Scaling-up fermentation of Escherichia coli for production of recombinant P64k protein from Neisseria meningitidis

Background: P64k is a Neisseria meningitidis high molecular weight protein present in meningococcal vaccine preparations. The lpdA gene, which encodes for this protein, was cloned in Escherichia coli and the P64k recombinant protein was expressed in E. coli K12 GC366 cells under the control of a tryptophan promoter. P64k was expressed as an intracellular soluble protein about 28% of the total cellular protein. Several scale-up criteria of fermentation processes were studied to obtain the recombinant P64k protein at the pilot production scale. Results: The best operational conditions at a larger scale production of P64k recombinant protein were studied and compared using the four following criteria: Constant Reynold's number (Re constant), Constant impeller tip speed (n di constant), Constant power consumption per unit liquid volume (P/V constant) and Constant volumetric oxygen transfer coefficients (KLa/k constant). The highest production of the recombinant protein was achieved based on the constant KLa/k scale-up fermentation criterion, calculating the aeration rate (Q) and the impeller agitation speed (n) by iterative process, keeping constant the KLa/k value from bench scale. The P64k protein total production at the 50 l culture scale was 546 mg l -1 in comparison with the 284 mg l -1 obtained at 1.5 l bench scale. Conclusions: The methodology described herein, for the KLa/k scale-up fermentation criterion, allowed us to obtain the P64k protein at 50 l scale. A fermentation process for the production of P64k protein from N. meningitidis was established, a protein to be used in future vaccine formulations in humans.

Intralesional administration of epidermal growth factor-based formulation (Heberprot-P) in chronic diabetic foot ulcer: treatment up to complete wound closure.

Previous studies have shown that an epidermal growth factor-based formulation (Heberprot-P) can enhance granulation of high-grade diabetic foot ulcers (DFU). The aim of this study was to explore the clinical effects of this administration up to complete wound closure. A pilot study in 20 diabetic patients with full-thickness lower extremity ulcers of more than 4 weeks of evolution was performed. Mean ulcer size was 16.3 +/- 21.3 cm(2). Intralesional injections of 75 microg of Heberprot-P three times per week were given up to complete wound healing. Full granulation response was achieved in all 20 patients in 23.6 +/- 3.8 days. Complete wound closure was obtained in 17 (85%) cases in 44.3 +/- 8.9 days. Amputation was not necessary in any case and only one relapse was notified. The most frequent adverse events were tremors, chills, pain and odour at site of administration and local infection. The therapeutic scheme of intralesional Heberprot-P administration up to complete closure can be safe and suitable to improve the therapeutic goal in terms of healing of chronic DFU.

Intralesional injections of Citoprot-P (recombinant human epidermal growth factor) in advanced diabetic foot ulcers with risk of amputation.

To investigate the efficacy and safety of recombinant human epidermal growth factor (rhEGF) in advanced diabetic foot ulcers (DFU) A double-blind trial was carried out to test two rhEGF dose levels in type 1 or 2 diabetes patients with Wagner's grade 3 or 4 ulcers, with high risk of amputation. Subjects were randomised to receive 75 (group I) or 25 mug (group II) rhEGF through intralesional injections, three times per week for 5-8 weeks together with standardised good wound care. Endpoints were granulation tissue formation, complete healing and need of amputation. Safety was assessed by clinical adverse events (AEs) and laboratory evaluations. Forty-one patients were included. After 5-8 weeks of treatment, 83% patients in the higher dose group and 61% in group II achieved useful granulation tissue covering more than 98% of the wound area. At long-term assessment, 13 (56.5%) patients healed in group I and 9 (50%) in group II. The mean time to complete healing in group I was 20.6 weeks (95% CI: 17.0-24.2) and 19.5 weeks (16.3-22.7) in group II. After 1-year follow-up, only one patient relapsed. Amputation was not necessary in 65% and 66.7% of groups I and II, respectively. The AEs rates were similar. The most frequent were sepsis (33%), burning sensation (29%), tremors, chills and local pain (25% each). rhEGF local injection enhances advanced DFU healing and reduces the risk of major amputation. No dose dependency was observed.