Safety Assessment of AAV2-hGDNF Administered Via Intracerebral Injection in Rats for Treatment of Parkinson's Disease

Glial cell line-derived neurotrophic factor (GDNF) is a potent neuroprotective biologic in Parkinson's disease models. Adeno-associated viral vector serotype 2 (AAV2)-human GDNF safety was assessed in rats treated with a single intracerebral dose of vehicle, 6.8 × 108, 6.8 × 109, or 5.2 × 1010 vector genomes (vg)/dose followed by interim sacrifices on day 7, 31, 90, and 376. There were no treatment-related effects observed on food consumption, body weight, hematology, clinical chemistry, coagulation parameters, neurobehavioral parameters, organ weights, or serum GDNF and anti-GDNF antibody levels. Increased serum anti-AAV2 neutralizing antibody titers were observed in the 5.2 × 1010 vg/dose group. Histopathological lesions were observed at the injection site in the 6.8 × 109 vg/dose (day 7) and 5.2 × 1010 vg/dose groups (days 7 and 31) and consisted of gliosis, mononuclear perivascular cuffing, intranuclear inclusion bodies, and/or apoptosis on day 7 and mononuclear perivascular cuffing on day 31. GDNF immunostaining was observed in the injection site in all dose groups through day 376 indicating no detectable impacts of anti-AAV2 neutralizing antibody. There was no evidence of increased expression of calcitonin gene-related peptide or Swann cell hyperplasia in the cervical and lumbar spinal cord or medulla oblongata at the 5.2 × 1010 vg/dose level indicating lack of hyperplastic effects. In conclusion, no systemic toxicity was observed, and the local toxicity observed at the injection site appeared to be reversible demonstrating a promising safety profile of intracerebral AAV2-GDNF delivery. Furthermore, an intracerebral dose of 6.8 × 108 AAV2-GDNF vg/dose was considered to be a no observed adverse effect level in rats.

Quantitative determination of apogossypol, a pro-apoptotic analog of gossypol, in mouse plasma using LC/MS/MS

A simple and selective liquid chromatography/tandem mass spectrometry (LC/MS/MS) method based on internal standard quantitation using apigenin as the internal standard has been developed and validated for the analysis of the gossypol analog apogossypol, a pro-apoptotic compound, in mouse plasma. The methodology involves protein precipitation of plasma samples followed by LC/MS/MS analysis. Ascorbic acid was added to the spiking solutions and plasma samples to stabilize the easily oxidized compound. Separation of apogossypol and the internal standard from the plasma matrix was achieved using a C18 column with a gradient elution profile consisting of 5mM ammonium acetate and methanol. The validated range of the method extended from 10 to 2000 ng/mL with accuracies of 85-115% and precision of <15%. The average recovery of apogossypol at three concentrations (50, 200 and 1000 ng/mL) assayed in triplicate using this methodology was determined to be 90.8+/-12.9%. Recovery for the internal standard (apigenin) at a concentration of 500 ng/mL was found to be 99.9+/-6.41%. Apogossypol concentrations of 50 ng/mL and above were found to be stable in extracted plasma for 24h when stored at 25 degrees C. This method has been applied to the determination of apogossypol concentrations in plasma collected from mice given an IV dose of apogossypol.

Increased antitumor activity, intratumor paclitaxel concentrations, and endothelial cell transport of cremophor-free, albumin-bound paclitaxel, ABI-007, compared with cremophor-based paclitaxel

ABI-007, an albumin-bound, 130-nm particle form of paclitaxel, was developed to avoid Cremophor/ethanol-associated toxicities in Cremophor-based paclitaxel (Taxol) and to exploit albumin receptor-mediated endothelial transport. We studied the antitumor activity, intratumoral paclitaxel accumulation, and endothelial transport for ABI-007 and Cremophor-based paclitaxel. Antitumor activity and mortality were assessed in nude mice bearing human tumor xenografts [lung (H522), breast (MX-1), ovarian (SK-OV-3), prostate (PC-3), and colon (HT29)] treated with ABI-007 or Cremophor-based paclitaxel. Intratumoral paclitaxel concentrations (MX-1-tumored mice) were compared for radiolabeled ABI-007 and Cremophor-based paclitaxel. In vitro endothelial transcytosis and Cremophor inhibition of paclitaxel binding to cells and albumin was compared for ABI-007 and Cremophor-based paclitaxel. Both ABI-007 and Cremophor-based paclitaxel caused tumor regression and prolonged survival; the order of sensitivity was lung > breast congruent with ovary > prostate > colon. The LD(50) and maximum tolerated dose for ABI-007 and Cremophor-based paclitaxel were 47 and 30 mg/kg/d and 30 and 13.4 mg/kg/d, respectively. At equitoxic dose, the ABI-007-treated groups showed more complete regressions, longer time to recurrence, longer doubling time, and prolonged survival. At equal dose, tumor paclitaxel area under the curve was 33% higher for ABI-007 versus Cremophor-based paclitaxel, indicating more effective intratumoral accumulation of ABI-007. Endothelial binding and transcytosis of paclitaxel were markedly higher for ABI-007 versus Cremophor-based paclitaxel, and this difference was abrogated by a known inhibitor of endothelial gp60 receptor/caveolar transport. In addition, Cremophor was found to inhibit binding of paclitaxel to endothelial cells and albumin. Enhanced endothelial cell binding and transcytosis for ABI-007 and inhibition by Cremophor in Cremophor-based paclitaxel may account in part for the greater efficacy and intratumor delivery of ABI-007.

