Effect of Tie-2 conditional deletion of BDNF on atherosclerosis in the ApoE null mutant mouse

The reduced expression (haplodeficiency) of the main brain derived neurotrophic factor receptor, namely TrkB is associated with reduced atherosclerosis, smooth muscle cells accumulation and collagen content in the lesion. These data support the concept that brain derived neurotrophic factor of vascular origin may contribute to atherosclerosis. However, to date, no experimental approach was possible to investigate this issue due to the lethality of brain derived neurotrophic factor null mice. To overcome these limitations, we generated a mouse model with a conditional deletion of brain derived neurotrophic factor in endothelial cells (Tie-2 Cre recombinase) on an atherosclerotic prone background (apolipoprotein E knock out) and investigated the effect of conditional brain derived neurotrophic factor deficiency on atherosclerosis. Despite brain derived neurotrophic factor reduction in the vascular wall, mice with conditional deletion of brain derived neurotrophic factor did not develop larger atherosclerotic lesion compared to controls. Smooth muscle cell content as well as the distribution of total and fibrillar collagen was similar in the atherosclerotic lesions from mice with brain derived neurotrophic factor conditional deficiency compared to controls. Finally an extended gene expression analysis failed to identify pro-atherogenic gene expression patterns among the animal with brain derived neurotrophic factor deficiency. In spite of the reduced brain derived neurotrophic factor expression, similar atherosclerosis development was observed in the brain derived neurotrophic factor conditional deficient mouse compared to controls. These pieces of evidence indicate that endothelial derived-brain derived neurotrophic factor is not a pro-atherogenic factor and would rather suggest to investigate the role of other TrkB activators on atherosclerosis.     

Nutrient-dependent requirement for SOD1 in lifespan extension by protein restriction in Drosophila melanogaster

Reactive oxygen species (ROS) modulate aging and aging-related diseases. Dietary composition is critical in modulating lifespan. However, how ROS modulate dietary effects on lifespan remains poorly understood. Superoxide dismutase 1 (SOD1) is a major cytosolic enzyme responsible for scavenging superoxides. Here we investigated the role of SOD1 in lifespan modulation by diet in Drosophila. We found that a high sugar-low protein (HS-LP) diet or low-calorie diet with low-sugar content, representing protein restriction, increased lifespan but not resistance to acute oxidative stress in wild-type flies, relative to a standard base diet. A low sugar-high protein diet had an opposite effect. Our genetic analysis indicated that SOD1 overexpression or dfoxo deletion did not alter lifespan patterns of flies responding to diets. However, sod1 reduction blunted lifespan extension by the HS-LP diet but not the low-calorie diet. HS-LP and low-calorie diets both reduced target of rapamycin (TOR) signaling and only the HS-LP diet increased oxidative damage. sod1 knockdown did not affect phosphorylation of S6 kinase, suggesting that SOD1 acts in parallel with or downstream of TOR signaling. Surprisingly, rapamycin decreased lifespan in sod1 mutant but not wild-type males fed the standard, HS-LP, and low-calorie diets, whereas antioxidant N-acetylcysteine only increased lifespan in sod1 mutant males fed the HS-LP diet, when compared to diet-matched controls. Our findings suggest that SOD1 is required for lifespan extension by protein restriction only when dietary sugar is high and support the context-dependent role of ROS in aging and caution the use of rapamycin and antioxidants in aging interventions.     

Lecithin cholesterol acyl transferase deficiency: molecular analysis of a mutated allele

Summary The enzyme, lecithin cholesterol acyltransferase (LCAT), is responsible for the esterification of plasma cholesterol mediating the transfer of an acyl group from lecithin to the 3-hydroxy group of cholesterol. Deficiency of the enzyme is a well-known syndrome with a widespread geographic occurrence. We have cloned an allele from a patient homozygous for the LCAT deficiency. The only change that we could detect is a C to T transition in the fourth exon of the gene; this causes a substitution of Arg for Trp at position 147 of the mature protein. The functional significance of such a substitution with respect to the enzyme defect was demonstrated by transfecting the mutated LCAT gene in the cell line COS-1.     

