In Vitro and Ex Vivo Models – The Tumor Microenvironment in a Flask

The MEMIC: An ex vivo system to model the complexity of the tumor microenvironment

Disease Models & Mechanisms ◽

10.1242/dmm.048942 ◽

2021 ◽

Author(s):

Libuše Janská ◽

Libi Anandi ◽

Nell C. Kirchberger ◽

Zoran S. Marinkovic ◽

Logan T. Schachtner ◽

...

Keyword(s):

Tumor Microenvironment ◽

Tumor Cells ◽

Ex Vivo ◽

Tumor Stroma ◽

Stem Cell Differentiation ◽

Blood Stream ◽

Direct Access ◽

Ex Vivo Model

There is an urgent need for accurate, scalable, and cost-efficient experimental systems to model the complexity of the tumor microenvironment. Here, we detail how to fabricate and use the Metabolic Microenvironment Chamber (MEMIC) – a 3D-printed ex vivo model of intratumoral heterogeneity. A major driver of the cellular and molecular diversity in tumors is the accessibility to the blood stream that provides key resources such as oxygen and nutrients. While some tumor cells have direct access to these resources, many others must survive under progressively more ischemic environments as they reside further from the vasculature. The MEMIC is designed to simulate the differential access to nutrients and allows co-culturing different cell types, such as tumor and immune cells. This system is optimized for live imaging and other microscopy-based approaches, and it is a powerful tool to study tumor features such as the effect of nutrient scarcity on tumor-stroma interactions. Due to its adaptable design and full experimental control, the MEMIC provide insights into the tumor microenvironment that would be difficult to obtain via other methods. As a proof of principle, we show that cells sense gradual changes in metabolite concentration resulting in multicellular spatial patterns of signal activation and cell proliferation. To illustrate the ease of studying cell-cell interactions in the MEMIC, we show that ischemic macrophages reduce epithelial features in neighboring tumor cells. We propose the MEMIC as a complement to standard in vitro and in vivo experiments, diversifying the tools available to accurately model, perturb, and monitor the tumor microenvironment, as well as to understand how extracellular metabolites affect other processes such as wound healing and stem cell differentiation.

862 Targeting PSGL-1, a novel macrophage checkpoint, repolarizes suppressive macrophages, induces an inflammatory tumor microenvironment, and suppresses tumor growth

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0862 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A915-A915

Author(s):

Phuong Nguyen ◽

Ryan Phennicie ◽

Kevin Kauffman ◽

Dominika Nowakowska ◽

Mohammad Zafari ◽

...

Keyword(s):

T Cell ◽

Tumor Microenvironment ◽

Tumor Growth ◽

Ex Vivo ◽

Tnf Alpha ◽

M2 Macrophages ◽

Humanized Mouse ◽

Cellular Assays ◽

Pdx Model

BackgroundMacrophages play an important role in cancer by modulating both the innate and adaptive parts of the immune system. In non-pathological conditions, multiple subsets of macrophages balance the immune response. In cancer, M2-like immune-suppressive tumor-associated macrophages (TAMs) dominate the tumor microenvironment (TME). TAMs promote tumor growth, support neo-angiogenesis and enable metastasis formation. Macrophage modulators driving macrophage repolarization from the M2-like to a pro-inflammatory M1-like phenotype are an attractive novel class of cancer immunotherapy. Here we present identification, validation, and pre-clinical data of a novel macrophage checkpoint, PSGL-1, which supports targeting this molecule for immune-oncology.MethodsTo assess the therapeutic potential of using anti-PSGL-1 antibodies to convert macrophage phenotype and the tumor microenvironment toward a more inflammatory state, we employed in vitro primary macrophage and multi-cellular assays, ex vivo patient-derived tumor cultures, and a humanized mouse PDX model.ResultsWithin the multiple subsets of macrophages, PSGL-1 is expressed at high levels on immune-suppressive TAMs and in vitro differentiated M2 macrophages. We show that targeting PSGL-1 via an antagonistic antibody repolarized M2 macrophages to a more M1-like state, both phenotypically and functionally as assessed in primary in vitro macrophage assays. Further, these repolarized M1-like macrophages enhanced the inflammatory response in complex multi-cellular assays, including SEB stimulated PBMC assays and mixed-lymphocyte reactions (MLRs).To establish a pre-clinical proof-of-concept for targeting PSGL-1, we turned to ex vivo cultures of fresh patient-derived primary tumors, where the complexity of the TME can be most preserved. RNA-seq data show that ex vivo cultures treated with anti-PD-1 antibody recapitulate TME changes in anti-PD-1 treated patients, including a strong T-cell IFN-gamma signature and a reduction in oncogenic pathway activation. Blocking PSGL-1 resulted in a robust pro-inflammatory signature driven by TNF-alpha/NF-kappa-B and chemokine-mediated signaling. The increase in TNF-alpha signaling was accompanied by reduction in oxidative phosphorylation and fatty acid metabolism. The increase in pro-inflammatory cytokine and chemokine production was confirmed by measuring secreted protein levels, further confirming the re-polarization of macrophages within a tumor setting.Lastly, we employed a humanized mouse PDX model of melanoma and show that anti-PSGL-1 treatment resulted in suppression of tumor growth favorably compared to anti-PD-1. At the cellular and molecular levels, anti-PSGL-1 treatment lead to a more enhanced inflammatory microenvironment, including a reduced M2:M1 macrophage ratio, increased antigen presentation, pro-inflammatory mediators, and effector T cell infiltration and activation.ConclusionsOur data support anti-PSGL-1 as a macrophage repolarizing agent and an effective macrophage-targeted therapy for Immuno-Oncology.

