[Optimizing the care management pathway of patients with ischemia and non-obstructive coronary arteries]. / Ottimizzazione del percorso clinico-gestionale del paziente con ischemia in assenza di malattia coronarica ostruttiva.

Ischemia with non-obstructive coronary arteries (INOCA) is defined by the coexistence of anginal symptoms and demonstrable ischemia, with no evidence of obstructive coronary arteries. The underlying mechanism of INOCA is coronary microvascular dysfunction with or without associated vasospasm. INOCA patients have recurrent symptoms, functional limitations, repeated access to the emergency department, impaired quality of life and a higher incidence of cardiovascular events than the general population. Although well described in chronic coronary syndrome guidelines, INOCA remains underdiagnosed in clinical practice because of insufficient awareness, lack of accurate diagnostic tools, and poorly standardized and consistent definitions to diagnose, both invasively and non-invasively, coronary microvascular dysfunction.To disseminate current scientific evidence on INOCA as a distinct clinical entity, during 2022 we conducted at 30 cardiology units all over the country a clinical practice improvement initiative, with the aim of developing uniform and shared management pathways for INOCA patients across different operational settings. The present document highlights the outcomes of this multidisciplinary initiative.

Predictive Value of Left Atrial and Ventricular Strain for the Detection of Atrial Fibrillation in Patients With Cryptogenic Stroke.

Background and Aims: Cryptogenic stroke (CS) is associated with a high rate of recurrences and adverse outcomes at long-term follow-up, especially due to its unknown etiology that often leads to ineffective secondary prevention. Asymptomatic atrial fibrillation (AF) could play an important pathophysiological role. Some studies have pointed to left atrial (LA) and left ventricular (LV) systolic and diastolic dysfunction as surrogate markers of AF. The aim of the study is to evaluate the relationship between echocardiographic parameters of LA and LV function, and the occurrence of AF revealed by continuous ECG monitoring in a cohort of patients with CS. Methods: Single-center prospective cohort study. Seventy-two patients with CS with insertable cardiac monitors (ICM) underwent transthoracic echocardiography (TTE). TTE was focused on LA and LV function, including both standard and longitudinal strain-derived parameters. All detected AF episodes lasting more than 2 min were considered. Results: Continuous ECG monitoring revealed subclinical AF in 23 patients (32%) at an average of 6.5 months after ICM implantation. Many echocardiographic parameters, indicating LA volume and LV systolic/diastolic function, were significantly associated with the occurrence of AF, suggesting the worst atrial function in the AF group. Furthermore, multivariable regression analysis revealed that peak atrial contraction strain and left ventricular strain were independently associated with AF (adjusted OR = 0.72, CI 95% 0.48-0.90, p = 0.005, and adjusted OR = 0.69, CI 95% 0.46-0.95, p = 0.041, respectively). Conclusion: In patients with CS, LA and LV strain analysis add predictive value for the occurrence of AF over clinical and morpho-functional echocardiographic parameters. Impaired booster pump strain and LV longitudinal strain are strong and independent predictors of AF.

Predictors of Mortality and Cardiovascular Outcome at 6 Months after Hospitalization for COVID-19.

Clinical outcome data of patients discharged after Coronavirus disease 2019 (COVID-19) are limited and no study has evaluated predictors of cardiovascular prognosis in this setting. Our aim was to assess short-term mortality and cardiovascular outcome after hospitalization for COVID-19. A prospective cohort of 296 consecutive patients discharged after COVID-19 from two Italian institutions during the first wave of the pandemic and followed up to 6 months was included. The primary endpoint was all-cause mortality. The co-primary endpoint was the incidence of the composite outcome of major adverse cardiac and cerebrovascular events (MACCE: cardiovascular death, myocardial infarction, stroke, pulmonary embolism, acute heart failure, or hospitalization for cardiovascular causes). The mean follow-up duration was 6 ± 2 months. The incidence of all-cause death was 4.7%. At multivariate analysis, age was the only independent predictor of mortality (aHR 1.08, 95% CI 1.01-1.16). MACCE occurred in 7.2% of patients. After adjustment, female sex (aHR 2.6, 95% CI 1.05-6.52), in-hospital acute heart failure during index hospitalization (aHR 3.45, 95% CI 1.19-10), and prevalent atrial fibrillation (aHR 3.05, 95% CI 1.13-8.24) significantly predicted the incident risk of MACCE. These findings may help to identify patients for whom a closer and more accurate surveillance after discharge for COVID-19 should be considered.

