Critical analysis of aortic dysmorphism in Marfan Syndrome

Introduction: Marfan syndrome (OMIM #154700) was described for the first time in 1896 by Antoine Bernard-Jean Marfan. It is characterized by its autosomal dominant inheritance pattern, affects 1:5000 of those born alive, and involves the gene that codifies the structural protein fribrillin-1. Fibrillin-1 is critical for the formation of the elastic system backbone and for the negative regulation of the cytokine transforming growth factor beta 1 (TGF-β1). In the syndrome this fibrillar component causes the degeneration of the fibers of the elastic system, which no longer sequesters matrix TGF-β, causing disorganization of the collagen fibers and vascular smooth muscles. The disease affects mainly the cardiovascular system, cardiovascular problems being the main cause of death. This is because arteries have large amounts of elastic fibers that rupture in an adverse process, causing mainly dissections and aneurisms, which have been better clariied in experimental studies with mice. Objective: The objective of this study was to conduct an etiopathogenic and molecular review to describe the advances in the understanding of blood vessel dysmorphism in the syndrome, especially of the aorta. Materials and Methods: For this purpose the literature of the last 35 years was extensively reviewed. Conclusion: The origin of the aortic dysmorphism in the syndrome stems from a number of events that begin with the mutation of the gene fibrillin-1, causing fragmentation of the aortic elastic fibers. Excess cytokine TGF-β increases the amount of metalloproteinases and of vascular smooth muscle cell apoptosis, leading to matrix remodeling and increasing the susceptibility of the vessel to an aneurysm or dissecting process.

Genetic variants of IL-11 associated with risk of Hirschsprung disease

BACKGROUND

Hirschsprung disease (HSCR) is a congenital and heterogeneous disorder characterized by the absence of enteric ganglia during enteric nervous system (ENS) development. Our recent genome-wide association study has identified a variant (rs6509940) of interleukin-11 (IL-11) as a potential susceptible locus for HSCR. As interleukins play important roles in the ENS, we further studied associations with HSCR of nine common single nucleotide polymorphisms (SNPs) on IL-11.

METHODS

Biopsy specimens or surgical materials from all patients that were tested for histological examination based on the absence of the enteric ganglia were collected. A total of nine SNPs on IL-11 were genotyped in 187 HSCR patients and 283 unaffected controls using TaqMan genotyping assay.

KEY RESULTS

Combined analysis revealed that several SNPs (minimum p = 1.57 × 10(-7) ) showed statistically significant associations with HSCR, even after Bonferroni correction (pcorr  = 1.73 × 10(-6) for the SNP). Moreover, the most common haplotype was strongly associated with HSCR (pcorr  = 2.20 × 10(-6) ). In further analysis among three HSCR subtypes (short segment, S-HSCR; long segment, L-HSCR; total colonic aganglionosis, TCA) based on the extent of aganglionic segment, the result showed a different association pattern depending on the subtypes (minimum pcorr  = 6.12 × 10(-5) for rs6509940 in S-HSCR; but no significant SNP in L-HSCR and TCA).

CONCLUSIONS & INFERENCES

Although further replication in a larger cohort and functional evaluations are needed, our findings suggest that genetic variations of IL-11 may be associated with the risk of HSCR and/or the mechanisms related to ENS development.

Association between arachidonate 5-lipoxygenase-activating protein (ALOX5AP) and lung function in a Korean population

Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) plays a role in the 5-lipoxygenase (LO) pathway, which includes the LTC(4), LTD(4), LTE(4) and LTB(4). These leukotrienes are known causative factors of asthma, allergy, atopy and cardiovascular diseases. ALOX5AP lacks enzyme activity and acts by helping 5-LO function. In this study, healthy and general subjects who live in rural and urban areas of Korea were tested for the association of ALOX5AP polymorphisms with lung function. Lung function was also estimated by calculating the predicted values for forced expiratory volume in one second (FEV(1) _%PRED) and the proportion of the forced vital capacity exhaled in the first second (FEV(1) /FVC_PRED). The linear regression was adjusted for residence area, gender, age, height and smoking status. The analysis revealed associations between FEV(1) and the single-nucleotide polymorphism (SNP) rs9506352 and the haplotype TCAC (permuted P-value < 0.05). The linkage disequilibrium block that included the significant SNPs overlapped with SNPs that were revealed previously to associate with myocardial infarction and asthma and to affect lung function. This study is the first to demonstrate the association between lung function and ALOX5AP polymorphisms in a healthy and general population.

