AimWe report the effects of long-term cola beverage drinking on glucose homeostasis, endocrine pancreas function and morphology in rats.MethodsWistar rats drank: water (group W), regular cola beverage (group C, sucrose sweetened) or “light” cola beverage (group L, artificially sweetened). After 6 months, 50% of the animals in each group were euthanized and the remaining animals consumed water for the next 6 months when euthanasia was performed. Biochemical assays, insulinemia determination, estimation of insulin resistance (HOMA-IR), morphometry and immunohistochemistry evaluations were performed in pancreas.ResultsHyperglycemia (16%, p<0.05), CoQ10 (coenzyme-Q10) decrease (−52%,p<0.01), strong hypertriglyceridemia (2.8-fold, p<0.01), hyperinsulinemia (2.4 fold, p<0.005) and HOMA-IR increase (2.7 fold, p<0.01) were observed in C. Group C showed a decrease in number of α cells (−42%, p<0.01) and β cells (−58%, p<0.001) and a moderate increase in α cells’ size after wash-out (+14%, p<0.001). Group L showed reduction in β cells’ size (−9%, p<0.001) and only after wash-out (L12) a 19% increase in size (p<0.0001) with 35% decrease in number of α cells (p<0.01). Groups C and L showed increase in α/β-cell ratio which was irreversible only in C (α/β = +38% in C6,+30% in C12, p<0.001vs.W6). Regular cola induced a striking increase in the cytoplasmic expression of Trx1 (Thioredoxin-1) (2.25-fold in C6 vs. W6; 2.7-fold in C12 vs. W12, p<0.0001) and Prx2 (Peroxiredoxin-2) (3-fold in C6 vs. W6; 2-fold in C12 vs. W12, p<0.0001). Light cola induced increase in Trx1 (3-fold) and Prx2 (2-fold) after wash-out (p<0.0001, L12 vs. W12).ConclusionGlucotoxicity may contribute to the loss of β cell function with depletion of insulin content. Oxidative stress, suggested by increased expression of thioredoxins and low circulating levels of CoQ10, may follow sustained hyperglycemia. A likely similar panorama may result from the effects of artificially sweetened cola though via other downstream routes.

BackgroundAtherosclerosis is a major health burden. Metabolic disorders had been associated with large consumption of soft drinks. The rising incidence of atherosclerosis and metabolic alterations warrants the study of long-term soft drink consumption’ effects on metabolism and atherosclerosis in genetic deficiency of apolipoprotein E which typically develops spontaneous atherosclerosis and metabolic alterations.MethodsApoE-/- mice were randomized in 3 groups accordingly with free access to: water (W), regular cola (C) or light cola (L). After 8 weeks, 50% of the animals in each group were euthanized (Treatment: W8, C8, L8). The remaining mice (all groups) drank water for 8 weeks and were euthanized (Washout: W16, C16, L16). Body weight and food and drink consumption were periodically measured. Blood was collected (biochemistry). At autopsy, transverse aortic sinus sections were serially cut and stained (histomorphometry); livers and kidneys were processed (microscopy). MANOVA (identification of variance factors) was followed by ANOVA and LSD tests (within-factor differences between levels). Conventionally a p< 0.05 was considered significant.ResultsTreatment increased drinking volumes (vs W8: 4 fold C8, p<0.0001; +47% L8, p<0.02). Only C reduced eating amounts (–54%, p<0.05 vs W8). I). Compared with W8: C8 developed hyperglycemia (+43%, p<0.03) and increased non-HDL cholesterol (+54%, p<0.05); L8 showed decreased glycemia (–15%, p<0.05 vs W8) and increased creatinine (2.5 fold, p<0.04), urea (+74, p<0.03) and aspartate-aminotransferase (2.8 fold, p<0.05). Hypercreatininemia was observed in L16 (2.7 fold vs W16, p<0.05). Hypertriglyceridemia (+91%, p<0.008) and hyperuremia (+68%, p<0.03) developed over time of study (age). II). Treatment caused plaque area increase (vs W8: 28% C8, p<0.02 and 50% L8, p<0.01; vs W16: 43% C16, p<0.05 and 68% L16, p<0.02) and stenosis (vs W8: 38% C8, p<0.04 and 57% L8, p<0.01; vs W16: 71% C16, p<0.01 and 46% L16, p<0.04). Age also caused plaque area increase (56%, p<0.04). Treatment- and age-effects on plaque enlargement were additive.ConclusionCola beverages caused atherosclerotic lesions’ enlargement with metabolic (C) or non metabolic disturbances (L). ApoE-/- mice were particularly sensitive to L treatment. These findings may likely relate to caramel colorant and non-nutritive sweeteners in cola drinks and have potential implications in particularly sensitive individuals.

