Toshihiko Nishisho

The a3 Isoform Vacuolar Type H+-ATPase Promotes Distant Metastasis in the Mouse B16 Melanoma Cells

Accumulating evidence indicates that the acidic microenvironments critically influence malignant behaviors of cancer including invasiveness, metastasis, and chemoresistance. Because the vacuolar-type H+-ATPase (V-ATPase) has been shown to cause extracellular acidification by pumping protons, we studied the role of V-ATPase in distant metastasis. Real-time PCR analysis revealed that the high-metastatic B16-F10 melanoma cells strongly expressed the a3 isoform V-ATPase compared to the low-metastatic B16 parental cells. Consistent with this, B16-F10 cells created acidic environments in lung metastases by acridine orange staining and strong a3 V-ATPase expression in bone metastases by immunohistochemistry. Immunocytochemical analysis showed B16-F10 cells expressed a3 V-ATPase not only in cytoplasm but also plasma membrane, whereas B16 parental cells exhibited its expression only in cytoplasm. Of note, knockdown of a3 V-ATPase suppressed invasiveness and migration with reduced MMP-2 and MMP-9 expression in B16-F10 cells and significantly decreased lung and bone metastases, despite that tumor growth was not altered. Importantly, administration of a specific V-ATPase a3 inhibitor FR167356 reduced bone metastasis of B16-F10 cells. These results suggest that a3 V-ATPase promotes distant metastasis of B16-F10 cells by creating acidic environments via proton secretion. Our results also suggest that inhibition of the development of cancer-associated acidic environments by suppressing a3 V-ATPase could be a novel therapeutic approach for the treatment of cancer metastasis. Mol Cancer Res; 9(7); 845–55. ©2011 AACR.

Involvement of acidic microenvironment in the pathophysiology of cancer-associated bone pain

Bone pain is one of the most common complications in cancer patients with bone metastases. Although the mechanism of cancer-associated bone pain is poorly understood, clinical observations that inhibitors of osteoclasts such as bisphosphonates (BPs) efficiently reduce bone pain suggest a potential role of osteoclasts, which play a central role in the development and progression of bone metastasis. Osteoclasts dissolve bone minerals by releasing protons through the a3 isoform of the vacuolar-H(+)-ATPase, creating acidic microenvironments. In addition, cancer cells, inflammatory cells and immune cells that reside in bone metastases also produce acidic conditions by releasing protons. It has been well-known that acidic conditions due to proton release cause pain. Our study showed that the sensory nociceptive neurons innervate bone and these neurons express acid-sensing nociceptors such as the acid-sensing ion channels and transient receptor potential channel-vanilloid subfamily members. Acid signals received by these nociceptors subsequently activate intracellular signaling pathways and transcription factors in sensory neurons. The understanding of the nociceptive events following proton release and subsequent creation of acidic microenvironments leads us to design novel molecular-based approaches for reducing bone pain associated with cancer and inflammation.

Acid Activation of Trpv1 Leads to an Up-Regulation of Calcitonin Gene-related Peptide Expression in Dorsal Root Ganglion Neurons via the CaMK-CREB Cascade: A Potential Mechanism of Inflammatory Pain

Increased CGRP expression in sensory neurons is associated with inflammatory pain. We examined the molecular basis of CGRP expression and found that acid-sensing nociceptor Trpv1 is activated under inflammatory acidic environments and up-regulates the CGRP expression through CaMK-CREB cascade.

Locally Administered Zoledronic Acid Therapy for Giant Cell Tumor of Bone

Giant cell tumor of bone is locally aggressive and occurs in the meta-epiphyseal region of long bones. Because of its high recurrence rate, local adjuvant therapies such as phenol or liquid nitrogen have been recommended. In the present study, zoledronic acid, a nitrogen-containing bisphosphonate, was administered locally as an adjuvant during a biopsy. An otherwise healthy 43-year-old man presented with pain and swelling in the right knee. Plain radiographs showed an osteolytic lesion of the right proximal tibia. An open biopsy was performed and the intraoperative pathologic diagnosis was giant cell tumor of bone. Following biopsy, the defect was filled with betatricalcium phosphate, and 4 mg of zoledronic acid was locally administered into the tumor lesion. Two months after the biopsy, curettage and bone grafting were performed. Sections were obtained during the curettage for histology to evaluate the response to bisphosphonate treatment. Histologic examination revealed massive tumor cell death in the lesion in which both stromal cells and osteoclast-like giant cells were necrotic. Curettage was performed and the defect was filled with a commercial preshaped hydroxyapatitetricalcium phosphate bone substitute. Eighteen months after curettage, the patient had regained full range of motion and good function of the knee, and radiographs at 18 months after curettage revealed no recurrence of giant cell tumor of bone.

Foraminoplastic transforaminal percutaneous endoscopic discectomy at the lumbosacral junction under local anesthesia in an elite rugby player

Percutaneous endoscopic discectomy (PED) is the least invasive disc surgery available at present. The procedure can be performed under local anesthesia and requires only an 8 mm skin incision. Furthermore, damage to the back muscle is considered minimal, which is particularly important for disc surgery in athletes. However, employing the transforaminal (TF) PED approach at the lumbosacral junction can be challenging due to anatomical constraints imposed by the iliac crest. In such cases, foraminoplasty is required in addition to the standard TF procedure. A 28-year-old man who was a very active rugby player visited us complaining of lower back and left leg pain. His visual analog scale (VAS) score for pain was 8/10 and 3/10, respectively. MRI revealed a herniated nucleus pulposus at L5-S level. TF-PED was planned; however, the anatomy of the iliac crest was later found to prevent access to the herniated mass. Foraminoplasty was therefore performed to enlarge the foramen, thereby allowing a cannula to be passed through the foramen into the canal without causing exiting nerve injury. The herniated mass was then successfully removed via the TF-PED procedure. Pain resolved after surgery, and his VAS score decreased to 0/10 for both back and leg pain. The patient returned to full rugby activity 8 weeks after surgery. In conclusion, even with an intracanalicular herniated mass at the lumbosacral junction, a TF-PED procedure is possible if additional foraminoplasty is adequately performed to enlarge the foramen.

