Solid Lipid Microparticles for Oral Delivery of Catalase: Focus on the Protein Structural Integrity and Gastric Protection.

Protein inactivation either during the production process or along the gastrointestinal tract is the major problem associated with the development of oral delivery systems for biological drugs. This work presents an evaluation of the structural integrity and the biological activity of a model protein, catalase, after its encapsulation in glyceryl trimyristate-based solid lipid microparticles (SLMs) obtained by the spray congealing technology. Circular dichroism and fluorescence spectroscopies were used to assess the integrity of catalase released from SLMs. The results confirmed that no conformational change occurred during the production process and both the secondary and tertiary structures were retained. Catalase is highly sensitive to temperature and undergoes denaturation above 60 °C; nevertheless, spray congealing allowed the retention of most biological activity due to the loading of the drug at the solid state, markedly reducing the risk of denaturation. Catalase activity after exposure to simulated gastric conditions (considering both acidic pH and the presence of gastric digestive hydrolases) ranged from 35 to 95% depending on the carrier: increasing of both the fatty acid chain length and the degree of substitution of the glyceride enhanced residual enzyme activity. SLMs allowed the protein release in a simulated intestinal environment and were not cytotoxic against HT29 cells. In conclusion, the encapsulation of proteins into SLMs by spray congealing might be a promising strategy for the formulation of nontoxic and inexpensive oral biotherapeutic products.

Protective Effects of Facilitated Removal of Blood Alcohol and Acetaldehyde Against Liver Injury in Animal Models Fed Alcohol and Anti-HIV Drugs.

BACKGROUND: We previously developed enzyme nanoparticles (ENP) of alcohol metabolism. This study was to evaluate protective effects of facilitated removal of blood alcohol and/or acetaldehyde on anti-HIV drugs and alcohol-induced liver injuries. METHODS: ENP were prepared for degrading alcohol completely (ENP1) or partially into acetaldehyde (ENP2), which were applied to mice of acute binge or chronic-binge alcohol feeding in the presence of antivirals (ritonavir and lopinavir). Liver pathologies were examined to assess the protective effects of ENP. RESULTS: In the acute model, ENP1 and ENP2 reduced the blood alcohol concentration (BAC) by 41 and 32%, respectively, within 4 hr, whereas in control without ENP, BAC was reduced only by 15%. Blood acetaldehyde concentration (BADC) was increased by 39% in alcohol-fed mice treated with ENP2 comparing to control. No significant effects of the anti-HIV drugs on BAC or BADC were observed. Plasma alanine aminotransferase (ALT) and expression of liver TNF-α were both significantly increased in the alcohol-fed mice, which were normalized by ENP1. In the presence of the antivirals, ALT was partially reduced by ENP1 or ENP2. In the chronic model, inflammation, fatty liver, and ALT were increased, which were deteriorated by the antivirals. ENP1 partially reduced BAC, BADC, ALT, and expression of inflammation markers of TNF-α, F4/80, and IL-6 and lipogenic factors of ACC, LXRα, and SREBP1. ENP2 reduced BAC without significant effects on ALT, inflammation, or lipogenesis. Antivirals and alcohol synergistically increased expression of organelle stress markers of CHOP, sXBP-1, ATF6, and GCP60. ENP1 reduced BAC, CHOP, and sXbp-1. However, no effects of ENP1 were found on ATF6 or GCP60. CONCLUSIONS: Removal of blood alcohol and acetaldehyde by the ENP protects the liver against alcoholic injuries, and the protection is less effective in chronic alcohol and antiviral feeding due to additional drug-induced organelle stresses.

Intrahepatic Delivery of Pegylated Catalase Is Protective in a Rat Ischemia/Reperfusion Injury Model.

