Vladislav Treska

Novel aspects of the pathogenesis of aneurysms of the abdominal aorta in humans

Aneurysm of the abdominal aorta (AAA) is a particular, specifically localized form of atherothrombosis, providing a unique human model of this disease. The pathogenesis of AAA is characterized by a breakdown of the extracellular matrix due to an excessive proteolytic activity, leading to potential arterial wall rupture. The roles of matrix metalloproteinases and plasmin generation in progression of AAA have been demonstrated both in animal models and in clinical studies. In the present review, we highlight recent studies addressing the role of the haemoglobin-rich, intraluminal thrombus and the adventitial response in the development of human AAA. The intraluminal thrombus exerts its pathogenic effect through platelet activation, fibrin formation, binding of plasminogen and its activators, and trapping of erythrocytes and neutrophils, leading to oxidative and proteolytic injury of the arterial wall. These events occur mainly at the intraluminal thrombus–circulating blood interface, and pathological mediators are conveyed outwards, where they promote matrix degradation of the arterial wall. In response, neo-angiogenesis, phagocytosis by mononuclear cells, and a shift from innate to adaptive immunity in the adventitia are observed. Abdominal aortic aneurysm thus represents an accessible spatiotemporal model of human atherothrombotic progression towards clinical events, the study of which should allow further understanding of its pathogenesis and the translation of pathogenic biological activities into diagnostic and therapeutic applications.

Relevance of miR-21 and miR-143 expression in tissue samples of colorectal carcinoma and its liver metastases

MicroRNAs, which are endogenously expressed regulatory noncoding RNAs, have an altered expression in colorectal cancer. The aim of our study was to assess the relationship of miR-21 and miR-143 expression to the prognostic/clinicopathological features of colorectal carcinoma (CRC) and colorectal liver metastases (CLM). The estimation was performed in 46 paired (tumor and control) tissue samples of CRC. Further, we studied 30 tissue samples of CLM. MiR-21 and miR-143 expressions were quantified by using the quantitative reverse transcription polymerase chain reaction method. Relation of miR-21 and miR-143 expression to disease-free interval (DFI) (Wilcoxon; P = 0.0026 and P = 0.0191, respectively) was recorded. There was shorter DFI in patients with a higher expression of miR-21 and, surprisingly, also in patients with a higher expression of miR-143, which is a putative tumor suppressor. There was a higher expression of miR-21 and lower expression of miR-143 in CRC tissue in comparison with adjacent normal colon tissue (P < 0.0001; P < 0.0001, respectively). Similarly, we observed a higher expression of miR-21 and a lower expression of miR-143 in CLM in comparison with normal colon tissue (P < 0.0001; P < 0.0001, respectively). Our results support the hypothesis about oncogenic function of miR-21 and show its relation to DFI. The role of miR-143 in carcinogenesis seems to be more complex.

Effect of cytomegalovirus viremia on subclinical rejection or interstitial fibrosis and tubular atrophy in protocol biopsy at 3 months in renal allograft recipients managed by preemptive therapy or antiviral prophylaxis.

Background. Cytomegalovirus (CMV) is a risk factor for acute renal allograft rejection. The aim of this study was to determine the impact of CMV viremia on subclinical rejection (SCR) and interstitial fibrosis and tubular atrophy (IF/TA) in protocol biopsy at 3 months after transplantation. Methods. A total of 118 consecutive renal transplant recipients at risk for CMV (donor and recipient CMV seropositive) were included and followed up prospectively. Protocol biopsies with sufficient tissue were obtained in 102 patients. CMV activity was monitored using real-time polymerase chain reaction in whole blood. Three-month prophylaxis with valacyclovir or ganciclovir was given in 60 patients, whereas the remaining 42 patients were managed by preemptive therapy. Multivariate logistic stepwise regression analysis was used to estimate the effect of CMV viremia and other covariates on SCR and IF/TA. Results. CMV viremia occurred in 41% of the patients with a median peak viral load of 1300 copies/mL. The incidence of SCR and IF/TA was 29% and 28%, respectively. CMV viremia was not a risk factor for SCR (OR=0.77, P=0.551); however, viremia of more than or equal to 2000 copies/mL increased the risk of IF/TA (OR=3.83, P=0.023). Biopsy-proven acute rejection (OR=3.34, P=0.009) and sirolimus-based immunosuppression (OR=6.13, P=0.008) were independent predictors of SCR. Delayed-graft function (OR=6.02, P=0.001) and donor age (OR=1.53 per 10-year increase, P=0.009) were associated with IF/TA. Conclusions. CMV viremia is not an independent risk factor for SCR. CMV viremia with viral load of more than or equal to 2000 copies/mL is associated with increased risk of IF/TA in protocol biopsy at 3 months after transplantation.