Upfront triple oral combination therapy including selexipag in a high-risk patient with idiopathic pulmonary arterial hypertension: a case report.

BACKGROUND: Selexipag is an oral selective prostacyclin IP receptor agonist approved in patients with low- and intermediate-risk pulmonary hypertension (PH); evidence in patients at high risk is lacking. CASE SUMMARY: A 42-year-old woman with worsening dyspnoea (World Health Organization functional class III-IV) and suspected PH at echocardiographic examination was evaluated in our Pulmonary Hypertension Centre. Right heart catheterization showed pre-capillary PH with reduced cardiac index and increased pulmonary vascular resistance. High-resolution computed tomography excluded parenchymal lung disease and ventilation/perfusion (V/Q) lung scan was negative for mismatched perfusion defects so the conclusive diagnosis was high-risk idiopathic pulmonary arterial hypertension (PAH). The patient refused an initial combination therapy including a parenteral prostacyclin analogue (PCA) in accordance with the ESC/ERS guidelines, so an off-label triple oral combination therapy including a phosphodiesterase-5 inhibitor, an endothelin receptor antagonist, and selexipag was started. At 3- and 6-month follow-up we found a clinical and haemodynamic improvement, so the patient was reclassified as low risk. Her clinical condition is currently stable. DISCUSSION: Despite the benefit of parenteral PCAs in high-risk PAH, low adherence to treatment may be explained by adverse side effects related to the intravenous route of administration. Given the potential effect seen in our patient, upfront triple oral combination therapy in PAH high-risk patients should be further evaluated in a controlled clinical trial.

Prognostic nutritional index in elderly patients hospitalized for acute heart failure.

AIMS: Acute heart failure (AHF) represents a frequent cause of hospitalization and is associated with significant mortality among elderly patients. Risk assessment models like the prognostic nutritional index (PNI) have been proposed to stratify the risk of death and identify patients requiring more intensive levels of care. We evaluated the predictive value of PNI for in-hospital and overall mortality in a cohort of consecutive elderly patients hospitalized for AHF. METHODS AND RESULTS: Prognostic nutritional index, laboratory, and clinical parameters were collected upon admission. PNI values were calculated from albumin concentration and lymphocyte count and reported on a continuous scale with lower values indicating worse prognosis. The primary outcome was overall all-cause mortality defined as death from any cause occurring during hospitalization up to 6 months after discharge. Cox proportional regression analysis was used to calculate hazard ratios (HRs) and the relative 95% confidence intervals (CIs). The study population included 344 patients (median age 84 years, range 65 to 101). During a median follow-up of 158 days (range 2 to 180 days), 75 patients (21.8%) died of whom 28 (8.1%) died during hospitalization. The median PNI was 34 (range 17 to 55). In univariable analysis, PNI was inversely associated with overall mortality (HR 0.90; 95% CI, 0.87 to 0.94) and in-hospital mortality (HR 0.91; 95% CI, 0.85 to 0.98). In multivariable analysis, PNI remained a significant predictor of overall mortality (HR 0.93; 95% CI, 0.89 to 0.98) after adjustment for age, anaemia, NT-proBNP values, and bedridden status. PNI values ≤34 were associated with a two-fold higher risk of overall mortality (HR 2.54; 95% CI, 1.52 to 4.24) and three-fold higher risk of in-hospital mortality (HR 3.37; 95% CI, 1.14 to 9.95). CONCLUSIONS: Low PNI values are associated with short-term and long-term mortality among elderly patients hospitalized for acute decompensated heart failure. Future studies are warranted to confirm these findings and evaluate the use of PNI to guide therapeutic decisions.

