J. Rioja

Low Doses of Insulin-Like Growth Factor-I Induce Mitochondrial Protection in Aging Rats

Serum IGF-I levels decline with age. We have recently reported that in aging rats the exogenous administration of IGF-I restores IGF-I circulating levels and age related-changes, improving glucose and lipid metabolisms, increasing testosterone levels and serum total antioxidant capability, and reducing oxidative damage in the brain and liver associated with a normalization of antioxidant enzyme activities. Understanding that mitochondria are one of the most important cellular targets of IGF-I, the aims of this study were to characterize mitochondrial dysfunction and study the effect of IGF-I therapy on mitochondria, leading to cellular protection in the following experimental groups: young controls, untreated old rats, and aging rats treated with IGF-I. Compared with young controls, untreated aging rats showed an increase of oxidative damage in isolated mitochondria with a mitochondrial dysfunction characterized by: depletion of membrane potential with increased proton leak rates and intramitochondrial free radical production, and a significant reduction of ATPase and complex IV activities. In addition, mitochondrial respiration from untreated aging rats was atractyloside insensitive, suggesting that the adenine nucleotide translocator was uncoupled. The adenine nucleotide translocator has been shown to be one of the most sensitive locations for pore opening. Accordingly, untreated aging rats showed a significant overexpression of the active fragment of caspases 3 and 9. IGF-I therapy corrected these parameters of mitochondrial dysfunction and reduced caspase activation. In conclusion, these results show that the cytoprotective effect of IGF-I is closely related to a mitochondrial protection, leading to reduce free radical production, oxidative damage, and apoptosis, and to increased ATP production.

Omega 3 fatty acids induce a marked reduction of apolipoprotein B48 when added to fluvastatin in patients with type 2 diabetes and mixed hyperlipidemia: a preliminary report

BackgorundMixed hyperlipidemia is common in patients with diabetes. Statins, the choice drugs, are effective at reducing lipoproteins that contain apolipoprotein B100, but they fail to exert good control over intestinal lipoproteins, which have an atherogenic potential. We describe the effect of prescription omega 3 fatty acids on the intestinal lipoproteins in patients with type 2 diabetes who were already receiving fluvastatin 80 mg per day.MethodsPatients with type 2 diabetes and mixed hyperlipidemia were recruited. Fasting lipid profile was taken when patients were treated with diet, diet plus 80 mg of fluvastatin and diet plus fluvastatin 80 mg and 4 g of prescription omega 3 fatty acids. The intestinal lipoproteins were quantified by the fasting concentration of apolipoprotein B48 using a commercial ELISA.ResultsThe addition of 4 g of prescription omega 3 was followed by significant reductions in the levels of triglycerides, VLDL triglycerides and the triglyceride/HDL cholesterol ratio, and an increase in HDL cholesterol (P < 0.05). Fluvastatin induced a reduction of 26% in B100 (P < 0.05) and 14% in B48 (NS). However, the addition of omega 3 fatty acids enhanced this reduction to 32% in B100 (NS) and up to 36% in B48 (P < 0.05).ConclusionOur preliminary findings therefore suggest an additional benefit on postprandial atherogenic particles when omega 3 fatty acids are added to standard treatment with fluvastatin.

Additive effects of LPL, APOA5 and APOE variant combinations on triglyceride levels and hypertriglyceridemia: results of the ICARIA genetic sub-study