Inflammation in the wall of abdominal aortic aneurysm and its role in the symptomatology of aneurysm.

Cytosol levels of cytokines [interleukins 1b, 6, 8 (IL-1b, 6, 8), tumor necrosis factor-alpha (TNF-alpha)] in aneurysm walls were evaluated in a prospective non-randomized study of 57 patients. The group was divided into two subgroups: Subgroup I (ruptured aneurysms, n=11) and Subgroup II (asymptomatic aneurysms, n=32). A control group consisted of 14 kidney donors. Aortic walls were examined by immunohistochemistry and microscopy to detect inflammatory cells. More pronounced inflammatory changes and higher cytosol cytokine levels [IL6 (p<0.001), IL8 (p<0.0003) and TNFalpha (p<0.002)] were found in the walls of ruptured aneurysms than in the asymptomatic aneurysms. Immunohistochemically, most cells within the inflammatory infiltrates stained positively with the monoclonal antibody to the leucocyte common antigen (CD 45). The majority were of B-cell origin, which was demonstrated by positive staining with the monoclonal antibody L26 directed against the CD 20 antigen. These results show that an inflammatory process plays a significant role in patients with ruptured abdominal aortic aneurysms (AAA). A means of modifying the inflammatory process in the wall of AAAs might play an important role in preventing aneurysm rupture.

Long-Term Outcomes of Pre-emptive Valganciclovir Compared with Valacyclovir Prophylaxis for Prevention of Cytomegalovirus in Renal Transplantation

Prevention of cytomegalovirus (CMV) is essential in organ transplantation. The two main strategies are pre-emptive therapy, in which one screens for and treats asymptomatic CMV viremia, and universal antiviral prophylaxis. We compared these strategies and examined long-term outcomes in a randomized, open-label, single-center trial. We randomly assigned 70 renal transplant recipients (CMV-seropositive recipient or donor) to 3-month prophylaxis with valacyclovir (n=34) or pre-emptive valganciclovir for significant CMV viremia detected at predefined assessments through month 12 (n=36). Among the 55 patients who had a protocol biopsy specimen available at 3 years to allow assessment of the primary outcome, 9 (38%) of 24 patients in the prophylaxis group and 6 (19%) of 31 patients in the pre-emptive therapy group had moderate to severe interstitial fibrosis and tubular atrophy (odds ratio, 2.50; 95% confidence interval, 0.74-8.43; P=0.22). The prophylaxis group had significantly higher intrarenal mRNA expression of genes involved in fibrogenesis. The occurrence of CMV disease was similar in both groups, but pre-emptive therapy improved 4-year graft survival (92% versus 74%; P=0.049) as a result of worse outcomes in patients with late-onset CMV viremia. In conclusion, compared with valacyclovir prophylaxis, pre-emptive valganciclovir therapy may lead to less severe interstitial fibrosis and tubular atrophy and to significantly better graft survival.

Effects of tempol, a free radical scavenger, on long-term hyperdynamic porcine bacteremia*