Pharmacodynamics and pharmacokinetics of SQ109, a new diamine-based antitubercular drug

SQ109 is a novel [1,2]-diamine-based ethambutol (EMB) analog developed from high-throughput combinatorial screening. The present study aimed at characterizing its pharmacodynamics and pharmacokinetics. The antimicrobial activity of SQ109 was confirmed in vitro (Mycobacterium tuberculosis-infected murine macrophages) and in vivo (M. tuberculosis-infected C57BL/6 mice) and compared to isoniazid (INH) and EMB. SQ109 showed potency and efficacy in inhibiting intracellular M. tuberculosis that was similar to INH, but superior to EMB. In vivo oral administration of SQ109 (0.1-25 mg kg(-1) day(-1)) to the mice for 28 days resulted in dose-dependent reductions of mycobacterial load in both spleen and lung comparable to that of EMB administered at 100 mg kg(-1) day(-1), but was less potent than INH at 25 mg kg(-1) day(-1). Monitoring of SQ109 levels in mouse tissues on days 1, 14 and 28 following 28-day oral administration (10 mg kg(-1) day(-1)) revealed that lungs and spleen contained the highest concentration of SQ109, at least 10 times above its MIC. Pharmacokinetic profiles of SQ109 in mice following a single administration showed its C(max) as 1038 (intravenous (i.v.)) and 135 ng ml(-1) (p.o.), with an oral T(max) of 0.31 h. The elimination t(1/2) of SQ109 was 3.5 (i.v.) and 5.2 h (p.o.). The oral bioavailability was 4%. However, SQ109 displayed a large volume of distribution into various tissues. The highest concentration of SQ109 was present in lung (>MIC), which was at least 120-fold (p.o.) and 180-fold (i.v.) higher than that in plasma. The next ranked tissues were spleen and kidney. SQ109 levels in most tissues after a single administration were significantly higher than that in blood. High tissue concentrations of SQ109 persisted for the observation period (10 h). This study demonstrated that SQ109 displays promising in vitro and in vivo antitubercular activity with favorable targeted tissue distribution properties.

Biodistribution of radiolabeled lipid-DNA complexes and DNA in mice

The tissue biodistribution and expression of [33P]DNA-1-[2-[9-(Z)-octadecenoyloxy]ethyl]]-2-[8](Z)-heptadece nyl]-3 -[hydroxyethyl]imidazolinium chloride (DOTIM):cholesterol complexes and 33P-radiolabeled DNA expressing chloramphenicol acetyl transferase (CAT; 4.7 kB) were studied after intravenous (iv) injection in ICR mice. Mice were injected with 200 microL of complex containing DNA at 3 mg/kg or DNA alone. One group received 8 microCi of radioactivity and were sacrificed at 5 and 20 min, and 1, 2, 4 and 24 h post-dose (n = 4/time point). A second group received the equivalent of 3.9 microCi of radioactivity and were sacrificed at 20 min, and 2 and 24 h for subsequent whole body autoradiographic analysis (WBA; n = 2/time point). The tissue distribution of intact DNA was assessed by Southern blot at 24 h post-dose, whereas the integrity of complexes and DNA incubated in heparinized whole blood was studied separately. In further studies, the time course of expression in lung tissue over a 48-h period was examined, and the relative lung-expression of purified open circular (OC) versus supercoiled (SC) DNA at 24 h was evaluated. Approximately 42% of the radioactivity was found in the lungs 5 min after injection and about half this percentage was found in the liver. By 2 h, only 5% remained in the lungs, but 48% was present in the liver. No other tissue accumulated >5% of the dose throughout the duration of the study. WBA radiograms confirmed the tissue distribution results and highlighted significant accumulation of radioactivity in bone over time. Southern Blot analysis demonstrated intact DNA in many tissues 24 h after dosing. In contrast, the majority of DNA incubated in blood was degraded within 2 h, although the complexes afforded some protection relative to DNA alone. The OC DNA expressed equivalently to SC DNA in lung tissue (OC = 1035 +/- 183 pg; SC = 856 +/- 257 pg/mg soluble protein, n = 6, mean +/- SEM) at 24 h, and detectable levels of CAT were present within 2 h of dosing (21.3 +/- 7.2 pg, n >/= 8, mean +/- SD). The results confirm that DNA-DOTIM:cholesterol complexes are initially deposited in the lungs after iv administration.

Immunological properties of glycolipids from membranes of Acholeplasma laidlawii

Glycolipids, the predominant class of lipids in the membranes of Acholeplasma laidlawii, are the haptenic determinants that react with anti-A. Laidlawii serum to fix complement. The predominant complement-fixing activity of the membrane glycolipids was associated with the monoglucoysyl diglyceride, diglucosyl diglyceride, glycerlphosphoryl diglucosyl diglyceride (GPDD), and an unknown lipid B, which did not react with ninhydrin but release glucose and glycerol and traces of phosphorus upon hydrolysis. The glycolipids monoglucosyl diglyceride and diglucosyl diglyceride or GPDD and unknown lipid B were paired as a result of their cross-reactions with selective antisera prepared with the aid of reconstituted membrane complexes containing membrane lipids. Reconstituted membrane complexes assembled from [14C]monoglucosyl diglyceride and delipidated membrane proteins gave optimal complement fixation titers before saturation of the complexes with the ]14C]monoglucosyl diglyceride. The phosphoglycolipid of the membrane, GPDD, was anticomplementary as a pure lipid, a cholesterol liposome, and a reconstituted membrane complex. This anticomplementary activity, which was caused by 3 mug of pure GPDD, affected both human and guinea pig complement. Although human C1, C4, C3, and C5 were not inhibited by GPDD, C2 was inhibited 10-fold by reconstituted membrane complexes containing 150 mug of GPDD. A role for this phosphoglycolipid is discussed in the hypothetical mechanism of inhibition of C2 attachment to SAC1, 4 sites.