Usefulness of MCP-1 Chemokine in the Monitoring of Patients with Coronary Artery Disease Subjected to Intensive Dietary Intervention: A Pilot Study.

Monocyte chemotactic protein-1 (MCP-1) plays an important role in the entire atherosclerotic process, from atherogenesis to destabilisation of the atherosclerotic plaque. The purpose of this study is to evaluate the effect of the dietary approaches to stop hypertension (DASH) diet in patients with coronary artery disease on the MCP-1 plasma concentration and to evaluate the potential usefulness of this chemokine as a marker of change in the volume and composition of coronary plaque. MATERIAL AND METHOD: As part of the dietary intervention to stop coronary atherosclerosis in computed tomography (DISCO-CT) study, patients were randomised to an intervention group (n = 40) in which the DASH diet was introduced, and to a control group (n = 39) with no dietary intervention. In the DASH group, dietary counselling was provided at all follow-up visits within 12 months of the follow-up period. MCP-1 plasma concentration was determined using enzyme-linked immunosorbent assay (ELISA). Coronary plaque analysis was performed using a semi-automated plaque analysis software system (QAngioCT, Medis, The Netherlands). RESULTS: In the DASH group, MCP-1 plasma concentration significantly decreased by 34.1 pg/mL (p = 0.01), while in the control group, the change in MPC-1 was not significant. Significant inverse correlations were revealed for the change in MCP-1 plasma concentration and change in the consumption of vitamin C and dietary fibre both in the DASH (r = -0.519, p = 0.0005; r = -0.353, p = 0.025, respectively) and in the control group (r = -0.488 p = 0.001; r = -0.502, p = 0.001, respectively). In patients with the highest decrease in percent atheroma volume (PAV), a significant positive correlation was observed between the change in MCP-1 plasma concentration and changes in PAV (r = 0.428, p = 0.033) and calcified plaque component (r = 0.468, p = 0.018), while the change in noncalcified plaque component correlated inversely with change in MCP1 (r = -0.459, p = 0.021). CONCLUSION: Dietary intervention based on the DASH diet model reduces the MCP-1plasma concentration, mostly due to an increased intake of plant-derived, fibre-rich foods and antioxidants. The change in MCP-1 plasma concentration seems to reflect changes in the atheroma volume and proportions between the calcified and non-calcified plaque elements.

The Effect of Intensive Dietary Intervention on the Level of RANTES and CXCL4 Chemokines in Patients with Non-Obstructive Coronary Artery Disease: A Randomised Study.

BACKGROUND: Inflammation is the key pathophysiological mechanism of the initiation and progression of atherosclerosis. The study objective was to assess the effects of a dietary intervention based on the model of the dietary approaches to stop hypertension (DASH) diet on the levels of chemokines RANTES and CXCL4 in patients with non-obstructive coronary artery disease. METHODS: As part of Dietary Intervention to Stop Coronary Atherosclerosis in Computed Tomography (DISCO-CT) study, patients were randomised to an intervention group (n = 40), where the DASH diet was introduced along with optimal pharmacotherapy, and to a control group (n = 39), with optimal pharmacotherapy alone. In the DASH group, systematic dietary counselling was provided for the follow-up period. RANTES and CXCL4 levels were determined using ELISA. RESULTS: In the DASH group, the RANTES level insignificantly reduced from 42.70 ± 21.1 ng/mL to 38.09 ± 18.5 ng/mL (p = 0.134), and the CXCL4 concentration significantly reduced from 12.38 ± 4.1 ng/mL to 8.36 ± 2.3 ng/mL (p = 0.0001). At the same time, an increase in the level of both chemokines was observed in the control group: RANTES from 34.69 ± 22.7 to 40.94 ± 20.0 ng/mL (p = 0.06) and CXCL4 from 10.98 ± 3.6 to 13.0 5± 4.8 ng/mL (p = 0.009). The difference between the changes in both groups was significant for both RANTES (p = 0.03) and CXCL4 (p = 0.00001). The RANTES/CXCL4 ratio reduced in the control group (from 3.52 ± 2.8 to 3.35 ± 2.8; p = 0.006), while in the DASH group, an increase was observed (from 3.54 ± 1.7 to 4.77 ± 2.4; p = 0.001). CONCLUSIONS: A 12-month-long intensive dietary intervention based on DASH diet guidelines as an addition to optimal pharmacotherapy causes changes in the levels of chemokines CXCL4 and RANTES and their mutual relationship in comparison to conventional treatment.

