Mononuclear Phagocyte System Function Research Articles

Beta-glucans in advanced CKD: role in endotoxaemia and inflammation

Background/aims(1–3)-β-D glucans (BG) are cellular components of yeasts and fungi. Elevated blood levels may be an adjunct in diagnosing invasive fungal infection, though can be high in dialysis patients without fungaemia. BG can also induce false positive signals in endotoxin detection assays (Limulus Amoebocyte Lysate [LAL] assay). We explored the relationship between BG levels, renal impairment, endotoxaemia and inflammation.MethodsWe measured serum BG levels, markers of inflammation and blood endotoxin levels in 20 controls, 20 with stages 1–3 chronic kidney disease (CKD), 20 with stages 4–5 CKD, 15 on peritoneal dialysis (PD) and 60 on haemodialysis (HD). Another 30 patients were studied before and after HD initiation.ResultsBG levels increased with advancing CKD, being highest in HD patients, 22% of whom had elevated levels (> 80 pg/ml). Levels increased significantly following HD initiation. Levels also correlated positively with CRP, TNFα, IL-6 levels, independently of CKD stage. Blood endotoxin was detectable by LAL assays in 10–53% of the CKD cohort, being most prevalent in the HD group, and correlating positively with BG levels. Adding BG blocking agent to the assay reduced endotoxin detection confining it to only 5% of HD patients. Levels of inflammatory markers were higher in those with detectable endotoxin - whether false- or true positives.ConclusionBG levels increased with decreasing renal function, being highest in dialysis patients. High BG levels were associated with false positive blood endotoxin signals, and with markers of inflammation, independently of CKD stage. The cause for high BG levels is unknown but could reflect increased gut permeability and altered mononuclear phagocytic system function.

Immunological and Toxicological Considerations for the Design of Liposomes

Liposomes hold great potential as gene and drug delivery vehicles due to their biocompatibility and modular properties, coupled with the major advantage of attenuating the risk of systemic toxicity from the encapsulated therapeutic agent. Decades of research have been dedicated to studying and optimizing liposomal formulations for a variety of medical applications, ranging from cancer therapeutics to analgesics. Some effort has also been made to elucidate the toxicities and immune responses that these drug formulations may elicit. Notably, intravenously injected liposomes can interact with plasma proteins, leading to opsonization, thereby altering the healthy cells they come into contact with during circulation and removal. Additionally, due to the pharmacokinetics of liposomes in circulation, drugs can end up sequestered in organs of the mononuclear phagocyte system, affecting liver and spleen function. Importantly, liposomal agents can also stimulate or suppress the immune system depending on their physiochemical properties, such as size, lipid composition, pegylation, and surface charge. Despite the surge in the clinical use of liposomal agents since 1995, there are still several drawbacks that limit their range of applications. This review presents a focused analysis of these limitations, with an emphasis on toxicity to healthy tissues and unfavorable immune responses, to shed light on key considerations that should be factored into the design and clinical use of liposomal formulations.

Impact of dietary Trichosporon mycotoxinivorans on ochratoxin A induced immunotoxicity; In vivo study

Ochratoxin A (OA), the secondary metabolite of certain Aspergillus and Penicillium species, is one of the potent biological immune-suppressor. The present study was designed to explore the in-vivo efficacy of Trichosporon mycotoxinivorans (TR); yeast strain isolated from the hindgut of the termite Mastotermes darwiniensis, against the immunotoxicity of OA in broiler birds. For this purpose, broiler chicks were offered diet added with TR (0.5, 1.0 or 2.0 g/kg feed) and/or OA (0.15, 0.3 or 1.0 mg/kg feed) for 42 days. Dietary OA at all levels, resulted in significant reduction (p ≤ 0.05) in the immune response of broiler birds as recorded by vacuolation and darkly stained pyknotic nuclei in bursa of Fabricius and thymus, humoral immune responses to sheep red blood cells (SRBC), in-vivo lymphoproliferative response to Phytohemagglutinin-P (PHA-P) and mononuclear phagocytic system function assay. Addition of TR in broiler diet significantly reduced (p ≤ 0.05) the immunotoxicity of OA at 0.15 and 0.30 mg/kg; however, against higher dietary level of OA (1.0 mg/kg), a partial protection was observed. Feeding TR alone had no immunomodulatory effect at any of tested level. Dietary addition of TR is proposed as an approach to combat the OA mediated immunological damages in broiler birds.