Ponatinib Induces Vascular Toxicity through the Notch-1 Signaling Pathway.

Ponatinib, a third-generation tyrosine kinase inhibitor (TKI), is the only approved TKI that is effective against T315I mutations in patients with chronic myeloid leukemia (CML). Specific activation of Notch signaling in CML cells by ponatinib can be considered as the "on-target effect" on the tumor and represents a therapeutic approach for CML. Nevertheless, ponatinib-induced vascular toxicity remains a serious concern, with underlying mechanisms being poorly understood. We aimed to determine the mechanisms of ponatinib-induced vascular toxicity, defining associated signaling pathways and identifying potential rescue strategies. We exposed human umbilical endothelial cells (HUVECs) to ponatinib or vehicle in the presence or absence of the neutralizing factor anti-Notch-1 antibody for exposure times of 0-72 h. Label-free proteomics and network analysis showed that protein cargo of HUVECs treated with ponatinib triggered apoptosis and inhibited vasculature development. We validated the proteomic data showing the inhibition of matrigel tube formation, an up-regulation of cleaved caspase-3 and a downregulation of phosphorylated AKT and phosphorylated eNOS. We delineated the signaling of ponatinib-induced vascular toxicity, demonstrating that ponatinib inhibits endothelial survival, reduces angiogenesis and induces endothelial senescence and apoptosis via the Notch-1 pathway. Ponatinib induced endothelial toxicity in vitro. Hyperactivation of Notch-1 in the vessels can lead to abnormal vascular development and vascular dysfunction. By hyperactivating Notch-1 in the vessels, ponatinib exerts an "on-target off tumor effect", which leads to deleterious effects and may explain the drug's vasculotoxicity. Selective blockade of Notch-1 prevented ponatinib-induced vascular toxicity.

VEGF/VEGF-R/RUNX2 Upregulation in Human Periodontal Ligament Stem Cells Seeded on Dual Acid Etched Titanium Disk.

In restorative dentistry, the main implants characteristic is the ability to promote the osseointegration process as the result of interaction between angiogenesis and osteogenesis events. On the other hand, implants cytocompatibility remains a necessary feature for the success of surgery. The purpose of the current study was to investigate the interaction between human periodontal stem cells and two different types of titanium surfaces, to verify their cytocompatibility and cell adhesion ability, and to detect osteogenic and angiogenic markers, trough cell viability assay (MTT), Confocal Laser Scanning Microscopy (CLSM), scanning electron microscopy (SEM), and gene expression (RT-PCR). The titanium surfaces, machined (CTRL) and dual acid etched (TEST), tested in culture with human periodontal ligament stem cells (hPDLSCs), were previously treated in two different ways, in order to evaluate the effects of CTRL and TEST and define the best implant surface. Furthermore, the average surface roughness (Ra) of both titanium surfaces, CTRL and TEST, has been assessed through atomic force microscopy (AFM). The vascular endothelial growth factor (VEGF) and Runt-related transcription factor 2 (RUNX2) expressions have been analyzed by RT-PCR, WB analysis, and confocal laser scanning microscopy. Data evidenced that the different morphology and topography of the TEST disk increased cell growth, cell adhesion, improved osteogenic and angiogenic events, as well osseointegration process. For this reason, the TEST surface was more biocompatible than the CTRL disk surface.

Co-expression of glycosylated aquaporin-1 and transcription factor NFAT5 contributes to aortic stiffness in diabetic and atherosclerosis-prone mice.

