Altered inflammation, paraoxonase-1 activity and HDL physicochemical properties in obese humans with and without Prader-Willi syndrome

Prader-Willi syndrome (PWS) represents the most common form of genetic obesity. Several studies confirm that obesity is associated with inflammation, oxidative stress and impairment of antioxidant systems; however, no data are available concerning PWS subjects. We compared levels of plasma lipids and C-reactive protein (CRP) in 30 subjects of 'normal' weight (18.5-25 kg/m(2)), 15 PWS obese (>30 kg/m(2)) subjects and 13 body mass index (BMI)-matched obese subjects not affected by PWS. In all subjects, we evaluated the levels of lipid hydroperoxides and the activity of paraoxonase-1 (PON1), an enzyme involved in the antioxidant and anti-inflammatory properties exerted by high-density lipoproteins (HDLs). Furthermore, using the fluorescent molecule of Laurdan, we investigated the physicochemical properties of HDLs isolated from normal weight and obese individuals. Altogether, our results demonstrated, for the first time, higher levels of lipid hydroperoxides and a lower PON1 activity in plasma of obese individuals with PWS with respect to normal-weight controls. These alterations are related to CRP levels, with a lower PON1:CRP ratio in PWS compared with non-PWS obese subjects. The study of Laurdan fluorescence parameters showed significant modifications of physicochemical properties in HDLs from PWS individuals. Whatever the cause of obesity, the increase of adiposity is associated with inflammation, oxidative stress and alterations in HDL compositional and functional properties.

Celiac disease, inflammation and oxidative damage: a nutrigenetic approach

Celiac disease (CD), a common heritable chronic inflammatory condition of the small intestine caused by permanent intolerance to gluten/gliadin (prolamin), is characterized by a complex interplay between genetic and environmental factors. Developments in proteomics have provided an important contribution to the understanding of the biochemical and immunological aspects of the disease and the mechanisms involved in toxicity of prolamins. It has been demonstrated that some gliadin peptides resistant to complete proteolytic digestion may directly affect intestinal cell structure and functions by modulating gene expression and oxidative stress. In recent years, the creation of the two research fields Nutrigenomics and Nutrigenetics, has enabled the elucidation of some interactions between diet, nutrients and genes. Various dietary components including long chain ω-3 fatty acids, plant flavonoids, and carotenoids have been demonstrated to modulate oxidative stress, gene expression and production of inflammatory mediators. Therefore their adoption could preserve intestinal barrier integrity, play a protective role against toxicity of gliadin peptides and have a role in nutritional therapy of celiac disease.

Correlation between lipoprotein(a) and lipid peroxidation in psoriasis: role of the enzyme paraoxonase-1

BACKGROUND

Psoriasis is a chronic, inflammatory skin disease associated with abnormal plasma lipid metabolism and with a high frequency of cardiovascular events. Modifications of plasma lipids and an increase in the levels of biochemical markers of lipid peroxidation have been reported in subjects with psoriasis, suggesting a relationship between psoriasis, lipoproteins and oxidative damage.

OBJECTIVES

To investigate further the relationship between lipoproteins and oxidative stress in psoriasis.

METHOD

The levels of plasma lipids, lipoprotein(a) [Lp(a)] and markers of lipid peroxidation were evaluated in subjects with psoriasis (n=23) and in controls (n=25). In the same subjects, the activity of paraoxonase-1 (PON1), an antioxidant and an anti-inflammatory enzyme associated with high-density lipoproteins, was investigated.

RESULTS

The results showed higher levels of Lp(a) in the serum of patients with psoriasis compared with controls (P<0·001). Higher levels of lipid hydroperoxides (P<0·001) and lower PON1 activity were observed in the serum of patients compared with healthy subjects, confirming that psoriasis is associated with oxidative stress. The imbalance between oxidative stress and antioxidant enzymes, and the increase of Lp(a) serum levels was related to the extent and severity of psoriasis. Finally, our results demonstrated that Lp(a) levels were positively correlated with markers of lipid peroxidation and negatively related to PON1 activity, suggesting that subjects with higher levels of Lp(a) are more exposed to oxidative damage.

