Saverio Muscoli

Hypolipemic and hypoglycaemic activity of bergamot polyphenols: From animal models to human studies

Bergamot juice produces hypolipemic activity in rats though the mechanism remains unclear. Here we investigated on the effect of bergamot extract (BPF) in diet-induced hyperlipemia in Wistar rats and in 237 patients suffering from hyperlipemia either associated or not with hyperglycaemia. BPF, given orally for 30 days to both rats and patients, reduces total and LDL cholesterol levels (an effect accompanied by elevation of cHDL), triglyceride levels and by a significant decrease in blood glucose. Moreover, BPF inhibited HMG-CoA reductase activity and enhanced reactive vasodilation thus representing an efficient phytotherapeutic approach in combating hyperlipemic and hyperglycaemic disorders.

Bergamot polyphenolic fraction enhances rosuvastatin-induced effect on LDL-cholesterol, LOX-1 expression and protein kinase B phosphorylation in patients with hyperlipidemia

BACKGROUND Statins are the most commonly prescribed drugs to reduce cardiometabolic risk. Besides the well-known efficacy of such compounds in both preventing and treating cardiometabolic disorders, some patients experience statin-induced side effects. We hypothesize that the use of natural bergamot-derived polyphenols may allow patients undergoing statin treatment to reduce effective doses while achieving target lipid values. The aim of the present study is to investigate the occurrence of an enhanced effect of bergamot-derived polyphenolic fraction (BPF) on rosuvastatin-induced hypolipidemic and vasoprotective response in patients with mixed hyperlipidemia. METHODS A prospective, open-label, parallel group, placebo-controlled study on 77 patients with elevated serum LDL-C and triglycerides was designed. Patients were randomly assigned to a control group receiving placebo (n=15), two groups receiving orally administered rosuvastatin (10 and 20mg/daily for 30 days; n=16 for each group), a group receiving BPF alone orally (1000 mg/daily for 30 days; n=15) and a group receiving BPF (1000 mg/daily given orally) plus rosuvastatin (10mg/daily for 30 days; n=15). RESULTS Both doses of rosuvastatin and BPF reduced total cholesterol, LDL-C, the LDL-C/HDL-C ratio and urinary mevalonate in hyperlipidemic patients, compared to control group. The cholesterol lowering effect was accompanied by reductions of malondialdehyde, oxyLDL receptor LOX-1 and phosphoPKB, which are all biomarkers of oxidative vascular damage, in peripheral polymorphonuclear cells. CONCLUSIONS Addition of BPF to rosuvastatin significantly enhanced rosuvastatin-induced effect on serum lipemic profile compared to rosuvastatin alone. This lipid-lowering effect was associated with significant reductions of biomarkers used for detecting oxidative vascular damage, suggesting a multi-action enhanced potential for BPF in patients on statin therapy.

The treatment of hyperuricemia

Hyperuricemia has long been established as the major etiologic factor in gout. Alongside with an inflammatory state triggered by urate crystal deposition in the joints, hyperuricemia displayed additional pathophysiological consequences leading to tissue inflammation mainly in the vascular wall. Thus, therapeutic strategies used to treat hyperuricemia in the past decades have often been focused on limiting acute episodes. Recently, evidence has been accumulated suggesting that chronic urate deposition requires a correct treatment not limited to acute episodes based on the modulation of the activity of key enzymes involved in metabolism and excretion of urate including xanthine oxidoreductase (XO) and URAT1. The present review article will try to summarize the most recent evidences on the efficacy of XO inhibitors and uricosuric compounds in lowering uric acid levels in both the bloodstream and peripheral tissues. In particular, we will focus on the effect of novel XO inhibitors in counteracting uric acid overproduction. On the other hand, the effect of lowering uric acid levels via XO inhibition will be correlated with attenuation oxidative stress which leads to endothelial dysfunction thereby contributing to the pathophysiology of diabetes, hypertension, arteriosclerosis, and chronic heart failure. Hence, scavenging and prevention of the XO generated oxygen radical accumulation emerge as an intriguing novel treatment option to counteract uric acid-induced tissue damages.