Objectives:Pretreatment with tempol, a membrane-permeable radical scavenger, has been shown to be protective in rodent models of endotoxic and Gram-positive shock. However, neither the pretreatment design nor hypodynamic endotoxic shock in rodents mimics the clinical scenario. Therefore, we investigated the effects of tempol in a posttreatment model of long-term, volume-resuscitated, hyperdynamic porcine bacteremia. Design:Prospective, randomized, controlled experimental study. Setting:University animal laboratory. Subjects:Sixteen anesthetized, mechanically ventilated, and instrumented pigs. Interventions:Sepsis was induced and maintained for 24 hrs with continuous infusion of live Pseudomonas aeruginosa. After 12 hrs of hyperdynamic sepsis, animals were randomized to receive either vehicle (control, n = 8) or continuous infusion of tempol (n = 8, 30 mg/kg/hr). Measurements and Main Results:Systemic and hepatosplanchnic hemodynamics, oxygen exchange, metabolism, ileal mucosal microcirculation, and tonometry as well as oxidative stress and coagulation variables were assessed before and after 12, 18, and 24 hrs of P. aeruginosa infusion. Tempol significantly attenuated reduction in mean arterial pressure. Despite comparable mesenteric macrocirculation, tempol attenuated the otherwise progressive deterioration in ileal mucosal microcirculation and prevented mucosal acidosis. By contrast, treatment with tempol failed to influence the P. aeruginosa-induced derangements of hepatosplanchnic redox state, liver lactate clearance, and regional acidosis but prevented the development of renal dysfunction. In addition, tempol reduced nitrosative stress without significant effect on the gradual increase in plasma 8-isoprostanes. Finally, tempol attenuated sepsis-induced endothelial (von Willebrand factor) and hemostatic dysfunction (thrombin-antithrombin complexes, plasminogen activator inhibitor-type 1). Conclusions:The radical scavenger tempol partially prevented live bacteria from causing key features of hemodynamic and metabolic derangements in porcine hyperdynamic sepsis and beneficially affected surrogate markers of sepsis-induced endothelial and coagulation dysfunction. Incomplete reduction of oxidative stress because of dilutional effects and/or missed optimal therapeutic window for antioxidant treatment when used in posttreatment approach may account for the only partial protection by tempol in this model.

A randomized prospective controlled trial of oral ganciclovir versus oral valacyclovir for prophylaxis of cytomegalovirus disease after renal transplantation

Abstract.Oral ganciclovir and valacyclovir reduce the incidence of cytomegalovirus (CMV) disease after renal transplantation (RTx). Our study was designed to compare the efficacy, costs, and safety of oral ganciclovir and valacyclovir in the prophylaxis of CMV disease over the first 6 months after RTx. A total of 38 patients was randomized to 3-month treatment with either oral ganciclovir (1 g t.i.d., n=14, GAN group) or oral valacyclovir (2 g q.i.d., n=12, VAL group). A third group (C, n=12) received no prophylaxis. The patients were monitored by CMV-nested PCR in whole blood. No differences were found between the groups in their demographic characteristics, immunosuppressive protocols, or donor and recipient CMV serology. Thirty-six out of 38 (94.7%) recipients were CMV-seropositive. Over the 6-month post-RTx period, there were 13 episodes of CMV disease in eight (66.7%) patients of the C group compared with none in the GAN and VAL groups (P=0.0005, GAN vs C; P=0.001, VAL vs C). The incidence of CMV viremia was 30.8%, 50.0%, and 91.7% in the GAN, VAL, and C groups, respectively (P=0.004, GAN vs C; P=0.07, VAL vs C; P=NS, GAN vs VAL). Treatment failure (death, graft loss, CMV disease, or withdrawal from study) occurred in 14.3%, 0% and 66.7% in the GAN, VAL, and C groups, respectively (P=0.014, GAN vs C; P=0.001, VAL vs C; P=NS, GAN vs VAL). The average CMV-associated costs per patient (in 2001 euros) were 2,449±1,178, 2,485±581, and 4,259±4,616 in the GAN, VAL, and C groups, respectively. Ganciclovir and valacyclovir were well tolerated, with ganciclovir having had to be withdrawn shortly in one patient only because of thrombocytopenia. In conclusion, oral ganciclovir and valacyclovir are equally safe and effective in the prophylaxis of CMV disease after RTx. Both are cost-effective and help reduce CMV-associated costs by some 40% compared with patients without prophylaxis.