CONCLUSIONS

Our results provide further evidence that oxidative stress and impairment of the antioxidant system in the plasma of patients may play a role in pathogenesis and progression of psoriasis and related complications.

Effect of dietary lipids on paraoxonase-1 activity and gene expression

AIMS

Aim of the paper was to summarize the literature about the effect of dietary lipids on activity of paraoxonase-1 (PON1), a multifunctional enzyme associated with high density lipoprotein (HDL). PON1 exerts a protective effect against oxidative damage of cells and lipoproteins and modulates the susceptibility of HDL and LDL to atherogenic modifications such as homocysteinylation.

DATA SYNTHESIS

The present review shows evidence that the amount and the composition of dietary lipids are key factors in the modulation of PON1. The effect of dietary lipids is also modulated by PON1 polymorphisms. The molecular mechanisms involved include an effect on PON1 hepatic synthesis or secretion and/or modification of PON1 interactions with HDL. Changes of PON1 activity could also be related to dietary intake of oxidized lipids that behave as PON1 inhibitors.

CONCLUSION

Dietary fatty acids by the modulation of PON1 gene expression and activity could constitute an useful approach for the prevention of human diseases associated with oxidative damage.

Peroxidation of lipoproteins in multiple sclerosis

Human plasma low density lipoproteins (LDL) and high density lipoproteins (HDL) are involved in the transport of lipids, modulate membrane lipid composition and regulate signal transduction. HDL-like lipoproteins have been shown also in human cerebrospinal fluid and it has been hypothesized that they could have a role in lipid transport in central nervous system. After synthesis, lipoproteins are susceptible to lipid peroxidation triggered by reactive oxygen species (ROS and RNS) produced by peripheral and brain cells. Aim of the paper has been to review the scientific literature on the role of lipid peroxidation of LDL and HDL in the molecular mechanisms of multiple sclerosis (MS). Several studies have demonstrated a significant increase in lipid peroxidation products in brain, plasma and cerebrospinal fluid of MS patients. The increase of antibodies against ox-LDL in plasma and the presence of ox-LDL in demyelinating plaques in MS brain suggests that the disease is associated with oxidative damage of lipoproteins. The impairment of antioxidant systems or an increase in the production of ROS and RNS could contribute to lipoprotein peroxidation in MS. Oxidized lipoproteins show several alterations of their functions, they are neurotoxic and have pro-inflammatory properties. Therefore lipoprotein lipid peroxidation products could be involved in demyelination and axonal injury in MS.

Polyomavirus BK replication in liver transplant candidates with normal renal function

Polyomavirus-associated nephropathy (PVAN) has a predilection for kidney rather than for other solid organ transplants such as the liver. Immunosuppression is widely recognized to be a major risk factor for PVAN development. Since end-stage liver disease (ESLD) patients are immunocompromised and immunosuppression is a major cause of BK virus reactivation, we sought to evaluate BK virus replication in patients listed for liver transplantation. From April to October 2010, we enrolled 20 patients listed for liver transplantation. BK virus load was measured by quantitative real-time polymerase chain reaction on plasma and urine samples. Viremia occurred in only 1 among 20 patients. We hypothesized that in ESLD patients, the low prevalence of BK virus infection may be related to the prevalent impairment of antibacterial immunity rather than to the viral-specific one. In BK virus reactivation, not only the immunodepressive state itself, but also the specific immunologic mechanisms involved may have a role.

Dental examiners consistency in applying the ICDAS criteria for a caries prevention community trial

AIM

To examine dental examiners' one-year consistency in utilizing the International Caries Detection and Assessment System (ICDAS) criteria after baseline training and calibration.