Identification of peptide coatings that enhance diffusive transport of nanoparticles through the tumor microenvironment

10.1101/659524 ◽

2019 ◽

Author(s):

Rashmi P. Mohanty ◽

Xinquan Liu ◽

Jae Y. Kim ◽

Xiujuan Peng ◽

Sahil Bhandari ◽

...

Keyword(s):

Tumor Microenvironment ◽

Physicochemical Properties ◽

Pancreatic Tumor ◽

Chemical Space ◽

Ex Vivo ◽

Negative Control ◽

Peptide Ligand ◽

Diffusive Transport ◽

Surface Chemistries

In solid tumors, increasing drug penetration promotes their regression and improves the therapeutic index of compounds. However, the heterogeneous extracellular matrix (ECM) acts a steric and interaction barrier that hinders effective transport of therapeutics, including nanomedicines. Specifically, the interactions between the ECM and surface physicochemical properties of nanomedicines (e.g. charge, hydrophobicity) impedes their diffusion and penetration. To address the challenges using existing surface chemistries, we used peptide-presenting phage libraries as a high-throughput approach to screen and identify peptides as coatings with desired physicochemical properties that improve diffusive transport through the tumor microenvironment. Through iterative screening against the ECM and identification by next-generation DNA sequencing and analysis, we selected individual clones and measured their transport by diffusion assays. Here, we identified a net-neutral charge, hydrophilic peptide P4 that facilitates significantly higher diffusive transport of phage than negative control through in vitro tumor ECM. Through alanine mutagenesis, we confirmed that the hydrophilicity, charge, and their spatial ordering impact diffusive transport. P4 phage clone exhibited almost 200-fold improved uptake in ex vivo pancreatic tumor xenografts compared to the negative control. Nanoparticles coated with P4 exhibited ∼40-fold improvement in diffusivity in pancreatic tumor tissues, and P4-coated particles demonstrated less hindered diffusivity through the ECM compared to particles functionalized with gold standard poly(ethylene) glycol or iRGD peptide ligand. By leveraging the power of molecular diversity using phage display, we can greatly expand the chemical space of surface chemistries that can improve the transport of nanomedicines through the complex tumor microenvironment to ultimately improve their efficacy.Abstract Figure

TAMI-47. EVALUATION OF THE EFFECT OF MICROENVIRONMENTAL STRESSES ON GLIOMA STEMNESS IN VITRO AND EX VIVO

Neuro-Oncology ◽

10.1093/neuonc/noaa215.934 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii223-ii223

Author(s):

Vasiliki Pantazopoulou ◽

Tracy Berg ◽

Alexander Pietras

Keyword(s):

