Biomedical subjects

B M McManus

Publications and source records attributed to B M McManus.

At least 19 recordsLinked to original sources

PubMed2007

Inhibition and recovery of maternal and foetal cholinesterase enzymes following fenitrothion administration in CD rats.

The purpose of this study was to characterize tissue esterase activity and blood fenitrothion concentrations in the rat dam and foetus following in-utero exposure to the organophosphate insecticide fenitrothion. Time-mated, 8-week-old rats were gavaged on gestation day 19 with 0, 5, or 25 mg fenitrothion kg-1. Fenitrothion was absorbed rapidly from the gastrointestinal tract, with peak maternal and foetal blood levels observed 0.5-1.0 h after dosing. Fenitrothion concentrations in maternal and foetal blood were virtually identical and demonstrated a non-linear dose-response relationship. Acetylcholinesterase and carboxylesterase activities in maternal liver and blood and in foetal liver and brain decreased within 30-60 min of fenitrothion exposure. Esterase inhibition occurred at a fenitrothion dose (5 mg kg-1) that has not been previously associated with reproductive toxicity, suggesting that esterase inhibition should be considered as the critical effect in risk assessments for this pesticide.

Animals↗

PubMed2003

BNips: a group of pro-apoptotic proteins in the Bcl-2 family.

BNip (formerly known as Nip) proteins, including homologues isolated from human, mouse and Caenorhabditis. elegans, are a relatively new subgroup of the Bcl-2 family. These proteins are classified into this family based on limited sequence homology with the Bcl-2 homology domain 3 and carboxyl terminal transmembrane domain. BNip proteins were first discovered based on their interaction with the adenovirus E1B 19 kDa/Bcl-2 family protein and since then, their roles in cell death pathways have been actively studied. However, the precise mechanisms by which the BNip proteins induce apoptosis and/or necrosis remain to be determined. To advance our knowledge, we have provided a summary and review of current literature regarding BNip proteins including comparative sequence analysis, mutational mapping of the functional domains, and cell death mechanisms involving disruption of mitochondrial homeostasis. Since BNip proteins are expressed at high levels in the heart as compared to other organs, their roles in cardiomyocyte injury during hypoxia or viral infection is a focus of this review. Finally, we discuss potential directions for further study on this increasingly important group of pro-apoptotic proteins.

Animals↗

PubMed2001

Endothelial cell apoptosis: biochemical characteristics and potential implications for atherosclerosis.

The high turnover of endothelial cells (EC) in atherosclerosis suggests that an increase in the frequency of both cell proliferation and cell death is important in the pathogenesis of this common disorder. Further, increased apoptosis of EC, smooth muscle cells (SMC) and immune cells has been observed in atheromatous plaques. Many pro-atherogenic factors, including oxidized low-density lipoproteins, angiotensin II and oxidative stress, can induce EC apoptosis. Such damage to the endothelium may be an initiating event in atherogenesis since EC apoptosis may compromise vasoregulation, increase SMC proliferation, SMC migration and blood coagulation. In addition, EC overlying vascular lesions have been shown to increase their expression of pro-apoptotic proteins, such as Fas and Bax, while decreasing levels of anti-apoptotic factors. Therefore, understanding EC apoptotic pathways that are altered in atherosclerosis may enable a greater understanding of disease pathogenesis and foster the development of new therapies. The present discussion outlines the biochemical characteristics of EC apoptosis and the role that altered regulation of apoptosis plays in vasculopathy.

Angiotensin II↗

PubMed2001

Overexpression of interleukin-6 aggravates viral myocarditis: impaired increase in tumor necrosis factor-alpha.

The process of inflammation and immune response is regulated by proinflammatory cytokines. Interleukin-6 (IL-6), one of the proinflammatory cytokines, plays a potentially critical role in viral-induced myocarditis. Our previous work demonstrates that exogenous IL-6 administration, given at the time of encephalomyocarditis virus (EMCV) inoculation in C3H/HeJ mice, has a protective effect on myocardium and improves survival rates. In the present study, we examined whether overexpression of IL-6 modified viral myocarditis. On day 3 and 10 after inoculation with EMCV, the ratio of heart weight to body weight and myocardial injury were significantly increased in IL-6 transgenic mice (IL-6TG). On day 3, a reduction of viral clearance was shown by the presence of elevated viral titers and viral replication in the heart of IL-6TG. The concentrations of serum tumor necrosis factor- alpha (TNF alpha) were dramatically increased in wild-type mice on day 1, in contrast, this change was not observed in IL-6TG. Treatment with recombinant human TNF (2 microg) significantly improved viral clearance in the IL-6TG hearts. Thus, overexpression of IL-6 promotes myocardial injury by interrupting both the cytokine network and viral clearance. These experiments suggest the possibility that IL-6 is one of the factors that accelerates tissue damage, including myocardial injury, in the viral myocarditis.