METHODS

A total of three examiners received baseline training/calibration by a "gold standard" examiner, and one year later re-calibration was conducted. For the baseline training/calibration, subjects aged 8-16 years, and for the re-calibration subjects aged five to six years were recruited for the study. The ICDAS criteria were used to classify visual caries lesion severity (0-6 scale), lesion activity (active/inactive), and presence of filling material (0-9 scale) of all available tooth surfaces of permanent and primary teeth. The examination used a clinical light, mirror and air syringe. Kappa (weighted: Wkappa, unweighted: Kappa) statistics were used to determine inter-and intra-examiner reliability at baseline and re-calibration.

RESULTS

For lesion severity and filling criteria, the baseline calibration on 35 subjects indicated an inter-rater Wkappa ranging from 0.69-0.92 and intra-rater Wkappa ranging from 0.81-0.92. Re-calibration on 22 subjects indicated an inter-rater Wkappa of 0.77-0.98 and intra-rater Wkappa ranged from 0.93-1.00. The Wkappa for filling was consistently in the excellent range, while lesion severity was in the good to excellent range. Activity kappa was in the poor to good range. All examiners improved with time.

CONCLUSIONS

The baseline training/calibration in ICDAS was crucial to maintain the stability of the examiners reliability over a one year period. The ICDAS can be an effective assessment tool for community-based clinical trials.

[What are the tools for post-occupational follow-up, how should they be performed and what are their performance, limits and benefit/risk ratio? Chest X-Ray and CT scan]

Chest radiography and computed tomography (CT) are the two radiological techniques used for the follow-up of people exposed to asbestos. Since the last conference of consensus (1999), the scientific literature has primarily covered high-resolution CT and high-resolution volume CT (HR-VCT). We consider in turn the contribution of digital thoracic radiography, recommendations for the performance of HR-VCT to ensure the quality of examination while controlling the delivered radiation dose, and the need to refer to the "CT atlas of benign diseases related to asbestos exposure", published by a group of French experts in 2007, for interpretation. The results of the published studies concerning radiography or CT are then reviewed. We note the great interobserver variability in the recognition of pleural plaques and asbestosis, indicating the need for adequate training of radiologists, and the importance of defining standardized, quantified criteria for CT abnormalities. The very low agreement between thoracic and general radiologists must be taken into account. The reading of CT scans in cases of occupational exposure to asbestos should be entrusted to thoracic radiologists or to general radiologists having validated specific training. A double interpretation of CT could be considered in medicosocial requests. CT is more sensitive than chest radiography in the detection of bronchial carcinoma but generates a great number of false positive results (96 to 99%). No scientific data are available to assess the role of imaging by either CT or chest radiography in the early detection of mesothelioma.

[Comparison of simple aspiration versus standard drainage in the treatment of large primary spontaneous pneumothorax]

BACKGROUND

Chest tube drainage is the standard treatment of a large spontaneous pneumothorax. Aspiration is an alternative technique that is simple and rapid to learn, and the success rate seems identical to chest tube drainage. Its widespread use justifies studies to define its place in the management strategy of spontaneous pneumothorax.

METHODS

We propose a multicentre, prospective, randomized, open trial with two parallel groups. The main objective is to compare the therapeutic efficacy of a simple aspiration with chest tube drainage for a first large spontaneous pneumothorax. The hypothesis is that aspiration is not inferior to a chest drain in its immediate effect. The secondary objectives are to compare the therapeutic efficacy at 24h and at one-week, the relapse rate at one year, and the tolerance and complications. A comparison of both the medical and economic aspects will be made. With an α-risk of 0.05 and a β-risk of 0.10, a proportion of failures of 30% expected in both groups and a target of non-inferiority of δ=0.15, the number of subjects to be included is 200 per group, totalling 400 in all.

EXPECTED RESULTS

In the case of equivalence, this study should help to better define the place of aspiration compared to chest tube drainage in the management of spontaneous pneumothorax.