Tumor Microenvironment ◽

Stromal Cells ◽

Ex Vivo ◽

Morphological Changes ◽

Side Population ◽

Therapy Resistance ◽

Cell Phenotype ◽

Vimentin Expression ◽

Perivascular Niche

Abstract Glioblastoma is the highest-grade glioma and most aggressive brain tumor, affecting both adults and children. Treatment includes surgery followed by chemotherapy, most frequently in the form of temozolomide treatment, radiation and in some cases by application of tumor-treating fields. Tumor recurrence is very common and is driven by cells exhibiting a treatment-resistant cancer stem cell phenotype, located in specific niches, namely the hypoxic and perivascular niche. While previous studies have delved into the role of the microenvironment in supporting glioma stemness and therapy resistance, little is known about how the stromal cells themselves respond to microenvironmental stresses. Here, we show that one cell type of the tumor microenvironment, the astrocyte, becomes activated after treatment with radiation, temozolomide or hypoxia in vitro, showing an increase in GFAP and Vimentin expression as well as morphological changes. Activated astrocytes also change their secretome, secreting cytokines such as IL6, IL7, CCL2 and CCL8, all associated with worse prognosis in several patient cohorts. Importantly, conditioned medium or extracellular matrix from activated astrocytes induce stemness features in glioma cells, measured by increased side population or radiation resistant fractions. To evaluate our findings in a more relevant model, we use an ex vivo organotypic culture system for brain sections from our experimental mouse model of glioma. Cultures are maintained for up to 21 days in 21%, 5% or 1% O2 with a high proportion of surviving tumor and stromal cells. We intend to use the ex vivo system to evaluate the effect of microenvironmental stresses on glioma stemness. Our study suggests that the tumor microenvironment that has been exposed to stressors such as radiation, chemotherapy or hypoxia is important in maintaining stemness and therefore treatment resistance in glioblastoma. Further research is required to address these stress-induced changes and provide better treatment options for glioblastoma patients.

Antimyeloma Effect of the Simultaneous Inhibition of MCL-1 (with S63845) and BCL-2 (with Venetoclax) in the Presence of the Microenvironment

Blood ◽

10.1182/blood-2018-99-116075 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 954-954

Author(s):

Esperanza M Algarín ◽

Andrea Díaz-Tejedor ◽

Pedro Mogollón ◽

Susana Hernández-García ◽

Luis Corchete ◽

...

Keyword(s):

Bone Marrow ◽

Tumor Microenvironment ◽

Board Of Directors ◽

Research Funding ◽

Ex Vivo ◽

Advisory Committees ◽

Stromal Microenvironment ◽

Castilla Y Leon

Abstract Background: Venetoclax is a BCL-2 inhibitor particularly effective in patients with multiple myeloma (MM) harboring the t(11;14). However, resistance to venetoclax has been linked to MCL-1 overexpression. On the other hand, it is wellknown that MM cells depend on MCL-1 rather than BCL-2 for survival, and this dependence has recently been reported to be enhanced by the tumor-associated microenvironment. Therefore, the combination of venetoclax with the potent MCL-1 inhibitor S63845 arises as a promising and novel approach for the treatment of MM. Aims: To evaluate the efficacy and mechanism of action of S63845 alone and in combination with venetoclax in absence and presence of the bone marrow tumor microenvironment in preclinical in vitro, ex vivo and in vivo models of MM. Methods: S63845 was provided by an agreement with Servier and Novartis. In vitro activity of S63845 and venetoclax alone and in combination was evaluated by bioluminescence on a MM cell line expressing luciferase (MM.1S-luc) in absence and presence of mesenchymal stromal cells isolated from bone marrow aspirates of MM patients (pMSCs). MM.1S cells cultured in absence or presence of pMSCs were analyzed for MCL-1 and BCL-2 protein levels by Western blot. Interactions between these anti-apoptotic proteins with the pro-apoptotic protein BIM were assessed by immunoprecipitation assays. The efficacy of S63845 and venetoclax alone and in combination was also evaluated ex vivo in MM cells and normal lymphocytes from MM patients. Finally, a disseminated MM model in BRG mice was used for in vivo studies. Results: S63845 and venetoclax showed a strong antimyeloma dose-dependent effect on MM.1S-luc cells co-cultured with pMSCs. However, whereas the presence of tumor-associated MSCs increased the IC50 value of venetoclax in MM.1S-luc cells from 6.2 to 9.8 mM, it reduced that of S63845 from 94.1 to 81 nM, suggesting a mild sensitization to this drug in the context of the microenvironment. Neither S63845 nor venetoclax affected pMSC viability even at high concentrations by MTT assay. The co-culture with the BM stromal microenvironment increased MCL-1 expression on untreated MM.1S cells in two out of four experiments performed with MSCs from different MM patients, whereas it surprisingly induced a decrease on BCL-2 levels in all of them. Treatment with S63845 completely blocked MCL-1 binding to BIM, both in the absence or presence of pMSCs but did not induce the compensatory increase of BCL-2/BIM complexes observed in MM.1S cells in monoculture. Venetoclax also completely blocked the binding of BCL-2 to BIM in MM.1S alone or in co-culture, and induced a similar compensatory increase of MCL-1/BIM complexes in both situations. Importantly, the double combination S63845 + venetoclax was significantly superior to both drugs in monotherapy in killing MM.1S-luc cells co-cultured in the presence of the stromal microenvironment. BIM immunoprecipitation assays showed that the double combination was able to counteract the compensatory upregulation of MCL-1 bound to BIM observed on MM.1S cells treated with venetoclax and to entirely disrupt BCL-2/BIM complexes, both in the absence and presence of pMSCs. Furthermore, S63845 + venetoclax increased the percentage of apoptotic MM plasma cells from three MM patients with respect to single treatments with moderate toxicity detected on normal lymphocytes, suggesting the existence of a therapeutic window for the double combination. Finally, the combination of S63845 + venetoclax clearly delayed tumor growth as compared with the agents in monotherapy in a disseminated model of MM with statistically significant differences from day 19 of treatment. This in vivo effect translated into a significatively improved survival for mice treated with the double combination (median 60 days) vs control mice (median 32 days; log-rank test P=0.045). Conclusion: Our preclinical data demonstrate the potent activity of the combination of venetoclax with S63845 in MM even in presence of the stromal associated-tumor microenvironment, and provides the rationale for the clinical development of this combination in relapsed or refractory MM patients. This project was supported by Novartis Pharmaceuticals and by the Spanish , ISCIII-FIS PI15/00067 and PI15/02156, GRS 1604/A/17 and CRMRTC de Castilla y León. Predoctoral grant to EMA by Consejería de Educación de Castilla y León. Disclosures Schoumacher: Servier: Employment. Banquet:Servier: Employment. Kraus-Berthier:servier: Employment. Kloos:Servier: Employment; Novartis: Other: Partnership. Halilovic:Novartis: Employment, Equity Ownership. Maacke:Novartis: Employment. Mateos:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Ocio:AbbVie: Consultancy; Novartis: Consultancy, Honoraria; BMS: Consultancy; Seattle Genetics: Consultancy; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Pharmamar: Consultancy; Sanofi: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Mundipharma: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Array Pharmaceuticals: Research Funding.