Reinforcing the Functionality of Mononuclear Phagocyte System to Control Tuberculosis.

The mononuclear phagocyte system (MPS) constitutes dendritic cells, monocytes, and macrophages. This system contributes to various functions that are essential for maintaining homeostasis, activation of innate immunity, and bridging it with the adaptive immunity. Consequently, MPS is highly important in bolstering immunity against the pathogens. However, MPS is the frontline cells in destroying Mycobacterium tuberculosis (Mtb), yet the bacterium prefers to reside in the hostile environment of macrophages. Therefore, it may be very interesting to study the struggle between Mtb and MPS to understand the outcome of the disease. In an event when MPS predominates Mtb, the host remains protected. By contrast, the situation becomes devastating when the pathogen tames and tunes the host MPS, which ultimately culminates into tuberculosis (TB). Hence, it becomes extremely crucial to reinvigorate MPS functionality to overwhelm Mtb and eliminate it. In this article, we discuss the strategies to bolster the function of MPS by exploiting the molecules associated with the innate immunity and highlight the mechanisms involved to overcome the Mtb-induced suppression of host immunity. In future, such approaches may provide an insight to develop immunotherapeutics to treat TB.

Immunostimulatory activity of glycopeptides from Paecilomyces sinensis under normal and cyclophosphamide induced immunosuppressive conditions in mice models.

The present study was designed to evaluate immune-modulating effects of the glycopeptide from Paecilomyces sinensis (CPS-II) by using mouse peritoneal macrophage and cytoxan (CTX) induced immunosuppression models. Our results from phagocytotic and mononuclear phagocytic system function assays showed that CPS-II stimulated phagocytosis of the phagocytes. A splenocyte proliferation assay showed that CPS-II acted to combine Concanavalin A (ConA) or lipopolysaccharides (LPS) in splenocyte proliferation. The results demonstrated that CPS-II increased the indices of the thymus and spleen. Hematological and histopathological analysis revealed the protective effect of CPS-II against CTX induced immunosuppression. CPS-II also significantly increased the expression of CD4(+) and CD8(+) splenic T lymphocytes, which were suppressed by CTX in peripheral blood. The expressions of serum cytokines related to immune function, including TNF-α, IL-6, and IFN-γ, were up-regulated in a dose-dependent manner. The expression of the transcription factor NF-κB in the spleen was enhanced after CPS-II-treatment. In conclusion, our results indicated that CPS-II was involved in immunostimulatory actions leading to its modulatory effects on immunosuppression, and one possible mechanism of action was to activate NF-κB.

Immunomodulatory activity of macromolecular polysaccharide isolated from Grifola frondosa

The present study was designed to evaluate the immune-modulating effects of the polysaccharide from Grifola frondosa (GFP) by using mouse peritoneal macrophage and cytoxan (CTX) induced immunosuppression models. Our results from the phagocytotic and mononuclear phagocytic system function assays showed that GFP-A (one component from GFP) stimulated the phagocytosis of the phagocytes. The splenocyte proliferation assay showed that GFP-A acted the effect combing ConA or LPS in splenocyte proliferation. The results showed that GFP-A increased indices of thymus and spleen, the levels of LDH and ACP in the spleen, the mRNA levels of IL-1β, IL-2, IL-6 and IFN-γ in splenocyte. And GFP-A also significantly increased the expression of CD4+ and CD8+ splenic T lymphocytes, which were suppressed by the CTX in peripheral blood. In conclusion, our results indicate that the GFP-A is involved in immunomodulatory effects leading to its modulatory effects on immunosuppression.

Coxiella burnetii Infection With Severe Hyperferritinemia in an Asplenic Patient.

Q fever is an uncommon but likely underreported zoonotic infection. Severe hyperferritinemia has been associated with hemophagocytic lymphohistiocytosis and other infectious diseases. In this study, we report a case of Coxiella burnetii infection in an asplenic patient complicated by severe hyperferritinemia and bone marrow infiltration. In this case, the marked ferritin elevation may have been an indicator of profound systemic macrophage activation due to preferential intracellular infection of this cell type by C burnetii, perhaps exacerbated by altered mononuclear phagocyte system function in the setting of asplenia.

