Platelet satellitism and dual surface immunoglobulin light-chain expression in circulating splenic marginal zone lymphoma cells.

Platelet satellitism is believed to be an in vitro phenomenon induced at room temperature in ethylenediamine tetraacetic acid-anticoagulated blood. Most reports involve neutrophils; involvement with circulating lymphoma cells are exceedingly rare. Normally, mature B cells exhibit allelic exclusion in which a single class of surface immunoglobulin light chains (either κ or λ) is expressed. The simultaneous expression of both κ and λ immunoglobulin light chains is rare. Herein, we report the unusual case of a patient with splenic marginal zone lymphoma in which circulating lymphoma cells express dual surface immunoglobulin light chains and exhibit platelet satellitism. In addition to clinical findings, a comprehensive analysis of the peripheral blood including correlated light and electron microscopy as well as flow cytometry are described.

Enhanced angiogenic efficacy through controlled and sustained delivery of FGF-2 and G-CSF from fibrin hydrogels containing ionic-albumin microspheres.

Neo-vessel formation in ischemic tissues relies on numerous growth factors and cell fractions for the formation of mature, stable, functional vasculature. However, the efforts to regenerate tissues typically rely on the administration of a single growth factor or cells alone. Conversely, polymeric matrices have been investigated extensively to deliver multiple growth factors at pre-determined rates to form stable blood vessels in ischemic tissues. We report on a novel sequential delivery system of a fibrin hydrogel containing ionic-albumin microspheres that allows for the controlled release of two growth factors. The use of this system was investigated in the context of therapeutic angiogenesis. Material properties were determined based on degree of swelling measurements and degradation characteristics. Release kinetics of model angiogenic polypeptides FGF-2 and G-CSF were determined using ELISA and the bioactivity of released protein was evaluated in human endothelial cell cultures. The release of growth factors from ionic-albumin microspheres was significantly delayed compared to the growth factor released from fibrin matrices in the absence of spheres. The scaffolds were implanted in a murine critical limb ischemia model at two concentrations, 40 ng (low) and 400 ng (high), restoring 92% of the blood flow in a normally perfused limb using a fibrin hydrogel releasing FGF-2 containing albumin-PLL microspheres releasing G-CSF (measured by LDPI at the high concentration), a 3.2-fold increase compared to untreated limbs. The extent of neo-vessel formation was delineated by immunohistochemical staining for capillary density (CD-31+) and mature vessel formation (α-SMA+). In conclusion, our study demonstrated that the release kinetics from our scaffold have distinct kinetics previously unpublished and the delivery of these factors resulted in hindlimb reperfusion, and robust capillary and mature vessel formation after 8 weeks compared to either growth factor alone or bolus administration of growth factor.

bFGF-containing electrospun gelatin scaffolds with controlled nano-architectural features for directed angiogenesis.

Current therapeutic angiogenesis strategies are focused on the development of biologically responsive scaffolds that can deliver multiple angiogenic cytokines and/or cells in ischemic regions. Herein, we report on a novel electrospinning approach to fabricate cytokine-containing nanofibrous scaffolds with tunable architecture to promote angiogenesis. Fiber diameter and uniformity were controlled by varying the concentration of the polymeric (i.e. gelatin) solution, the feed rate, needle to collector distance, and electric field potential between the collector plate and injection needle. Scaffold fiber orientation (random vs. aligned) was achieved by alternating the polarity of two parallel electrodes placed on the collector plate thus dictating fiber deposition patterns. Basic fibroblast growth factor (bFGF) was physically immobilized within the gelatin scaffolds at variable concentrations and human umbilical vein endothelial cells (HUVEC) were seeded on the top of the scaffolds. Cell proliferation and migration was assessed as a function of growth factor loading and scaffold architecture. HUVECs successfully adhered onto gelatin B scaffolds and cell proliferation was directly proportional to the loading concentrations of the growth factor (0-100 bFGF ng/mL). Fiber orientation had a pronounced effect on cell morphology and orientation. Cells were spread along the fibers of the electrospun scaffolds with the aligned orientation and developed a spindle-like morphology parallel to the scaffold's fibers. In contrast, cells seeded onto the scaffolds with random fiber orientation, did not demonstrate any directionality and appeared to have a rounder shape. Capillary formation (i.e. sprouts length and number of sprouts per bead), assessed in a 3-D in vitro angiogenesis assay, was a function of bFGF loading concentration (0 ng, 50 ng and 100 ng per scaffold) for both types of electrospun scaffolds (i.e. with aligned or random fiber orientation).