Pilot study on liposomal recombinant human superoxide dismutase for the treatment of Peyronie's disease

OBJECTIVE

To assess the efficacy and safety of liposomally encapsulated recombinant human superoxide dismutase (lrhSOD) for the treatment of Peyronie's disease.

METHODS

In an uncontrolled phase-2 study, 20 patients with Peyronie's disease were treated with a gel containing lrhSOD (1.5 mg/g). Patients with penile deviation of >45 degrees or plaque calcifications of >5 mm were regarded as candidates for surgical correction and excluded from this study.

RESULTS

Elimination of pain was observed in 7/13 patients (in 2 patients after only 3 days of therapy), and an almost complete resolution of pain was reported by the remaining 6/13 patients. Plaque size was reduced in 8/14 patients. Minimal improvement of penile deviation was observed in 3/12 patients. Post-therapeutic improvement of sexual function, mainly due to cessation of pain, was reported by 12/15 patients. No systemic or local side effects were observed.

CONCLUSION

In the present study, 100% pain relief as well as a plaque size reduction in 56% of Peyronie's disease patients were observed after a maximum of 6 weeks of lrhSOD therapy. The convenience and safety of lrhSOD gel therapy were superior compared to other current regimens. The present results suggest that lrhSOD gel is a promising treatment for patients with early stage Peyronie's disease. Early institution of lrhSOD therapy may prevent disease progression to penile deviation. The present preliminary results are the basis of a placebo-controlled randomized study.

Characterisation of peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase A and its N-glycans

Peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase A (PNGase A) was purified from almonds (Prunus amygdalus var. dulcis). Contrary to previous results in the literature, the enzyme appeared to be a heterodimer with subunits of 55 and 27 kDa when analysed by SDS/PAGE and two-dimensional electrophoresis. Peaks corresponding to molecular masses of 54.2, 21.2 and 75.5 kDa were observed with matrix-assisted laser-desorption/ionization mass spectrometry. The N-terminal sequences of the larger and the smaller chain were determined to be LASGYHSWAD and EPTPLHDFPP, respectively. Both polypeptides reacted with concanavalin A, indicating their glycoprotein nature. Upon digestion of PNGase with pepsin, the N-linked oligosaccharides were released with active PNGase and analysed as their 2-aminopyridine derivatives by two-dimensional HPLC and by matrix-assisted laser-desorption mass spectrometry. The most abundant N-glycan of the four species found exhibited the well known vacuole type structure, i.e. the pentasaccharide core with xylose and alpha1,3-linked fucose. The other structures either had an additional mannose residue and/or lacked the fucose. PNGase A was largely but not absolutely resistant to self-deglycosylation. However, only at an extremely high enzyme/substrate ratio, N-glycans released from PNGase A itself caused a detectable contamination of a PNGase digest of a glycopeptide.

Cytokine activity assay by means of proliferation measured in plane convex microtiter wells

A new assay to measure cell proliferation by turbidimetric evaluation of cultures in specially designed microtiter plates was set up. The IL-2-dependent proliferation of CTLL-2 cell line was used as a model. The novel microtiter plate detection system, the General Cell Screening System (GCSS) was used for the evaluation of the cell proliferation assay. The test system utilizes the population growth rate (mu) of the cells. The tests were performed in specially designed microtiter plates which were read in a scanning spectrophotometer. These results were compared with colorimetric assays, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) as substrates. In contrast to conventional methods, the presently described system is not an end-point method, this means that cell growth can be observed over a certain period and is not limited to a single moment during the period of cell growth. Another advantage is the reduction of manual manipulations and the avoidance of toxic or radioactive substances and organic solvents. Therefore, a higher number of samples can be analyzed compared to other methods. The range for detection was 0.015-10 units IL-2 per well, and the accuracy is in the range of < 0.005 standard deviation.

Purification of human recombinant superoxide dismutase by isoelectric focusing in a multicompartment electrolyzer with zwitterionic membranes

Human recombinant superoxide dismutase (SOD), purified to homogeneity, is resolved by both conventional isoelectric focusing and immobilized pH gradients into three bands, with isoelectric points (pIs) in the pH range 4.8 to 5.1, the pI 4.80 form representing the minor component. Due to the fact that this enzyme is expressed in E. coli, N-terminal acetylation or glycosylation should be ruled out. When purified by small-scale preparative isoelectric focusing in immobilized pH gradient gels, it was found that, upon subsequent analysis, the pI 5.07 form would band in the same position, but the intermediate pI 4.92 band would split into the upper (pI 5.07) and the lower (pI 4.80) species, in nearly the same amounts, whereas the lowest pI component would always generate both the intermediate and upper forms. Enzymatic essays pointed out that these three isoforms had nearly the same specific activity, slightly higher than that of the starting material. Metal analysis indicated that all three forms contained the same metal/protein ratio, approaching the value Cu2Zn2-SOD, as reported in the literature. Circular dichroism spectra of the pI 4.80 and 5.07 forms showed the same profile in the 190-240 nm range, but marked differences in the 250-350 nm region. Treatment with EDTA produces 1-2 additional, slightly higher pI isoforms, whereas treatment with KCN generates a number of higher pI components, reaching pI values as high as pH 7, with nearly complete disappearance of the three major SOD isoforms. It is concluded that these three isoforms could represent interconvertible species, the highest pI component representing the most stable conformer.

Determination of immune complexes by high-performance gel chromatography (positive cooperativity of antibody-antigen reaction)

Positive cooperativity of antibody-antigen complex formation using human Cu/Zn superoxide dismutase and a murine monoclonal antibody as model is demonstrated by high-performance gel chromatography using TSK G3000sw and TSK G4000sw columns. Three different antibody-antigen complexes named Type I, II and III composed from two antigen molecules+two antibody molecules, two antigen molecules+one antibody molecule and one antigen molecule+one antibody molecule could be separated. The degree and ratio of complexes present in solution depends mainly on the ratios of antibody and antigen.

Scale-up of recombinant protein purification by hydrophobic interaction chromatography

The scale-up of hydrophobic interaction chromatography is described. Human recombinant superoxide dismutase was used as a model. The scale-up was performed by keeping the height to diameter (H/D) ratio of the column constant. The success of scale-up was evaluated by reversed-phase high-performance liquid chromatography of the eluted material. The wrong H/D ratio causes decreased resolution.