Approach for Fabricating Tissue Engineered Vascular Grafts with Stable Endothelialization

A major roadblock in the development of tissue engineered vascular grafts (TEVGs) is achieving construct endothelialization that is stable under physiological stresses. The aim of the current study was to validate an approach for generating a mechanically stable layer of endothelial cells (ECs) in the lumen of TEVGs. To accomplish this goal, a unique method was developed to fabricate a thin EC layer using poly(ethylene glycol) diacrylate (PEGDA) as an intercellular “cementing” agent. This EC layer was subsequently bonded to the lumen of a tubular scaffold to generate a bi-layered construct. The viability of bovine aortic endothelial cells (BAECs) through the “cementing” process was assessed. “Cemented” EC layer expression of desired phenotypic markers (AcLDL uptake, VE-cadherin, eNOS, PECAM-1) as well as of injury-associated markers (E-selectin, SM22α) was also examined. These studies indicated that the “cementing” process allowed ECs to maintain high viability and expression of mature EC markers while not significantly stimulating primary injury pathways. Finally, the stability of the “cemented” EC layers under abrupt application of high shear pulsatile flow (~11 dyn/cm², P _avg ~ 95 mmHg, ΔP ~ 20 mmHg) was evaluated and compared to that of conventionally “seeded” EC layers. Whereas the “cemented” ECs remained fully intact following 48 h of pulsatile flow, the “seeded” EC layers delaminated after less than 1 h of flow. Furthermore, the ability to extend this approach to degradable PEGDA “cements” permissive of cell elongation was demonstrated. Combined, these results validate an approach for fabricating bi-layered TEVGs with stable endothelialization.     

A double-blind, randomized, placebo-controlled, prophylaxis study of adjunctive gabapentin for bipolar disorder

OBJECTIVE: To conduct the first randomized, controlled trial assessing the prophylactic efficacy of gabapentin in bipolar disorder. METHOD: We conducted a 1-year, double-blind, randomized, comparative, placebo-controlled, parallel-group, multicenter study. As this was a pure prophylactic trial, only euthymic bipolar I and II patients (DSM-IV) were randomly assigned in a 1:1 ratio to gabapentin (N = 13) or placebo (N = 12) added to the current treatment (lithium, valproate, carbamazepine, or any combination but not antipsychotics or antidepressants). Subjects participated in the study for 12 months. The primary efficacy parameter was the Clinical Global Impressions scale for Bipolar Illness, Modified (CGI-BP-M), which was assessed at all visits. Other assessments were the Young Mania Rating Scale (YMRS), Hamilton Rating Scale for Depression (HAM-D), Hamilton Rating Scale for Anxiety (HAM-A), Pittsburgh Sleep Quality Index (PSQI), and the systematic collection of reported adverse events. Data were collected from May 1999 to February 2004. RESULTS: The change from baseline to month 12 in mean CGI-BP-M scores between groups was statistically significant (p = .0046). Mean score change from baseline to endpoint in the gabapentin group was -2.1, and the mean score change in the placebo group was -0.6. No emerging manic or depressive symptoms were seen in either group as measured with the YMRS, HAM-D, HAM-A, and PSQI. In the PSQI-6 subscale (use of sleeping medication), the mean score change at month 12 in the gabapentin group was 0.9, and the mean score change in the placebo group was 0.05 (p = .0267). Overall, gabapentin was well tolerated. CONCLUSION: This small, randomized clinical trial comparing the prophylactic efficacy of adjunctive gabapentin to placebo suggests that, despite lack of acute efficacy, treatment with gabapentin might provide some benefit on the long-term outcome of bipolar disorder.     

Outcome of acute idiosyncratic drug-induced liver injury: Long-term follow-up in a hepatotoxicity registry

A chronic adverse reaction may occur in some instances of drug-induced liver injury (DILI), even despite drug cessation. In our study, we obtained records from a Spanish registry and evaluated cases of DILI with biochemical evidence of long-term damage. Chronic outcome was defined as a persistent biochemical abnormality of hepatocellular pattern of damage more than 3 months after drug withdrawal or more than 6 months after cholestatic/mixed damage. Data on 28 patients with a chronic clinical evolution (mean follow-up 20 months) between November 1995 and October 2005 were retrieved (18 female; overall mean age 55 yr) and accounted for 5.7% of total idiosyncratic DILI cases (n = 493) submitted to the registry. The main drug classes were cardiovascular and central nervous system (28.5% and 25%, respectively), which, in contrast, represented only 9.8% and 13%, respectively, of all DILI cases. The most frequent causative drugs were amoxicillin-clavulanate (4 of 69 cases), bentazepam (3 of 7 cases), atorvastatin (2 of 7 cases), and captopril (2 of 5 cases). Patients with cholestatic/mixed injury (18 of 194 cases [9%]) were more prone to chronicity than patients with hepatocellular injury (10 of 240 cases; P < .031). In the case of chronic hepatocellular injury, 3 patients progressed to cirrhosis and 2 to chronic hepatitis. In the cholestatic/mixed group, liver biopsy indicated cirrhosis in 1 patient and ductal lesions in 3 patients. In conclusion, cholestatic/mixed type of damage is more prone to become chronic while, in the hepatocellular pattern, the severity is greater. Cardiovascular and central nervous system drugs are the main groups leading to chronic liver damage.     