BackgroundHypertriglyceridemia (HTG) is a well-established independent risk factor for cardiovascular disease and the influence of several genetic variants in genes related with triglyceride (TG) metabolism has been described, including LPL, APOA5 and APOE. The combined analysis of these polymorphisms could produce clinically meaningful complementary information.MethodsA subgroup of the ICARIA study comprising 1825 Spanish subjects (80% men, mean age 36 years) was genotyped for the LPL-HindIII (rs320), S447X (rs328), D9N (rs1801177) and N291S (rs268) polymorphisms, the APOA5-S19W (rs3135506) and -1131T/C (rs662799) variants, and the APOE polymorphism (rs429358; rs7412) using PCR and restriction analysis and TaqMan assays. We used regression analyses to examine their combined effects on TG levels (with the log-transformed variable) and the association of variant combinations with TG levels and hypertriglyceridemia (TG ≥ 1.69 mmol/L), including the covariates: gender, age, waist circumference, blood glucose, blood pressure, smoking and alcohol consumption.ResultsWe found a significant lowering effect of the LPL-HindIII and S447X polymorphisms (p < 0.0001). In addition, the D9N, N291S, S19W and -1131T/C variants and the APOE-ε4 allele were significantly associated with an independent additive TG-raising effect (p < 0.05, p < 0.01, p < 0.001, p < 0.0001 and p < 0.001, respectively). Grouping individuals according to the presence of TG-lowering or TG-raising polymorphisms showed significant differences in TG levels (p < 0.0001), with the lowest levels exhibited by carriers of two lowering variants (10.2% reduction in TG geometric mean with respect to individuals who were homozygous for the frequent alleles of all the variants), and the highest levels in carriers of raising combinations (25.1% mean TG increase). Thus, carrying two lowering variants was protective against HTG (OR = 0.62; 95% CI, 0.39-0.98; p = 0.042) and having one single raising polymorphism (OR = 1.20; 95% CI, 1.39-2.87; p < 0.001) or more (2 or 3 raising variants; OR = 2.90; 95% CI, 1.56-5.41; p < 0.001) were associated with HTG.ConclusionOur results showed a significant independent additive effect on TG levels of the LPL polymorphisms HindIII, S447X, D9N and N291S; the S19W and -1131T/C variants of APOA5, and the ε4 allele of APOE in our study population. Moreover, some of the variant combinations studied were significantly associated with the absence or the presence of hypertriglyceridemia.

Lipoprotein lipase activity and mass, apolipoprotein C-II mass and polymorphisms of apolipoproteins E and A5 in subjects with prior acute hypertriglyceridaemic pancreatitis

BackgroundSevere hypertriglyceridaemia due to chylomicronemia may trigger an acute pancreatitis. However, the basic underlying mechanism is usually not well understood. We decided to analyze some proteins involved in the catabolism of triglyceride-rich lipoproteins in patients with severe hypertriglyceridaemia.MethodsTwenty-four survivors of acute hypertriglyceridaemic pancreatitis (cases) and 31 patients with severe hypertriglyceridaemia (controls) were included. Clinical and anthropometrical data, chylomicronaemia, lipoprotein profile, postheparin lipoprotein lipase mass and activity, hepatic lipase activity, apolipoprotein C II and CIII mass, apo E and A5 polymorphisms were assessed.ResultsOnly five cases were found to have LPL mass and activity deficiency, all of them thin and having the first episode in childhood. No cases had apolipoprotein CII deficiency. No significant differences were found between the non-deficient LPL cases and the controls in terms of obesity, diabetes, alcohol consumption, drug therapy, gender distribution, evidence of fasting chylomicronaemia, lipid levels, LPL activity and mass, hepatic lipase activity, CII and CIII mass or apo E polymorphisms. However, the SNP S19W of apo A5 tended to be more prevalent in cases than controls (40% vs. 23%, NS).ConclusionPrimary defects in LPL and C-II are rare in survivors of acute hypertriglyceridaemic pancreatitis; lipase activity measurements should be restricted to those having their first episode during chilhood.

Exploring the value of apoB48 as a marker for atherosclerosis in clinical practice.

