Delayed post-treatment with bone marrow-derived mesenchymal stem cells is neurorestorative of striatal medium-spiny projection neurons and improves motor function after neonatal rat hypoxia-ischemia

Perinatal hypoxia-ischemia is a major cause of striatal injury and may lead to cerebral palsy. This study investigated whether delayed administration of bone marrow-derived mesenchymal stem cells (MSCs), at one week after neonatal rat hypoxia-ischemia, was neurorestorative of striatal medium-spiny projection neurons and improved motor function. The effect of a subcutaneous injection of a high-dose, or a low-dose, of MSCs was investigated in stereological studies. Postnatal day (PN) 7 pups were subjected to hypoxia-ischemia. At PN14, pups received treatment with either MSCs or diluent. A subset of high-dose pups, and their diluent control pups, were also injected intraperitoneally with bromodeoxyuridine (BrdU), every 24h, on PN15, PN16 and PN17. This permitted tracking of the migration and survival of neuroblasts originating from the subventricular zone into the adjacent injured striatum. Pups were euthanized on PN21 and the absolute number of striatal medium-spiny projection neurons was measured after immunostaining for DARPP-32 (dopamine- and cAMP-regulated phosphoprotein-32), double immunostaining for BrdU and DARPP-32, and after cresyl violet staining alone. The absolute number of striatal immunostained calretinin interneurons was also measured. There was a statistically significant increase in the absolute number of DARPP-32-positive, BrdU/DARPP-32-positive, and cresyl violet-stained striatal medium-spiny projection neurons, and fewer striatal calretinin interneurons, in the high-dose mesenchymal stem cell (MSC) group compared to their diluent counterparts. A high-dose of MSCs restored the absolute number of these neurons to normal uninjured levels, when compared with previous stereological data on the absolute number of cresyl violet-stained striatal medium-spiny projection neurons in the normal uninjured brain. For the low-dose experiment, in which cresyl violet-stained striatal medium-spiny neurons alone were measured, there was a lower statistically significant increase in their absolute number in the MSC group compared to their diluent controls. Investigation of behavior in another cohort of animals showed that delayed administration of a high-dose of bone marrow-derived MSCs, at one week after neonatal rat hypoxia-ischemia, improved motor function on the cylinder test. Thus, delayed therapy with a high- or low-dose of adult MSCs, at one week after injury, is effective in restoring the loss of striatal medium-spiny projection neurons after neonatal rat hypoxia-ischemia and a high-dose of MSCs improved motor function.

Gamithromycin plasma and skin pharmacokinetics in sheep

This study assessed the plasma kinetics and skin/plasma concentration ratio of the azalide antibiotic gamithromycin (ZACTRAN(®), Merial) in sheep after a single subcutaneous administration at 6 mg/kg bodyweight. Gamithromycin concentrations in plasma samples collected at various intervals up to 21 days following treatment and metacarpal skin obtained from animals at two, five and ten days after treatment were determined by liquid chromatography-tandem mass spectrometry methods. After administration, gamithromycin was rapidly absorbed, and individual maximum plasma concentrations were observed within 6 hours post-dose. Plasma peak concentration was 573 ± 168 ng/ml. The mean area under the plasma concentration versus time curve extrapolated to infinity was 8.00 ± 1.41 µg · hr/ml, and the mean terminal half-life was 34.5 ± 5.4 hours. Gamithromycin skin concentrations were much higher than the plasma concentrations resulting in skin/plasma concentration ratios of approximately 21, 58, and 138 at two, five and ten days post-dose, respectively, demonstrating extensive distribution to skin tissue.

Efficacy, safety, pharmacokinetics and immunogenicity of abatacept administered subcutaneously or intravenously in Japanese patients with rheumatoid arthritis and inadequate response to methotrexate: a Phase II/III, randomized study

OBJECTIVE

To evaluate efficacy and safety of subcutaneous (SC) and intravenous (IV) abatacept and background methotrexate (MTX) in Japanese patients with rheumatoid arthritis (RA) and inadequate response to MTX (MTX-IR).

METHODS

Double-dummy, double-blind study (NCT01001832); 118 adults with ≥ 10 swollen joints, ≥ 12 tender joints and C-reactive protein (CRP) ≥ 0.8 mg/dL randomized 1:1 to SC abatacept (125 mg weekly) with IV loading (∼10 mg/kg on Day 1), or IV abatacept (∼10 mg/kg monthly) for 169 days, both also receiving MTX (6-8 mg/week). Primary endpoint was Day 169 American College of Rheumatology (ACR)20 response; other efficacy endpoints, safety and immunogenicity were assessed.