DASH diet decreases CXCL4 plasma concentration in patients diagnosed with coronary atherosclerotic lesions.

BACKGROUND AND AIMS: Aim of this study involved assessment of the intensive intervention concerning lifestyle based on the DASH diet model on plasma concentration of CXCL4 chemokine among patients with coronary atherosclerosis. METHODS AND RESULTS: The Dietary Intervention to Stop Coronary Atherosclerosis in Computed Tomography Study randomized patients with stable CAD to an interventional group (n = 41), where DASH diet was implemented and the control group (n = 40) without dietary intervention. Dietary counselling was provided to DASH group during all 6 control visits within 6 months of observation. During the study, body weight and body composition were controlled using the bioimpedance method. CXCL4 concentration was determined with the use of ELISA test. Within the DASH group, a significant decrease in body weight, a decrease in high sensitivity C-reactive protein concentration (-0.32 ± 2.8 mg/l; p < 0.05), as well as a decrease in CXCL4 concentration (-3.35 ± 3.4 ng/ml; p < 0.0001) were observed. Occurring changes were not statistically significant within the control group. CONCLUSIONS: DASH diet lessens CXCL4 concentration among patients with a stable CAD, however, further research is necessary in order to confirm aforementioned results and evaluate the impact on atherosclerotic plaque. THIS TRIAL WAS REGISTERED AT: www.clinicaltrials.gov as NCT02571803.

The bioactivity of flavonoid glucuronides and free aglycones in the context of their absorption, II phase metabolism and deconjugation at the inflammation site.

One of the most spread group of phenolics are flavonoids. Many studies focusing on the digestion and bioavailability of flavonoids have been carried out. Several possible directions of flavonoid metabolism are suspected and described in the literature. The aim of the present study was to evaluate the bioactivity of 8 flavonoid 3-O- and 7-O- glucuronides and 7 free aglycones on inflammatory response of PMNs and HUVECs in the context of their fate in humans after oral intake. The present study for the first time compared the activity of several most popular in plant flavonol and flavone aglycones and their beta-glucuronides. The results showed that in all in vitro experiments only aglycones have anti-inflammatory activity in PMNs and HUVECs models in the concentration range 1-50 µM. The most significant influence on the inflammatory response was observed in the case of HUVECs. Compounds were able to down-regulate levels of adhesion molecules (ICAM, VCAM and E-selectin). The possible deconjugation phenomenon at the inflammation site was evaluated using enzymes produces by stimulated PMNs. This is the first report suggesting the role of ß-glucuronidase in the inflammatory process taking place on the inflammation site. Additionally, the anti-inflammatory effect was significantly better for flavones.

Caffeic acid derivatives isolated from Galinsoga parviflora herb protected human dermal fibroblasts from UVA-radiation.

BACKGROUND: Among solar radiation, ultraviolet light is the most harmful for the skin, because of intracellular reactive oxygen species formation, leading to oxidative stress, cell damage and apoptosis. Crucial role in skin protection against oxidative stress play antioxidant enzymes regulated by Nrf2 transcription factor. Some plant-derived polyphenols are known to protect skin fibroblasts against UV through induction of Nrf2-dependent antioxidant genes expression. PURPOSE: We previously found out that water extracts from Galinsoga sp. herb protected human dermal fibroblasts against UVA-induced oxidative stress and apoptosis. However, which compounds were responsible for such protective action remained unclear. Here, we investigated photoprotective potential and mechanism of action of two main isolated compounds, 2,3,5(2,4,5)-tricaffeoylaltraric acid and 2,4(3,5)-dicaffeoylglucaric acid, on human dermal fibroblasts (NHDF). STUDY DESIGN/METHODS: NHDF cells were pretreated with tested compounds (6.25-50 µM) and irradiated with UVA (25 J/cm2). Intracellular ROS and GSH level, cell viability, cell membrane integrity and apoptosis were measured. HO-1 protein expression and Nrf2 transcription factor activation were also assessed. RESULTS: Cells pretreated with tested compounds prior to UVA showed inhibition of intracellular ROS formation and increase of GSH level. Significant increase of cell viability was also observed, as well as decrease of LDH release and a the rate of apoptotic cells in comparison to untreated cells. Furthermore, tested compounds increased HO-1 expression and activated the Nrf2 transcription factor in NHDF cells. CONCLUSION: Present study demonstrated that caffeic acid derivatives present in Galinsoga parviflora herb, in particular tricaffeoylaltraric acid may protect dermal fibroblasts against UVA-induced oxidative stress through activation of intracellular antioxidative system. Such caffeic acid derivatives are bioactive compounds which might prevent UV-induced photoageing and photocarcinogenesis.