BACKGROUND: Ischemia/reperfusion injury (IRI) can occur during liver surgery. Endogenous catalase is important to cellular antioxidant defenses and is critical to IRI prevention. Pegylation of catalase (PEG-CAT) improves its therapeutic potential by extending plasma half-life, but systemic administration of exogenous PEG-CAT has been only mildly therapeutic for hepatic IRI. Here, we investigated the protective effects of direct intrahepatic delivery of PEG-CAT during IRI using a rat hilar clamp model. MATERIALS AND METHODS: PEG-CAT was tested in vitro and in vivo. In vitro, enriched rat liver cell populations were subjected to oxidative stress injury (H2O2), and measures of cell health and viability were assessed. In vivo, rats underwent segmental (70%) hepatic warm ischemia for 1 h, followed by 6 h of reperfusion, and plasma alanine aminotransferase and aspartate aminotransferase, tissue malondialdehyde, adenosine triphosphate, and GSH, and histology were assessed. RESULTS: In vitro, PEG-CAT pretreatment of liver cells showed substantial uptake and protection against oxidative stress injury. In vivo, direct intrahepatic, but not systemic, delivery of PEG-CAT during IRI significantly reduced alanine aminotransferase and aspartate aminotransferase in a time-dependent manner (P < 0.01, P < 0.0001, respectively, for all time points) compared to control. Similarly, tissue malondialdehyde (P = 0.0048), adenosine triphosphate (P = 0.019), and GSH (P = 0.0015), and the degree of centrilobular necrosis, were improved by intrahepatic compared to systemic PEG-CAT delivery. CONCLUSIONS: Direct intrahepatic administration of PEG-CAT achieved significant protection against IRI by reducing the volume distribution and taking advantage of the substantial hepatic first-pass uptake of this molecule. The mode of delivery was an important factor for protection against hepatic IRI by PEG-CAT.

Lipid-Coated, pH-Sensitive Magnesium Phosphate Particles for Intracellular Protein Delivery.

PURPOSE: To develop cationic lipid-coated magnesium phosphate nanoparticles (LPP) for intracellular catalase (CAT) delivery. METHODS: Magnesium phosphate nanoparticles (MgP NP) were prepared by micro-emulsion precipitation and mixed with catalase-loaded cationic liposomes (DOTAP/cholesterol) to yield LPP formulation of catalase (LPP-CAT). The size and ζ-potential of LPP-CAT were measured by dynamic light scattering. The pH-sensitivity of LPP-CAT was determined by monitoring their degradation of hydrogen peroxide (H2O2) and their morphologies under transmission electron microscopy (TEM) at pH 7.4 and 5.5. The ability of LPP-CAT to protect MCF-7 cells against hydrogen peroxide was measured by MTS assay. ROS levels in EA.hy926 cells were measured after treatment with LPP-CAT. RESULTS: LPP-CAT were successfully prepared and carried an average diameter of <300 nm and ζ -potential of about +40 mV. At pH 5.5, LPP-CAT degraded H2O2 almost 4-fold as fast as pH 7.4 and displayed drastic morphological changes of an osmotic explosion. LPP-CAT protected MCF-7 cells from lethal level of exogenous H2O2 and significantly lowered the ROS levels in EA.hy926 cells. A lipid with a pH-sensitive conformational switch (flipid) further enhanced the protein delivery of LPP-CAT. CONCLUSION: LPP represents a promising nano-system for intracellular protein delivery.

Medium containing different concentrations of catalase as a strategy for optimising sperm parameters and chromatin in normospermic persons.

The aim of this study was to comprise the effect of catalase on sperm parameters and chromatin in normospermic persons. Semen samples were obtained from fertile men. A certain amount of different concentrations of catalase (0.1, 1, 10, 50, 100, 150 and 200 IU.ml) was added to each vial containing semen. Control group had similar condition to treated groups without treatment. Treatment was done for one hour in incubator and 4 and 24 hr in room temperature. Sperm parameters (motility, viability and morphology) and chromatin were evaluated after incubation. The results show that percentage of motility was insignificantly increased at concentration of 100 IU.ml catalase. This increase was higher than other examined concentration in all incubation time. The increase in sperm motility had significant difference in concentrations of 100 IU.ml with other concentrations. Other parameters showed no significant difference in all concentrations. Regarding the health of sperm chromatin, low concentrations of catalase had significant effect on this variable. This effect was more in low concentrations than high concentrations. This study showed the use of lower concentrations of antioxidant can improve the sperm parameters and chromatin quality. The low concentrations of catalase led to protection of chromatin and optimisation of sperm parameters.