Determinants of the clinical expression of amoxicillin-clavulanate hepatotoxicity: a prospective series from Spain

Amoxicillin-clavulanate (AC) hepatotoxicity has been reported to exhibit a higher predominance of cholestatic types of damage, especially in males. However, the determinants of its clinical expression are unknown. This study prospectively evaluated the profile of AC hepatotoxicity. Data on all cases of hepatotoxicity reported to the Spanish Registry attributed to AC and assessed as definite or probable on the Council for International Organizations of Medical Sciences (CIOMS) scale were collated and compared to published case series. Hepatotoxicity related to amoxicillin-clavulanate was identified in 69 patients (36 males; mean age 56 years) representing 14% of all cases of hepatotoxicity submitted to the Registry. There was an overall sex distribution and the predominant pattern of lesion was hepatocellular (36%) which occurred at a shorter duration of treatment (P < .03). Mean time lapse between therapy initiation and jaundice onset was 16 days. Late onset of symptoms following end of treatment occurred in half the cases. Multiple logistic regression analysis identified advancing age as the factor associated with the development of cholestatic/mixed type of injury (odds ratio for an age interval for 1 year: 1.045 [95% CI = 1.013-1.078; P = .005). An unfavorable outcome was seen in 7% of patients. In conclusion, age is the most important determinant in the biochemical expression of AC hepatotoxicity; younger age is associated with cytolytic damage and shorter treatment duration, whereas cholestatic/mixed type of damage is related to older age and prolonged AC therapy.     

Improving adjunctive treatment in pulmonary embolism and fibrinolytic therapy. The role of enoxaparin and weight-adjusted unfractionated heparin

Aim The role of enoxaparin and weight-adjusted unfractionated heparin (UH) as adjunct to fibrinolytic therapy in pulmonary embolism is unknown. Methods In a prospective, open-label, controlled multicenter trial, 80 patients with high-risk pulmonary embolism were enrolled. Forty patients received alteplase infusion plus weight-adjusted UH (24–48 h) and then enoxaparin (7 days). In control group, UH standard regimen was used. There were not differences on pulmonary embolism extension, (P 0.63) and right ventricular hypokinesis (P 0.07) in both groups. In terms of in-hospital survival (P 0.009), escalation treatment (P < 0.001) and in-hospital stay (P < 0.001) study group had better outcome than opposite group. In a 30 (P < 0.001) and 90 (P < 0.001) days follow-up pulmonary perfusion was improved in patients who received enoxaparin versus heparin alone without increasing major bleeding complications. Conclusion Enoxaparin and weight-adjusted intravenous UH as adjunct to 1-h alteplase infusion improve in-hospital and follow-up outcome compared to heparin alone in high-risk PE. This paper was written with unforgettable memory of Hector Garcia.     

Epidemiological Cutoff Values for Fluconazole,Itraconazole, Posaconazole,and Voriconazole for Six Candida Species as Determined by the Colorimetric Sensititre YeastOne Method