Development of photoprotective, antiphototoxic, and antiphotogenotoxic formulations of ocular drugs with fluoroquinolones.

The development of innovative solutions in photosafety of photolabile pharmaceutical products may help to reduce the adverse effects of these products, caused by light exposure. Providing new data in this area of study is particularly important in case of drugs applied topically on sensitive organs such as eyes. The main goal of this research is to investigate whether two potential excipients, namely: p-coumaric acid and benzophenone-4, affect the photodegradation, phototoxicity and photogenotoxicity of water solutions of four fluoroquinolones: ciprofloxacin, lomefloxacin, fleroxacin and clinafloxacin. We conducted a set of bioassays combined with the application of high-performance liquid chromatography and mass spectrometry techniques. The significant reduction of phototoxic and photogenotoxic abilities was evaluated in mixtures with ciprofloxacin and p-coumaric acid by using the umu test with Salmonella typhimurium TA1535/pSK1002, the methylthiazol tetrazolium reduction assay, and the micronucleus assay with the V79 cell line. In the bacterial assay the opposite effect was observed for the formulation with lomefloxacin and p-coumaric acid. This may be explained by the significant differences in the profile of the lomefloxacin photodegradation products. Further, the photoprotective and antiphotomutagenic abilities of ciprofloxacin mixed with benzophenone-4 were assessed. Promising results obtained in compositions with ciprofloxacin may be a basis for further research. Nevertheless, the increase in the DNA damage potential in mixtures with p-coumaric acid and two other antibiotics shows the importance of the safety evaluation of such innovative combinations.

New Insight into the Synthesis and Biological Activity of the Polymeric Materials Consisting of Folic Acid and ß-Cyclodextrin.

This work presents a very new look at folate targeting and is focused on synthesizing and assessing the biological activity of folic acid-targeted drug delivery materials based on ß-cyclodextrin. Both folic acid and ß-cyclodextrin have been covalently conjugated to branched polyethylenimine as the polymeric vector. Host-guest inclusion of folic acid into a ß-cyclodextrin cavity, demonstrated by means of the spectroscopic methods (2-D NMR, IR, UV-Vis), is found to be of crucial importance for biological activity of nanotherapeutics. This paper describes the very first example of the versatile synthetic approach to create the polymeric biosystems, where folic acid activity is not limited by the inclusion phenomenon. Cytotoxicity of the obtained polymeric materials against Lewis lung carcinoma cells is determined by neutral red uptake assay. Folate receptor-binding studies reveal that the developed synthetic approach enables full exploitation of the potential of folic acid as a targeting ligand.

Supplementation with omega-3 acids after myocardial infarction and modification of inflammatory markers in light of the patients' diet: a preliminary study.

BACKGROUND: Neuroendocrine activation, activation of proinflammatory cytokines and platelets, and endothelial dysfunction play a significant role in the development of heart failure (HF). AIM: The aim of the work was to assess the effect of supplementation with EPA and DHA in a daily dose of 1 g on selected inflammatory markers and platelet activation in patients with HF after recent myocardial infarction in light of their diet. METHODS: This preliminary study was a randomised, double-blind trial involving 30 patients with post-infarction HF. One group received a product containing 1 g of omega-3 acids, while the other received placebo, i.e. corn oil 1 g daily for 12 weeks. At baseline and at week 12, venous blood was obtained in the fasted state in order to determine the following parameters: NT-proBNP, fibrinogen, INR, creatinine clearance, serum lipid profile, hsCRP, troponin, glucose, transaminases, GGTP, MCP-1, pentraxin 3, and CD-40. To evaluate the patient's diet and dietary intake of omega-3 acids, a 24-h dietary interview and the Block's Food Frequency Questionnaire (FFQ) were applied. RESULTS: Supplementation of omega-3 acids in a dose of 1 g per day had no effect on lipid or inflammatory parameters, with the exception of pentraxin 3. In both groups, after three months of supplementation, overall consumption of energy and saturated fatty acids was significantly higher (p < 0.05). CONCLUSIONS: Potential benefits associated with supplementation were nullified by a highly atherogenic diet. Apparently, supplementation of omega-3 acids without simultaneous dietary education and nutrition control does not bring the expected effect. Further research involving a larger group of patients is needed to better understand the relationship between patient's diet and the effectiveness of omega-3 supplementation.