877 PSGL-1 blocking antibodies repolarize tumor associated macrophages, reduce suppressive myeloid populations and induce inflammation in the tumor microenvironment, leading to suppression of tumor growth

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.877 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A919-A919

Author(s):

Phuong Nguyen ◽

Jessica Ritter ◽

Mohammad Zafari ◽

Denise Manfra ◽

Veronica Komoroski ◽

...

Keyword(s):

T Cells ◽

Tumor Microenvironment ◽

Medical School ◽

Ex Vivo ◽

Humanized Mouse ◽

Massachusetts Medical School ◽

Pdx Model ◽

University Of Massachusetts ◽

The University

BackgroundSuppressive myeloid cell populations in the tumor microenvironment (TME) are associated with worse survival of cancer patients and low effectiveness of T cell checkpoint inhibitors. Recently, several early clinical trials have produced positive data for therapies aimed at repolarizing immuno-suppressive myeloid populations in the TME. One new macrophage repolarizing target, PSGL-1 (P-selectin glycoprotein ligand-1), is expressed at high levels on suppressive tumor-associated macrophages (TAMs) and in vitro differentiated M2 macrophages. PSGL-1 has been shown to have an immune-modulatory activity, which includes its role in maintaining an immuno-suppressive macrophage state.MethodsTo assess the ability of PSGL-1 antibodies to convert macrophages and the tumor microenvironment from an immuno-suppressive toward a pro-inflammatory state, we employed in vitro primary macrophage and multi-cellular assays, ex vivo patient-derived tumor cultures, and a humanized mouse PDX model.ResultsWe have determined that our lead anti-PSGL-1 antibody repolarized M2-like macrophages to a more M1-like state both phenotypically and functionally as assessed in primary in vitro macrophage assays. Transcriptomics profiling of M2c macrophages showed that the anti-PSGL-1 antibody upregulated TNF-alpha/NF-kB and chemokine-mediated signaling, while downregulating oxidative phosphorylation, fatty acid metabolism and Myc signaling pathways, consistent with a broad M2-to-M1 shift of the macrophage state. Furthermore, these repolarized M1-like macrophages enhanced the inflammatory response in complex multi-cellular assays.Pre-clinical efficacy of the anti-PSGL-1 antibody was demonstrated using ex vivo cultures of fresh patient-derived tumors that preserve the cellular heterogeneity of the TME. Anti-PSGL-1 increased production of inflammatory cytokines and chemokines involved in immune activation of the TME and T cell recruitment.Lastly, our lead anti-PSGL-1 antibody also showed in vivo anti-tumor effect in a humanized mouse PDX model of melanoma. The antibody suppressed tumor growth to a significantly greater degree compared to anti-PD-1. At the cellular and molecular levels, the anti-PSGL-1 treatment led to a more enhanced inflammatory microenvironment, including a reduced M2:M1 macrophage ratio, and an increase in systemic pro-inflammatory mediators. Compared to anti-PD-1 monotherapy, anti-PSGL-1 alone and in combination with anti-PD-1 increased the fraction of effector CD8+ T cells among the infiltrating T cells. Significant combination effects of anti-PSGL-1 plus anti-PD-1 were seen at the cellular and molecular levels within the tumor tissue, the spleen, and peripheral blood.ConclusionsThe data presented here provide biological and mechanistic support for clinical testing of antibodies targeting PSGL-1 for the treatment of cancer.Ethics ApprovalAll legal and ethical requirements were met with regards to the humane treatment of animals described in the study. The animal study was conducted in compliance with IACUC PROTO202000042 and the institutional assurance certification of the University of Massachusetts Medical School. The University of Massachusetts Medical School is fully accredited by AAALAC and has an Animal Welfare Assurance on file with the Office of Laboratory Animal Welfare (OLAW).

