Wastes to worth: value added products from fruit and vegetable wastes

Abstract

The concentrations of phenolics and other phytochemicals present in the peels, pulp/pomace and seeds of many fruits and vegetables namely citrus, apples, peaches, pears, banana, pomegranate, berries, mangoes, onions, potatoes, tomatoes and sugar beet are generally substantially higher than in their respective edible tissues, suggesting these wastes and residues to be the potential sources for isolating bio-active compounds. The antioxidants (polyphenolic and other phytochemicals) and other bio-active compounds from these sources exhibit anti-cancer, anti-microbial (pathogens), anti-oxidative and immune-modulatory effects. In addition they reduce incidence of cardiovascular diseases and capillary fragility, inhibit platelet aggregation and prevent thrombosis, oxidative stress, osteoporosis and diabetes in vertebrates. Specifically, the phenolics and flavonoids present in apple, date pit, rambutan (Nephelium lappaceum) peel, tomato peel extracts strongly inhibit tumour-cell proliferation. Penta-O-galloyl-glucoside (PGG) present in mango seed kernel extract and mango peel is used in pharmaceutical industries as it possesses anti-tumor, antioxidant, anti-cardiovascular and hepato-protective effects. The terpenoid and flavonoids in banana foliage exhibit anthelmintic properties. Pomace of apple, pear, orange, peach, blackcurrant, cherry, artichoke, asparagus, onion, raspberry, tomato and carrot, durian seeds (gelling and thickening agents), mango peels, date pits, cauliflower trimmings, empty pea pods and okara are used as dietary fibre supplements and as a functional ingredient in processed food products due to the presence of pectins and carotenoids and bound antioxidants. Some of the fruit and vegetable wastes are excellent source of biopigments; examples being betalains in beet root pulp and carotenoid in carrot pulp. Tomato seeds, banana peel, rambutan and mango seed kernel, passion fruit seed, black currant, date pits are good sources of edible oil rich in polyunsaturated fatty acids. Many fruit and vegetable wastes are used as a substrate for the production of organic acids (citric, lactic and ferulic acids), single cell protein, essential oils, exogenous enzymes, bio-ethanol/methanol, bio-pesticides, bio-sorbants, bio-degradable plastic, bio-fertilizers, bio-preservatives and edible mushrooms. Some have potential to decrease the emission of enteric methane.

Standardization of human IL-29 (IFN-λ1): establishment of a World Health Organization international reference reagent for IL-29 (IFN-λ1)

Human interleukin-29 (IL-29), a helical cytokine with interferon-like activities, is currently being developed as a clinical biotherapeutic to treat chronic hepatitis C infection and some cancers. As such, the World Health Organization (WHO) has recognized a need for biological standardization of IL-29 and the establishment of an internationally available reference reagent of IL-29. In order to accomplish this, an international collaborative study that evaluates WHO candidate reference reagents of IL-29 was instigated by the National Institute for Biological Standards and Control (NIBSC) in 2010 and was carried out in the succeeding year. Two preparations of human sequence recombinant IL-29, one expressed in murine NS0 cells and the other in Escherichia coli, were formulated and lyophilized at NIBSC before evaluation in the collaborative study for their suitability to serve as a reference reagent. The preparations were tested by 6 laboratories from 4 countries using in vitro bioassays and also evaluated for thermal stability within the NIBSC laboratory. On the basis of the results of the collaborative study, both preparations, 07/212 (NS0-derived) and 10/176 (E. coli-derived) were judged sufficiently active and stable to serve as a reference reagent. However, since IL-29 produced in E. coli is in development for clinical applications, it was recommended that the preparation coded 10/176 be established as the WHO international reference reagent for human IL-29. This recommendation was accepted, and the IL-29 preparation coded 10/176 was formally established by the WHO ECBS at its meeting in October 2012 as the WHO international reference reagent for IL-29 with an assigned unitage of 5,000 reference units per ampoule.