Cardioprotective effects of Aronia melanocarpa anthocynanins. From laboratory experiments to clinical practice.

The role of polyphenols in the cardiovascular diseases prevention is still a matter of scientific discussion. However, recent clinical studies indicate that intake of anthocyanins and in a lesser extent procyanidins can participate in prevention of hypertension and type 2 diabetes. Fruits of Aronia melanocarpa (chokeberry) are known to be a reach source of these polyphenols. Moreover, its extracts were shown to express strong antioxidant, antiinflammatory, vasorelaxant and antithrombotic properties. The aim of the review is to summarize the results of the hitherto research regarding the biological effects at the molecular and clinical level.

Anthocyans-rich Aronia melanocarpa extract possesses ability to protect endothelial progenitor cells against angiotensin II induced dysfunction.

BACKGROUND: Endothelial progenitor cells (EPC) may provide protection against atherosclerosis and plaque rupture by their innate ability to replace dysfunctional or damaged endothelial cells in plaque microvessels. There is evidence that angiotensin II may impair the angiogenic functions of EPCs in the atherosclerotic plaque by accelerating senescence and inhibiting their proliferation through oxidative stress induction. PURPOSE: In this study, we examined whether chokeberry (Aronia melanocarpa) fruit extract, containing mainly anthocyanins with potent antioxidative properties, could protect EPCs against angiotensin-induced oxidative stress. METHODS: EPCs were isolated from peripheral blood of young healthy volunteers and cultivated on fibronectin-coated plates in the presence or absence of angiotensin II (1 µM) and chokeberry extract (1-25 µg/ml). RESULTS: EPCs exposed to chokeberry extract prior to angiotensin II showed a significant increase of proliferation and telomerase activity, and a decrease in the percentage of senescent cells and intracellular ROS formation in comparison to angiotensin II treated cells. Furthermore, extract increased migration ability, adhesion to fibronectin and the angiogenic potential of EPC in vitro diminished by angiotensin II in a concentration-dependent manner. That effect was related to the activation of the Nrf2 transcription factor and the increase of HO-1 expression. CONCLUSIONS: Our results suggested that chokeberry extract may protect EPCs against angiotensin II-induced dysfunction and could play a potential role in the prevention of coronary artery disease.

Antigenotoxic, anti-photogenotoxic and antioxidant activities of natural naphthoquinone shikonin and acetylshikonin and Arnebia euchroma callus extracts evaluated by the umu-test and EPR method.

The aim of this study was to evaluate the antigenotoxic and antioxidant potential of shikonin (SH), acetylshikonin (ACS) and Arnebia euchroma callus extract (EXT). The antigenotoxic activity was investigated by the umu-test as the inhibition of the SOS system induction caused by genotoxic chemical agents - 4-nitroquinoline oxide and 2-aminoanthracene. Moreover the ability of SH, ACS and EXT to prevent photogenotoxicity triggered by chlorpromazine under UVA irradiation was measured. The cytotoxicity of EXT toward V79 Chinese hamster cell line was additionally assessed. Shikonin and acetylshikonin had no effect on 4-NQO induced genotoxicity whereas EXT demonstrated an unclear effect. The protection against 2AA induced genotoxicity was observed for all tested substances. The highest protection was demonstrated for EXT with inhibition of 66%. SH and ACS reduced 2AA genotoxicity with inhibition of about 60%. Under UVA the strongest and dose-dependent activity was observed for EXT. Acetylshikonin was a weak anti-photogenotoxin whereas shikonin had no clear effect. EXT was highly cytotoxic toward the V79 cell line - the cells' morphology was affected seriously and apoptosis was impacted. The antioxidant activity of SH, ACS and EXT was studied by means of electron paramagnetic resonance spectroscopy using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. All three samples exhibited radical scavenging properties.