Innate and adaptive immune functions of peyer's patch monocyte-derived cells.

Peyer's patches (PPs) are primary inductive sites of mucosal immunity. Defining PP mononuclear phagocyte system (MPS) is thus crucial to understand the initiation of mucosal immune response. We provide a comprehensive analysis of the phenotype, distribution, ontogeny, lifespan, function, and transcriptional profile of PP MPS. We show that monocytes give rise to macrophages and to lysozyme-expressing dendritic cells (LysoDCs), which are both involved in particulate antigen uptake, display strong innate antiviral and antibacterial gene signatures, and, upon TLR7 stimulation, secrete IL-6 and TNF, but neither IL-10 nor IFNγ. However, unlike macrophages, LysoDCs display a rapid renewal rate, strongly express genes of the MHCII presentation pathway, and prime naive helper T cells for IFNγ production. Our results show that monocytes differentiate locally into LysoDCs and macrophages, which display distinct features from their adjacent villus counterparts.

Development of a fluorescence-based in vivo phagocytosis assay to measure mononuclear phagocyte system function in the rat

The mononuclear phagocyte system (MPS) which provides protection against infection is made up of phagocytic cells that engulf and digest bacteria or other foreign substances. Suppression of the MPS may lead to decreased clearance of pathogenic microbes. Drug delivery systems and immunomodulatory therapeutics that target phagocytes have a potential to inhibit MPS function. Available methods to measure inhibition of MPS function use uptake of radioactively-labeled cells or labor-intensive semi-quantitative histologic techniques. The objective of this work was to develop a non-radioactive quantitative method to measure MPS function in vivo by administering heat-killed E. coli conjugated to a pH-sensitive fluorescent dye (Bioparticles®). Fluorescence of the Bioparticles® is increased at low pH when they are in phagocytic lysosomes. The amount of Bioparticles® phagocytosed by MPS organs in rats was determined by measuring fluorescence intensity in livers and spleens ex vivo using an IVIS® Spectrum Pre-clinical In Vivo Imaging System. Phagocytosis of the particles by peripheral blood neutrophils was measured by flow cytometry. To assess method sensitivity, compounds likely to suppress the MPS [clodronate-containing liposomes, carboxylate-modified latex particles, maleic vinyl ether (MVE) polymer] were administered to rats prior to injection of the Bioparticles®. The E. coli particles consistently co-localized with macrophage markers in the liver but not in the spleen. All of the compounds tested decreased phagocytosis in the liver, but had no consistent effects on phagocytic activity in the spleen. In addition, administration of clodronate liposomes and MVE polymer increased the percentage of peripheral blood neutrophils that phagocytosed the Bioparticles®. In conclusion, an in vivo rat model was developed that measures phagocytosis of E. coli particles in the liver and may be used to assess the impact of test compounds on MPS function. Still, the detection of inhibition of splenic macrophage function will require further assay development.

Polysaccharides from Enteromorpha prolifera enhance the immunity of normal mice

The effects of polysaccharides from Enteromorpha prolifera (PEP) on cell-mediated immunity, humoral immunity and mononuclear phagocytic system function were evaluated to assess the immunomodulatory potential of these macromolecules. Relevant immunological mechanisms were verified by biochemical assays and western blot analysis. Results showed that PEP could induce splenocyte proliferation. In vivo experiments on Kunming mice confirmed that PEP could improve cell-mediated immunity, humoral immunity and mononuclear phagocytic system function. To illustrate the mechanism, we determined several immune-related enzymes in the thymus and spleen. The results indicated that PEP could enhance the activities of alkaline phosphatase, superoxide dismutase and lactate dehydrogenase. PEP could also increase the level of NF-κB. These results suggested that PEP exhibited potent immunomodulatory properties and could be used as a novel potential immunostimulant in food and pharmaceutical industries.