Increased stiffness characterizes the early change in the arterial wall with subclinical atherosclerosis. Proteins inducing arterial stiffness in diabetes and hypercholesterolaemia are largely unknown. This study aimed at determining the pattern of protein expression in stiffening aorta of diabetic and hypercholesterolaemic mice. Male Ins2+/Akita mice were crossbred with ApoE-/- (Ins2+/Akita : ApoE-/- ) mice. Relative aortic distension (relD) values were determined by ultrasound analysis and arterial stiffness modulators by immunoblotting. Compared with age- and sex-matched C57/BL6 control mice, the aortas of Ins2+/Akita , ApoE-/- and Ins2+/Akita :ApoE-/- mice showed increased aortic stiffness. The aortas of Ins2+/Akita , ApoE-/- and Ins2+/Akita :ApoE-/- mice showed greater expression of VCAM-1, collagen type III, NADPH oxidase and iNOS, as well as reduced elastin, with increased collagen type III-to-elastin ratio. The aorta of Ins2+/Akita and Ins2+/Akita :ApoE-/- mice showed higher expression of eNOS and cytoskeletal remodelling proteins, such as F-actin and α-smooth muscle actin, in addition to increased glycosylated aquaporin (AQP)-1 and transcription factor NFAT5, which control the expression of genes activated by high glucose-induced hyperosmotic stress. Diabetic and hypercholesterolaemic mice have increased aortic stiffness. The association of AQP1 and NFAT5 co-expression with aortic stiffness in diabetes and hypercholesterolaemia may represent a novel molecular pathway or therapeutic target.

Association of the European Society of Cardiology echocardiographic probability grading for pulmonary hypertension with short and mid-term clinical outcomes after heart valve surgery.

BACKGROUND AND AIMS: Pulmonary hypertension (PH) is associated with higher mortality and morbidity after valvular heart surgery, mainly through its adverse effect on right ventricular hemodynamic. Recently, the European Society of Cardiology (ESC) PH guidelines introduced a PH probability grading that lists additional parameters related to right ventricular dimensions. We evaluated the impact of such score on short- and mid-term outcomes in patients undergoing left heart valvular surgery. METHODS AND RESULTS: We included 60 consecutive patients (mean age 70 ±â€¯9 years) undergoing left heart valvular surgery with or without coronary artery bypass. Patients were divided into 3 groups according to the PH probability: "low" (n = 18), "intermediate" (n = 18), or "high" (n = 24). The high PH probability group had higher rate of World Health Organization-Functional Class (WHO-FC) III and IV, hemodynamic complications, deaths, major bleeding events and infections after heart surgery than the other groups. A "high" PH probability was associated with reduced right ventricular systolic function, as measured by the fractional area change (FAC), but not with the tricuspid annular plane systolic excursion (TAPSE). CONCLUSION: The high PH probability as evaluated by the ESC PH echocardiographic probability model, is associated with increased short- and mid-term mortality and morbidity and reduced right ventricular systolic function after cardiac surgery, Thus, additional echocardiographic parameters assessing PH probability are valuable tools to stratify risk in patients undergoing cardiac surgery.

Impaired enzymatic reactive aldehyde-detoxifying capacity and glutathione peroxidase activity in the aged human arterial tissue.

It is not known whether aging alters the enzymatic reactive aldehyde- and lipid hydroperoxide-detoxifying capacity of the human arterial tissue favoring vascular oxidative stress. To address this issue, we studied the specific enzymatic activities of class 1, 2 and 3 aldehyde dehydrogenase (ALDH1, ALDH2 and ALDH3), glutathione S­transferase (isozyme A4-4, GSTA4-4) and aldose reductase (AR), namely the major reactive aldehyde-scavenging enzymes, together with the activity of the lipid hydroperoxide-removing enzyme glutathione peroxidase (GSH-Px), in superior thyroid arteries (STA) specimens obtained in the thyroid surgery setting in aged subjects (age 72.3 ±â€¯3.6 years) and young adult controls (age 31.9 ±â€¯3.5 years). Vascular lipid peroxidation was also studied by assessing in STA fluorescent damage products of lipid peroxidation (FDPL), which reflect oxidant-induced 4­hydroxynonenal and lipid hydroperoxide formation. Remarkably, the activities of ALDH1, ALDH2, ALDH3, GSTA4-4, AR and GSH-Px were significantly lower, and FDPL levels higher, in the arterial tissue of the aged subjects than in that of the young adult controls. Moreover, the enzymatic activities were inversely and significantly correlated with the levels of FDPL in the arterial tissue of both the aged and young subjects, highlighting their vascular antioxidant/antilipoperoxidative role in vivo. Thus, aging impairs the enzymatic reactive aldehyde-detoxifying capacity and GSH-Px activity of the human arterial tissue eventually favoring vascular oxidative stress.

