Pharmacological inhibition of the F1 -ATPase/P2Y1 pathway suppresses the effect of apolipoprotein A1 on endothelial nitric oxide synthesis and vasorelaxation

AIM

The contribution of apolipoprotein A1 (APOA1), the major apolipoprotein of high-density lipoprotein (HDL), to endothelium-dependent vasodilatation is unclear, and there is little information regarding endothelial receptors involved in this effect. Ecto-F₁ -ATPase is a receptor for APOA1, and its activity in endothelial cells is coupled to adenosine diphosphate (ADP)-sensitive P2Y receptors (P2Y ADP receptors). Ecto-F₁ -ATPase is involved in APOA1-mediated cell proliferation and HDL transcytosis. Here, we investigated the effect of lipid-free APOA1 and the involvement of ecto-F₁ -ATPase and P2Y ADP receptors on nitric oxide (NO) synthesis and the regulation of vascular tone.

METHOD

Nitric oxide synthesis was assessed in human endothelial cells from umbilical veins (HUVECs) and isolated mouse aortas. Changes in vascular tone were evaluated by isometric force measurements in isolated human umbilical and placental veins and by assessing femoral artery blood flow in conscious mice.

RESULTS

Physiological concentrations of lipid-free APOA1 enhanced endothelial NO synthesis, which was abolished by inhibitors of endothelial nitric oxide synthase (eNOS) and of the ecto-F₁ -ATPase/P2Y₁ axis. Accordingly, APOA1 inhibited vasoconstriction induced by thromboxane A2 receptor agonist and increased femoral artery blood flow in mice. These effects were blunted by inhibitors of eNOS, ecto-F₁ -ATPase and P2Y₁ receptor.

CONCLUSIONS

Using a pharmacological approach, we thus found that APOA1 promotes endothelial NO production and thereby controls vascular tone in a process that requires activation of the ecto-F₁ -ATPase/P2Y₁ pathway by APOA1. Pharmacological targeting of this pathway with respect to vascular diseases should be explored.

Hepatitis C virus recurrence after liver transplantation: how to treat and when

Chronic hepatitis C (CHC) is an important cause of cirrhosis and hepatocellular carcinoma and a common indication of liver transplantation (LT). Recurrence of hepatitis C occurs universally after LT with an accelerated course of the natural history of CHC in the graft. Treatment of hepatitis C before transplantation is the most effective strategy because it prevents graft reinfection, but applicability is low with pegylated interferon regimens. Treatment after LT is the strategy more frequently used. A sustained viral response (SVR) is achieved by one-third of those treated with dual therapy and is associated with better outcomes after LT. Triple therapy with protease inhibitors after LT has efficacy to 60%-70% of SVR but is associated with higher rates of secondary effects and drug-drug interactions that require an intensified and frequent monitoring of calcineurin inhibitors during treatment. In the near future, interferon-free regimens with new oral antiviral drugs will likely prevent viral reinfection before or after LT, and shorter treatment regimens and less toxicity are expected.

Endothelium trans differentiated from Wharton's jelly mesenchymal cells promote tissue regeneration: potential role of soluble pro-angiogenic factors

BACKGROUND

Mesenchymal stem cells have a high capacity for trans-differentiation toward many adult cell types, including endothelial cells. Feto-placental tissue, such as Wharton's jelly is a potential source of mesenchymal stem cells with low immunogenic capacity; make them an excellent source of progenitor cells with a potential use for tissue repair. We evaluated whether administration of endothelial cells derived from mesenchymal stem cells isolated from Wharton's jelly (hWMSCs) can accelerate tissue repair in vivo.

METHODS

Mesenchymal stem cells were isolated from human Wharton's jelly by digestion with collagenase type I. Endothelial trans-differentiation was induced for 14 (hWMSC-End14d) and 30 (hWMSC-End30d) days. Cell phenotyping was performed using mesenchymal (CD90, CD73, CD105) and endothelial (Tie-2, KDR, eNOS, ICAM-1) markers. Endothelial trans-differentiation was demonstrated by the expression of endothelial markers and their ability to synthesize nitric oxide (NO).