Dual effect of hypochlorite in the modification of high density lipoproteins

HDL-cholesterol levels are inversely correlated to the risk of cardiovascular disease. In recent years the concept that not only the quantity, but also the quality of HDL is related to their atheroprotective function has gained momentum. In fact several studies have showed that HDL can shift their properties from anti-atherogenic to pro-atherogenic upon chemical or enzymatic "modification". However, not all kind of modifications affect the antiatherogenic properties of HDL. For example, tyrosylation of HDL improves its ability to remove cholesterol from cultured cells and inhibits mice atherosclerotic lesion formation; oxidation of HDL(3) with 15-lipoxygenase or with copper ions for short time induce the formation of pre-β-migrating particles that are highly effective as cholesterol acceptors from lipid laden cells. Myeloperoxidase modifies HDL and apoA-I and reduces their ability to promote ABCA1-mediated cholesterol efflux. In the present study we show that modification with low concentration HOCl (a myeloperoxidase product) induces the formation of pre-β-migrating particles, thus improving the function of HDL in the reverse cholesterol transport, without affecting the anti-inflammatory activity. At higher HOCl concentration, pre-β-migrating particles were not detectable and the anti-inflammatory properties of HDL were lost. These findings suggest that during early phases of inflammation, when a low HOCl concentration is generated, changes in HDL occur that increase their ability to remove cholesterol and sparing anti-inflammatory properties; later during acute inflammation, when higher HOCl concentration are present changes in HDL occur that severely decrease their ability to remove cholesterol from macrophages and to protect endothelial cells from pro-inflammatory stimuli.     

Lower Rate of Cardiovascular Complications in Patients on Bolus Insulin Analogues: A Retrospective Population-Based Cohort Study

Background

Few studies are available evaluating the impact of rapid-acting insulin analogues on long-term diabetes outcomes. Our aim was to compare the use of rapid-acting insulin analogues versus human regular insulin in relation to the occurrence of diabetic complications in a cohort of diabetic patients through the analysis of administrative databases.

Methods

A population-based cohort study was conducted using administrative data from four local health authorities in the Abruzzo Region (900,000 inhabitants). Diabetic patients free of macrovascular disease at baseline and treated either with human regular insulin or rapid-acting insulin analogues were followed for a maximum of 3 years. The incidence of diabetic complications was ascertained by hospital discharge claims. Hazard ratios (HRs) and 95% CIs of any diabetic complication and macrovascular, microvascular and metabolic complications were estimated separately using Cox proportional hazard models adjusted for patients’ characteristics and anti-diabetic drug use. Propensity score matching was also used to adjust for significant difference in the baseline characteristics between the two treatment groups.

Results

A total of 2,286 patients were included: 914 receiving human regular insulin and 1,372 rapid-acting insulin analogues. During the follow-up, 286 (31.3%) incident events occurred in the human regular insulin group and 235 (17.1%) in the rapid-acting insulin analogue group. After propensity score-based matched-pair analyses, rapid-acting insulin analogues users had a HR of 0.73 (0.58–0.92) for any diabetes-related complication and HRs of 0.73 (0.55–0.93) and 0.55 (0.32–0.96) for macrovascular and metabolic complications respectively, as compared with human regular insulin users. No difference between the two groups was found for microvascular complications.

Conclusions

Our findings suggest that the use of rapid-acting insulin analogues is associated with a lower risk of cardiovascular and metabolic complications compared with human regular insulin use.     