Common promoter polymorphism in monocyte differentiation antigen CD14 is associated with serum triglyceride levels and body mass index in non-diabetic individuals

AIMS

Growing evidence supports the hypothesis that chronic low-grade inflammation related to innate immunity may play an important role in the pathophysiology of Type 2 diabetes mellitus (T2DM). The monocyte differentiation antigen CD14 gene (CD14) acts as the receptor for lipopolysaccharide (LPS) and augments monocyte/macrophage inflammatory responses.

METHODS

We have sequenced the gene, including all exons, exon/intron boundaries, and the -1.5 kb of the 5' flanking region. Two common loci (minor allele frequency > 0.05) were genotyped in 775 T2DM patients and 316 control subjects recruited in the Korean T2DM Study.

RESULTS

Eight polymorphisms, including four non-synonymous forms, were identified in CD14. No polymorphisms were found in association with T2DM. However, one common promoter SNP (-260T>C) was significantly associated with both the serum triglyceride level (TG) and body mass index (BMI) in non-diabetic control subjects. Individuals who carried the minor allele (C) had higher TG levels (1.65 +/- 0.81 vs. 1.46 +/- 0.80 mmol/l; P = 0.0007) and BMI (23.96 +/- 3.00 vs. 23.28 +/- 3.22 kg/m(2); P = 0.04) as compared with subjects carrying T/T genotypes.

CONCLUSION

Our data suggest that lipid metabolism and obesity, important pathophysiological elements of T2DM and the metabolic syndrome, are regulated by complex mechanisms that include the CD14 gene polymorphism-mediated genetic propensity to non-specific inflammatory responses.

Secretory production of Arthrobacter levan fructotransferase from recombinant Escherichia coli

Levan fructotransferase (LFTase) from Arthrobacter ureafaciens K2032 was expressed with N-terminal fusion of a LacZ-derived secretion motif (TMITNSSSVP) using the lac promoter system in recombinant Escherichia coli JM109 [pUDF-A81]. In flask cultures, recombinant enzyme activity was detected in culture media, and sequence analysis of N-terminal residues showed that about 40% of the extracellular recombinant LFTase had an authentic N-terminus. In a fed-batch bioreactor containing recombinant E. coli at high cell concentrations (OD(600)>200), the extracellular LFTase accumulated to 46000 U ml(-1) (approximately 2.0 g l(-1)) which was almost 40% of total (intra- and extracellular) recombinant LFTase. The synthesized recombinant enzyme was secreted soon after gene expression was induced by IPTG. Prolonged high secretion caused cell lysis and growth inhibition during the production phase in fed-batch cultures. When lactose was added by continuous feed mode, the secretion of recombinant LFTase and hence the cell lysis were significantly delayed in spite of the increased synthesis level. Therefore the induced cell culture of recombinant E. coli could grow up to a much higher cell concentration with continuing recombinant enzyme synthesis. In the case of the controlled feed of lactose, the maximum activities (U ml(-1)) of total and extracellular LFTase were nearly 100% and 70% higher, respectively.

Favorable effect of new artificial liver support on survival of patients with fulminant hepatic failure

The two most serious symptoms of fulminant hepatic failure are bleeding and hepatic coma. To overcome these problems, we developed an artificial liver support system comprising a combination of plasma exchange and hemodiafiltration using a high performance membrane. We treated 67 patients with fulminant hepatic failure. Of these, 65 patients (97.0%) regained normal consciousness, and 55 patients (80.9%) were kept alert as long as we continued to apply this system. All 7 patients (100%) with fulminant hepatitis caused by hepatitis A virus infection and 9 of 12 patients (75%) with fulminant hepatitis caused by acute hepatitis B (HB) virus infection survived. In addition, 7 of 15 HB virus carriers (46.7%) who developed fulminant hepatitis and 11 of 29 patients (37.9%) with fulminant hepatitis caused by non-A, non-B hepatitis viruses survived. The overall survival rate was 37 of 67 patients (55.2%). Our artificial liver support system allows as high a survival rate as liver transplantation.

Functional activity in host and graft lymphoid tissue of rats receiving syngeneic heterotopic small bowel transplants with portal or systemic drainage

Adult Lewis rats received syngeneic accessory small bowel transplants (SBT) with venous drainage to the portal vein (PV) or the inferior vena cava (IVC)/hetero-portal (HP) or hetero-systemic (HS) grafts, respectively. At varying times thereafter (5-300 days post-transplantation) animals were killed and cells from different lymphoid organs were tested in vitro for their generation of lymphoproliferative and cytotoxic T-cell responses, as well as their ability to produce a variety of lymphokines after alloantigen or mitogen stimulation. Despite marked decreases in cell recovery in Peyer's Patches of HS rats, no significant loss of cell function (on a per cell basis) was noted in any animal group. Total recovered activity per organ was decreased in small intestinal tissue (host and graft) of HS recipients regardless of the assay under study.

