Convergence of Cells from the Progenitor Fraction of Adult Olfactory Bulb Tissue to Remyelinating Glia in Demyelinating Spinal Cord Lesions

Progenitor cells isolated from adult brain tissue are important tools for experimental studies of remyelination. Cells harvested from neurogenic regions in the adult brain such as the subependymal zone have demonstrated remyelination potential. Multipotent cells from the progenitor fraction have been isolated from the adult olfactory bulb (OB) but their potential to remyelinate has not been studied. cell bodies adjacent to and surrounding peripheral-type myelin rings.We report that neural cells from the progenitor fraction of the adult rat OB grown in monolayers can be expanded for several passages in culture and that upon transplantation into a demyelinated spinal cord lesion provide extensive remyelination without ectopic neuronal differentiation

Confocal photomicrographs of immunolabeled cells from OB cultures.

<p>OB cells at P4 labeled for a number of antigens, including nestin, A2B5, GFAP, TUJ-1 and O4 indicating that immature proliferative cells and cell of all three neural lineages can be generated from the progenitor fraction in these cultures. The scale bars are 10 µm.</p

Plastic section light microscopy of grafted X-EB lesioned spinal cord.

<p>Progressive magnifications of semithin plastic sections through X-EB lesioned spinal cord 3 weeks after grafting with OB cells show the lesion site at low power in panel A, filled with grafted cells. The fiduciary notch (asterisk) identifies the left side of the spinal cord. Higher magnification of the boxed regions in subsequent panels shows myelinated axons, many of which are associated with large cytoplasmic and nuclear regions characteristic of peripheral myelination. The scale bar is 1 mm in A, 400 µm in B, 40 µm in C, and 10 µm in D.</p

Confocal photomicrographs of immunohistochemistry performed on grafted X-EB spinal cord tissue.

<p>The illustration in A shows the location of panels B and C. GFP⁺ cells were grafted into the X-EB lesion and survived well. NeuN⁺ profiles in the dorsal horn were found among GFP⁺ cells. Grafted cells did not differentiate into neurons, as GFP⁺ cells did not label for NeuN (B). GFAP⁺ cells were observed primarily outside the lesion; transplanted cells did not assume a GFAP⁺ profile, as GFP⁺ cells did not also label with the antibody to GFAP (C). Progressive magnifications of the boxed region of GFP⁺ OB cells (D, E) show close apposition of GFP⁺ cells with P0-positive myelin. Some MBP⁺ profiles were also found among grafted cells, indicating the generation of some central myelin in the graft site (F). Scale bar is: 80 µm in B and C, 40 µm in D and F, and 20 µm in E.</p

Ultrastructural characteristics of remyelinated axons in the dorsal funiculus of the spinal cord after OB cell grafting.

<p>In panels A and B, myelin-forming OB cells had large nuclear and cytoplasmic regions characteristic of peripheral myelin-forming cells; collagen (arrows in B) was detected in the extracellular space. Examination at higher magnification shows basal lamina surrounding the myelin-forming cells (arrowheads in A inset). C. Immunoelectron microscopy for GFP shows GFP⁺ cells remyelinating the demyelinated axons. Counterstaining for these sections was minimal and dark staining shows electron dense immunoperoxidase reaction product. D. Boxed area from C shows the electron dense reaction product in the cytoplasm and nuclei of cells forming myelin. The scale bar is 5 µm in A, 1 µm in B, 5 µm in C, and 1 µm in D.</p

Comparative Transduction Efficiency of AAV Vector Serotypes 1–6 in the Substantia Nigra and Striatum of the Primate Brain

Vectors derived from adeno-associated virus (AAV) are promising candidates for neural cell transduction in vivo because they are nonpathogenic and achieve long-term transduction in the central nervous system. AAV serotype 2 (AAV2) is the most widely used AAV vector in clinical trials based largely on its ability to transduce neural cells in the rodent and primate brain. Prior work in rodents suggests that other serotypes might be more efficient; however, a systematic evaluation of vector transduction efficiency has not yet been performed in the primate brain. In this study, AAV viral vectors of serotypes 1–6 with an enhanced green-fluorescent protein (GFP) reporter gene were generated at comparable titers, and injected in equal amounts into the brains of Chlorocebus sabaeus. Vector injections were placed in the substantia nigra (SN) and the caudate nucleus (CD). One month after injection, immunohistochemistry for GFP was performed and the total number of GFP+ cells was calculated using unbiased stereology. AAV5 was the most efficient vector, not only transducing significantly more cells than any other serotype, but also transducing both NeuN+ and glial-fibrillary-acidic protein positive (GFAP+) cells. These results suggest that AAV5 is a more effective vector than AAV2 at delivering potentially therapeutic transgenes to the nigrostriatal system of the primate brain