Protective effects of Zhuyeqing liquor on the immune function of normal and immunosuppressed mice in vivo

BackgroundZhuyeqing Liquor (ZYQL), a well-known Chinese traditional health liquor, has various biological properties, including anti-oxidant, anti-inflammatory, immunoenhancement and cardiovascular protective effects.MethodsThe protective effects of Zhuyeqing Liquor (ZYQL) on the immune function was investigated in vivo in normal healthy mice and immunosuppressed mice treated with Cyclophosphamide (Cy, 100 mg/kg) by intraperitoneal injection on days 4, 8 and 12. ZYQL (100, 200 and 400 mg/kg) was administered via gavage daily for 14 days. The phagocytotic function of mononuclear phagocytic system was detected with carbon clearance methods, the levels of interleukin-6 (IL-6) and interferon-gamma (IFN-γ) in serum were detected with Enzyme linked immunosorbent assay (ELISA). Immune organs were weighed and organ indexes (organ weight/body weight) of thymus and spleen were calculated. Meanwhile, the activity of lysozyme (LSZ) in serum and the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) in spleen tissue were measured.ResultsZYQL significantly upgrades the K value for clearance of carbon particles in normal mice treated with ZYQL (400 mg/kg) and immunosuppressed mice treated with ZYQL (100, 200 and 400 mg/kg) together with Cy (100 mg/kg) in vivo. The treatment of ZYQL (100, 200 and 400 mg/kg) effectively increased the activity of serum lysozyme as well as promoted the serum levels of IL-6 and IFN-γ in normal mice and immunosuppressed mice. Furthermore, ZYQL (100, 200 and 400 mg/kg) had an antioxidant effects in immune system by enhancing the antioxidant enzyme activity of SOD, CAT and GSH-Px in vivo. In addition, ZYQL (100, 200 and 400 mg/kg) effectively elevated the Cy-induced decreased organ index (thymus and spleen).ConclusionsThe present work shows that the dose-dependent administration of ZYQL is capable of influencing immune responses, which implying that its valuable functional health may be attributed partly to its protective effects for the immune function.

Translational Studies of Phenotypic Probes for the Mononuclear Phagocyte System and Liposomal Pharmacology

As nanoparticles (NPs) are cleared via phagocytes of the mononuclear phagocyte system (MPS), we hypothesized that the function of circulating monocytes and dendritic cells (MO/DC) in blood can predict NP clearance (CL). We measured MO/DC phagocytosis and reactive oxygen species (ROS) production in mice, rats, dogs, and patients with refractory solid tumors. Pharmacokinetic studies of polyethylene glycol (PEG)-encapsulated liposomal doxorubicin (PEGylated liposomal doxirubicin [PLD]), CKD-602 (S-CKD602), and cisplatin (SPI-077) were performed at the maximum tolerated dose. MO/DC function was also evaluated in patients with recurrent epithelial ovarian cancer (EOC) administered PLD. Across species, a positive association was observed between cell function and CL of PEGylated liposomes. In patients with EOC, associations were observed between PLD CL and phagocytosis (R(2) = 0.43, P = 0.04) and ROS production (R(2) = 0.61, P = 0.008) in blood MO/DC. These findings suggest that probes of MPS function may help predict PEGylated liposome CL across species and PLD CL in patients with EOC.

Amelioration of Ochratoxin A-induced immunotoxic effects by silymarin and vitamin E in White Leghorn cockerels

Silymarin (SL) is the bioactive extract of the plant Silybum marianum and Vitamin E (VE) is an important anti-oxidant. The present study was designed to evaluate potential ameliorative effects of SL and VE against Ochratoxin A (OTA)-induced immunotoxic effects in White Leghorn cockerels. One day-old birds were divided into 12 groups (20 birds/group) and fed basal diets amended with OTA (1.0 or 2.0 mg/kg) alone or in combination with SL (10 g/kg) and/or VE (200 mg/kg) for 42 days. Immunological in situ responses, including antibody formation against sheep red blood cells (7 and 14 days after both primary and booster injections), lymphoproliferative responses to avian tuberculin (30 days of age), and mononuclear phagocytic system function (i.e. by clearance of injected carbon particles) assay (42 days of age), were assessed. Results suggested that silymarin and Vitamin E alone or in combination ameliorated the immunotoxic effects induced by 1.0 mg OTA/kg but could not significantly impact on the effect from ingestion of 2.0 mg OTA/kg. The results of the present study suggested that both SL and VE possess an ability to ameliorate OTA-induced immunotoxicity in chicks. However, it remains to be determined whether/what SL:OTA or VE:OTA ratios are required to assure such mitigation of OTA-induced immunotoxicities.