The protective effect of bergamot oil extract on lecitine-like oxyLDL receptor-1 expression in balloon injury-related neointima formation

Lectin-like oxyLDL receptor-1 (LOX-1) has recently been suggested to be involved in smooth muscle cell (SMC) proliferation and neointima formation in injured blood vessels. This study evaluates the effect of the nonvolatile fraction (NVF), the antioxidant component of bergamot essential oil (BEO), on LOX-1 expression and free radical generation in a model of rat angioplasty. Common carotid arteries injured by balloon angioplasty were removed after 14 days for histopathological, biochemical, and immunohistochemical studies. Balloon injury led to a significant restenosis with SMC proliferation and neointima formation, accompanied by increased expression of LOX-1 receptor, malondialdehyde and superoxide formation, and nitrotyrosine staining. Pretreatment of rats with BEO-NVF reduced the neointima proliferation together with free radical formation and LOX-1 expression in a dose-dependent manner. These results suggest that natural antioxidants may be relevant in the treatment of vascular disorders in which proliferation of SMCs and oxyLDL-related endothelial cell dysfunction are involved.

Oxidized LDL attenuates protective autophagy and induces apoptotic cell death of endothelial cells: Role of oxidative stress and LOX-1 receptor expression

BACKGROUND Overproduction of oxidized-low density lipoproteins (oxyLDLs) has been found to contribute in endothelial cell (EC) dysfunction thereby leading to atherosclerosis development and progression. In particular, oxyLDLs lead to apoptotic cell death of EC via oxidative stress production, mostly subsequent to the overexpression of the scavenger receptor LOX-1. Here, we hypothesize that LOX-1 expression in EC represents a crucial event which attenuates protective autophagic response, thereby enhancing programmed endothelial cell death. METHODS AND RESULTS Bovine aortic endothelial cells (BAECs) in culture were exposed to oxyLDL (1-100 μM). After 48 h incubation, oxyLDL produced pronounced malondialdehyde (MDA) elevation and apoptotic cell death of BAEC as detected by FACS analysis, an effect counteracted by antioxidant N-acetyl-cysteine (NAC) as well as by the NO-donor SNAP. OxyLDL-induced apoptotic cell death was also accompanied by reduced VEGF-dependent phosphorylation of constitutive NO synthase (cNOS) in BAEC and consistent attenuation of autophagic response as detected by the expression of Beclin-1 and LC3, two reliable biomarkers of autophagy. Moreover, silencing LOX-1 receptor significantly restored LC3 expression in oxyLDL-treated BAEC, thus suggesting a key role of LOX-1 overproduction in oxyLDL-induced endothelial dysfunction. CONCLUSIONS OxyLDL leads to impaired NO generation and apoptotic cell death in BAECs. This effect occurs via the overexpression of LOX-1 and subsequent attenuation of protective autophagic response thereby contributing to the pathophysiology of oxyLDL-induced endothelial dysfunction which characterizes early stages of atherosclerotic process.

The effect of peroxynitrite decomposition catalyst MnTBAP on aldehyde dehydrogenase-2 nitration by organic nitrates: role in nitrate tolerance.

Bioconversion of glyceryl trinitrate (GTN) into nitric oxide (NO) by aldehyde dehydrogenase-2 (ALDH-2) is a crucial mechanism which drives vasodilatory and antiplatelet effect of organic nitrates in vitro and in vivo. Oxidative stress generated by overproduction of free radical species, mostly superoxide anions and NO-derived peroxynitrite, has been suggested to play a pivotal role in the development of nitrate tolerance, though the mechanism still remains unclear. Here we studied the free radical-dependent impairment of ALDH-2 in platelets as well as vascular tissues undergoing organic nitrate ester tolerance and potential benefit when using the selective peroxynitrite decomposition catalyst Mn(III) tetrakis (4-Benzoic acid) porphyrin (MnTBAP). Washed human platelets were made tolerant to nitrates via incubation with GTN for 4h. This was expressed by attenuation of platelet aggregation induced by thrombin (40U/mL), an effect accompanied by GTN-related induction of cGMP levels in platelets undergoing thrombin-induced aggregation. Both effects were associated to attenuated GTN-induced nitrite formation in platelets supernatants and to prominent nitration of ALDH-2, the GTN to NO metabolizing enzyme, suggesting that GTN tolerance was associated to reduced NO formation via impairment of ALDH-2. These effects were all antagonized by co-incubation of platelets with MnTBAP, which restored GTN-induced responses in tolerant platelets. Comparable effect was found under in in vivo settings. Indeed, MnTBAP (10mg/kg, i.p.) significantly restored the hypotensive effect of bolus injection of GTN in rats made tolerants to organic nitrates via chronic administration of isosorbide-5-mononitrate (IS-5-MN), thus confirming the role of peroxynitrite overproduction in the development of tolerance to vascular responses induced by organic nitrates. In conclusion, oxidative stress subsequent to prolonged use of organic nitrates, which occurs via nitration of ALDH-2, represents a key event in GTN tolerance, an effect counteracted both in vitro and in vivo by novel peroxynitrite decomposition catalyst.