Association of serum bilirubin with oxidant damage of human atherosclerotic plaques and the severity of atherosclerosis.

Bilirubin has protective effects against atherosclerotic cardiovascular diseases hypothetically due to its antioxidant-antilipoperoxidative properties. Thus, we investigated whether serum bilirubin is associated with oxidant damage, namely lipid peroxidation, of human atherosclerotic plaques and the severity of atherosclerosis. In this regard, we correlated the levels of serum total bilirubin (STB), direct (conjugated) bilirubin (SDB) and indirect (unconjugated) bilirubin (SIB) with those of fluorescent damage products of lipid peroxidation (FDPL) and lipid hydroperoxides (LOOH) of 32 endarterectomy-derived carotid atherosclerotic plaques. Moreover, we compared the levels of serum bilirubin and plaque lipoperoxides between two groups of patients of the study population with different severity of atherosclerosis as judged by the carotid stenosis degree, i.e., <90% (group A, n = 23) and ≥90% (group B, n = 9). Remarkably, the levels of STB were strongly inversely correlated with those of plaque FDPL (rS = -0.70, P < 0.0001) and LOOH (rS = -0.66, P < 0.0001), as were those of SIB (FDPL: rS = -0.68, P < 0.0001; LOOH: rS = -0.63, P < 0.0001). SDB had a weaker association with plaque FDPL (rS = -0.41, P < 0.05) and LOOH (rS = -0.35, P < 0.05). Moreover, the levels of STB, SDB and SIB were lower and those of plaque lipoperoxides higher in group B than in group A, pointing to the association of serum bilirubin and plaque oxidant burden with the severity of atherosclerosis. In conclusion, lowered serum bilirubin is associated with oxidant damage of human atherosclerotic plaques and the severity of atherosclerosis.

Iron status and oxidative stress in the aged rabbit heart.

Altered iron status may be relevant to the pathophysiology of aging. We have assessed redox-active catalytic low molecular weight iron (LMWI), non-heme iron (NHI), heme iron (HI), and total iron (TI) in the aerobically perfused hearts of aged rabbits (AR, about 4.5years old) and young adult control rabbits (YACR, 3-4months old); myocardial lipid and protein oxidations were also assessed as oxidative stress biomarkers. The levels of LMWI and NHI, as well as of lipid and protein oxidation, were higher, while HI content was lower, in the hearts of AR than in those of YACR; TI did not differ significantly between the two groups. Together with these findings, hemodynamic dysfunction, namely heightened end-diastolic pressure (EDP) and lowered coronary flow (CF), occurred in the AR hearts. Notably, such pattern of hemodynamic dysfunction associated with myocardial oxidant damage occurred in the hearts of other YACR perfused in the presence of a cell-permeable form of iron, i.e., the iron/hydroxyquinoline complex, pointing to the involvement of catalytic iron in the aged heart damage. Moreover, as shown in other AR, heart perfusion in the presence of the iron chelator deferoxamine (0.6mM or 3.6mM) reduced the myocardial levels of LMWI, without significantly affecting those of NHI, HI, and TI; concomitantly, in AR deferoxamine lowered myocardial lipid and protein oxidation, and reduced EDP with a tendency to augment CF. Instead, deferoxamine, even at high concentration of 3.6mM, had no significant effects in the YACR. In conclusion, altered iron status with catalytic LMWI burden occurs in the aged rabbit heart, eventually resulting in iron-dependent cardiac oxidative stress and hemodynamic dysfunction.