Animals↗

PubMed2001

Mitochondrial release of apoptosis-inducing factor and cytochrome c during smooth muscle cell apoptosis.

Photodynamic therapy (PDT) is under investigation for the treatment of intimal hyperplastia in conditions such as atherosclerosis and restenosis. Although smooth muscle cells (SMCs) may be a key target for treatment, the effects of PDT on these cells are poorly characterized. In the present study, apoptosis was induced in primary human aortic SMCs by the combination of the photosensitizer verteporfin and visible light. After PDT, an increase in mitochondrial cytochrome c (cyt c) and apoptosis-inducing factor (AIF) levels were detected in the cytosol immediately and their levels increased steadily up to 2 hours. Cytosolic levels of the pro-apoptotic Bcl-2 family member Bax decreased reciprocally throughout this period, but this change did not occur before cyt c release. Confocal microscopy revealed a diffuse staining pattern of cyt c within apoptotic cells as compared to a distinct mitochondrial staining in normal cells. AIF translocated from mitochondria to the nucleus during the progression of apoptosis. After cyt c release, caspase-9 and caspase-3 processing was visible by 1 hour and caspase-6, -7, and -8 processing was apparent by 2 hours after PDT. In summary, these results demonstrate for the first time the cellular redistribution of mitochondrial AIF during SMC apoptosis, as well as the early release of cyt c and the subsequent activation of multiple caspases during PDT-induced SMC apoptosis.

Aorta↗

PubMed2001

Apoptosis in cardiac transplant rejection.

Apoptosis occurs in human cardiac allograft rejection and may occur with all degrees of rejection and even in its absence. The prevalence and severity of apoptosis is determined predominantly by the intensity of macrophage infiltration and may be mediated by NO-related mechanisms. Apoptosis of interstitial, endothelial, and inflammatory cells is also present in heart allografts and may influence the degree and extent of vascular injury contributing to allograft rejection. Ongoing apoptosis of inflammatory cells suggests an immunoregulatory role. Studies of the involvement of NO in myocyte damage and Fas-FasL interactions in peripheral tolerance have raised the exciting possibility that these pathways can be exploited in a beneficial way. Further understanding of the role of apoptosis and the cellular and biochemical mechanisms that are involved in cardiac myocyte death and in inflammatory, endothelial, and interstitial cell death may provide insights into therapeutic modalities to suppress allograft rejection and vasculopathy.

Animals↗

PubMed2001

Complete inhibition of intimal hyperplasia by perivascular delivery of paclitaxel in balloon-injured rat carotid arteries.

PURPOSE: To determine whether perivascular delivery of paclitaxel prevents luminal narrowing after balloon injury by inhibiting intimal hyperplasia. MATERIALS AND METHODS: Immediately after balloon injury of the entire left common carotid artery, three slow-release formulations of paclitaxel or control formulations without drug were applied around a distal segment of the artery. The noninjured right carotid arteries were evaluated as a control. The animals were maintained for 14 and 28 days (n = 5 in each group at each time interval). Histology, immunohistochemistry, and morphometric analysis were performed. RESULTS: Injured nontreated arteries exhibited a pronounced intimal hyperplasia (0.185 +/- 0.01 mm2 at 14 days and 0.189 +/- 0.01 mm2 at 28 days) and a marked reduction in luminal area (44% at 14 days and 43% at 28 days). Medial area and the number of medial cells increased by 44% and 45%, respectively, at 14 days, and by 22% and 37%, respectively, at 28 days. Injured arteries treated with perivascular paclitaxel did not show any intimal hyperplasia, and luminal area was increased in five of six groups and was unchanged in one group. These arteries had an increased medial area but they had fewer medial cells than noninjured arteries. Injured arteries treated with control implants without paclitaxel exhibited intimal hyperplasia and luminal narrowing. CONCLUSION: Perivascular slow release of paclitaxel totally inhibits intimal hyperplasia and prevents luminal narrowing after balloon injury. Because of its efficacy, perivascular paclitaxel represents a possible approach for prevention of restenosis in humans.