Self-Supplied Tumor Oxygenation through Separated Liposomal Delivery of H2O2 and Catalase for Enhanced Radio-Immunotherapy of Cancer.

The recent years have witnessed the blooming of cancer immunotherapy, as well as their combinational use together with other existing cancer treatment techniques including radiotherapy. However, hypoxia is one of several causes of the immunosuppressive tumor microenvironment (TME). Herein, we develop an innovative strategy to relieve tumor hypoxia by delivering exogenous H2O2 into tumors and the subsequent catalase-triggered H2O2 decomposition. In our experiment, H2O2 and catalase are separately loaded within stealthy liposomes. After intravenous (iv) preinjection of CAT@liposome, another dose of H2O2@liposome is injected 4 h later. The sustainably released H2O2 could be decomposed by CAT@liposome, resulting in a long lasting effect in tumor oxygenation enhancement. As the result, the combination treatment by CAT@liposome plus H2O2@liposome offers remarkably enhanced therapeutic effects in cancer radiotherapy as observed in a mouse tumor model as well as a more clinically relevant patient-derived xenograft tumor model. Moreover, the relieved tumor hypoxia would reverse the immunosuppressive TME to favor antitumor immunities, further enhancing the combined radio-immunotherapy with cytotoxic T lymphocyte-associated antigen 4 (CTLA4) blockade. This work presents a simple yet effective strategy to promote tumor oxygenation via sequential delivering catalase and exogenous H2O2 into tumors using well-established liposomal carriers, showing great potential for clinical translation in radio-immunotherapy of cancer.

Effects of formulation development methods on the stability of model protein pharmaceuticals embedded in solid lipid matrices.

This study was conducted to investigate the influence of formulation development methods on the stability (secondary structure, aggregation, and biological activity) of protein drugs embedded in lipid matrices. Catalase, horseradish peroxidase, and α-chymotrypsin were employed as model proteins, while Precirol® AT05 (glyceryl palmitostearate) was used as lipid matrix. Protein-loaded lipid matrices were prepared using melting and mixing and wet granulation methods. Attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy, size exclusion chromatography (SEC) and biological activity analyses were performed. ATR FT-IR analysis indicated significant interference of the lipid with the protein amide-I band, which was eliminated using spectral subtraction. Wet granulation method induced more changes in protein secondary structure compared to melting and mixing method. SEC analysis gave evidence of protein aggregation for catalase upon adopting the wet granulation method. The biological activity of catalase was found to reduce significantly than other two proteins upon using wet granulation method, which might be ascribed to both secondary structure alterations and the formation of aggregates. Horseradish peroxidase and α-chymotrypsin did not form any soluble aggregates. In conclusion, melting and mixing method emerged as a better incorporation method compared to wet granulation because of better stability shown by the formulated proteins.

Catalase-Laden Microdevices for Cell-Mediated Enzyme Delivery.

Enzymes have been used to treat various human diseases and traumas. However, the therapeutic utility of free enzymes is impeded by their short circulation time, lack of targeting ability, immunogenicity, and inability to cross biological barriers. Cell-mediated drug delivery approach offers the unique capability to overcome these limitations, but the traditional cell-mediated enzyme delivery techniques suffer from drawbacks such as risk of intracellular degradation of and low loading capacity for the payload enzyme. This article presents the development of a novel cell-mediated enzyme delivery technique featuring the use of micrometer-sized disk-shaped particles termed microdevices. The microdevices are fabricated by layer-by-layer assembly and soft lithography with catalase being used as a model therapeutic enzyme. The amount of catalase in the microdevices can be controlled with the number of catalase layers. Catalase in the microdevices is catalytically active, and active catalase is slowly released from the microdevices. Moreover, cell-microdevice complexes are produced by attaching the catalase-laden microdevices to the external surface of both K562 cells and mouse embryonic stem cells. This technique is potentially applicable to other enzymes and cells and promises to be clinically useful.