Cellular function of the mononuclear phagocyte system (MPS) as a phenotypic probe for pharmacokinetics (PK) and pharmacodynamics (PD) of PEGylated liposomal doxorubicin (PLD) in patients with recurrent ovarian cancer.

2591 Background: A phenotypic probe is a test that can be administered to a patient as a potential indicator of a drug’s PK/PD which can then be used to individualize therapy. Since nanoparticles are cleared via the MPS, including blood monocytes (MO), we hypothesize that circulating MO could potentially play a major role in, and be a surrogate marker of nanoparticle clearance (CL). Furthermore, we postulate that the ability to measure MO functional activity in blood samples can be used to predict CL and subsequently PD endpoints such as progression free survival (PFS) and hand-foot syndrome (HFS), in patients (pt). Methods: PLD 30/40 mg/m2 IV x 1 with or without carboplatin (AUC = 5 mg/mL/min) was administered to pts (n=10) with recurrent ovarian cancer. Serial PK samples were obtained at time 0 to day 28 post dose. Plasma was processed to measure encapsulated and released doxorubicin using solid phase separation and HPLC. Data was analyzed with WinNonlin to obtain PK parameters. MO and granulocyte phagocytic function (uptake of FITC-labeled opsonized E. Coli) and oxidative burst activity (intracellular oxidation of dihydrorhodamine 123) were assessed via flow cytometry at 0, 48, 96 h, and on day 28. For both assays, changes in mean fluorescence intensity of the gated MO population, following incubation of whole blood with the appropriate substrate, served as an index of activity. Pts were followed from the first dose of PLD until time of disease progression. Results: There was a direct linear relationship between encapsulated doxorubicin CL and both phagocytosis (R2 = 0.87) and oxidative burst activity (R2 = 0.64) in blood MO. Similarly, phagocytosis (R2 = 0.77) and oxidative burst probes correlated with PFS (R2 = 0.67) in the 4 pts who progressed while on PLD. Oxidative burst also correlated with degree of HFS (R2 = 0.56). There was no relationship between phagocytosis and oxidative burst in granulocytes and PK/PD of PLD. Conclusions: These findings indicate that probes of MPS function predict PLD CL, HFS and PFS and thus may be useful for individualizing PLD therapy in ovarian cancer and other malignancies.

Technetium-99m sulfur colloid (TSC) as a phenotypic probe for predicting pharmacokinetics (PK) and palmar-plantar erythrodysesthesia (PPE) toxicity of pegylated liposomal doxorubicin (PLD) in patients (pts) with recurrent epithelial ovarian cancer (EOC).

5050 Background: There is significant variability in the PK and PD (efficacy and toxicity) of PLD. Clearance (CL) of PLD has been proposed to occur primarily via uptake by cells of the mononuclear phagocyte system (MPS) mainly located in the liver, spleen, and blood. TSC is a radioactive colloid used clinically for diagnostic and functional imaging of the MPS. Our aim is to evaluate TSC as a phenotypic probe of MPS activity, which may predict PLD PK and PPE toxicity in pts (n=9) with EOC. Methods: Prior to administration of PLD on cycle 1 day 1 (C1D1), TSC was administered at 10 mCi IVP × 1. Dynamic planar and SPECT/CT images of the liver, spleen and hands were acquired using a gamma camera. Blood samples were collected up to 60 min after TSC and analyzed for radioactivity using a gamma counter. On C1D1, PLD was administered at 40 mg/m2 alone or at 30 mg/m2 in combination with carboplatin IV over 1 to 3 h. Serial PK samples were obtained from 0h to 672h post PLD dose. Plasma was processed to measure encapsulated and released doxorubicin (dox) using solid phase separation and HPLC. CL of PLD and TSC were calculated by non-compartmental analysis. The grade of PPE toxicity was determined by NCI CTCAE (v4.03) criteria. Results: Nine patients have undergone TSC imaging and eight patients completed TSC blood PK and PLD plasma PK studies. There was a positive linear relationship between TSC CL and encapsulated dox CL (R2 = 0.61, p=0.02). When patients were subdivided, there was a stronger relationship between TSC CL and encapsulated dox CL (R2 = 0.81, p=0.03) in pts receiving PLD monotherapy. A positive relationship using Spearman’s correlation (ρ=0.84, p=0.006) was also found between maximum grade PPE toxicity developed and estimated AUC of encapsulated dox in hands [(TSC AUCBlood)/(TSC AUCHand)*Encapsulated Dox AUCPlasma]. Conclusions: These results suggest that TSC is a probe for MPS function and PLD PK and PD and may be used to individualize PLD therapy in pts with EOC. In addition, our findings suggest TSC may be able to predict the development of PPE in patients.