Angiogenesis Inhibitors↗

PubMed2001

Fas ligand and TRAIL augment the effect of photodynamic therapy on the induction of apoptosis in JURKAT cells.

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) and Fas ligand (FasL) trigger apoptosis by stimulating the formation of a death inducing signaling complex at the cytoplasmic terminus of their respective receptors. Photodynamic therapy (PDT) is an approved treatment for several types of cancer as well as for age-related macular degeneration and is under investigation for different cancer, ocular, autoimmune and cardiovascular indications. The effect of low dose PDT in combination with TRAIL and FasL on Jurkat lymphoma cell apoptosis was examined. Individually, TRAIL, FasL, and PDT could induce apoptosis in these cells. However, at suboptimal levels of PDT, the number of cells undergoing apoptosis was increased when recombinant FasL and/or TRAIL were added. Additive effects of these treatments were evident for different apoptosis parameters including DNA fragmentation, caspase processing and activity and caspase substrate degradation. Overall, these results provide evidence that PDT-treated cells may be more likely to undergo apoptosis when also exposed to receptor-mediated signals delivered by factors such as TRAIL or FasL. For PDT, immune cell-mediated death receptor ligation may represent a way whereby tumor cells that have withstood the direct effects of photosensitization may be eliminated.

Apoptosis↗

PubMed2001

Hepatic over-expression of peroxisome proliferator activated receptor gamma2 in the ob/ob mouse model of non-insulin dependent diabetes mellitus.

Studies of the molecular basis of insulin resistance have focused on the peroxisome proliferator activated receptor gamma (PPARgamma, gamma1 and gamma2). The aim of this study was to determine whether the insulin resistance in liver of diabetic animals is associated with abnormal expression of these receptors. PPARgamma mRNA and protein expression levels were quantified in liver of 9-week-old male ob/ob mice as a model of diabetes and compared to age- and gender-matched wild type control animals of the same genetic background. Semi-quantitative reverse transcription-polymerase chain reaction, using 18S rRNA as an internal standard, indicated that PPARgamma2 mRNA was significantly upregulated in ob/ob liver vs. that in wild type mice. Western blotting revealed greater immunoreactivity of PPARgamma2 in liver from ob/ob mice relative to that in wild type mice. An index of insulin resistance (product of serum glucose and insulin concentration) was correlated with liver PPARgamma2 mRNA expression (r = 0.776; p < 0.001). The findings that liver PPARgamma2 expression is (1) significantly elevated in the ob/ob model of diabetes and (2) positively associated with an index of insulin resistance, suggests a possible compensatory response through which type II diabetic and obese organisms strive to maintain insulin sensitivity of the liver.

Adipose Tissue↗

PubMed2001

Advances in experimental dyslipidemia and atherosclerosis.

Among the models of dyslipidemia and atherosclerosis, a number of wild-type, naturally defective, and genetically modified animals (rabbits, mice, pigeons, dogs, pigs, and monkeys) have been characterized. In particular, their similarities to and differences from humans in respect to relevant biochemical, physiologic, and pathologic conditions have been evaluated. Features of atherosclerotic lesions and their specific relationship to plasma lipoprotein particles have been critically reviewed and summarized. All animal models studied have limitations: the most significant advantages and disadvantages of using a specific animal species are outlined here. New insights in lipid metabolism and genetic background with regard to variations in pathogenesis of dyslipidemia-associated atherogenesis have also been reviewed. Evidence suggests that among wild-type species, strains of White Carneau pigeons and Watanabe Heritable Hyperlipidemic and St. Thomas's Hospital rabbits are preferable to the cholesterol-fed wild-type animal species in dyslipidemia and atherosclerosis research. Evidence for the usefulness of both wild-type and transgenic animals in studying the involvement of inflammatory pathways and Chlamydia pneumoniae infection in pathogenesis of atherosclerosis has also been summarized. Transgenic mice and rabbits are excellent tools for studying specific gene-related disorders. However, despite these significant achievements in animal experimentation, there are no suitable animal models for several rare types of fatal dyslipidemia-associated disorders such as phytosterolemia and cerebrotendinous xanthomatosis. An excellent model of diabetic atherosclerosis is unavailable. The question of reversibility of atherosclerosis still remains unanswered. Further work is needed to overcome these deficiencies.