RESULTS

hWMSCs can be differentiated into adipocytes, osteocytes, chondrocytes and endothelial cells. Moreover, these cells show high expression of CD73, CD90 and CD105 but low expression of endothelial markers prior to differentiation. hWMSCs-End express high levels of endothelial markers at 14 and 30 days of culture, and also they can synthesize NO. Injection of hWMSC-End30d in a mouse model of skin injury significantly accelerated wound healing compared with animals injected with undifferentiated hWMSC or injected with vehicle alone. These effects were also observed in animals that received conditioned media from hWMSC-End30d cultures.

CONCLUSION

These results demonstrate that mesenchymal stem cells isolated from Wharton's jelly can be cultured in vitro and trans-differentiated into endothelial cells. Differentiated hWMSC-End may promote neovascularization and tissue repair in vivo through the secretion of soluble pro-angiogenic factors.

Role of lectin-like oxidized low density lipoprotein-1 in fetoplacental vascular dysfunction in preeclampsia

The bioavailability of nitric oxide (NO) represents a key marker in vascular health. A decrease in NO induces a pathological condition denominated endothelial dysfunction, syndrome observed in different pathologies, such as obesity, diabetes, kidney disease, cardiovascular disease, and preeclampsia (PE). PE is one of the major risks for maternal death and fetal loss. Recent studies suggest that the placenta of pregnant women with PE express high levels of lectin-like oxidized LDL receptor-1 (LOX-1), which induces endothelial dysfunction by increasing reactive oxygen species (ROS) and decreasing intracellular NO. Besides LOX-1 activation induces changes in migration and apoptosis of syncytiotrophoblast cells. However, the role of this receptor in placental tissue is still unknown. In this review we will describes the physiological roles of LOX-1 in normal placenta development and the potential involvement of this receptor in the pathophysiology of PE.

Liver transplantation and hepatitis C

Hepatitis C virus (HCV)-related end-stage cirrhosis with/without hepatocellular carcinoma is the primary indication for liver transplantation in many countries. Unfortunately, HCV is not eliminated by transplantation and graft re-infection is the rule, resulting in HCV-related graft disease. The natural history of recurrent hepatitis is variable; overall, progression to cirrhosis occurs in 20-30% and allograft failure in 10% after 5-10 years from transplantation. The use of poor quality organs, particularly from old donors, has a significant negative impact on disease severity and transplant outcome. In contrast, antiviral therapy, particularly if it results in permanent eradication of the virus, is associated with improved histology, reduced rate of graft decompensation and enhanced outcome. Disease monitoring, through protocol liver biopsies and new non-invasive tools, is essential to select patients at need of antiviral therapy. Peginterferon with ribavirin, used similarly to what is done in the non-transplant setting, is currently the treatment of choice; sustained viral response is achieved in about 35% of cases. Side effects, particularly anemia, are extremely frequent and sometimes severe (rejection, de novo autoimmune hepatitis). Retransplantation (RT) is the last option for the small subset of patients with allograft failure due to HCV recurrence who fulfil minimum criteria based on RT survival models.

Indications for and results of liver retransplantation

Liver retransplantation (LRT) is the only therapeutic option for the irreversible failure of a hepatic graft. The aim of this study was to evaluate our rate, indications, postoperative morbidity and mortality and patient survival at one and 5 years after LRT. 1,260 liver transplants (LT) were performed between 1991 and 2006, 79 were LRT (6.3%). During the first LT, there were no apparent differences between patients who did or did not require LRT. The most common reasons for LRT were hepatic artery thrombosis (31.6%), recurrence of hepatitis C virus cirrhosis (30.4%) and primary graft non function (21.5%). The actuarial survival rates at one and 5 years were 83% and 69% among those without LRT versus 71% and 61% among those with early LRT, and 64% and 34% among those with late LRT (p < 0.001). Although high morbidity and mortality were associated with LRT, it seems that this therapeutic option is valid for patients with early hepatic loss, although not when the graft loss is late. It becomes necessary to define the minimal acceptable results so that patients can benefit from LRT.