Effect of Aliskiren on Circulating Endothelial Progenitor Cells and Vascular Function in Patients With Type 2 Diabetes and Essential Hypertension

BACKGROUND The aim of this study was to investigate the effects of aliskiren on vascular function and endothelial progenitor cells (EPCs) in patients with type 2 diabetes and essential hypertension. METHODS The study enrolled type 2 diabetic patients aged &gt; 50 years under stable glycemic control and first diagnosed mild essential hypertension. In phase A (n = 20), patients received aliskiren 150-300mg daily for 3 months. In phase B (n = 12), hydrochlorothiazide (HCTZ) 12.5-25mg daily substituted for aliskiren for 3 more months. At baseline and at the end of each phase, we assessed (i) brachial blood pressure (BBP); (ii) central aortic systolic pressure (CSP), aortic augmentation index (Aix), and pulse wave velocity (PWV) as markers of arterial stiffness; (iii) brachial artery flow-mediated dilatation (FMD) as a marker of endothelial function; (iv) left ventricular (LV) twisting and untwisting as markers of LV function and (v) EPC numbers in culture of peripheral blood mononuclear cells. RESULTS Aliskiren similarly reduced BBP and CSP, increased FMD (P &lt; 0.001) and EPC numbers (P &lt; 0.001), decreased PWV and Aix (P &lt; 0.05), and improved LV twisting and untwisting (P &lt; 0.05). Although substitution of HCTZ sustained BBP at similar levels, CSP and echocardiographic indices nearly returned at baseline levels, and the improvement of FMD, PWV, Aix, and EPC numbers was abolished. CONCLUSIONS Aliskiren had a favorable effect on endothelial function and EPCs, reduced arterial stiffness, and improved LV twisting and untwisting. These effects were independent of BBP lowering, as they were not observed after the achievement of similar values of BBP with HCTZ

Implication of lipoprotein associated phospholipase A2 activity in oxLDL uptake by macrophages

Recognition and uptake of oxidized LDL (oxLDL) by scavenger receptors of macrophages and foam cell formation are mediated by the oxidatively modified apolipoprotein B (ApoB) and lipid moiety of oxLDL. A great amount of oxidized phosphatidylcholine (oxPC) of oxLDL is hydrolyzed at the sn-2 position by lipoprotein associated phospholipase A2 (Lp-PLA2) to lysophosphatidylcholine and small oxidation products. This study examines the involvement of Lp-PLA2 in the uptake of oxLDL by mouse peritoneal macrophages. LDL with intact Lp-PLA2 activity [LDL (+)] and LDL with completely inhibited Lp-PLA2 activity [LDL (-)] were subjected to oxidation with 5 μM CuSO4 for 6 h [moderately oxLDL (MoxLDL)], or 24 h [heavily oxLDL (HoxLDL)] and peritoneal macrophages were incubated with these preparations. The uptake of MoxLDL(-) was about 30% increased compared with that of MoxLDL(+), and HoxLDL(-) uptake was about 20% increased compared with that of HoxLDL(+). Inhibition of Lp-PLA2 activity had no effect on the uptake of ApoB-liposomes conjugates with ApoB isolated from MoxLDL(-), MoxLDL(+), HoxLDL(-), and HoxLDL(+). Liposomes prepared from the lipid extract of MoxLDL(-), MoxLDL(+), HoxLDL(-), and HoxLDL(+) exhibited a similar pattern to that observed in the uptake of the corresponding intact lipoproteins. This study suggests that the progressive inactivation of Lp-PLA2 during LDL oxidation leads to an increased uptake of oxLDL by macrophages, which could be primarily attributed to the increased uptake of the oxidized phospholipids enriched lipid moiety of oxLDL