A prospective evaluation of iron deficiency anemia in the GI endoscopy setting: role of standard endoscopy, videocapsule endoscopy, and CT-enteroclysis.

BACKGROUND: Iron deficiency anemia (IDA) is a frequently encountered condition in clinical practice. After conventional endoscopy, the cause of anemia remains unknown in up to 40% of patients. OBJECTIVE: To evaluate prospectively the diagnostic efficacy of a systematic endoscopic approach to IDA and to compare the diagnostic yield of videocapsule endoscopy (VCE) and CT-enteroclysis in endoscopy-negative patients. DESIGN: Consecutive patients with IDA were enrolled prospectively. SETTING: Open-access endoscopy within an academic hospital. PATIENTS: This study involved 189 patients with IDA, including 98 women and 91 men; mean (±standard deviation) age 68 years±16.6 years. INTERVENTION: Patients with IDA underwent gastroscopy and colonoscopy plus ileoscopy. Endoscopy-negative patients were further blindly evaluated by both CT-enteroclysis and VCE. MAIN OUTCOME MEASUREMENTS: Diagnostic yield of conventional endoscopy; diagnostic yield of VCE versus CT-enteroclysis. RESULTS: Endoscopy results were positive in 144 of 189 patients (76.2%). CT-enteroclysis and VCE allowed a diagnosis in 37 of 45 endoscopy-negative patients (82.2%). Overall, VCE was superior to CT-enteroclysis (77.8% vs 22.2%; P<.001), in particular when flat lesions were found. LIMITATIONS: Single-center study. CONCLUSION: A systematic approach to IDA, which includes standard endoscopy, VCE, and CT-enteroclysis allows an overall diagnostic rate of 95.7%; however, CT-enteroclysis should be limited to cases of nondiagnostic VCE.

Serum albumin and biomolecular oxidative damage of human atherosclerotic plaques.

OBJECTIVES: To investigate the association of serum albumin (SA) with oxidative damage of human atherosclerotic plaques and the severity of atherosclerosis. DESIGN AND METHODS: Correlation of the levels of SA with those of lipid and protein oxidation of endarterectomy-removed carotid atherosclerotic plaques; SA and plaque oxidative biomarkers comparison between 2 groups of patients with different severity of atherosclerotic carotid stenosis, i.e. <90% (group I) or ≥90% (group II). RESULTS: SA was strongly inversely correlated with plaque oxidative damage; SA was lower and plaque oxidative damage higher in group II than group I. CONCLUSIONS: Lowered SA is associated with oxidative damage of atherosclerotic plaques and the severity of atherosclerosis.

Inhibitory activity of salicylic acid on lipoxygenase-dependent lipid peroxidation.

BACKGROUND: Since iron is essential for lipoxygenase activity and salicylic acid (SA) can interact with the metal, possible lipoxygenase inhibition by SA was investigated. METHODS: Kinetic spectrophotometric evaluation of enzymatic lipid peroxidation catalyzed by soybean lipoxygenase (SLO), rabbit reticulocyte 15-lipoxygenase (RR15-LOX), porcine leukocyte 12-lipoxygenase (PL12-LOX) and human recombinant 5-lipoxygenase (HR5-LOX) with and without SA. RESULTS: SA inhibited linoleic, arachidonic and docosahexaenoic acid or human lipoprotein peroxidation catalyzed by SLO with IC50 of, respectively, 107, 153, 47 and 108 microM. Using the same substrates, SA inhibited RR15-LOX with IC50 of, respectively, 49, 63, 27 and 51 microM. Further, arachidonic acid peroxidation catalyzed by PL12-LOX and HR5-LOX was inhibited by SA with IC50 of 101 and 168 microM, respectively. Enzymatic inhibition was complete, reversible and non-competitive. Conceivably due to its lower hydrophobicity, aspirin was less effective, indicating acetylation-independent enzyme inhibition. SA and aspirin were ineffective peroxyl radical scavengers but readily reduced Fe3+, i.e. FeCl3, to Fe2+, suggesting their capacity to reduce Fe3+ at the enzyme active site. Indeed, similar to the catecholic redox inhibitor nordihydroguaiaretic acid, SA inhibited with the same efficiency both ferric and the native ferrous SLO form, indicating that these compounds reduce the active ferric enzyme leading to its inactivation. GENERAL SIGNIFICANCE: SA can inhibit lipoxygenase-catalyzed lipid peroxidation at therapeutic concentrations, suggesting its possible inhibitory activity against enzymatic lipid peroxidation in the clinical setting.