Challenges for Engineers in Biomedical and Clinical Sciences

Challenges for Engineers in Biomedical and Clinical Sciences

Allometric scaling of pegylated liposomal anticancer drugs

Pegylated liposomal formulations contain lipid conjugated to polyethylene glycol. The disposition of encapsulated drug is dictated by the composition of the liposome, thus altering the pharmacokinetic (PK) profile of the drug. Allometric scaling is based on a power-log relationship between body weight (W) and drug clearance (CL) among mammals and has been used to compare the disposition of nonliposomal drugs across species. The objectives of this study were to use allometric scaling to: (1) compare the disposition of pegylated liposomal drugs across speciesand determine the best scaling model and (2) predict PK parameters of pegylated liposomal drugs in humans. The PK of pegylated liposomal CKD-602 (S-CKD602), doxorubicin (Doxil®), and cisplatin (SPI-077) were compared. PK studies ofS-CKD602, Doxil®, and SPI-077 were performed at the maximum tolerated dose (MTD) in male and female mice, rats, dogs and patients with refractory solid tumors. The allometric equation used to evaluate the relationship between W and CL in each species was CL = a(W)(m) (a = empirical coefficient; m = allometric exponent). Substitution of physiological variables other than body weight, such as factors representative of the mononuclear phagocyte system (MPS) were evaluated. Dedrick Plots and Maximum Life-Span Potential (MLP) were used to determine scaling feasibility. Standard allometry demonstrated a relationship between clearance of S-CKD602, Doxil®, and SPI-077 and body, spleen, liver, and kidney weights, total monocyte count, and spleen and liver blood flow. However, using scaling to predict CL of these agents in humans often resulted in differences >30%. Despite a strong correlation between body weight and MPS-associated variables with CL among preclinical species, the use of the equations did not predict CL. Thus, new methods of allometric scaling and measures of MPS function need to be developed.

Technetium-99m sulfur colloid (TSC) as a phenotypic probe for the pharmacokinetics (PK) and pharmacodynamics (PD) of pegylated liposomal doxorubicin (PLD) in patients (pts) with recurrent epithelial ovarian cancer (EOC).

2582 Background: There is significant inter- and intra-patient variability in the PK and PD (efficacy and toxicity) of PLD in pts with EOC and other malignancies. This has been attributed to age and gender, but more specifically, may be related to the mononuclear phagocyte system (MPS). Clearance (CL) of PLD has been proposed to occur primarily via uptake by monocytes, dendritic cells, and macrophages mainly located in the liver, spleen, and blood. TSC is a radioactive colloid used clinically for diagnostic and functional imaging of the MPS. Our aim is to evaluate TSC as a phenotypic probe of MPS activity, which may predict PLD PK and PD in pts with EOC. Methods: Prior to (day -7 to -1) administration of PLD on cycle 1 day 1 (C1D1), TSC was administered at 10 mCi IV × 1. Dynamic planar and SPECT/CT images of the liver and spleen were acquired using a gamma camera. Blood samples were collected up to 60 min after TSC and analyzed for radioactivity using a gamma counter. On C1D1, PLD was administered at 40 mg/m2 alone or at 30 mg/m2 in combination with carboplatin IV over 1 to 1.5 h. Serial blood samples were collected up to 28 days after PLD. Plasma samples were processed to measure encapsulated (encap) and released doxorubicin via HPLC with fluorescence. Results: Six pts have undergone TSC imaging and blood PK, and PLD plasma PK studies. Mean ± SD encap doxorubicin CL and TSC CL were 25.4 ± 4.1 mL/h and 18.9 ± 5.4 mL/h, respectively. There was a positive linear relationship between TSC CL and encap doxorubicin CL (R2 = 0.58). Mean ± SD of encap doxorubicin area under the concentration versus time curve (AUC) and TSC splenic outflow were 2.4 ± 0.5 mg/mL·h and 0.5 ± 0.1 s-1, respectively. There was a positive linear relationship between TSC splenic outflow and encap doxorubicin AUC (R2 = 0.85). There was no relationship between TSC AUC in the liver and spleen and PLD PK. Conclusions: These results suggest that TSC is a probe for MPS function and PLD PK and may be used to individualize PLD therapy in pts with EOC and other malignancies. Evaluation of the relationship between TSC and PLD PD is undergoing further investigation.