Optimization of novel pentablock copolymer based composite formulation for sustained delivery of peptide/protein in the treatment of ocular diseases.

This manuscript is focussed on the development of pentablock (PB) copolymer based sustained release formulation for the treatment of posterior segment ocular diseases. We have successfully synthesised biodegradable and biocompatible PB copolymers for the preparation of nanoparticles (NPs) and thermosensitive gel. Achieving high drug loading with hydrophilic biotherapeutics (peptides/proteins) is a challenging task. Moreover, small intravitreal injection volume (≤100 µL) requires high loading to develop a long term (six months) sustained release formulation. We have successfully investigated various formulation parameters to achieve maximum peptide/protein (octreotide, insulin, lysozyme, IgG-Fab, IgG, and catalase) loading in PB NPs. Improvement in drug loading can facilitate delivery of larger doses of therapeutic proteins via limited injection volume. A composite formulation comprised of NPs in gel system exhibited sustained release (without burst effect) of peptides and proteins, may serve as a platform technology for the treatment of posterior segment ocular diseases.

ICAM-1 targeted catalase encapsulated PLGA-b-PEG nanoparticles against vascular oxidative stress.

Targeted delivery of therapeutics is the favourable idea, whereas it is possible to distribute the therapeutically active drug molecule only to the site of action. For this purpose, in this study, catalase encapsulated poly(D,L-lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-b-PEG) nanoparticles were developed and an endothelial target molecule (anti-ICAM-1) was conjugated to this carrier system in order to decrease the oxidative stress level in the target site. According to the enzymatic activity results, initial catalase activity of nanoparticles was increased from 27.39 U/mg to up to 45.66 U/mg by adding 5 mg/mL bovine serum albumin (BSA). After 4 h, initial catalase activity was preserved up to 46.98% while free catalase retained less than 4% of its activity in proteolytic environment. Furthermore, FITC labelled anti-ICAM-1 targeted catalase encapsulated nanoparticles (anti-ICAM-1/CatNPs) were rapidly taken up by cultured endothelial cells and concomitantly endothelial cells were resistant to H2O2 induced oxidative impairment.

Q10-triggered facial vitiligo.

BACKGROUND: Generation and accumulation of reactive oxygen/nitrogen species in the epidermis of patients with vitiligo has been widely documented. Moreover, semiquinone radical-mediated sensitivity has been shown in blood lymphocytes of these patients. OBJECTIVES: To determine the possible mechanism behind Q10-induced facial vitiligo. METHODS: This was a clinical assessment supported by in vivo Fourier transform-Raman spectroscopy and repigmentation. RESULTS: Topical Q10 application generated hydrogen peroxide (H2 O2 ) leading in turn to facial vitiligo in susceptible individuals. Proof of the basic result stemmed from reduction of epidermal H2 O2 by using narrowband ultraviolet B-activated propseudocatalase PC-KUS in association with cessation of depigmentation and repigmentation of the lost skin colour. CONCLUSIONS: Over-the-counter availability of Q10-containing topical formulations can be harmful to individuals susceptible to vitiligo.

Reactive oxygen species regulate osteopontin expression in a murine model of postischemic neovascularization.