In the absence of clinical breakpoints (CBP), epidemiological cutoff values (ECVs) are useful to separate wild-type (WT) isolates (without mechanisms of resistance) from non-WT isolates (those that can harbor some resistance mechanisms), which is the goal of susceptibility tests. Sensititre YeastOne (SYO) is a widely used method to determine susceptibility of Candida spp. to antifungal agents. The CLSI CBP have been established, but not for the SYO method. The ECVs for four azoles, obtained using MIC distributions determined by the SYO method, were calculated via five methods (three statistical methods and based on the MIC₅₀ and modal MIC). Respectively, the median ECVs (in mg/liter) of the five methods for fluconazole, itraconazole, posaconazole, and voriconazole (in parentheses: the percentage of isolates inhibited by MICs equal to or less than the ECVs; the number of isolates tested) were as follows: 2 (94.4%; 944), 0.5 (96.7%; 942), 0.25 (97.6%; 673), and 0.06 (96.7%; 849) for Candida albicans; 4 (86.1%; 642), 0.5 (99.4%; 642), 0.12 (93.9%; 392), and 0.06 (86.9%; 559) for C. parapsilosis; 8 (94.9%; 175), 1 (93.7%; 175), 2 (93.6%; 125), and 0.25 (90.4%; 167) for C. tropicalis; 128 (98.6%; 212), 4 (95.8%; 212), 4 (96.0%; 173), and 2 (98.5; 205) for C. glabrata; 256 (100%; 53), 1 (98.1%; 53), 1 (100%; 33), and 1 (97.9%; 48) for C. krusei; 4 (89.2%; 93), 0.5 (100%; 93), 0.25 (100%; 33), and 0.06 (87.7%; 73) for C. orthopsilosis. All methods included ≥94% of isolates and yielded similar ECVs (within 1 dilution). These ECVs would be suitable for monitoring emergence of isolates with reduced susceptibility by using the SYO method.     

Abnormal methylation of the common PARK2 and PACRG promoter is associated with downregulation of gene expression in acute lymphoblastic leukemia and chronic myeloid leukemia

The PARK2 gene, previously identified as a mutated target in patients with autosomal recessive juvenile parkinsonism (ARJP), has recently been found to be a candidate tumor suppressor gene in ovarian, breast, lung and hepatocellular carcinoma that maps to the third common fragile site (CFS) FRA6E. PARK2 is linked to a novel described PACRG gene by a bidirectional promoter containing a defined CpG island in its common promoter region. We have studied the role of promoter hypermethylation in the regulation of PARK2 and PACRG expression in different tumor cell lines and primary patient samples. Abnormal methylation of the common promoter of PARK2 and PACRG was observed in 26% of patients with acute lymphoblastic leukemia and 20% of patients with chronic myelogenous leukemia (CML) in lymphoid blast crisis, but not in ovarian, breast, lung, neuroblastoma, astrocytoma or colon cancer cells. Abnormal methylation resulted in downregulation of PARK2 and PACRG gene expression, while demethylation of ALL cells resulted in demethylation of the promoter and upregulation of PARK2 and PACRG expression. By FISH, we demonstrated that a lack of PARK2 and PACRG expression was due to biallelic hypermethylation and not to deletion of either PARK2 or PACRG in ALL. In conclusion, our results demonstrate for the first time that the candidate tumor suppressor genes PARK2 and PACRG are epigenetically regulated in human leukemia, suggesting that abnormal methylation and regulation of PARK2 and PACRG may play a role in the pathogenesis and development of this hematological neoplasm.     

Haemodynamic and tubular renal dysfunction in rats with sustained arterial calcinosis

1. In humans, two of the principal characteristics of vascular ageing are arterial wall calcification and decreased arterial distensibility, which induce organ damage. To amplify arterial calcium accumulation in laboratory animals, it is necessary to use an overdose of vitamin D(3). 2. The aim of the present study was to assess the impact of arterial calcium overload on renal function. 3. Adult male Wistar rats were randomly divided into two groups: control and treated rats. Treated rats were injected 10 days before the experiment with a single dose of vitamin D(3) (300 000 IU/kg, i.m.). 4. Treated rats showed a decrease in renal blood flow and glomerular filtration rate. Tubular parameters were not modified under basal conditions. In contrast, a statistically significant increase in the fractional excretion of Na, K, Ca and H(2)O were observed in treated rats after the acute increment of sodium distal delivery, suggesting that the reabsorptive capacity of the thick ascending limb may be altered in treated rats. 5. Thus, Na(+)/K(+)-ATPase activity was evaluated in homogenates from renal cortex and medulla. Rats with arterial calcinosis presented a diminished activity of Na(+)/K(+)-ATPase in medulla homogenates. 6. An increment in the abundance of the Na-K-2Cl cotransporter (NKCC2) was observed in renal medulla homogenates from treated rats. It is suggested that this may compensate for the inefficiency of Na(+)/K(+)-ATPase under basal conditions but, in the presence of acute distal sodium overload, the increment in NKCC2 abundance may not be sufficient to compensate for the decrease in Na(+)/K(+)-ATPase activity. 7. In summary, in our experimental model of arterial calcinosis, renal function is impaired, presenting a vascular compromise and altered function of the medullar thick ascending limb that becomes evident in the presence of acute high distal sodium delivery.