Eur J Clin Invest 2012; 42 (7): 702–708

Cognitive Dysfunctions in Middle-Aged Type 2 Diabetic Patients and Neuroimaging Correlations: A Cross-Sectional Study

BACKGROUND/OBJECTIVE The aim was to assess the neuropsychological performance of a group of middle-aged patients with well-controlled type 2 diabetes mellitus (T2DM) and to examine whether the neuropsychological deficits correlate with structural and functional brain alterations. METHODS We compared 25 subjects with T2DM aged 45-65 years with 25 control participants matched for age, gender, and educational level. The neuropsychological battery was designed to examine executive functions, attention, information processing speed, and verbal memory. Severity of depression was assessed using the Hamilton Depression Rating Scale and cardiovascular risk factors were assessed using the Framingham Cardiovascular Risk Profile Score. The presence of at least one APOEε4 allele was determined. Reduced gray matter density was analyzed using voxel-based morphometry and brain glucose metabolic changes were assessed by 18FDG-PET. RESULTS T2DM subjects had significantly lower scores than subjects without T2DM in the Trail-making Test B (p < 0.004), Color-Word Stroop test (p < 0.005), Semantic Fluency (p < 0.006), Digit-Symbol modalities test (p < 0.02), Text Recall from the Wechsler Memory Scale (p < 0.0001), Rey-Osterrieth Complex Figure-copy (p < 0.004), and delayed reproduction (p < 0.03). Worse executive functions and memory functioning correlated predominantly with less gray matter density and reduced glucose metabolism in the orbital and prefrontal cortex, temporal (middle gyrus, parahippocampus and uncus), and cerebellum regions (p < 0.001). CONCLUSIONS T2DM subjects presented cognitive dysfunctions compared with controls. Clinical-neuroimaging correlations corresponded to brain changes (reduced gray matter density and glucose metabolism) mainly in fronto-temporal areas.

Postprandial apolipoprotein B48 is associated with asymptomatic peripheral arterial disease: a study in patients with type 2 diabetes and controls.

BACKGROUND Postprandial hyperlipidemia is a common feature in type 2 diabetes; our aim was to investigate whether there is an association between subclinical peripheral arterial disease (PAD) and the levels of apolipoprotein B48, as a specific marker for postprandial lipidemia. METHODS We enrolled 101 patients with type 2 diabetes and 73 controls free from clinical cardiovascular disease. Main outcome measures were the presence of subclinical PAD, assessed by the ankle-brachial index, and the intestinal particles measured as the concentration of apolipoprotein B48 at fasting and 4h after a mixed breakfast. RESULTS No control had subclinical PAD. Of the 101 diabetic patients, 21 had subclinical PAD. The levels of apo B48, both fasting and postprandial, were only significantly raised in the diabetic patients who had PAD. The diabetic patients without vascular disease had similar concentrations of triglycerides and apo B48 to the controls. In binary logistic regression analyses, only smoking and postprandial B48 levels, in addition to diabetes, were independently associated with PAD. On the other hand, PAD but not diabetes was associated with the fasting and postprandial levels of apo B48. CONCLUSION Our study suggests that apolipoprotein B48 levels might be a marker of occult PAD in patients suffering from type 2 diabetes mellitus. Accordingly, subclinical PAD should be taken into account in studies on postprandial lipidemia involving patients with diabetes.

Association of the -250G/A promoter polymorphism of the hepatic lipase gene with the risk of peripheral arterial disease in type 2 diabetic patients

AIM This study aimed to investigate the association between a polymorphism in the hepatic lipase (LIPC) gene promoter and the presence of peripheral arterial disease (PAD) in persons with type 2 diabetes. PATIENT AND METHODS We evaluated 120 type 2 diabetics and identified those with PAD according to the ankle-arm index. The G-250A polymorphisms in the promoter of the LIPC gene were studied by PCR restriction. A logistic regression analysis was performed to determine the association between the rare allele and PAD. RESULTS The prevalence of PAD was 19%. The frequency of the -250A allele was 0.211 in the group without PAD and 0.395 in the group with PAD (P<.05). Carriers of the -250A allele differed only in the ankle-arm index (0.92+/-0.12 for carriers vs. 1.00+/-0.12 for noncarriers, P<.05), with the difference remaining significant after adjustment for covariates (age; sex; waist-to-hip ratio; body mass index; duration of diabetes; smoking; hypertension; glycated hemoglobin; triglycerides; HDL cholesterol; LDL cholesterol; small, dense LDL cholesterol). Only smoking [odds ratio (OR)=6.93, 95% confidence interval (CI)=2.12-22.69, P=.001] and the -250A allele (OR=2.89, 95% CI=1.07-7.84, P=.036) were significantly associated with vascular disease in the logistic regression analysis. CONCLUSIONS Patients with type 2 diabetes who are carriers of the rare -250A allele in the promoter of the hepatic lipase gene are susceptible to PAD.