OBJECTIVE: Previous findings from our laboratory demonstrated that neovascularization was impaired in osteopontin (OPN) knockout animals. However, the mechanisms responsible for the regulation of OPN expression in the setting of ischemia remain undefined. Therefore, we sought to determine whether OPN is upregulated in response to ischemia and hypothesized that hydrogen peroxide (H(2)O(2)) is a critical component of the signaling mechanism by which OPN expression is upregulated in response to ischemia in vivo. METHODS AND RESULTS: To determine whether ischemic injury upregulates OPN, we used a murine model of hindlimb ischemia. Femoral artery ligation in C57BL/6 mice significantly increased OPN expression and H(2)O(2) production. Infusion of C57BL/6 mice with polyethylene glycol-catalase (10 000 U/kg per day) or the use of transgenic mice with smooth muscle cell-specific catalase overexpression blunted ischemia-induced OPN, suggesting ischemia-induced OPN expression is H(2)O(2)-dependent. Decreased H(2)O(2)-mediated OPN blunted reperfusion and collateral formation in vivo. In contrast, the overexpression of OPN using lentivirus restored neovascularization. CONCLUSIONS: Scavenging H(2)O(2) blocks ischemia-induced OPN expression, providing evidence that ischemia-induced OPN expression is H(2)O(2) dependent. Decreased OPN expression impaired neovascularization, whereas overexpression of OPN increased angiogenesis, supporting our hypothesis that OPN is a critical mediator of postischemic neovascularization and a potential novel therapeutic target for inducing new vessel growth.

PEGylated human catalase elicits potent therapeutic effects on H1N1 influenza-induced pneumonia in mice.

Therapeutic recombinant human catalase (rhCAT) can quench infection-induced reactive oxygen species (ROS), thereby alleviating the associated tissue damage. Although the intranasal route is efficient to deliver native rhCAT to the lung, the therapeutic effect is limited by rapid elimination from the blood. In this study, we modified rhCAT with the active polymer, polyethylene glycol monomethyl ether (PEG)-5000, and analyzed the pharmacokinetics of PEGylated rhCAT in mice. The high tetra-PEGylation ratio was about 60%, and PEGylation prolonged the half-life of rhCAT in serum (75 vs. 13.5 min for native rhCAT). The protective effects of PEG-rhCAT were investigated in a mouse model of influenza virus A (H1N1)-associated pneumonia. PEG-rhCAT was more effectively delivered than native rhCAT and was associated with higher survival ratio, less extensive lung injuries, reduced ROS levels, and lower viral replication. Collectively, these findings indicate that PEGylation can enhance the therapeutic efficacy of native rhCAT and suggest that PEGylated rhCAT may represent a novel complement therapy for H1N1 influenza-induced pneumonia.

Catalase improves motility, vitality and DNA integrity of cryopreserved human spermatozoa.

Cryopreservation of human spermatozoa offers a pre-therapeutic possibility of preserving progenity in patients with testicular tumours. We aimed to investigate effects of cryopreservation and addition of catalase on sperm motility, vitality and DNA integrity in fresh and swim-up spermatozoa. Semen samples were collected from 50 fertile men. Each sample was divided into two parts. First part was subdivided into two equal aliquots: both cryopreserved with and without catalase. The second part was subdivided into two equal aliquots: both processed by swim up and then cryopreserved with or without catalase. Semen analyses, sperm vitality and sperm DNA integrity were performed. Sperm concentration showed significant decrease while percentage of progressive motility, sperm vitality and % of DNA damage showed significant increase in processed and cryopreserved processed samples when compared with fresh and cryopreserved fresh samples. There was no significant difference in sperm concentration while there was significant increase in % of progressive motility and sperm vitality and % of DNA damage showed significant decrease in samples with catalase when compared with samples without catalase (either fresh or processed). Catalase supplementation (fresh and processed) during cryopreservation results in better post-thawing percentage of progressive motility and percentage of sperm vitality and improved DNA integrity.

Effects of pergolide mesylate on transduction efficiency of PEP-1-catalase protein.