Hemodynamic patterns of residual interatrial communication after transcatheter MitraClip repair.

Aims We sought to assess the hemodynamic sequel and the therapy adopted in patients treated with MitraClip system, who experienced a persistent interatrial communication (IAC) after the procedure. Methods From January 2012 to March 2013, 28 consecutive patients (mean age 74 ± 8 years) underwent transcatheter MitraClip repair, as part of an ongoing prospective study to assess the IAC. Results Acute procedural success was 100% and a 30-days survival of 97% was reported. Immediately after the procedure, a residual IAC was present in all patients with an average diameter of 0.51 ± 0.39 cm. At 30 days, IAC was detected in 81% of patients with a diameter of 0.45 ± 0.31 cm (P = 0.53). To date, three patients developed different hemodynamic impairment secondary to the residual IAC, requiring percutaneous closure of the defect. Conclusion Anatomic and hemodynamic criteria for early recognition of harmful residual IAC have to be identified, in order to select those patients who are benefited the most from atrial septal defect closure.

Transcatheter aortic valve implantation through distal axillary artery: novel option for vascular access.

Aims We describe an alternative access approach for patients undergoing transcatheter aortic valve implantation (TAVI) using surgical cut down of the distal axillary artery, in cases wherein transfemoral access is not feasible. Methods From January 2012 to July 2013, 61 patients (59% men; mean age 81 ± 8 years) underwent TAVI at our institution. The mean logistic EuroSCORE and EuroSCORE II were 36 ± 24 and 14 ± 10, respectively. We assessed device success, 30-day safety and clinical efficacy using VARC II criteria. Results TAVI was performed with the CoreValve Revalving System (CRS) (Medtronic Inc., Minneapolis, Minnesota, USA) in all cases, using transfemoral approach in 57 patients and distal trans-axillary route in four patients. A device was successfully implanted in 94%, without any major intraprocedural complications. One case of acute kidney disease, four cases of minor vascular complication and two cases of life-threatening bleeding occurred after the procedure for pericardial bleeding requiring pericardiocentesis. Permanent pacemaker was implanted in 26% of patients. There was no instance of in-hospital mortality, while two deaths (3%) occurred in the first 30 days. The total procedure time (skin-to-skin) was longer in the trans-axillary group secondary to surgical management of access site (P = 0.027), whereas revalving and fluoroscopy time were similar (P = 0.95 and P = 0.83, respectively). Conclusion The location and anatomical relations of the distal axillary artery make it a safer, reproducible and operator friendly access option for TAVI.

Percutaneous closure of patent foramen ovale with Atriasept II device in nickel allergic patients.

There are concerns about percutaneous closure of patent foramen ovale (PFO) using nitinol-alloys devices in patients with nickel hypersensitivity. We describe our experience with Atriasept II (Cardia Eagan, Minnesota, USA) used in four patients with known nickel allergy. No intraprocedural or in-hospital adverse events occurred. The follow-up was negative for allergic manifestations, without complications, as assessed by echocardiography. Because of the risk of adverse outcomes in nickel-allergic patients, devices with higher biocompatibility, low-profile, and low nickel content should be preferred in cases of known hypersensitivity. Atriasept II, containing less metallic material, appears to be a safe option in allergic patients undergoing PFO closure.

Trans-catheter mitral valve implantation for mitral regurgitation: clinical case description and literature review.

Trans-catheter mitral valve implantation (TMVI) is actually the most attractive technique for treating patients with severe mitral regurgitation, who are denied surgical therapy. Recently, trans-catheter implantation of aortic biological prosthesis in mitral position has been done in compassionate cases, and very few experiences of TMVI in native non-calcified valves have been recently reported in very-high-risk patients, mainly with functional mitral regurgitation.Here, we report our case of TMVI using the second-generation CardiAQ prostheisis (CardiAQ Valve Technologies, Irvine, California, USA), reviewing the current state of the art.