[Old donors in liver transplantation for chronic hepatitis C]

BACKGROUND

the natural history of recurrent hepatitis C after liver transplantation (LT) is extremely variable, with progression to allograft failure in a substantial proportion of patients. The identification of factors associated with this poorer outcome may improve results. While donor age has been identified as one of the most important factors, the actual options to modify this variable are limited.

OBJECTIVES

a) to describe the natural history of HCV(+) liver transplant recipients depending on donor age ( < or = 50 years), including clinical, biochemical, and histological outcomes; and b) to identify in the subgroup of organ recipients from aged donors (= 50 years) factors associated with an aggressive course.

METHODS

a retrospective study of clinical and histological data including protocol liver biopsies for 162 HCV (+) liver transplant patients between 1997 and 2001 with at least one year of follow-up. Aggressive recurrent hepatitis C was defined as a progression to fibrosis > 1 during the first year post-LT, development of a cholestatic form of recurrent hepatitis C, and /or graft failure due to HCV during the first five years post-LT. Factors analyzed as potentially associated with recurrent hepatitis C included: a) recipient-related: demographics (age, sex), pre-transplantation (hepatocellular carcinoma, Child-Pugh classification, history of alcohol, HBV serological markers, antiviral treatment, nutritional status, biochemical variables); b) donor-related: demographics (age, sex), cause of death, grade of steatosis defined as minimal vs. moderate-severe > 10%); c) surgery-related: cold preservation and rewarming time, duration of procedure, blood transfusion; and d) post-LT management-related: immunosuppression, liver enzymes in the first 14 days post-LT, acute hepatitis post-LT, surgical complications (vascular and/or biliary).

RESULTS

patients were divided into two groups according to donor age group 1 ( < 50 years), n = 83, 51%, and group 2 (= 50 years), n = 79, 49%). Median follow-up was 5 years (range: 3 months-8.5 years). Aggressive recurrent hepatitis C occurred significantly more frequently in the older donor group (64 vs. 20.5%, p < 0.0001). In this group, potent immunosuppression -triple and quadruple regimens- (p = 0.04) and acute hepatitis post-LT (p = 0.03) were the only variables associated with aggressive recurrence. Degree of donor steatosis was not associated with the prognosis of recurrent hepatitis C.

CONCLUSION

the use of aged donors is partly responsible for the accelerated progression of hepatitis C after LT. When old donors are used we should avoid over-immunosuppression, and probably evaluate antiviral therapy in those with acute recurrent hepatitis C.

Clinical benefits of antiviral therapy in patients with recurrent hepatitis C following liver transplantation

Pegylated interferon (pegIFN) and ribavirin eradicates hepatitis C virus (HCV) in one third of liver recipients with recurrent disease. Side effects are frequent and potentially life threatening. Our aim was to define the long-term benefits of antiviral therapy in recurrent HCV. Eighty-nine (89) recipients (genotype 1: 86.5%) were treated with IFN (n = 31) or pegIFN (n = 58) plus ribavirin and 75 untreated contemporaneous disease-matched controls. The major end point was survival from transplantation. Survival, progression to cirrhosis and clinical decompensation since start of therapy were compared between sustained virologic responders (SVRs) and nonresponders (NRs). Results revealed 44 patients died during the follow-up (20% treated vs. 35% controls; p = 0.05). Patient survival was higher in treated compared to controls (7 years: 74% vs. 62%; p = 0.04). Among treated patients, an SVR was achieved in 37% (IFN 16% vs. peg-IFN 48%; p = 0.03). About 2/33 SVRs and 16/56 NRs died (p = 0.01) due to HCV-disease (56%), IFN-induced rejection (11%), both causes (11%) or others (22%). Five-year survival was greater in SVRs than in NRs (93% vs. 69%, p = 0.032). In patients without baseline cirrhosis, progression to cirrhosis occurred more frequently in NRs (27/42 vs. 6/16; p = 0.06). The 5-year risk of graft decompensation was higher in NRs (33% vs. 16%; p = 0.04). Antiviral therapy is associated with improved long-term outcome in recurrent HCV.

[Endoscopic treatment of pancreatitis and its complications]

OBJECTIVES

To study the long- and short-term safety and efficacy of endoscopic treatment of pancreatitis and its complications in our environment.