RESULTS

Similar proportions of patients achieved ACR20 responses at Day 169 with SC (91.5% [95% CI 81.3, 97.2]) and IV abatacept (83.1% [71.0, 91.6]). ACR50/70 responses, adjusted mean changes from baseline in Health Assessment Questionnaire-Disability Index scores and remission rates (28-joint Disease Activity Score [CRP] < 2.6) were also comparable between groups. Serious adverse event frequencies (5.1% vs. 3.4%) were similar with both formulations. One patient per group tested seropositive for immunogenicity. Weekly SC abatacept dosing achieved mean serum concentrations > 10 μg/mL (minimum therapeutic target).

CONCLUSIONS

SC abatacept demonstrated comparable efficacy and safety to IV abatacept, with low immunogenicity rates, in MTX-IR Japanese patients with RA.

A noticeable phenomenon: thiol terminal PEG enhances the immunogenicity of PEGylated emulsions injected intravenously or subcutaneously into rats

Repeated intravenous injection of long-circulating methoxy-polyethylene glycol (PEG)-liposomes alters the pharmacokinetics and biodistribution of the second administration, regarded as the "accelerated blood clearance (ABC) phenomenon." Nevertheless, the effect of terminal groups of distearoylphosphatidylethanolamine-polyethylene glycol (DSPE-PEG) on the induction of the ABC phenomenon had not been reported previously. In this study, rats were injected intravenously or subcutaneously with PEG coated emulsions (DE) which were prepared using PEG terminated with either the methoxyl (OCH3), hydroxyl (OH), amino (NH2), carboxyl (COOH), or thiol (SH) group. DE-OCH3 demonstrated the longest prolonged half-life in vivo after a single intravenous injection, followed by DE-SH and DE-COOH. In contrast, DE-OH was rapidly removed from the blood circulation, as was DE-NH2. Moreover, we observed a strong positive relationship between the circulation time of initially injected PEGylated emulsions and the extent to which the ABC phenomenon was induced, but a exception of DE-SH increasing the ABC effect. Furthermore, the present study suggested that thiols might stimulate the proliferation and differentiation of B cells to induce the fastest clearance of the second intravenous administration by inducing the synthesis of the cell membrane and cytosolic proteins or reacting with follicular dendritic cells. The results strongly suggested that thiol groups played a stimulatory role in the immune response and provided a considerable implication for multiple drug therapy of thiol groups.

Image of tumor metastasis and inflammatory lymph node enlargement by contrast-enhanced ultrasonography

AIM: To compare the difference between tumor-induced lymph node enlargement and inflammation-induced lymph node enlargement by contrast-enhanced ultrasonography and pathological findings.

METHODS: A model of tumor-induced lymph node metastasis was prepared by embedding a VX2 tumor into the hind paws of white rabbits. A model of inflammation-induced enlargement was prepared by injecting a suspension of Escherichia coli into separate hind paws of white rabbits. Then, a solution of Sonazoid™ (GE Healthcare, Oslo, Norway) was injected subcutaneously in the proximity of the lesion followed by contrast-enhanced ultrasonography of the enlarged popliteal lymph nodes.

RESULTS: In the contrast-enhanced ultrasonography of the tumor-induced metastasis model, the sentinel lymph node was imaged. An area of filling defect was observed in that enlarged lymph node. In the histology examination, the area of filling defect corresponded to the metastatic lesion of the tumor. Contrast-enhanced ultrasonography of the model on inflammation-induced lymph node enlargement, and that of the acute inflammation model performed 3-7 d later, revealed dense staining that was comparatively uniform. The pathological findings showed acute lymphadenitis mainly due to infiltration of inflammatory cells. Contrast-enhanced ultrasonography that was performed 28 d post-infection in the acute inflammation model showed speckled staining. Inflammation-induced cell infiltration and fiberization, which are findings of chronic lymphadenitis, were seen in the pathological findings.

CONCLUSION: Sentinel lymph node imaging was made possible by subcutaneous injection of Sonazoid™. Contrast-enhanced ultrasonography was suggested to be useful in differentiating tumor-induced enlargement and inflammation-induced enlargement of lymph nodes.