The low transduction efficiency of various proteins is an obstacle to their therapeutic application. However, protein transduction domains (PTDs) are well-known for a highly effective tool for exogenous protein delivery to cells. We examined the effects of pergolide mesylate (PM) on the transduction of PEP-1-catalase into HaCaT human keratinocytes and mice skin and on the anti-inflammatory activity of PEP-1-catatase against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation using Western blot and histological analysis. PM enhanced the time- and dose-dependent transduction of PEP-1-catalase into HaCaT cells without affecting the cellular toxicity. In a mouse edema model, PEP-1-catalase inhibited the increased expressions of inflammatory mediators and cytokines such as cyclooxygenase-2, inducible nitric oxide synthase, interleukin-6 and -1ß, and tumor necrosis factor-α induced by TPA. On the other hand, PM alone failed to exert any significant anti-inflammatory effects. However, the anti-inflammatory effect of co-treatment with PEP-1-catalase and PM was more potent than that of PEP-1-catalase alone. Our results indicate that PM may enhance the delivery of PTDs fusion therapeutic proteins to target cells and tissues and has potential to increase their therapeutic effects of such drugs against various diseases.

E. coli Membrane Vesicles as a Catalase Carrier for Long-Term Tumor Hypoxia Relief to Enhance Radiotherapy.

Hypoxia is one of the most important factors that limit the effect of radiotherapy, and the abundant H2O2 in tumor tissues will also aggravate hypoxia-induced radiotherapy resistance. Delivering catalase to decompose H2O2 into oxygen is an effective strategy to relieve tumor hypoxia and radiotherapy resistance. However, low stability limits catalase's in vivo application, which is one of the most common limitations for almost all proteins' internal utilization. Here, we develop catalase containing E. coli membrane vesicles (EMs) with excellent protease resistance to relieve tumor hypoxia for a long time. Even treated with 100-fold of protease, EMs showed higher catalase activity than free catalase. After being injected into tumors post 12 h, EMs maintained their hypoxia relief ability while free catalase lost its activity. Our results indicate that EMs might be an excellent catalase delivery for tumor hypoxia relief. Combined with their immune stimulation features, EMs could enhance radiotherapy and induce antitumor immune memory effectively.

Brain Targeting and Toxicological Assessment of the Extracellular Vesicle-Packaged Antioxidant Catalase-SKL Following Intranasal Administration in Mice.

The antioxidant enzyme catalase represents an important therapeutic target due to its role in mitigating cellular reactive oxygen species that contribute to the pathogenesis of many disease states. Catalase-SKL (CAT-SKL), a genetically engineered, peroxisome-targeted, catalase derivative, was developed in order to increase the therapeutic potential of the enzyme, and has previously been shown to be effective in combating oxidative stress in a variety of in vitro and in vivo models, thereby mitigating cellular degeneration and death. In the present study we addressed important considerations for the development of an extracellular vesicle-packaged version of CAT-SKL (evCAT-SKL) as a therapeutic for neurodegenerative diseases by investigating its delivery potential to the brain when administered intranasally, and safety by assessing off-target toxicity in a mouse model. Mice received weekly intranasal administrations of evCAT-SKL or empty extracellular vesicles for 4 weeks. Fluorescent labeling for CAT-SKL was observed throughout all sections of the brain in evCAT-SKL-treated mice, but not in empty extracellular vesicle-treated mice. Furthermore, we found no evidence of gross or histological abnormalities following evCAT-SKL or empty extracellular vesicle treatment in a full-body toxicological analysis. Combined, the successful brain targeting and the lack of off-target toxicity demonstrates that intranasal delivery of extracellular vesicle-packaged CAT-SKL holds promise as a therapeutic for addressing neurological disorders.

Supplementation with Exogenous Catalase from Penicillium notatum in the Diet Ameliorates Lipopolysaccharide-Induced Intestinal Oxidative Damage through Affecting Intestinal Antioxidant Capacity and Microbiota in Weaned Pigs.