Amiodarone inhibits tocopherol-mediated human lipoprotein peroxidation.

It is unknown whether lipoprotein tocopherol-mediated peroxidation (TMP) is influenced by peculiar drug physicochemical properties such as hydrophobicity. Thus, we studied the effect of the extremely hydrophobic agent amiodarone on human non-HDL TMP. The drug, albeit devoid of specific radical-scavenging effects, inhibited TMP at therapeutic concentrations and with an efficiency similar to that of the physiological co-antioxidant ascorbic acid, showing indeed an IC(50) of 5microM. A comparable efficiency was observed with human LDL, and with a pure LDL-VLDL mixture. TMP was also inhibited by other hydrophobic cationic amphiphiles without radical-scavenging activity, namely desethylamiodarone, chlorpromazine, clomipramine, promethazine, promazine, verapamil, bromhexine, propranolol, mepivacaine, metoprolol, tramadol and ranitidine, whose anti-TMP potency was far lower than that of amiodarone and related to drug hydrophobicity degree. Further, TMP was strongly inhibited by butylhydroxytoluene, a lipophilic radical scavenger. Hydrophobic acidic (diclofenac, indomethacin, ibuprofen and ketoprofen) or neutral (n-hexane, anthracene, o-xylene and toluene) compounds could not instead inhibit TMP, indicating a stringent requirement for drug basicity in the pharmacological inhibition of TMP. Amiodarone effectiveness was lowered by lipoprotein alpha-tocopherol enrichment, suggesting some drug-alpha-tocopherol interaction and less lipid pharmacological protection at higher alpha-tocopheroxyl radical generation. Drug anti-TMP activity may so be related to electrostatic and hydrophobic interactions with lipoprotein alpha-tocopherol and lipid moiety, resulting in decreased radical phase transfer and lipid propensity to undergo radical-driven peroxidation. In conclusions, primarily drug basicity and then hydrophobicity are solely relevant to TMP inhibition. Amiodarone, at therapeutic concentrations, has anti-TMP properties, which could occur in the clinical setting.

Visceral sensitivity and symptoms in patients with constipation- or diarrhea-predominant irritable bowel syndrome (IBS): effect of a low-fat intraduodenal infusion.

BACKGROUND: Visceral hypersensitivity is common in Irritable Bowel Syndrome (IBS) patients, and symptoms exacerbate postprandially. Yet the effects of nutrients on visceral sensitivity and symptoms in these patients have not been fully explored. AIMS: To evaluate the differences of visceral sensitivity and symptoms in healthy subjects and IBS patients during fasting and intraduodenal lipids infusion. METHODS: Graded rectal distensions at fixed tension levels were performed in 16 IBS patients (8 IBS-C and 8 IBS-D) and 6 healthy subjects before and during intraduodenal lipids infusion at 0.5 kcal/min. Tension levels were increased in 4 gr increments up to 64 gr or discomfort during both conditions. At each step, perception and symptoms were measured by means of a validated questionnaire. RESULTS: In basal conditions, perception thresholds in IBS patients and health were, respectively, 8 +/- 2 gr versus 32 +/- 9 gr (p < 0.001) with no changes during lipids. Intraduodenal lipids infusion significantly lowered threshold of discomfort in IBS patients in comparison to fasting (24 +/- 6 gr vs 34 +/- 4 gr; p < 0.05), while health tolerated all distension without discomfort. No differences of compliance, perception, or discomfort were observed between the two subgroups of patients at each tension step. The predominant symptom elicited in patients with IBS-C was abdominal pain (54%), while patients with IBS-D exhibited urgency (63%, p < 0.005); this pattern was maintained during lipids. CONCLUSIONS: Intraduodenal lipids increase visceral sensitivity in both IBS-C and IBS-D; symptoms specificity in response to rectal distension is maintained in the postprandial period. Lipids may be responsible for the postprandial symptoms exacerbation in IBS.