PATIENTS AND METHODS

We performed a retrospective analysis of 43 patients with chronic pancreatitis, acute pancreatitis complicated with pseudocyst, and pancreatic fistula diagnosed by endoscopic retrograde cholangiopancreatography who were suitable for endoscopic treatment.

RESULTS

Endoscopic treatment was attempted in 35 patients. The indication for treatment was pain in 17 patients (48.5%), jaundice in 7 (20%), pseudocyst in 10 (28.5%) and suspected external fistula in 1 (3%). The technique was successfully performed in 28 (80%). Of the patients with pain, pancreatic prosthesis was inserted in 13 and extracorporeal lithotripsy was applied in 6. Sixty-five percent of the patients improved. Of the 7 patients with jaundice, all had secondary stenosis of the biliary tract. Treatment was applied in 2, who showed partial improvement. Of the 15 patients with pseudocyst, endoscopic treatment was indicated in 10; the technique was successfully performed in 8 and complete resolution was achieved in 7 (87.5%). The patient with external fistula was treated with transpapillary prosthesis and complete resolution of disruption of Wirsung's duct was achieved. Overall improvement in successfully treated patients was: complete in 19 (68%), partial in 3 (18%), no improvement in 4 (14%) and 2 patients were lost to treatment. There were 4 short-term complications. There were 4 deaths and one was related to the technique.

CONCLUSIONS

Endoscopic treatment of chronic pain in chronic pancreatitis, pseudocysts and fistulas was effective in our environment with a low rate of complications.

[Endoscopic treatment combined with extracorporeal shock wave lithotripsy of difficult bile duct stones]

OBJECTIVES

The aim of this study was to determine the safety and effectiveness of extracorporeal shock wave lithotripsy (ESWL) in difficult bile duct stones resistant to endoscopic extraction.

PATIENTS AND METHOD

From January 1997 to February 2002, combined treatment with endoscopy and ESWL was used in 19 patients who had undergone unsuccessful endoscopic bile duct stone extraction after sphincterotomy. The procedure was carried out using analgesic and sedative drugs or deep sedation, prophylactic antibiotic therapy, and monitoring of vital signs. Bile duct stone localization was performed by contrast injection through nasobiliary drainage and fluoroscopy. After each ESWL session, lavage was performed through drainage and stone fragments were extracted endoscopically.

RESULTS

The 19 patients presented high surgical risk due to advanced aged and/or concomitant diseases. All presented jaundice and pain and nine (47.3%) presented associated cholangitis. Thirty ESWL sessions were performed (1.57 sessions per patient), with a mean of 2,120 shock waves per session. In 16 of the 19 patients (84.2%), combined treatment with ESWL and subsequent instrumental endoscopic extraction achieved complete clearance of the biliary tract. The treatment failed in 3 patients who were referred for surgical treatment. No early or late complications were observed, except in one patient who presented a self-limiting febrile syndrome.

CONCLUSIONS

Therapeutic endoscopy combined with ESWL is safe and effective in patients with difficult bile duct stones. It represents a therapeutic alternative in patients at high surgical risk.

[Sciatica secondary to a presacral abscess as the first manifestation of Crohn's disease]

Presacral abscess is a rare musculoskeletal complication of Crohn's disease. The clinical picture is sometimes insidious and a delay in diagnosis may increase morbidity. Abdominal-pelvic computerized axial tomography (CAT) has proven to be very useful in the diagnosis of this entity, which usually requires surgical treatment. We present the case of a 22-year-old man who presented to hospital for colic-type abdominal pain of 6 months' evolution and intermittent episodes of joint pain. The patient also presented mechanical pain in the right gluteus muscle of two weeks' evolution irradiating to the posterior side of the muscle. Complementary investigations confirmed the suspected diagnosis of Crohn's disease and showed presacral abscess. Treatment was surgical.

Are posttransplantation protocol liver biopsies useful in the long term?