Abstract 373: Allometric scaling of the pharmacokinetics of pegylated liposomal anticancer drugs

Abstract Background: Pegylated liposomal formulations contain lipid conjugated to polyethylene glycol. These formulations of anticancer agents have been designed to prolong the drug circulation time, increase tumor delivery, and improve the therapeutic index. The disposition of encapsulated drug is dictated by the liposomal carriers, thus altering the pharmacokinetic (PK) profile of the drug. Allometric scaling is based on a power-log relationship between body weight (W) and drug clearance (CL) among mammals and has been used to compare the PK of small molecule drugs across species. However, it has not been used to compare PK of liposomes or nanoparticle agents. The objectives of this study were to use allometric scaling to: 1) compare the disposition of pegylated liposomal drugs across species and determine the best scaling model, and 2) predict PK parameters of pegylated liposomal drugs in patients. Methods: PK studies of pegylated liposomal CKD-602 (S-CKD602), pegylated liposomal doxorubicin (PLD), and pegylated liposomal cisplatin (SPI-077) were performed at the maximum tolerated dose (MTD) in male and female rats and dogs and in patients with advanced solid tumors as part of phase I studies. Plasma samples were analyzed for sum total (encapsulated + released) drug. The standard allometric equation, CL = a(W)m (a = empirical coefficient; m = allometric exponent) was used to evaluate the relationship between W and CL in each species. The relationship between measures of the mononuclear phagocyte system (MPS) and CL were also evaluated, by substituting the MPS-associated factors for W (liver weight, spleen weight, spleen blood flow, liver blood flow, and monocyte count). Dedrick Plots were used to determine scaling feasibility. Results: Standard allometric scaling using W showed that CL scaled across all agents: [S-CKD602 (R2 = 0.92), PLD (R2 = 0.90), and SPI-077 (R2 = 0.98).] However, the percent (%) difference from scaled predicted and observed PK parameters in humans were still > 30%. All MPS associated factors showed correlation with the CL of all three agents (R2 > 0.90). Based on R2 values, total monocyte count displayed the strongest correlation (R2 = 0.99) with drug clearance across the three species for all three agents. Conclusions: The model that scaled CL the best across all species was the standard allometric method when using potential measures of the MPS, including liver weight, spleen weight, and total monocyte count compared to W. The selection of PK parameters, physiological variables, and pegylated liposomal agent used in this study all contribute to the determination of the optimal scaling method. However, a consistent and predictive allometric model with new methods of allometric scaling and measures of MPS function need to be developed for pegylated liposomal agents. This potential new method could then be used to facilitate the development of future liposomal and nanoparticle agents. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 373. doi:10.1158/1538-7445.AM2011-373

Immunomodulatory activity in vitro and in vivo of polysaccharide from Potentilla anserina

The polysaccharide (PAP) from Potentilla anserina was evaluated for modulating effects by using mouse peritoneal macrophage and the immunosuppressed-model cyclophosphamide-induced. Phagocytotic and mononuclear phagocytic system function assays showed that PAP stimulated the phagocytosis of phagocyte. Splenocyte proliferation assay showed that PAP acted the effect combining Con A or LPS in splenocyte proliferation. The parameters detected showed that PAP increased thymus and spleen indices, the levels of LDH and ACP in the spleen, and IL-10and IFN-γ in serum in immunosuppressed mice. The results suggest that PAP is involved in immunomodulatory effects leading to the exploration for PAP as a potential immunostimulant.