No abstract

AimThe purpose of this study was to investigate the effect of moderate intensity exercise on kidney in an animal model of high consumption of cola soft drinks.MethodsForty-eight Wistar Kyoto rats (age: 16 weeks; weight: 350–400 g) were assigned to the following groups: WR (water runners) drank water and submitted to aerobic exercise; CR (cola runners) drank cola and submitted to aerobic exercise; WS (water sedentary) and CS (cola sedentary), not exercised groups. The aerobic exercise was performed for 5 days per week throughout the study (24 weeks) and the exercise intensity was gradually increased during the first 8 weeks until it reached 20 meters / minute for 30 minutes. Body weight, lipid profile, glycemia, plasma creatinine levels, atherogenic index of plasma (AIP) and systolic blood pressure (SBP) were determined. After 6 months all rats were sacrificed. A kidney histopathological score was obtained using a semiquantitative scale. Glomerular size and glomerulosclerosis were estimated by point-counting. The oxidative stress and pro-inflammatory status were explored by immunohistochemistry. A one way analysis of variance (ANOVA) with Tukey-Kramer post-hoc test or the Kruskal-Wallis test with Dunn’s post-hoc test was used for statistics. A value of p < 0.05 was considered significant.ResultsAt 6 months, an increased consumption of cola soft drink was shown in CS and CR compared with water consumers (p<0.0001). Chronic cola consumption was associated with increased plasma triglycerides, AIP, heart rate, histopathological score, glomerulosclerosis, oxidative stress and pro-inflammatory status. On the other hand, moderate exercise prevented these findings. No difference was observed in the body weight, SBP, glycemia, cholesterol and plasma creatinine levels across experimental groups.ConclusionsThis study warns about the consequences of chronic consumption of cola drinks on lipid metabolism, especially regarding renal health. Additionally, these findings emphasize the protective role of exercise training on renal damage.

PurposeThis study evaluates whether the daily practice of an exercise routine might protect from endocrine pancreas damage in cola drinking rats.MethodsForty-eight Wistar rats were randomly assigned to 4 groups depending on a) beverage consumption ad libitum, water (W) or cola beverage (C), and b) physical activity, sedentary (S) or treadmill running (R). Accordingly, 4 groups were studied: WS (water sedentary), WR (water runner), CS (cola sedentary) and CR (cola runner). Body weight, nutritional data, plasma levels of glucose, creatinine, total cholesterol and cholesterol fractions, and triglycerides (enzymocolorimetry), and systolic blood pressure (plethysmography) were measured. After 6 months, euthanasia was performed (overdose sodium thiopental). Pancreatic tissue was immediately excised and conventionally processed for morphometrical and immunohistochemical determinations.ResultsThe effects of running and chronic cola drinking on pancreas morphology showed interaction (p<0.001) rather than simple summation. Cola drinking (CS vs WS) reduced median pancreatic islet area (-30%, 1.8 104 μm2 vs 2.58 104 μm2, p<0.0001) and median β-cell mass (-43%, 3.81 mg vs 6.73 mg, p<0.0001), and increased median α/β ratio (+49%, 0.64 vs 0.43, p< 0.001). In water drinking rats (WR vs WS), running reduced median α-cell mass (-48%, 1.48 mg vs 2.82 mg, p<0.001) and α/β ratio (-56%, 0.19 vs 0.43, p<0.0001). Differently, in cola drinking rats (CR vs CS), running partially restored median islet area (+15%, 2.06 104 μm2 vs 1.79 104 μm2, p<0.05), increased median β-cell mass (+47%, 5.59 mg vs 3.81 mg, p <0.0001) and reduced median α/β ratio (-6%, 0.60 vs 0.64, p<0.05).ConclusionThis study is likely the first reporting experimental evidence of the beneficial effect of exercise on pancreatic morphology in cola-drinking rats. Presently, the increase of nearly 50% in β cells mass by running in cola drinking rats is by far the most relevant finding. Moderate running, advisably indicated in cola consumers and patients at risk of diabetes, finds here experimental support.