Copper, zinc superoxide dismutase plus hydrogen peroxide: a catalytic system for human lipoprotein oxidation.

We report for the first time that bovine or human CuZnSOD plus H2O2 can catalyze human lipoprotein oxidation, inducing like free copper ions a typical oxidative kinetics with lag and propagation phases. Free copper released from CuZnSOD by H2O2, but not enzyme peroxidase activity and carbonate radical anion, is responsible for lipoprotein oxidation, which is indeed totally inhibited by copper chelators and BHT but unaffected by bicarbonate. Moreover, lipoprotein oxidation is significantly counteracted by the OH* scavengers formate and azide, which can enter the active site of CuZnSOD and decrease copper release through scavenging of copper-bound OH*; benzoate and ethanol, which cannot enter, are instead ineffective, indicating no oxidative involvement of free OH* escaped from the enzyme active site. The possibility of CuZnSOD/H2O2-catalyzed lipoprotein oxidation in vivo is discussed.

Dihydrolipoic acid inhibits 15-lipoxygenase-dependent lipid peroxidation.

The potential antioxidant effects of the hydrophobic therapeutic agent lipoic acid (LA) and of its reduced form dihydrolipoic acid (DHLA) on the peroxidation of either linoleic acid or human non-HDL fraction catalyzed by soybean 15-lipoxygenase (SLO) and rabbit reticulocyte 15-lipoxygenase (RR15-LOX) were investigated. DHLA, but not LA, did inhibit SLO-dependent lipid peroxidation, showing an IC(50) of 15 microM with linoleic acid and 5 microM with the non-HDL fraction. In specific experiments performed with linoleic acid, inhibition of SLO activity by DHLA was irreversible and of a complete, noncompetitive type. In comparison with DHLA, the well-known lipoxygenase inhibitor nordihydroguaiaretic acid and the nonspecific iron reductant sodium dithionite inhibited SLO-dependent linoleic acid peroxidation with an IC(50) of 4 and 100 microM, respectively, while the hydrophilic thiol N-acetylcysteine, albeit possessing iron-reducing and radical-scavenging properties, was ineffective. Remarkably, DHLA, but not LA, was also able to inhibit the peroxidation of linoleic acid and of the non-HDL fraction catalyzed by RR15-LOX with an IC(50) of, respectively, 10 and 5 microM. Finally, DHLA, but once again not LA, could readily reduce simple ferric ions and scavenge efficiently the stable free radical 1,1-diphenyl-2-pycrylhydrazyl in ethanol; DHLA was considerably less effective against 2,2'-azobis(2-amidinopropane) dihydrochloride-mediated, peroxyl radical-induced non-HDL peroxidation, showing an IC(50) of 850 microM. Thus, DHLA, at therapeutically relevant concentrations, can counteract 15-lipoxygenase-dependent lipid peroxidation; this antioxidant effect may stem primarily from reduction of the active ferric 15-lipoxygenase form to the inactive ferrous state after DHLA-enzyme hydrophobic interaction and, possibly, from scavenging of fatty acid peroxyl radicals formed during lipoperoxidative processes. Inhibition of 15-lipoxygenase oxidative activity by DHLA could occur in the clinical setting, eventually resulting in specific antioxidant and antiatherogenic effects.