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| Date: 08-31-2015 | HC# 031564-527 |
Re: Pilot Study Suggests Ginkgo Extract Potential for Reducing Risk of Cardiovascular Disease in Patients with Metabolic Syndrome
Siegel G, Ermilov E, Knes O, Rodríguez M. Combined lowering of low grade systemic inflammation and insulin resistance in metabolic syndrome patients treated with Ginkgo biloba. Atherosclerosis. December 2014;237(2):584-588.
Metabolic syndrome, associated with the development of type 2 diabetes and cardiovascular disease, is partially defined by abnormal concentrations of blood glucose, reduced insulin sensitivity, and elevated inflammation. It has been demonstrated that insulin resistance and low-grade systemic inflammation, factors of metabolic syndrome, predict cardiovascular disease risk. A common tool to gauge insulin resistance is the homeostatic model assessment of insulin resistance (HOMA-IR), a calculation made from fasting glucose and insulin concentrations. To assess inflammation, measurements of the inflammation marker high-sensitivity C-reactive protein (hs-CRP) can be informative. Ginkgo (Ginkgo biloba, Ginkgoaceae) extract has been shown to have beneficial effects on the vasculature. This observational study reports the impact of ginkgo leaf extract EGb 761®(Rökan® novo [W. Spitzner Arzneimittelfabrik GmbH; Ettlingen, Germany]; Tebonin® [Schwabe Pharmaceuticals; Karlsruhe, Germany]) on HOMA-IR and hs-CRP, as well as a host of other metabolic markers, in patients with metabolic syndrome.
This study was done at the Phase I-II study clinic of the UMHAPT University Hospital in Sofia, Bulgaria. Included patients had metabolic syndrome and did not ingest "cholesterol- and/or fat-rich" foods during the 1-month run-in phase of the study. Eleven patients (2 men and 9 women) were between 26-48 years old and were all smokers. Also, 9 patients had blood lipoprotein(a) [Lp(a), a risk factor in cardiovascular disease] at levels of > 30 mg/dL. Patients took 240 mg per day of EGb 761 for 2 months. Patients were not allowed to take statins, calcium antagonists, or nitrite compounds. No adverse effects were reported for this dosage.
Blood serum was collected to measure HOMA-IR and hs-CRP. Additionally, precursors to atherosclerosis or markers of cardiovascular disease, such as nanoplaque formation and size, oxidized low-density lipoprotein cholesterol (oxLDL) to LDL ratio (oxLDL/LDL), myeloperoxidase (MPO, a marker of oxidative stress and inflammation), an isoform of prostaglandin F2α (8-iso-PGF2α), interleukin 6 (IL-6, a marker of inflammation), Lp(a), and matrix metalloproteinase 9 (MMP-9), were also measured. Also, the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), as well as vascular contractility markers cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), were assessed.
Following 2 months of EGb 761 supplementation, both HOMA-IR and hs-CRP were significantly decreased (from 3.07 ± 0.63 to 2.60 ± 0.51 mU/L × mg/dL, P<0.0120, and from 8.85 ± 4.09 to 4.92 ± 2.51 mg/L, P<0.0436, respectively). There was a significant correlation between the changes in HOMA-IR and IL-6 (r=0.71, P<0.035) and a trend in correlation with changes in hs-CRP and IL-6 (r=0.58, P<0.059) but not between those of HOMA-IR and hs-CRP (r=0.68, P<0.1352). There were significant decreases in nanoplaque formation and size, oxLDL/LDL, MPO, 8-iso-PGF2α, IL-6, Lp(a), and MMP-9 (P<0.05 for all). Also, there were significant elevations in SOD and GPx activity (P<0.01 for both) and cAMP and cGMP (P<0.001 for both).
This pilot study shows that following ginkgo extract EGb 761 supplementation, HOMA-IR, a gauge of insulin resistance, and hs-CRP and IL-6 concentrations, prominent markers of inflammation, were significantly decreased. This supports the conclusion that EGb 761 consumption may result in improved insulin sensitivity and decreased inflammation, which are critical aspects of metabolic syndrome that increase the risk of cardiovascular disease and mortality. It is mentioned that the sample size here is small, and future studies will ideally incorporate larger numbers of patients and focus on functional outcomes, in addition to molecular markers. In summary, EGb 761 demonstrated a good potential for the adjunctive treatment of metabolic syndrome to help prevent greater risks.
This study was supported by a research grant from Schwabe Pharmaceuticals.
—Amy C. Keller, PhD