The present study aimed to explore the protective effects of exogenous catalase (CAT) from microorganisms against lipopolysaccharide (LPS)-induced intestinal injury and its molecular mechanism in weaned pigs. Fifty-four weaned pigs (21 days of age) were randomly allocated to CON, LPS, and LPS+CAT groups. The pigs in CON and LPS groups were fed a basal diet, whereas the pigs in LPS+CAT group fed the basal diet with 2,000 mg/kg CAT supplementation for 35 days. On day 36, six pigs were selected from each group, and LPS and LPS+CAT groups were administered with LPS (50 µg/kg body weight). Meanwhile, CON group was injected with an equivalent amount of sterile saline. Results showed that LPS administration damaged intestinal mucosa morphology and barrier. However, CAT supplementation alleviated the deleterious effects caused by LPS challenge through enhancing intestinal antioxidant capacity which was benefited to decrease proinflammatory cytokines concentrations and suppress enterocyte apoptosis. Besides, LPS-induced gut microbiota dysbiosis was significantly shifted by CAT through decreasing mainly Streptococcus and Escherichia-Shigella. Our study suggested that dietary supplemented with 2,000 mg/kg catalase was conducive to improve intestinal development and protect against LPS-induced intestinal mucosa injury via enhancing intestinal antioxidant capacity and altering microbiota composition in weaned pigs. IMPORTANCE Exogenous CAT derived from microorganisms has been widely used in food, medicine, and other industries. Recent study also found that exogenous CAT supplementation could improve growth performance and antioxidant capacity of weaned pigs. However, it is still unknown that whether dietary exogenous CAT supplementation can provide a defense against the oxidative stress-induced intestinal damage in weaned pigs. Our current study suggested that dietary supplemented with 2,000 mg/kg CAT was conducive to improve intestinal development and protect against LPS-induced intestinal mucosa injury via enhancing intestinal antioxidant capacity and altering microbiota composition in weaned pigs. Moreover, this study will also assist in developing of CAT produced by microorganisms to attenuate various oxidative stress-induced injury or diseases.

Therapeutic effect of lecithinized superoxide dismutase on bleomycin-induced pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is thought to involve inflammatory infiltration of leukocytes, lung injury induced by reactive oxygen species (ROS), in particular superoxide anion, and fibrosis (collagen deposition). No treatment has been shown to improve definitively the prognosis for IPF patients. Superoxide dismutase (SOD) catalyzes the dismutation of superoxide anion to hydrogen peroxide, which is subsequently detoxified by catalase. Lecithinized SOD (PC-SOD) has overcome clinical limitations of SOD, including low tissue affinity and low stability in plasma. In this study, we examined the effect of PC-SOD on bleomycin-induced pulmonary fibrosis. Severity of the bleomycin-induced fibrosis in mice was assessed by various methods, including determination of hydroxyproline levels in lung tissue. Intravenous administration of PC-SOD suppressed the bleomycin-induced increase in the number of leukocytes in bronchoalveolar lavage fluid. Bleomycin-induced collagen deposition and increased hydroxyproline levels in the lung were also suppressed in animals treated with PC-SOD, suggesting that PC-SOD suppresses bleomycin-induced pulmonary fibrosis. The dose-response profile of PC-SOD was bell-shaped, but concurrent administration of catalase restored the ameliorative effect at high doses of PC-SOD. Intratracheal administration or inhalation of PC-SOD also attenuated the bleomycin-induced inflammatory response and fibrosis. The bell-shaped dose-response profile of PC-SOD was not observed for these routes of administration. We consider that, compared with intravenous administration, inhalation of PC-SOD may be a more therapeutically beneficial route of administration due to the higher safety and quality of life of the patient treated with this drug.

Benefits of catalase overexpression in renal proximal tubular cells.

The intrarenal renin-angiotensin system and reactive oxygen species contribute to the progression of chronic kidney disease. Godin et al. applied transgenic methods to prove renoprotection by catalase. They show that all of the pathological effects of overexpression of angiotensinogen can be attributed to stimulation of hydrogen peroxide pathways. This indicates a protective role for catalase and underscores the importance of the intrarenal renin-angiotensin system in renal disease.