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OBJECT Low lumbar osteoporotic vertebral collapse (OVC) has not been well documented compared with OVC of the thoracolumbar spine. The differences between low lumbar and thoracolumbar lesions should be studied to provide better treatment. The aim of this study was to clarify the clinical and imaging features as well as outcomes of low lumbar OVC and to discuss the appropriate surgical treatment. METHODS Thirty patients (10 men; 20 women; mean age 79.3 ± 4.7 years [range 70–88 years]) with low lumbar OVC affecting levels below L-3 underwent surgical treatment. The clinical symptoms, morphological features of affected vertebra, sagittal spinopelvic alignment, neurological status before and after surgery, and surgical procedures were reviewed at a mean follow-up period of 2.4 years. RESULTS The main clinical symptom was radicular leg pain. Most patients had old compression fractures at the thoracolumbar level. The affected vertebra was flat-type and concave or H-shaped type, not wedge type as often found in thoracolumbar OVC. There were mismatches between pelvic incidence and lumbar lordosis on plain radiographs. On CT and MR images, foraminal stenosis was seen in 18 patients (60%) and canal stenosis in 24 patients (80%). Decompression with short fusion using a posterior approach was performed. Augmentations of vertebroplasty, posterolateral fusion, and posterior lumbar interbody fusion were performed based on the presence/absence of local kyphosis of lumbar spine, cleft formation, and/or intervertebral instability. Although the neurological and visual analog scale scores improved postoperatively, 8 patients (26.7%) developed postoperative complications mainly related to instrumentation failure. In patients with postoperative complications, lumbar spine bone mineral density was significantly low, but the spinopelvic alignment showed no correlation when compared with those without complications. CONCLUSIONS The main types of low lumbar OVC were flat-type and concave type, which resulted in neurological symptoms by retropulsed bony fragments generating foraminal stenosis and/or canal stenosis. For patients with low lumbar OVC, decompression of the foraminal and canal stenosis with short fusion surgery via posterior approach can improve neurological symptoms. Since these patients are elderly with poor bone quality and other complications, treatments for both OVC and osteoporosis should be provided to achieve good clinical outcome.

SummaryThe blood-brain barrier (BBB) is composed of four cell populations, brain endothelial cells (BECs), pericytes, neurons, and astrocytes. Its role is to precisely regulate the microenvironment of the brain through selective substance crossing. Here we generated an in vitro model of the BBB by differentiating human induced pluripotent stem cells (hiPSCs) into all four populations. When the four hiPSC-derived populations were co-cultured, endothelial cells (ECs) were endowed with features consistent with BECs, including a high expression of nutrient transporters (CAT3, MFSD2A) and efflux transporters (ABCA1, BCRP, PGP, MRP5), and strong barrier function based on tight junctions. Neuron-derived Dll1, which activates Notch signaling in ECs, was essential for the BEC specification. We performed in vitro BBB permeability tests and assessed ten clinical drugs by nanoLC-MS/MS, finding a good correlation with the BBB permeability reported in previous cases. This technology should be useful for research on human BBB physiology, pathology, and drug development.

CD271 is a marker of bone marrow MSCs with enhanced differentiation capacity for bone or cartilage repair. However, the nature of CD271+ MSCs from adipose tissue (AT) is less well understood. Here, we investigated the differentiation, wound healing and angiogenic capacity of plastic adherent MSCs (PA MSCs) versus CD271+ MSCs from AT. There was no difference in the extent to which PA MSCs and CD271+ MSCs formed osteoblasts, adipocytes or chondrocytes in vitro . In contrast, CD271+ MSCs transplanted into athymic rats significantly enhanced osteochondral wound healing with reduced vascularisation in the repair tissue compared to PA MSCs and control animals; there was little histological evidence of mature articular cartilage formation in all animals. Conditioned medium from CD271+ MSC cultures was less angiogenic than PA MSC conditioned medium, and had little effect on endothelial cell migration or endothelial tubule formation in vitro . The low angiogenic activity of CD271+ MSCs and improved early stage tissue repair of osteochondral lesions when transplanted, along with a comparable differentiation capacity along mesenchymal lineages when induced, suggests that these selected cells are a better candidate than PA MSCs for the repair of cartilaginous tissue.

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