Plasma redox status is impaired in the portacaval shunted rat – the risk of the reduced antioxidant ability

BackgroundPortacaval shunting in rats produces a reduction of hepatic oxidant scavenging ability. Since this imbalance in hepatic oxidant/antioxidant homeostasis could coexist with systemic changes of oxidant stress/antioxidant status, plasma oxidants and antioxidant redox status in plasma of portacaval shunted-rats were determined.ResultsMale Wistar male: Control (n = 11) and with portacaval shunt (PCS; n = 11) were used. Plasma levels of the oxidant serum advanced oxidation protein products (AOPP), lipid hydroperoxides (LOOH), the antioxidant total thiol (GSH) and total antioxidant status (TAX) were measured. Albumin, ammonia, Aspartate-aminotransferase (AST), Alanine-aminotransferase (ALT), thiostatin and alpha-1-acid glycoprotein (α1-AGP) were also assayed 4 weeks after the operation. AOPPs were significantly higher (50.51 ± 17.87 vs. 36.25 ± 7.21 μM; p = 0.02) and TAX was significantly lower (0.65 ± 0.03 vs. 0.73 ± 0.06 mM; p = 0.007) in PCS compared to control rats. Also, there was hypoalbuminemia (2.54 ± 0.08 vs. 2.89 ± 0.18 g/dl; p = 0.0001) and hyperammonemia (274.00 ± 92.25 vs. 104.00 ± 48.05 μM; p = 0.0001) and an increase of thiostatin (0.23 ± 0.04 vs. 0.09 ± 0.01 mg/ml; p = 0.001) in rats with a portacaval shunt. The serum concentration of ammonia is correlated with albumin levels (r = 0.624; p = 0.04) and TAX correlates with liver weight (r = 0.729; p = 0.017) and albumin levels (r = 0.79; p = 0.007)ConclusionThese findings suggest that in rats with a portacaval shunt a systemic reduction of oxidant scavenging ability, correlated with hyperammonemia, is principally produced. It could be hypothesized, therefore, that the reduced antioxidant defences would mediate a systemic inflammation.

5‐HT1A Receptor Activation before Acute Stress Counteracted the Induced Long‐Term Behavioral Effects

Abstract: The long‐term behavioral consequences of acute immobilization (IMMO) in rats and the effects of 5‐HT1A receptor activation (8‐OH‐DPAT: 0.3 mg/kg, sc) were studied. Corticosterone levels after IMMO with previous 8‐OH‐DPAT treatment were also studied. Twenty‐four hours after IMMO (3 h), rats performed conditioned (passive avoidance) and unconditioned (escape behavior) anxiety tests in the elevated T maze. Pre‐exposure to IMMO induces long‐term behavioral changes in contrast with control rats. These behavioral alterations include an increase of anxiogenic responses, such as exploratory behavior and passive avoidance response. This effect was counteracted by 8‐OH‐DPAT pretreatment and reversed by WAY‐100635 when administered before 8‐OH‐DPAT. Serum corticosterone levels increased during the first hour of stress and after 8‐OH‐DPAT administration. Our results support the hypothesis that involvement of acute stress is crucial in the anxiety‐like behaviors and in the potentiation of fear. The activation of 5‐HT1A receptors counteracted the long‐term effects induced by IMMO.