Predictive parameters after molecular absorbent recirculating system treatment integrated with model for end stage liver disease model in patients with acute-on-chronic liver failure

AIM

The aim of study was to highlight parameters that in association with Model for End-stage Liver Disease (MELD) provide predictive criteria for long-term survival after treatment with the Molecular Adsorbent Recirculating System (MARS). Two homogenous groups were studied: one treated with standard medical therapy (SMT) and the other, with MARS.

MATERIALS AND METHODS

Twenty acute-on-chronic liver failure patients on the waiting list for liver transplantation and affected by alcoholic cirrhosis with similar MELD scores (20-29) were evaluated for 7 days from inclusion and for 6-month survival. Ten patients (seven males and three females) were treated with MARS. Their mean age was 48.5 years (range = 35-61). The number of MARS applications was six for 6 consecutive days, and the length of the applications was 8 hours. Ten other patients (seven males and three females) were treated with SMT, including prophylaxis against bacterial infections and judicious use of diuretics. The precipitating factors were also treated appropriately. The mean age of the patients was 51 years (range = 37-64). All the variables that were significant upon univariate analysis were enrolled in a receiver operating characteristic analysis, with the intention to detect predictive parameters for patient death at 6 months. We considered a significant area under curve (AUC) value to be greater than 0.5.

RESULTS

Among 11 patients who died within 6 months there were in the MARS group and eight in the SMT group: the 3- and 6-month patient survival rates were 90% and 70% versus 30% and 20% in the two groups, respectively. Nine measures resulted in an AUC > 0.5: DeltaMELD; interleukin (IL)-8; IL-6; tumor necrosis factor- alpha, MELD score; creatinine, bilirubin international normalized ratio (INR) and cardiac index. DeltaMELD and postoperative IL-8 concentrations showed better results (AUC = 0.899), followed by postoperative creatinine (AUC = 0.879), postoperative cardiac index (AUC = 0.833), and postoperative INR (AUC = 0.818). Postoperative creatinine showed the best sensitivity (100%), while IL-8, the best specificity (88.9%).

CONCLUSION

A combination of biochemical and clinical variables probably represent the best way to predict the survival of patients, allowing physicians to select the best therapies for each patient.

Meaning of early polyomavirus-BK replication post kidney transplant

Polyomavirus BK (BKV) infection is ubiquitous in the human population. Under immunosuppression, BKV can undergo reactivation resulting in viral replication. What really happens in the early hours posttransplantation is not clearly defined; the meaning of early viremia and viruria is not clear. BKV viremia is considered a marker of infection. The aim of our study was to investigate the prevalence of early BKV infection in kidney transplant patients, to evaluate the relationship to infections at 3 and 6 months and the association with recipient, donor, and graft features. We enrolled 36 kidney transplanted patients from May 2006 to April 2007. BKV load was measured on plasma and urine samples by Q-PCR at 12 hours (T(0)/early) as well as 3 (T(3)) and 6 (T(6)) months thereafter. A high percentage of BKV infections were detectable in the first hours after transplantation (33.3%), which remained unchanged to month 6 post transplantation. Moreover, patients who were positive at T(0) had a high probability of remaining positive thereafter. The number of copies in plasma samples tended to increase at 3 months and to decrease thereafter, whereas the urine viral load tended to steadily increase. Among BKV-positive patients, we identified 2 groups according to viremic state at T(0): 9 patients (group A); who were already positive and remained so to T(6) 5 and 3 patients who turned positive at 3 or at 6 months, respectively (group B). Group A included 75% of positive patients at T(0) and 90% of positive patients at either T(3) or T(6) (P = .007). The most important contribution of our study was to highlight the presence of BKV infection in renal transplant recipients from the first hours posttransplantation. This condition seemed to be the most important risk factor for persistent infection in the first 6 months.