Controversy exists about the usefulness of yearly protocol liver biopsies after liver transplantation, mainly among patients with normal transaminase levels. The aim of this study is to determine (1) the prevalence and cause of histological liver injury in transplant recipients with a minimum histological follow-up of 1 year (n = 254), and (2) the correlation between histological findings and transaminase values. The main indication for liver transplantation was viral-related cirrhosis (61%; 86% caused by hepatitis C virus [HCV]). Protocol liver biopsies were performed yearly for the first 5 years in HCV-infected transplant recipients and at 1 and 5 years in the remaining patients. Histological liver injury included several categories of liver damage (hepatitis, rejection, steatohepatitis, cholangitis, and Budd-Chiari-like lesions). Among biopsy specimens categorized as hepatitis, severe hepatitis was defined as the presence of stage 3 or greater fibrosis. The prevalence of liver injury increased significantly with time (42% v 56% at 1 and 5 years, respectively; P =.09) and was significantly greater in patients who underwent transplantation for HCV-related cirrhosis than in those who underwent transplantation for other reasons (P =.0001). The most frequent category of liver injury was hepatitis (97% and 96% at 1 and 5 years, respectively). Although a proportion of patients with liver injury (12% to 29%) had normal transaminase values, this percentage was almost null in patients with severe hepatitis. Normal histological characteristics were found in the vast majority of non-HCV-infected transplant recipients with normal transaminase values. Given the high prevalence of abnormal histological findings, particularly the increase over time of those defined as severe, protocol liver biopsies are clearly justified in HCV-infected transplant recipients. Conversely, given the rarity of abnormal histological findings, protocol liver biopsies should be questioned in non-HCV-infected transplant recipients with normal transaminase values.

[Azathioprine and 5-ASA in the prevention of postoperative recurrence of Crohn's disease]

Recurrence of Crohn's disease (CD) lesions in the neo-ileum after apparently curative resection frequently occurs after surgery. The most appropriate prophylactic treatment has not been clearly defined. This study evaluated the efficacy of 5-ASA and azathioprine in decreasing postoperative recurrence and analysed the presence of variables associated with recurrence. Thirty-nine patients (mean age 32.8 years, range 18-61) with a history of ileal or ileocecal surgical resection were studied. They received 5-ASA (3 mg/day) or azathioprine (50 mg/day) immediately after the operation and for 2 years thereafter. Patients were followed clinically (Crohn's disease activity index) and serologically every 3 months and by imaging methods every 6 months. The latter included colonoscopy with ileoscopy and if not available, small bowel barium or ultrasonographic study. Laboratory tests included ESR, C-reactive protein, white blood cell and platelet count, fibrinogen and albumin. The end-point evaluated included clinical recurrence (CR), serological recurrence (SR: alteration of at least three of the above-mentioned variables) and morphologic recurrence (MR: endoscopic recurrence > 1 according to Rutgeerts score or radiological or ultrasonographic recurrence). Eighteen patients received azathioprine and 21 received 5-ASA. Thirty-four patients were evaluated. The cumulative proportion of patients with recurrence was 29% (CR), 35% (SR) and 50% (MR). Statistical analysis did not show significant differences between the two groups. Twenty-seven patients completed the 2-year study (11 in the azathioprine group and 16 in the 5-ASA group). Crude relapse rates were 37% (CR), 44% (SR) and 69% (MR) in the 5-ASA group and 36% (CR), 45% (SR) and 64% (MR) in the azathioprine group. No statistically significant differences were observed between groups. No variables associated with recurrence were detected. In conclusion, treatment does not prevent a high percentage of postsurgical recurrence. 5-ASA (3 g/day) and azathioprine (50 mg/day) showed similar efficacy in the prevention of recurrence.

[Cyclosporin in an oral microemulsion as the initial treatment of corticoid-refractory ulcerative colitis]

AIM

To assess the efficacy of oral microemulsion cyclosporin as the initial treatment of active ulcerative colitis refractory to steroid therapy.

PATIENTS AND METHODS

The evolution of five patients treated with a dose of 5 mg/kg/day was analyzed.

RESULTS

Oral microemulsion cyclosporin controlled acute attacks of the disease and led to remission during the 3 months of treatment in four of the five patients. Average hospital stay was 5.5 days.

CONCLUSIONS

Oral microemulsion cyclosporin is an effective treatment in ulcerative colitis. Its administration is simple, the use of venous catheters is avoided and it may reduce mean hospital stay.