Nectarine promotes longevity in Drosophila melanogaster

Fruits containing high antioxidant capacities and other bioactivities are ideal for promoting longevity and health span. However, few fruits are known to improve the survival and health span in animals, let alone the underlying mechanisms. Here we investigate the effects of nectarine, a globally consumed fruit, on life span and health span in Drosophila melanogaster. Wild-type flies were fed standard, dietary restriction (DR), or high-fat diet supplemented with 0-4% nectarine extract. We measured life span, food intake, locomotor activity, fecundity, gene expression changes, and oxidative damage indicated by the level of 4-hydroxynonenal-protein adduct in these flies. We also measured life span, locomotor activity, and oxidative damage in sod1 mutant flies on the standard diet supplemented with 0-4% nectarine. Supplementation with 4% nectarine extended life span, increased fecundity, and decreased expression of some metabolic genes, including a key gluconeogenesis gene, PEPCK, and oxidative stress-response genes, including peroxiredoxins, in female wild-type flies fed the standard, DR, or high-fat diet. Nectarine reduced oxidative damage in wild-type females fed the high-fat diet. Moreover, nectarine improved the survival of and reduced oxidative damage in female sod1 mutant flies. Together, these findings suggest that nectarine promotes longevity and health span partly by modulating glucose metabolism and reducing oxidative damage.     

Chemo-Predictive Assay for Targeting Cancer Stem-Like Cells in Patients Affected by Brain Tumors

Administration of ineffective anticancer therapy is associated with unnecessary toxicity and development of resistant clones. Cancer stem-like cells (CSLCs) resist chemotherapy, thereby causing relapse of the disease. Thus, development of a test that identifies the most effective chemotherapy management offers great promise for individualized anticancer treatments. We have developed an ex vivo chemotherapy sensitivity assay (ChemoID), which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents. Two patients, a 21-year old male (patient 1) and a 5-month female (patient 2), affected by anaplastic WHO grade-III ependymoma were screened using the ChemoID assay. Patient 1 was found sensitive to the combination of irinotecan and bevacizumab, which resulted in a prolonged disease progression free period of 18 months. Following recurrence, the combination of various chemotherapy drugs was tested again with the ChemoID assay. We found that benzyl isothiocyanate (BITC) greatly increased the chemosensitivity of the ependymoma cells to the combination of irinotecan and bevacizumab. After patient 1 was treated for two months with irinotecan, bevacizumab and supplements of cruciferous vegetable extracts containing BITC, we observed over 50% tumoral regression in comparison with pre-ChemoID scan as evidenced by MRI. Patient 2 was found resistant to all treatments tested and following 6 cycles of vincristine, carboplatin, cyclophosphamide, etoposide, and cisplatin in various combinations, the tumor of this patient rapidly progressed and proton beam therapy was recommended. As expected animal studies conducted with patient derived xenografts treated with ChemoID screened drugs recapitulated the clinical observation. This assay demonstrates that patients with the same histological stage and grade of cancer may vary considerably in their clinical response, suggesting that ChemoID testing which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents could lead to more effective and personalized anticancer treatments in the future.     

Parameters of tubulo-glomerular function in anesthetized rabbits with acute kidney insufficiency

We have induced acute renal failure (ARF) in barbiturate anesthetized rabbits, through warm ischaemia of 30 or 60 min duration caused by transient bilateral occlusion of renal arteries. In this model we have monitored some renal performance parameters, before and 4 hours after reperfusion, aiming to characterize ARF in this animal species. Glomerular filtration rate (determined by the inulin clearance technique) was of 9.74 +/- 0.48 ml min-1 in 4 rabbits before injury and declined by 91% (60 min ischemia) during the first reperfusion hour. In 6 rabbits undergoing 30 min occlusion, pre-ARF values of 10.70 +/- 0.98 ml min-1 declined by 47%. In both groups no recovery was observed in the following hours. Tubular enzymes (alanine-amino-peptidase, AAP and N-acetyl-beta-glucosaminidase, NAG) were released into urines before injury at the rate of 1.11 +/- 0.18 and 1.32 +/- 0.41 mU min-1, respectively, in the 30 min model (3 animals/group). During ARF, maximal AAP output was five-fold increased (5.83 +/- 0.35 mU min-1), whereas NAG was unmodified. On the other hand, renal haemodynamics in 5 rabbits did not change after the ischaemic procedure: total renal blood flow (44 +/- 5 ml min-1) and renal vascular resistances (225 +/- 26 Pa ml-min) displayed less than 10% variations throughout the reperfusion period. We concluded that ARF in rabbits can be reliably and reproducibly monitored and that the pathogenesis of the disease, in our situation, is attributable mainly to tubular cell damage and not to impairment of the vascular component of renal performance.