Determination of in vitro antioxidant and UV-protecting activity of aqueous and ethanolic extracts from Galinsoga parviflora and Galinsoga quadriradiata herb.

Galinsoga species are used in folk medicine as anti-inflammatory agents and accelerators for wound healing. They also have reported antioxidant activity. We examined aqueous and ethanolic extracts derived from the Galinsoga herb as potential photoprotectors, as the role of reactive oxygen species (ROS) has implicated in skin damage. The extracts used in the study were standardized by determining the sum of flavonoids, and the amount of caffeic acid and its derivatives. The antioxidant activity of the extracts was evaluated by examining the scavenging of two radicals (O2(-) and H2O2) generated in cell-free systems. We also examined the effect on ROS generation by human skin fibroblasts after UV irradiation. In addition we determined the cytotoxicity of the extracts and their protective effect against damage caused by UV irradiation (MTT test, LDH release test and staining with annexine V-FITC/PI). Our findings show that the ethanolic extracts from the herb have cytotoxic effects, while the aqueous extracts from Galinsoga herb have protective activity, in part due to their ability to inhibit ROS generation. In the conclusion the aqueous extracts from the both tested species may be effective as photoprotectors.

Evaluation of photodegradation, phototoxicity and photogenotoxicity of ofloxacin in ointments with sunscreens and in solutions.

Fluoroquinolones are widely used anti-bacterial agents that are known to exhibit moderate to severe phototoxicity. Furthermore some of them reveal photogenotoxicity under UV irradiation. Incidence of side effects due to light exposure may be augmented, if the medicament is used topically. The main goal of this work was to compare the extent of photodegradation of ofloxacin in ointments with various excipients: hydrated or non-hydrated base and the addition of sunscreens: bisoctrizole (Tinosorb M) and bemotrizinol (Tinosorb S). The next goal of present work was the analysis of phototoxicity and photogenotoxicity of ofloxacin photodegradation products in tested ointments and in solutions with the umu-test, the test of mitotic gene conversion with Saccharomyces cerevisiae D7 and the micronucleus assay with V79 Chinese hamster cell line. At the same time an attempt was made to determinate the photodegradation products of ofloxacin in different unguents variants. We observed a significant photoprotective effect in ointment with Tinosorb M. We did not evaluated relevant differences regarding the genotoxicity and toxicity of unguents. However, the pre-irradiated ofloxacin solutions in comparison to samples stored in the dark were significantly more genotoxic to bacteria, slightly increased the number of micronuclei in V79 cell line and were toxic to the yeast strain.

Pro-apoptotic properties of (1,3)(1,4)-ß-D-glucan from Avena sativa on human melanoma HTB-140 cells in vitro.

In this study, the growth-inhibitory effect of polysaccharide (1,3)(1,4)-ß-D-glucan from oat, Avena sativa L. grains was explored on the human skin melanoma HTB-140 cells in vitro. The oat ß-D-glucan (OBG) exerted cytotoxic action on HTB-140 cells. After 24h of incubation, LD50 (concentration at which 50% of the cells were found dead) was obtained of 194.6 ± 9.8 µg/mL. The oat ß-D-glucan caused a concentration-dependent increase of caspase-3/-7 activation and appearance of phosphatidylserine on the external surface of cellular membranes where it was bound to annexin V-FITC, demonstrating the induction of apoptosis. Intracellular ATP level decreased along with the mitochondrial potential, which suggested a mitochondrial pathway of apoptosis. A cell cycle analysis showed increase in the number of apoptotic cells, increase in the number of cells in G1 phase and decrease in the number of cells in G2/M. Although the detailed mechanism for the anti-tumor activity of the oat ß-D-glucan still needs further investigation, this study provides preliminary insights into this direction along with perspectives of developing it as an anti-tumor agent.

Assessing carbon-encapsulated iron nanoparticles cytotoxicity in Lewis lung carcinoma cells.