Establishment of the first international standard for PEGylated granulocyte colony stimulating factor (PEG-G-CSF): report of an international collaborative study

We assessed the feasibility of developing a suitable international reference standard for determination of in vitro biological activity of human sequence recombinant PEG-G-CSF products with a 20kD linear PEG linked to the N-terminal methionyl residue of G-CSF (INN Filgrastim), produced using a conjugation process and coupling chemistry similar to that employed for the lead PEGfilgrastim product. Based on initial data which showed that the current WHO 2nd international standard, IS for G-CSF (09/136) or alternatively, a PEG-G-CSF standard with a unitage traceable to the G-CSF IS may potentially serve as the IS for PEG-G-CSF products, two candidate preparations of PEG-G-CSF were formulated and lyophilized at NIBSC. These preparations were tested by 23 laboratories using in vitro bioassays in a multi-centre collaborative study. Results indicated that on the basis of parallelism, the current WHO 2nd IS for G-CSF or any of the PEG-G-CSF samples could be used as the international standard for PEG-G-CSF preparations. However, because of the variability in potency estimates seen when PEG-G-CSF preparations were compared with the current WHO 2nd IS for G-CSF, a candidate PEG-G-CSF was suitable as the WHO IS. The preparation 12/188 was judged suitable to serve as the WHO IS based on in vitro biological activity data. Therefore, the preparation coded 12/188 was established by the WHO Expert Committee on Biological Standardization (ECBS) in 2013 as the WHO 1st IS for human PEGylated G-CSF with an assigned in vitro bioactivity of 10,000IU per ampoule.

Detection of anti-cytokine antibodies and their clinical relevance

Cytokines regulate many aspects of cell growth and differentiation and play pivotal roles in the orchestration of immune defence against invading pathogens. Though 'self' proteins, they are potentially immunogenic and can give rise to anti-cytokine autoantibodies (aCA). The main foci of the article are a critical summary of the various methodologies applied for detecting and measuring aCA and a broad review of studies of the occurrence, characterization and clinical relevance of aCA in normal healthy individuals, patients with autoimmune diseases or microbial infections and aCA in patients whose disease is treated with recombinant cytokine products. The need for technical and methodological improvement of assays, including validation and standardization, together with approaches to harmonize calculation and reporting of results is also discussed.

Severity of the TGN1412 trial disaster cytokine storm correlated with IL-2 release

Aim

To determine if cytokine release with a solid phase assay is predictive of adverse responses for a range of therapeutic mAbs.

Methods

Cytokine ELISAs and a multi-array system were used to compare responses generated by different therapeutic mAbs using a solid phase assay. Flow cytometry was employed to determine the cellular source of those cytokines.

Results

Only TGN1412 and muromonab-CD3 stimulated CD4+ T-cell mediated cytokine release characterized by significant (all P < 0.0001) IFNγ, TNFα, IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17 and IL-22 release, comparable with T-cell mitogen. Significantly greater (P < 0.0001) IL-2 release with TGN1412 (2894–6051 pg ml⁻¹) compared with muromonab-CD3 (62–262 pg ml⁻¹) differentiated otherwise comparable cytokine responses. Likewise, TGN1412 stimulated significantly more (P = 0.0001) IL-2 producing CD4+ T-cells than muromonab-CD3 and induced Th1, Th2, Th17 and Th22 subsets that co-release this cytokine. Significant TNFα release was observed with bevacizumab (P = 0.0001), trastuzumab (P = 0.0031) and alemtuzumab (P = 0.0177), but no significant IL-2 release. TGN1412 and muromonab-CD3 caused pro-inflammatory cytokine release despite significantly (both P < 0.0001) increasing numbers of T-cells with a regulatory phenotype.

Conclusions

The severity of the adverse response to TGN1412 compared with muromonab-CD3 and other therapeutic mAbs correlates with the level of IL-2 release.

Use of a standardized MxA protein measurement-based assay for validation of assays for the assessment of neutralizing antibodies against interferon-β

Effective monitoring of the development of neutralizing antibodies (NAbs) against IFN-β in multiple sclerosis (MS) patients on IFN-β therapy is important for clinical decision making and disease management. To date, antiviral assays have been the favored approach for NAb determination, but variations in assay conditions between laboratories and the increasing use of novel assays have contributed to the reporting of inconsistent antibody data between laboratories and between products. This study, undertaken at the request of the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA), is a joint effort by manufacturers of IFN-β products (approved in Europe) towards harmonization of a NAb assay that facilitates generation of comparable NAb data, which, in conjunction with clinical outcomes, should prove useful for clinicians treating MS patients with IFN-β products. This article describes the standardized cellular myxovirus resistance protein A (MxA) protein measurement-based assay for detection of IFN-β NAbs and its use for the validation of assays used for the quantitative determination of such antibodies. Although titers varied between laboratories and the products used, utilization of IFN-β1a rather than IFN-β1b as the challenge antigen produced more consistent results in the NAb assay. Adoption of the standardized assay improves comparability between laboratories circumventing problems that arise when different, nonstandardized assays are employed for immunogenicity assessment. Based on the data, the EMA recommended for standardization purposes, the use of IFN-β1a in NAb assays, independent of the therapeutic product used for therapy and validation of new NAb procedures against the standardized assay described.