Migration patterns of lymphocytes following syngeneic heterotopic small bowel transplantation in rodents

Adult rats received syngeneic accessory small bowel grafts with venous drainage to either the portal vein (hetero-portal) or the inferior vena cava (hetero-systemic). Lymphoid cell recovery in different lymphoid organs (spleen, pooled peripheral lymph nodes, mesenteric nodes, Peyer's Patches) was evaluated at varying times (days 0-300) post-grafting. While minimal changes were observed for cell recovery in other organ tissues, lymphocyte recovery in Peyer's Patches of both host and graft small intestine of hetero-systemic animals was decreased from 10- to 100-fold with respect to hetero-portal recipients or non-operated controls. These changes were seen throughout the time course of the study. In additional experiments, lymphoid cells from different organs/donors were labelled in vitro with 111In and injected intravenously into normal/transplanted recipients. Recovery of 111In in various organs was assessed at 1 and 6 h postinjection. The major change seen was in the decreased ability of mononuclear cells derived from Peyer's Patches to migrate to small intestinal tissue (host and graft) in hetero-systemic recipients. In addition, Peyer's Patch cells from these animals 'homed' poorly to small intestine in non-operated animals by comparison with cells from normal rats (or hetero-portal donors).

Altered cell trafficking in mesenteric lymphoid tissue following syngeneic heterotopic small bowel transplantation in rodents

These data indicate that in rat heterotopic syngeneic SBT, the venous drainage system of the graft has profound effects on cell recovery in the gut-associated lymphoid tissue of both graft and host. Depending on the functional status of the same lymphoid tissue (Gorezynski, personal communication, 1992) one could thus anticipate significant perturbation of host-antigraft (and GVH) reactivity in allogeneic situations according to the venous drainage used. The mechanism(s) responsible for these effects have not been investigated. However, one testable hypothesis is that (a) factor(s) from the gut can control lymphoid recirculation within the mesenteric lymphoid tissue, and that this (these) factor(s) are absorbed under normal circumstances by hepatic tissue.

Comparison of functional activity in host and graft mesenteric lymphoid tissue of rats receiving syngeneic heterotopic small bowel allografts with portal or systemic drainage

With the accompanying paper these studies provide further evidence that functionally important lymphoid cell trafficking takes place in mesenteric tissue under the apparent control of factor(s) filtered by hepatic tissue. The role that these regulatory mechanisms have to play on survival of vascular allografts with venous drainage into either the portal or systemic circulation remains to be elucidated.

[Hemodynamic and microcirculatory changes in the liver in experimental acute pancreatitis of dogs]

To investigate the hemodynamic changes of the liver in acute pancreatitis the microcirculation of the liver, portal venous flow, hepatic artery blood flow, cardiac index were measured in 15 dogs with acute pancreatitis induced by autologous bile and trypsin injection into the main pancreatic duct during the experimental period for 5 hrs. The effect of protease inhibitor (PATM) in a dose of 3 mg/kg/kg/hr on those hemodynamic changes was investigated in another series of acute pancreatitis in dogs. In acute pancreatitis hepatic microcirculation decreased to 26 +/- 15 ml/min/100g at 5 hrs after onset of pancreatitis, portal venous flow and hepatic artery flow decreased to 86 +/- 16 ml/min and 66 +/- 30 ml/min at 5 hrs, respectively. The administration of PATM maintained the portal blood flow during the first 2 hrs and showed a trend of decreasing to 219 +/- 93 ml/min at 5 hrs. The hepatic microcirculation showed 77 +/- 25 ml/min/100g and 72 +/- 14 ml/min/100g at 1 and 2 hrs respectively and then decreased to 47 +/- 21 ml/min/100g at 5 hrs. We concluded hemodynamic and microcirculatory changes of the liver in acute pancreatitis was disturbed due to the decreased portal and hepatic artery flow, however, the administration of PATM has an effect of improvement of liver microcirculation.