Animals↗

PubMed2001

Bcl-2 increases emptying of endoplasmic reticulum Ca2+ stores during photodynamic therapy-induced apoptosis.

Photodynamic therapy (PDT) is clinically approved for the treatment of several types of cancer as well as age-related macular degeneration, the leading cause of blindness in the elderly. PDT using the photosensitizer verteporfin has been previously shown to induce rapid apoptosis via a mitochondrial-caspase activation pathway. The impact of PDT on other cellular organelles such as the endoplasmic reticulum (ER) is undefined. The effect of PDT on intracellular Ca2+ ([Ca2+]i) in control and Bcl-2-overexpressing HeLa cells was assessed. A greater [Ca2+]i transient was observed for Bcl-2 overexpressing cells in response to PDT. The PDT-induced Ca2+ release was due to the emptying of Ca2+ from ER and possibly mitochondrial stores and was not due to an influx of Ca2+ from the medium. For Bcl-2-transfected cells, the release of Ca2+ was incomplete as determined by a further [Ca2+]i transient produced by the addition of the Ca2+ ionophore ionomycin after PDT. Furthermore, extrusion of Ca2+ was not hindered while ER-mediated sequestration of Ca2+ was impaired after PDT. Impairment of ER-mediated sequestration of Ca2+ may be due to the immediate caspase-independent depletion of sarco/endoplasmic reticulum Ca2+ ATPase-2 (SERCA2) that occurred in response to PDT in birth HeLa/Neo and Bcl-2 overexpressed HeLa cells. In summary, PDT induced the rapid degradation of SERCA2 and release of ER and mitochondrial Ca2+ stores. Although overexpression of Bcl-2 did not protect against SERCA2 degradation, it may influence the release of Ca2+ from ER and mitochondrial stores in PDT-treated cells.

Apoptosis↗

PubMed2001

Pathophysiology of apolipoprotein E deficiency in mice: relevance to apo E-related disorders in humans.

Apolipoprotein E (apo E) deficiency (or its abnormalities in humans) is associated with a series of pathological conditions including dyslipidemia, atherosclerosis, Alzheimer's disease, and shorter life span. The purpose of this study was to characterize these conditions in apo E-deficient C57BL/6J mice and relate them to human disorders. Deletion of apo E gene in mice is associated with changes in lipoprotein metabolism [plasma total cholesterol (TC) (>+400%), HDL cholesterol (-80%), HDL/TC, and HDL/LDL ratios (-93% and -96%, respectively), esterification rate in apo B-depleted plasma (+100%), plasma triglyceride (+200%), hepatic HMG-CoA reductase activity (-50%), hepatic cholesterol content (+30%)], decreased plasma homocyst(e)ine and glucose levels, and severe atherosclerosis and cutaneous xanthomatosis. Hepatic and lipoprotein lipase activities, hepatic LDL receptor function, and organ antioxidant capacity remain unchanged. Several histological/immunohistological stainings failed to detect potential markers for neurodegenerative disease in the brain of 37-wk-old male apo E-KO mice. Apo E-KO mice may have normal growth and development, but advanced atherosclerosis and xanthomatosis may indirectly reduce their life span. Apo E plays a crucial role in regulation of lipid metabolism and atherogenesis without affecting lipase activities, endogenous antioxidant capacity, or appearance of neurodegenerative markers in 37-wk-old male mice.

Animals↗

PubMed2001

Specific inhibition of coxsackievirus B3 translation and replication by phosphorothioate antisense oligodeoxynucleotides.

The 5' and 3' untranslated regions (UTRs) of coxsackievirus B3 (CVB3) RNA form highly ordered secondary structures that have been confirmed to play important regulatory roles in viral cap-independent internal translation initiation and RNA replication. We previously demonstrated that deletions in different regions of the 5' UTR significantly reduced viral RNA translation and infectivity. Such observations suggested strongly that viral RNA translation and replication could be blocked if highly specific antisense oligodeoxynucleotides (AS-ODNs) were applied to target crucial sites within the 5' and 3' UTRs. In this study, seven phosphorothioate AS-ODNs were synthesized, and the antiviral activity was evaluated by Lipofectin transfection of HeLa cells with AS-ODNs followed by infection of CVB3. Analysis by Western blotting, reverse transcription-PCR, and viral plaque assay demonstrated that viral protein synthesis, genome replication, and infectivity of CVB3 were strongly inhibited by the AS-ODNs complementary to different regions of the 5' and 3' UTRs. The most effective sites are located at the proximate terminus of the 5' UTR (AS-1), the proximate terminus of the 3' UTR (AS-7), the core sequence of the internal ribosome entry site (AS-2), and the translation initiation codon region (AS-4). These AS-ODNs showed highly sequence-specific and dose-dependent inhibitory effects on both viral protein synthesis and RNA replication. It is noteworthy that the highest inhibitory activities were obtained with AS-1 and AS-7 targeting the termini of the 5' and 3' UTRs. The percent inhibition values of AS-1 and AS-7 for CVB3 protein VP1 synthesis and RNA replication were 70.6 and 79.6 for AS-1 and 73.7 and 79.7 for AS-7, respectively. These data suggest that CVB3 infectivity can be inhibited effectively by AS-ODNs.