Phytogalactolipid dLGG Inhibits Mouse Melanoma Brain Metastasis through Regulating Oxylipin Activity and Re-Programming Macrophage Polarity in the Tumor Microenvironment

Cancers ◽

10.3390/cancers13164120 ◽

2021 ◽

Vol 13 (16) ◽

pp. 4120

Author(s):

Chung-Chih Yang ◽

Meng-Ting Chang ◽

Cheng-Kuei Chang ◽

Lie-Fen Shyur

Keyword(s):

Tumor Microenvironment ◽

Brain Metastasis ◽

Ex Vivo ◽

Cytotoxic T Cells ◽

3D Culture ◽

Tumor Control ◽

Cancer Therapies ◽

Melanoma Brain Metastasis ◽

Organ Tissue

Current conventional cancer therapies for melanoma brain metastasis (MBM) remain ineffective. In this study, we demonstrated the bioefficacy of a phyto-glyceroglycolipid, 1,2-di-O-α-linolenoyl-3-O-β-galactopyranosyl-sn-glycerol (dLGG) alone, or in combination with liposomal doxorubicin (Lip-DOX) or Avastin against MBM in a syngeneic B16BM4COX−2/Luc brain-seeking melanoma mouse model. Treatment with dLGG–10, dLGG–25, dLGG–10 + Avastin–5, Lipo-DOX–2, dLGG–10 + Lipo-DOX–2 or Lipo-DOX–2 + Avastin–5 suppressed, respectively, 17.9%, 59.1%, 55.7%, 16.2%, 44.5% and 72.4% of MBM in mice relative to the untreated tumor control. Metastatic PD-L1+ melanoma cells, infiltration of M2-like macrophages and CD31+ endothelial cells, and high expression levels of 15-LOX/CYP450 4A enzymes in the brain tumor microenvironment of the tumor control mice were significantly attenuated in dLGG-treated mice; conversely, M1-like resident microglia and cytotoxic T cells were increased. A lipidomics study showed that dLGG promoted B16BM4 cells to secrete oxylipins 9,10-/12,13-EpOMEs into the culture medium. Furthermore, the conditioned medium of B16BM4 cells pretreated with dLGG or 9,10-EpOMEs + 12,13-EpOMEs drove M2-like macrophages to polarize into M1-like macrophages in vitro. An ex vivo 3D-culture assay further demonstrated that dLGG, 9,10-EpOME or 9,10-EpOME + 12,13-EpOME pretreatment attenuated B16BM4 cells invading brain tissue, and prevented microglia/macrophages infiltrating into the interface of melanoma plug and brain organ/tissue. In summary, this report provides a novel therapeutic strategy and mechanistic insights into phytogalactolipid dLGG for combating MBM.

Simulating the human tumor microenvironment in colorectal cancer organoids in vitro and in vivo

10.1101/822684 ◽

2019 ◽

Author(s):

Mahesh Devarasetty ◽

Anthony Dominijanni ◽

Samuel Herberg ◽

Ethan Shelkey ◽

Aleksander Skardal ◽

...