Reactive syringofibroadenomatous hyperplasia in peristomal skin with formation of hybrid epidermal-colonic mucosa glandular structures, intraepidermal areas of sebaceous differentiation, induction of hair follicles, and features of human papillomavirus infection : a diagnostic pitfall

We report a case of reactive syringofibroadenomatous hyperplasia in peristomal skin. The patient was a 62-year-old woman who had undergone abdominoperineal resection of the rectum for rectal adenocarcinoma with subsequent colostomy 2 years earlier. Clinically, a nodule and small, whitish, warty lesions developed at the outer margin of the stoma extending onto the adjacent skin. Following a clinical suspicion of adenocarcinoma, recurrent at the colostomy site, a 5 × 4 × 3-cm excision of the peristomal skin and the affected portion of the stoma was performed and submitted for histologic examination. The biopsy revealed a peculiar composite lesion of reactive syringofibroadenomatous hyperplasia and the excised part of the stoma. Several unusual histopathological features were detected in the syringofibroadenomatous part of the lesion such as the formation of plentiful hybrid epidermal-colonic mucosa glandular structures, intraepidermal areas of sebaceous differentiation, koilocytic changes, induction of rudimentary hair follicles, and intradermal mucinous lakes. The cellular composition of the glandular structures was mainly similar to that seen in a normal colonic mucosa epithelium. They also contained occasional Paneth cells. Being located at a distance from the stoma, these accentuated colonic mucosa epithelial glands reaching the epidermis may be a diagnostic pitfall prompting the consideration of adenocarcinoma involving the stoma. The rudimentary follicles and sebaceous differentiation were probably induced by an altered stroma and/or human papillomavirus (HPV): HPV, type 36 was identified by PCR using consensus primers followed by sequencing of the PCR products.

Immunohistochemical Detection of Cancer Stem Cell Related Markers CD44 and CD133 in Metastatic Colorectal Cancer Patients

Aim. The goal of this study was to semiquantitatively detect presence of cancer stem cells markers CD44 and CD133 in immunohistochemically stained paired samples of colorectal cancer (CRC) and colorectal liver metastases (CLM). Level of staining intensity was compared to clinical and pathological characteristics of tumors with the aim to identify impact of CD44 or CD133 expression on tumor behavior. Patients and Methods. Formalin fixed paraffin embedded samples from 94 patients with colorectal tumor and liver metastases were collected at Sikls Department of Pathology. Samples were stained by antibodies against CD44 and CD133. Presence and intensity of staining was assessed semiquantitatively by three trained researchers. Results. Patients with higher level of CD133 staining in CRC had longer disease free interval (Cox-Mantel P = 0.0244), whereas we found no relation between CD44 expression and overall survival or disease free interval. CD133 expression in CRC and CLM differed based on CRC grading; in case of CD44 we found differences in staining intensity in individual stages of tumor lymph node invasion. Conclusion. Effect of cancer stem cell markers on prognosis of colorectal cancer can vary depending on pathological classification of tumor, and we have shown that CD133, generally considered to be a negative marker, can bear also clinically positive prognostic information in group of patients with colorectal liver metastases.

Esophageal stents for less invasive treatment of mediastinitis.

Introduction In spite of the progress in diagnosis and therapeutic options, esophageal perforation resulting in mediastinitis is a very serious condition with a high morbidity. Aim To evaluate the use of esophageal stents for the treatment of patients suffering from mediastinitis. Material and methods Retrospective (2008–2012) analysis of a group of patients requiring surgical treatment. The evaluation was focused on the cause of perforation, stent type and its parameters, the surgical method used, duration of stenting and total length of treatment. Results In total, 16 patients were treated by stenting. All patients were treated with the stent being placed across the defect in the esophagus. Mediastinitis was accessed and drained with the aid of a thoracotomy or thoracolaparotomy (8 cases), or using a combination of a laparotomy/laparostomy and pleural drainage (5 cases). The most basic interventions were either pleural or external cervical drainage (3 and 1 cases, respectively). One patient, in whom a stricture had developed at the healed perforation, was subjected to esophageal resection. Four patients died. The average period that the stent was left in situ was 53.7 days. The average period of hospitalization of those patients who survived was 53.4 days. Conclusions Using stents in therapy neither increased survival (mortality of 25%), nor decreased the length of therapy of patients once mediastinitis had developed. The main advantage of stenting is the preservation of the native esophagus and the reduced extent of surgical mediastinal drainage.