Vasodilation by agents such as bradykinin and ATP is dependent on nitric oxide, the endothelium-dependent relaxing factor (EDRF). The release of EDRF results in elevation of cGMP in endothelial and smooth muscle cells (9). The signaling pathway that leads to increases in cGMP is not completely understood. The role of protein kinase C (PKC) in the elevation of cGMP induced by ATP and bradykinin was studied in cultured porcine aortic endothelial cells, by measuring PKC phosphorylation of a substrate and by measuring cGMP levels by radioimmunoassay. Extracellular ATP and bradykinin simultaneously elevated cGMP levels and PKC activity. The PKC inhibitors staurosporine, calphostin C, and Cremophor EL (T. Tamaoki and H. Nakano. Bio/Technology 8: 732–735, 1990; F. K. Zhao, L. F. Chuang, M. Israel, and R. Y. Chuang. Biochem. Biophys. Res. Commun. 159: 1359–1367, 1989) prevented the elevation of cGMP elicited by ATP and reduced that produced by bradykinin. Cremophor did not affect the elevation of cGMP by nitroprusside, an agent that directly increases guanylate cyclase activity (9). The PKC activator phorbol 12-myristate 13-acetate, but not a phorbol ester analog inactive on PKC, also elevated cGMP levels. These results suggest that EDRF agonists elevate cGMP in endothelial cells via PKC stimulation.

This study was conducted in order to evaluate the effect of cola beverages drinking on atherosclerosisand test the hypothesis whether cola beverages consumption at early life stages might affect the development and progression of atherosclerosis later in life.ApoE−/− C57BL/6J mice (8 week-old) were randomized in 3 groups (n = 20 each) according to free accessto water (W), sucrose sweetened carbonated cola drink(C) or aspartame-acesulfame K sweetened carbonated ‘light’ cola drink (L)for the next 8 weeks. Drinking treatment was ended by switching C and L groups to drinking water. Four mice per group and time were sequentially euthanized: before treatment (8weeks-old), at the end of treatment (16 weeks-old) and after treatment discontinuation (20 weeks-old, 24 weeks-old, 30 week-old mice). Aortic roots and livers were harvested, processed for histology and serial cross-sections were stained. Aortic plaque area was analyzed and plaque/media-ratio was calculated.Early consumption of cola drinks accelerated atherosclerotic plaque progression favoring the interaction between macrophages and myofibroblasts, without the participation of either T lymphocytes or proliferative activity. Plaque/media-ratio varied according to drink treatment (F2,54 = 3.433, p<0.04) and mice age (F4,54 = 5.009, p<0.03) and was higher in C and L groups compared with age-matched W group (p<0.05 at 16 weeks and 20 weeks, p<0.01 at 24 weeks and 30 weeks). Natural evolution of atherosclerosis in ApoE−/− mice (W group) evidenced atherosclerosis acceleration in parallel with a rapid increase in liver inflammation around the 20 weeks of age.Cola drinking within the 8–16 weeks of age accelerated atherosclerosis progression in ApoE−/− mice favoring aortic plaque enlargement (inward remodeling) over media thinning all over the study time. Data suggest that cola drinking at early life stages may predispose to atherosclerosis progression later in life in ApoE−/− mice.

We report experimental evidence confirming renal histopathology, proinflammatory mediators, and oxidative metabolism induced by cola drinking. Male Wistar rats drank ad libitum regular cola (C, n = 12) or tap water (W, n = 12). Measures. Body weight, nutritional data, plasma glucose, cholesterol fractions, TG, urea, creatinine, coenzyme Q10, SBP, and echocardiograms (0 mo and 6 mo). At 6 months euthanasia was performed. Kidneys were processed for histopathology and immunohistochemistry (semiquantitative). Compared with W, C rats showed (I) overweight (+8%, p < 0.05), hyperglycemia (+11%, p < 0.05), hypertriglyceridemia (2-fold, p < 0.001), higher AIP (2-fold, p < 0.01), and lower Q10 level (−55%, p < 0.05); (II) increased LV diastolic diameter (+9%, p < 0.05) and volume (systolic +24%, p < 0.05), posterior wall thinning (−8%, p < 0.05), and larger cardiac output (+24%, p < 0.05); (III) glomerulosclerosis (+21%, p < 0.05), histopathology (+13%, p < 0.05), higher tubular expression of IL-6 (7-fold, p < 0.001), and TNFα (4-fold, p < 0.001). (IV) Correlations were found for LV dimensions with IL-6 (74%, p < 0.001) and TNFα (52%, p < 0.001) and fully abolished after TG and Q10 control. Chronic cola drinking induced cardiac remodeling associated with increase in proinflammatory cytokines and renal damage. Hypertriglyceridemia and oxidative stress were key factors. Hypertriglyceridemic lipotoxicity in the context of defective antioxidant/anti-inflammatory protection due to low Q10 level might play a key role in cardiorenal disorder induced by chronic cola drinking in rats.