Detection of neutralizing antibodies to erythropoietin by inhibition of rHuEPO-stimulated EGR1 gene expression in the UT-7/EPO cell line

Recombinant erythropoietin (rHuEPO) is used extensively to treat anaemia associated with chronic kidney disease. However, the development of neutralizing antibodies (NAbs) to rHuEPO can result in the development of antibody-mediated pure red cell aplasia (PRCA). The detection of NAb in patient sera by in vitro bioassay relies on the inhibition of a cellular response to rHuEPO. Current bioassays for rHuEPO measure proliferation in responsive cell lines such as the erythroleukaemic cell lines, UT-7 and UT-7/EPO, the latter sensitized to EPO. Using these cell lines, we show the dose-responsive induction of both PIM1 and EGR1 gene expression in UT-7 cells and of EGR1 in UT-7/EPO cells. The expression of EGR1 in UT-7/EPO cells in response to rHuEPO was comparable to the proliferative response measured by (3)H-thymidine incorporation and could be inhibited by serum from a patient with NAb-mediated PRCA in a dilution-dependent manner. Bioassays based on the induction of endogenous gene expression are comparable to current bioassays but are considerably quicker given that incubation time is decreased from 2-3 days to 50 min. Measurement of EGR1 gene expression in response to rHuEPO in UT-7/EPO cells offers a rapid, non-radioactive and automatable alternative to current assays for the detection of rHuEPO NAbs.

Strategies and assays for the assessment of unwanted immunogenicity

The assessment of unwanted immunogenicity associated with biological products continues to be a major issue for the biotechnology industry. Monitoring of unwanted immunogenicity during the development of the product from pre-clinical stage through clinical trials is now a regulatory expectation with extended post-marketing commitments required for at least some of these products. Prospective planning of immunogenicity studies incorporating appropriately devised strategies is critical if valid conclusions concerning the immunogenicity profile of a product are to be derived. An important consideration of such studies is the selection of optimized, rigorously validated and standardized methodologies for detection and characterization of antibodies with emphasis on desired assay design, assay controls, and performance criteria. Binding assays with different formats and detection systems, radioimmuno-precipitation assays or surface plasmon resonance procedures are often used as the basis for a screening assay. For assessing the neutralizing capacity of the antibodies, however, a neutralization assay is an absolute requirement. Therefore, a panel of methods is usually necessary for a detailed understanding of the type(s) of antibodies induced against a therapeutic product. This manuscript considers briefly the benefits and limitations of the different techniques available for antibody detection and characterization. A strategy that can be adopted for the assessment of unwanted immunogenicity of therapeutic products is also suggested.

Treatment of colitis with a commensal gut bacterium engineered to secrete human TGF-β1 under the control of dietary xylan 1

BACKGROUND

While cytokine therapy and the use of immunosuppressive cytokines such as transforming growth factor-β (TGF-β) offer great potential for the treatment of inflammatory bowel disease (IBD), issues concerning formulation, stability in vivo, delivery to target tissues, and potential toxicity need to be addressed. In consideration of these problems we engineered the human commensal bacterium Bacteroides ovatus for the controlled in situ delivery of TGF-β(1) and treatment of colitis.

METHODS

Sequence encoding the human tgf-β1 gene was cloned downstream of the xylanase promoter in the xylan operon of B. ovatus by homologous recombination. Resulting recombinants (BO-TGF) were tested for TGF-β production in the presence and absence of polysaccharide xylan in vitro and in vivo, and used to treat experimental murine colitis. Clinical and pathological scores were used to assess the effectiveness of therapy. Colonic inflammatory markers including inflammatory cytokine expression were assessed by colorimetric assay and real-time polymerase chain reaction (PCR).

RESULTS

BO-TGF secreted high levels of biologically active dimeric TGF-β in vitro and in vivo in a xylan-controlled manner. Administration of xylan in drinking water to BO-TGF-treated mice resulted in a significant clinical improvement of colitis, accelerating healing of damaged colonic epithelium, reducing inflammatory cell infiltration, reducing expression of proinflammatory cytokines, and promoting production of mucin-rich goblet cells in colonic crypts. These beneficial effects are comparable and in most cases superior to that achieved by conventional steroid therapy.

CONCLUSIONS

This novel drug delivery system has potential for the targeted and controlled delivery of TGF-β(1) and other immunotherapeutic agents for the long-term management of various bowel disorders.