Carbon-encapsulated iron nanoparticles (CEINs) have been considered as attractive candidates for several biomedical applications. In the present study, we synthesized CEINs (the mean diameter 40-80 nm) using a carbon arc route, and the as-synthesized CEINs were characterized (scanning and transmission electron microscopy, dynamic light scattering, turbidimetry, Zeta potential) and further tested as raw and purified nanomaterials containing the carbon surface modified with acidic groups. For cytotoxicity evaluation, we applied a battery of different methods (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, lactate dehydrogenase, calcein AM/propidium iodide, annexin V/propidium iodide, JC-1, cell cycle assay, Zeta potential, TEM and inductively coupled plasma mass spectrometry) to address the strategic cytotoxic endpoints of Lewis lung carcinoma cells due to CEIN (0.0001-100 µg ml(-1) ) exposures in vitro. Our studies evidence that incubation of Lewis lung carcinoma cells with CEINs is accompanied in substantial changes of zeta potential in cells and these effects may result in different internalization profiles. The results show that CEINs increased the mitochondrial and cell membrane cytotoxicity; however, the raw CEIN material (Fe@C/Fe) produced higher toxicities than the rest of the CEINs studied to data. The study showed that non-modified CEINs (Fe@C/Fe and Fe@C) elevated some pro-apoptotic events to a greater extent compared to that of the surface-modified CEINs (Fe@C-COOH and Fe@C-(CH2 )2 COOH). They also diminished the mitochondrial membrane potentials. In contrast to non-modified CEINs, the surface-functionalized nanoparticles caused the concentration- and time-dependent arrest of the S phase in cells. Taken all together, our results shed new light on the rational design of CEINs, as their geometry, hydrodynamic and, in particular, surface characteristics are important features in selecting CEINs as future nanomaterials for nanomedicine applications.

Oleuropein and oleacein may restore biological functions of endothelial progenitor cells impaired by angiotensin II via activation of Nrf2/heme oxygenase-1 pathway.

Endothelial progenitor cells (EPCs) are responsible for neovascularization of ischaemic tissue and may participate in re-endothelization of an injured arterial wall. There is evidence that angiotensin II, by an increase of gp91phox expression and induction of ROS generation, accelerates cell senescence and impairs functions of EPCs. Oleacein is a main phenolic compound from olive oil, whereas oleuropein is present in olive leaves. Both compounds possess antioxidative, hypotensive and anti-inflammatory properties and show beneficial activity on the cardiovascular system. In this study, we examined whether oleoeuropein and oleacein could protect EPCs against impairment of their functions due to angiotensin-induced cell senescence. CD31(+)/VEGFR-2(+) cells were isolated from young healthy volunteers blood samples and cultured on fibronectin-coated plates with angiotensin (1.0µM) in presence or absence of increasing concentrations (from 1.0 to 10.0 µM) of oleoeuropein or oleacein. As compared to angiotensin II-treated cells, EPCs exposed to oleacein or oleuropein prior to angiotensin II showed a significant increase of proliferation and telomerase activity, and a decrease in the percentage of senescent cells and intracellular ROS formation. Oleacein and oleuropein restored migration, adhesion and tube formation of EPCs diminished by angiotensin II in a concentration-dependent manner. This effect was related to NF-E2-related factor 2 (Nrf2) transcription factor activation and the increase of heme oxygenase-1 (HO-1) expression.

Silymarin inhibits endothelial progenitor cells' senescence and protects against the antiproliferative activity of rapamycin: preliminary study.

Rapamycin, an antiproliferative agent used on drug-eluting stents, induces endothelial progenitor cells (EPCs) senescence through telomerase inactivation and may impair the reendothelization of an injured arterial wall, leading to thrombosis. We examined whether silymarin, a complex of flavonolignans with hepatoprotective and antioxidative properties, can protect EPCs against rapamycin-induced senescence. Mononuclear cells were isolated from peripheral blood of healthy volunteers. EPCs were cultured in endothelial cell growth medium-2 in the presence or absence of rapamycin (0.1 ng/mL) and/or silymarin (12.5­50 µg/mL). EPCs senescence­associated b-galactosidase activity, telomerase activity, and prolifertive activity were measured. The influence on tubular-like structure formation in vitro was investigated, and colony-forming assay on methylcellulose plates was performed. Silymarin increased telomerase activity 3-fold, reduced the number of senescent cells, and increased EPC proliferative activity (up to 64%) in comparison with cells cultured with rapamycin alone. Moreover, silymarin partially prevented impairment of tubular-like structure formation in Matrigel by rapamycin. These findings suggest that silymarin counteracts the inhibitory effects of rapamycin in EPCs. Silymarin may protect EPCs against the antiproliferative effects of rapamycin and restore their reconstructive ability.