could be confirmed at the point of uptake; the flap was then transferred to the defect by rotating the pedicle at the identified point. The vascularity of the flap could also be checked intraoperatively through ICG angiography. The tip of the flap that showed weak ICG fluorescence indicated epidermal necrosis. Nevertheless, the entire flap was viable and enabled good functionality without tumor recurrence and metastasis after 5 years. Using ICG angiography, DBRAPF could be performed smoothly, easily, and safely.

Interleukin-6 stimulates Akt and p38 MAPK phosphorylation and fibroblast migration in non-diabetic but not diabetic mice

Persistent inflammatory environment and abnormal macrophage activation are characteristics of chronic diabetic wounds. Here, we attempted to characterize the differences in macrophage activation and temporal variations in cytokine expression in diabetic and non-diabetic wounds, with a focus on interleukin (IL)-6 mRNA expression and the p38 MAPK and PI3K/Akt signaling pathways. Cutaneous wound closure, CD68- and arginase-1 (Arg-1)-expressing macrophages, and cytokine mRNA expression were examined in non-diabetic and streptozotocin-induced type 1 diabetic mice at different time points after injury. The effect of IL-6 on p38 MAPK and Akt phosphorylation was investigated, and an in vitro scratch assay was performed to determine the role of IL-6 in primary skin fibroblast migration. Before injury, mRNA expression levels of the inflammatory markers iNOS, IL-6, and TNF-α were higher in diabetic mice; however, IL-6 expression was significantly lower 6 h post injury in diabetic wounds than that in non-diabetic wounds. Non-diabetic wounds exhibited increased p38 MAPK and Akt phosphorylation; however, no such increase was found in diabetic wounds. In fibroblasts from non-diabetic mice, IL-6 increased the phosphorylation of p38 MAPK and levels of its downstream factor CREB, and also significantly increased Akt phosphorylation and levels of its upstream factor P13K. These effects of IL-6 were not detected in fibroblasts derived from the diabetic mice. In scratch assays, IL-6 stimulated the migration of primary cultured skin fibroblasts from the non-diabetic mice, and the inhibition of p38 MAPK was found to markedly suppress IL-6–stimulated fibroblast migration. These findings underscore the critical differences between diabetic and non-diabetic wounds in terms of macrophage activation, cytokine mRNA expression profile, and involvement of the IL-6-stimulated p38 MAPK–Akt signaling pathway. Aberrant macrophage activation and abnormalities in the cytokine mRNA expression profile during different phases of wound healing should be addressed when designing effective therapeutic modalities for refractory diabetic wounds.

A synthetic leukotriene B4 receptor type 2 agonist accelerates the cutaneous wound healing process in diabetic rats by indirect stimulation of fibroblasts and direct stimulation of keratinocytes

AIMS The synthetic leukotriene B4 receptor type 2 (BLT2) agonist CAY10583 (CAY) accelerates wound healing in diabetic mice by promoting keratinocyte migration. However, its effects on fibroblast activity and granulation are unknown. We investigated the mechanisms by which CAY promotes wound healing. METHODS CAY was applied to wounds on streptozotocin-induced diabetic rats, and wound closure, granulation thickness, and epithelialization gaps were analyzed. BLT2 expression was examined by RT-PCR. Migration and proliferation were studied by scratch assays and MTS assays. Keratinocyte supernatants with CAY were applied to fibroblasts, and cytokines were measured by enzyme-linked immunosorbent assays. RESULTS CAY significantly accelerated wound healing in diabetic rats (CAY, 78.05±12.22% vs. control, 59.84±11.09%; p=0.0222), with increased re-epithelialization and granulation compared to controls. BLT2 was expressed in keratinocytes, but not in fibroblasts. Keratinocyte treatment with the CAY supernatant enhanced fibroblast proliferation and migration (fibroblast scratch closure: CAY, 75.95±4.09% vs. control, 49.69±4.49%; p<0.0001). CAY-treated keratinocytes exhibited increased TGF-β1 and bFGF expression. CONCLUSIONS CAY directly promotes keratinocyte migration and indirectly enhances fibroblast proliferation by increasing keratinocyte production of TGF-β1 and bFGF, accelerating wound closure. CAY is a promising pharmaceutical agent for diabetic wounds.