Keyword(s):

Colorectal Cancer ◽

Tumor Microenvironment ◽

Cancer Progression ◽

Ex Vivo ◽

Human Tumor ◽

Cancer Therapeutics ◽

Low Grade ◽

Ecm Architecture

AbstractThe tumor microenvironment (TME) plays a significant role in cancer growth and metastasis. Bioengineered models of the TME will advance our understanding of cancer progression and facilitate identification of novel anti-cancer therapeutics that target TME components such as extracellular matrix (ECM) and stromal cells. However, most current in vitro models fail to recapitulate the extensive features of the human tumor stroma, especially ECM architecture, and are not exposed to intact body physiology. On the other hand, in vivo animal models do not accurately capture human tumor architecture. Using the features of biopsied colorectal cancer (CRC) tissue as a guide, we address these deficiencies by creating human organoids containing a colonic stromal ECM layer and CRC spheroids. Organoids were studied in vitro and upon implantation in mice for 28 days. We show that the stromal ECM micro-architecture, generated in vitro, was maintained in vivo for at least 28 days. Furthermore, comparisons with biopsied CRC tumors revealed that organoids with orderly structured TMEs induce an epithelial phenotype in CRC cells, similar to low-grade tumors, compared to a mesenchymal phenotype observed in disordered TMEs, similar to high-grade tumors. Altogether, these results are the first demonstration of replicating the human tumor ECM architecture in biofabricated tumor organoids under ex vivo and in vivo conditions.

Effects of the Tibetan herbal preparation PADMA 28 on blood lipids and lipid oxidisability in subjects with mild hypercholesterolaemia

VASA ◽

10.1024/0301-1526.34.1.11 ◽

2005 ◽

Vol 34 (1) ◽

pp. 11-17 ◽

Cited By ~ 12

Author(s):

Brunner-La Rocca ◽

Schindler ◽

Schlumpf ◽

Saller ◽

Suter

Keyword(s):

Endothelial Dysfunction ◽

Blood Lipids ◽

Ex Vivo ◽

Hdl Cholesterol ◽

Blood Lipid ◽

Tibetan Medicine ◽

Double Blind ◽

Intraarterial Infusion ◽

Padma 28

Background: Previous studies showed an anti-atherosclerotic effect of PADMA 28, an herbal formula based on Tibetan medicine. As the mechanisms of action are not fully understood, we investigated whether PADMA 28 may lower blood lipids and lipid oxidisability, and affect early endothelial dysfunction. Patients and methods: Sixty otherwise healthy subjects with total cholesterol ≥5.2 mmol/l and < 8.0 mmol/l were randomly assigned to placebo or PADMA 28, 3 x 2 capsules daily, for 4 weeks (double-blind). Blood lipids (total, LDL-, and HDL-cholesterol, triglycerides, Apo-lipoprotein A1 and B) and ex vivo lipid oxidisability were measured before and after treatment. In a subset of 24 subjects, endothelial function was assessed using venous occlusion plethysmography with intraarterial infusion of acetylcholine. Isolated LDL and plasma both untreated and pre-treated with PADMA 28 extract were oxidised by the radical generator AAPH. Conjugated diene formation was measured at 245 nm. Results: Blood lipids did not change during the study in both groups. In contrast to previous reports in mild hypercholesterolaemia, no endothelial dysfunction was seen and, consequently, was not influenced by therapy. Ex vivo blood lipid oxidisability was significantly reduced with PADMA 28 (area under curve: 5.29 ± 1.62 to 4.99 ± 1.46, p = 0.01), and remained unchanged in the placebo group (5.33 ± 1.88 to 5.18 ± 1.78, p > 0.1). This effect persisted one week after cessation of medication. In vitro experiments confirmed the prevention of lipid peroxidation in the presence of PADMA 28 extracts. Persistent protection was also seen for LDL isolated from PADMA 28-pretreated blood after being subjected to rigorous purification. Conclusions: This study suggests that the inhibition of blood lipid oxidisability by PADMA 28 may play a role in its anti-atherosclerotic effect.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000116 ◽

2012 ◽

Vol 82 (3) ◽

pp. 228-232 ◽

Cited By ~ 7

Author(s):

Mauro Serafini ◽

Giuseppa Morabito

Keyword(s):

Antioxidant Capacity ◽

Dietary Intervention ◽

Ex Vivo ◽

The Body ◽

Dietary Polyphenols ◽

Enzymatic Antioxidant ◽

Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.