Enterovirus B, Human↗

PubMed2001

Photodynamic therapy: shedding light on the biochemical pathways regulating porphyrin-mediated cell death.

Photodynamic therapy (PDT) is a clinically approved treatment for the ocular condition age-related macular degeneration, and certain types of cancer. PDT is also under investigation for other ocular, as well as, immune-mediated and cardiovascular indications. PDT is a two step procedure. In the first step, the photosensitizer, usually a porphyrin derivative, is administered and taken up by cells. The second step involves activation of the photosensitizer with a specific wavelength of visible light. Exposure to light of an activating wavelength generates reactive oxygen species within cells containing photosensitizer. PDT with porphyrin photosensitizers induces rapid apoptotic cell death, an event which may be attributed to the close association of these compounds with mitochondria. Thus, PDT is an attractive method to treat ailments such as cancer, viral infections, autoimmune disorders and certain cardiovascular diseases in which the apoptotic program may be compromised. The present review examines the cellular events triggered at lethal and sublethal PDT doses and their relationship to the subsequent effects exerted upon cells.

Animals↗

PubMed2000

Endothelial and myogenic regulation of coronary artery tone in the mouse.

Ventricular septal (150-200 microm) arteries were isolated from the hearts of six-week-old CD-1 mice and mounted on a pressure myograph. Equilibration of the vessels at 70 mm Hg for 60 min resulted in the development of spontaneous myogenic tone. Maximum tone observed in these vessels greatly exceeded that previously reported in septal arteries from rats. Inhibition of endothelin ET(A) and endothelin ET(B) receptors with bosentan (1 and 10 microM) reduced basal tone. Endothelin release required intact endothelial cells. The alpha(1)-adrenceptor selective agonists phenylephrine and methoxamine did not cause change in coronary tone, while the alpha(2)-adrenceptor selective agonists 6-allyl-2-amino5,6,7, 8-tetrahydro-4H-thiazolo-[4,5-d]azepin-dihydrochloride (BHT 920) and clonidine produced vasodilatation. Noradrenaline (1 nM-10 microM) induced a concentration-dependent vasodilatation, which was inhibited by concurrent treatment with yohimbine (10 microM) and propranolol (20 microM). Vasodilatation due to BHT 920 was abolished with vessel denudation, indicating the endothelial location of alpha(2)-adrenoceptors. Acetylcholine (1 nM-10 microM) caused an endothelium dependent vasodilatation; inhibition of nitric oxide synthase with N(omega)-nitro-L-arginine methyl ester attenuated this response. The endothelium-dependent vasodilators bradykinin and substance P produced no vasomotor effect in mouse coronary arteries. Differences between human and murine responses may impact on the relevance of the mouse coronary artery for use as a potential model of human coronary vessel diseases.

Adrenergic beta-Antagonists↗

PubMed2000

Host gene regulation during coxsackievirus B3 infection in mice: assessment by microarrays.

Host genetic responses that characterize enteroviral myocarditis have not yet been determined. The injurious and inflammatory process in heart muscle may reflect host responses of benefit to the virus and ultimately result in congestive heart failure and dilated cardiomyopathy. On the other hand, host responses within the myocardium may secure the host against acute or protracted damage. To investigate the nature of modified gene expression in comparison with normal tissue, mRNA species were assessed in myocardium using cDNA microarray technology at days 3, 9, and 30 after infection. Of 7000 clones initially screened, 169 known genes had a level of expression significantly different at 1 or more postinfection time points as compared with baseline. The known regulated genes were sorted according to their functional groups and normalized expression patterns and, subsequently, interpreted in the context of viremic, inflammatory, and healing phases of the myocarditic process.