[Renal microcirculation in experimental acute pancreatitis of dogs--the effect of pancreatic protease inhibitor and dopamine]

To understand the renal microcirculation in acute pancreatitis is important to know the pathophysiology of renal insufficiency frequently observed as one of multiple organ failures in severe acute pancreatitis. In mongrel dogs acute pancreatitis was experimentally introduced by autologous bile added trypsin injection into the pancreatic duct. The effect of new synthesized pancreatic protease inhibitor (PATM) and dopamine in a dose of 3mg/kg/hr and 10 micrograms/kg/min were investigated, respectively. In acute pancreatitis dogs, renal arterial blood flow and renal tissue blood flow immediately fell and gradually decreased in time course of experiment and renal vascular resistance increased from 2 hours after onset of pancreatitis. When pancreatic protease inhibitor (PATM) was infused in acute pancreatitis dogs, blood pressure and pulse pressure relatively preserved during the experiment. Renal blood flow and renal tissue blood flow were maintained during the first 1 hour and thereafter slightly decreased, however which was less than that of no PATM treated dogs. When dopamine was infused in acute pancreatitis dogs, blood pressure was maintained during the first 90 minutes thereafter remarkably decreased. Renal blood flow was maintained within 60 minutes, however it remarkably decreased at the end of the experiment. This study suggested that renal microcirculation was disturbed from early period of acute pancreatitis in dogs and pancreatic protease inhibitor (PATM) had a beneficial effect of maintain the renal microcirculation.

Pancreatic microcirculation of dogs measured by hydrogen gas generated by electrolysis

Electrochemically generated hydrogen gas was used to measure pancreatic regional blood flow in dogs by Koshu's method. This method is not necessary to inhale H2 gas and it is possible to generate H2 gas from H3O- in tissue in precise areas and to measure pancreatic regional blood flow easily, immediately, and steadily. Reliability and reproducibility were as good as for the H2 gas clearance method. Although the H2 gas clearance method has disadvantages in measuring pancreatic regional blood flow, especially in hypocirculation and in small animals, this new method can be used effectively. It will be useful in the investigation and examination of pathologic conditions in small animals and in humans.

[Pathophysiology and treatment of severe pancreatitis]

The current study was designed to characterize toxic substances in hemorrhagic ascitic fluid by using in vivo dogs model and to examine the toxicity of hemorrhagic ascitic fluid by using an in vivo mice model injecting the fluid intraperitoneally. Our experiment showed that high levels of bradykinin, histamine and prostaglandin E were found in serum and in hemorrhagic ascitic fluid which reported as toxic substances during severe pancreatitis. A similar finding was also obtained clinically in four patients with severe acute pancreatitis. The mortality rate on 72 hours following the intraperitoneal injection of 2.0 and 3.0 ml of ascitic fluid were 66.0% and 89.7% respectively. Mice which died following the injection of ascitic fluid showed shock lung at autopsy. These results indicate that peritoneal lavage might be an effective method for the treatment of severe pancreatitis. We evaluated 25 patients with severe acute pancreatitis clinically. Laparotomy and drainage operations were performed in 16 patients of these patients. Twelve among 16 patient had good results. The cause of death were multiorgan failures.

Toxic products in hemorrhagic ascitic fluid generated during experimental acute hemorrhagic pancreatitis in dogs and a treatment which reduces their effect

Toxic substances produced in hemorrhagic ascitic fluid during experimental hemorrhagic pancreatitis in dogs were investigated. An average of 394 ml of ascitic fluid was produced within 5 h after the induction of acute pancreatitis by intraductal injection of a mixture of autologous bile and trypsin. Hemorrhagic ascitic fluid was collected under sterile conditions, which was confirmed by aerobic and anaerobic culture and a Limulus test. The sterile fluid was injected intraperitoneally into mice in doses of 2 and 3 ml, and the mortality rate 72 h after injection was 66.0 and 88.4%, respectively. It contained high concentrations of pancreatic enzymes, including trypsin and esterase activity, as well as bradykinin, histamine and prostaglandin. Autopsy and histological examination of mice revealed shock with lung damage. The results suggest that hemorrhagic ascitic fluid produced in pancreatitis may be an important factor for early deaths in acute pancreatitis. When a new synthetic antiprotease (nafamstat mesilate) in a dosage of 0.2 mg was mixed with 1 ml of ascitic fluid, trypsin was not detectable, and bradykinin was reduced 1.0 ng/ml from 8.0 ng/ml, while esterase activity decreased to one tenth of its previous activity. The mortality following injection of the solution decreased to 26.7 and 80.6%, respectively. These results indicate that peritoneal lavage with a solution containing antiprotease may be an effective treatment for hemorrhagic acute pancreatitis.