Angiogenesis and myogenesis in mouse tibialis anterior muscles during distraction osteogenesis: VEGF, its receptors, and myogenin genes expression.

Angiogenesis and myogenesis occur in the surrounding skeletal muscles following distraction osteogenesis, but their molecular mechanisms remain unclear. The present study investigated morphological features of lengthened muscles and the time course change of vascular endothelial growth factor (VEGF), its receptors (VEGFR‐1 and VEGFR‐2) and myogenin gene expression profiles related to angiogenesis and myogenesis in tibialis anterior (TA) muscles with a mouse model of distraction osteogenesis, which involves 1 week of waiting period (latency phase), 2 weeks of intermittent distraction (distraction phase), and 5 weeks of remodeling period (consolidation phase). Macroscopic findings showed that lengthened TA muscles increased to approximately 42% longer and 10% heavier at the end of the process when compared to pre‐surgery. During the distraction phase, VEGF and its receptors were induced in the vascular endothelial cells, myogenin‐positive satellite cells and myocytes, and subsequently, capillary progression and myogenesis were increased. Real‐time RT‐PCR showed that Vegf, Vegfr‐1, Vegfr‐2, and myogenin genes expression was enhanced during the muscle lengthening. Vegf and Vegfr‐1 were upregulated following the recession of angiogenesis at the consolidation phase. We conclude that upregulation of VEGF and its receptors by mechanical tension‐stress could be involved in the process of angiogenesis and myogenesis in lengthened muscles.

State-of-the-art ultrasonographic findings in lower extremity sports injuries

Athletes sometimes experience overuse injuries. To diagnose these injuries, ultrasonography is often more useful than plain radiography, computed tomography (CT), or magnetic resonance imaging (MRI). Ultrasonography can show both bone and soft tissue from various angles as needed, providing great detail in many cases. In conditions such as osteochondrosis or enthesopathies such as Osgood-Schlatter disease, Sinding-Larsen-Johansson disease, bipartite patella, osteochondritis dissecans of the knee, painful accessory navicular,and jumpers knee, ultrasonography can reveal certain types of bony irregularities or neovascularization of the surrounding tissue. In patients of enthesopathy, ultrasonography can show the degenerative changes at the insertion of the tendon. Given its usefulness in treatment, ultrasonography is expected to become essential in the management of overuse injuries affecting the lower limb in athletes. J. Med. Invest. 62: 109-113, August, 2015.

Discoscopic Findings of High Signal Intensity Zones on Magnetic Resonance Imaging of Lumbar Intervertebral Discs

A 32-year-old man underwent radiofrequency thermal annuloplasty (TA) with percutaneous endoscopic discectomy (PED) under local anesthesia for chronic low back pain. His diagnosis was discogenic pain with a high signal intensity zone (HIZ) in the posterior corner of the L4-5 disc. Flexion pain was sporadic, and steroid injection was given twice for severe pain. After the third episode of strong pain, PED and TA were conducted. The discoscope was inserted into the posterior annulus and revealed a migrated white nucleus pulposus which was stained blue. Then, after moving the discoscope to the site of the HIZ, a migrated slightly red nucleus pulposus was found, suggesting inflammation and/or new vessels penetrating the mass. After removing the fragment, the HIZ site was ablated by TA. To our knowledge, this is the first report of the discoscopic findings of HIZ of the lumbar intervertebral disc.

Percutaneous Endoscopic Lumbar Discectomy for a Huge Herniated Disc Causing Acute Cauda Equina Syndrome: A Case Report

Microsurgery for lumbar disc herniation that requires surgical intervention has been well described. The methods vary from traditional open discectomy to minimally invasive techniques. All need adequate preanesthetic preparation of patients as general anesthesia is required for the procedure, and nerve monitoring is necessary to prevent iatrogenic nerve injury. Conventional surgical techniques sometimes require the removal of the corresponding lamina to assess the nerve root and herniated disc, and this may increase the risk for posterior instability of the vertebral body. Should this occur, fusion surgery may be needed, further increasing morbidity and cost. We present here a case of lumbar herniated disc fragments causing acute cauda equina syndrome that were endoscopically resected through a transforaminal approach in an awake patient under local anesthesia. Percutaneous endoscopic discectomy under local anesthesia proved to be a better alternative to open back surgery as it made immediate intervention possible, was associated with fewer perioperative complications and morbidity, minimized soft tissue damage, and allowed early rehabilitation with a better outcome and greater patient satisfaction. In addition to these advantages, percutaneous endoscopic discectomy protects other approaches that may be needed in subsequent surgeries, whether open or minimally invasive.

State of the art: Intraoperative neuromonitoring in spinal deformity surgery

Application of deformity correction spinal surgery has increased substantially over the past three decades in parallel with improvements in surgical techniques. Intraoperative neuromonitoring (IOM) techniques,including somatosensory evoked potentials (SEPs), muscle evoked potentials (MEPs), and spontaneous electromyography (free-run EMG), have also improved surgical outcome by reducing the risk of iatrogenic neural injury. In this article, we review IOM techniques and their applications in spinal deformity surgery. We also summarize results of selected studies including hundreds of spinal correction surgeries. These studies indicate that multimodal IOM of both motor and sensory responses is superior to either modality alone for reducing the incidence of neural injury during surgery. J. Med. Invest. 62: 103-108, August, 2015.