Animals↗

PubMed2000

Profound inhibition of myogenic tone in rat cardiac allografts is due to eNOS- and iNOS-based nitric oxide and an intrinsic defect in vascular smooth muscle contraction.

BACKGROUND: The physiological consequences of inducible NO synthase (iNOS) expression were studied in allograft coronary arteries by pressure myography. METHODS AND RESULTS: Septal coronary arteries (diameter, 200.6+/-3.3 microm) were harvested from allograft and isograft hearts, and their myogenic properties were measured before and after iNOS and nonselective NOS inhibition with aminoguanidine (AG, 100 micromol/L) and N(G)-nitro-L-arginine methyl ester (L-NAME) (200 micromol/L). Fura 2 fluorescence microscopy was used to measure [Ca(2+)](i) in isolated endothelial cells. Monoclonal anti-iNOS immunostains demonstrated iNOS protein in day 2, 7, 14, and 28 allograft vessels, but only in day 2 isograft vessels. Myogenic tone was profoundly inhibited in allograft vessels from day 4 onward. In day 4 allograft vessels, these differences were abolished by L-NAME but not AG, suggesting greater basal release of eNOS-based NO from allograft endothelium. Fluorescence measurements confirmed elevation of [Ca(2+)](i) in day 4 allograft endothelium, providing a mechanism for enhanced eNOS activity. For days 7 to 28, AG potentiated myogenic tone in allograft but not isograft vessels, indicating that vasoactive iNOS-based NO was present. In mature vessels, constriction via agonist- and depolarization-mediated mechanisms showed parallel inhibition, suggesting an intrinsic defect in vascular smooth muscle cell contraction. CONCLUSIONS: Our data indicate that the profound inhibition of myogenic tone in allograft arteries involves direct vasodilation by eNOS- and iNOS-based NO, as well as an intrinsic defect in vascular smooth muscle contraction. The hemodynamic profile resulting from these changes in allograft resistance vessel function would favor movement of extracellular fluid from the intravascular space into the myocardial interstitium, resulting in edema, increased ventricular stiffness, and poor ventricular performance.

Animals↗

PubMed2000

Phenotypic correction of feline lipoprotein lipase deficiency by adenoviral gene transfer.

Previous studies have revealed that adenovirus-mediated ectopic liver expression of human LPL (huLPL) can efficiently mediate plasma triacylglycerol (TG) catabolism in mice despite its native expression in adipose and muscle tissue. We aimed to explore the feasibility of liver-directed gene transfer and enzyme replacement for human LPL deficiency in a larger, naturally occurring feline animal model of complete LPL deficiency that is remarkably similar in phenotype to the human disorder. A cohort of LPL-deficient (LPL -/-) cats was given an intravenous injection of 8 x 10(9) PFU/kg of a CMV promoter/enhancer-driven, E1/E3-deleted adenoviral (Ad) vector containing a 1.36-kb huLPL cDNA (Ad-LPL) or reporter alkaline phosphatase gene (Ad-AP). After Ad-LPL administration, active, heparin-releasable huLPL was readily detected along with a 10-fold reduction in plasma TGs, disappearance of plasma TG-rich lipoproteins up to day 14, and enhanced clearance of an excess intravenous fat load on day 9. However, antibody against the huLPL protein was detected on day 14 in cats receiving Ad-LPL and adenovirus-specific neutralizing antibody was present 7 days after gene transfer in both cat cohorts. Tissue-specific expression of the huLPL transgene relative to controls was confirmed by RT-PCR. While huLPL expression was evident in the liver, other tissues including spleen and lung expressed huLPL message, in direct correlation with histological evidence of increased Oil red O (ORO)-positive neutral lipid influx. In contrast, intravenous LPL enzyme replacement therapy (ERT) led to rapid disappearance of 9000 mU/kg of active bovine LPL enzyme from the circulation, with t1/2 occurring at <10 min in two LPL-/- cats. Heparin injection 1 hr later released <10% of the original bovine LPL, further indicating its rapid systemic clearance, inactivation, or degradation as well as its ineffectiveness as a viable therapeutic alternative for complete LPL deficiency. Although LPL gene transfer and expression via this first-generation Ad vector was limited by the immune response against both the human LPL protein and adenovirus our results clearly provide a key advance supporting further development of LPL gene therapy as a viable therapeutic option for clinical LPL deficiency.

Adenoviridae↗