Folate metabolism in the superior cervical ganglion histochemical study

Summary By means of histochemical methods, folic acid, dihydrofolate reductase and NADH₂-cytochrome-C-reductase were studied in the bovine superior cervical ganglion, in parallel with quantitative estimations of dihydrofolate reductase activity and in connection with the process of ageing. Various levels of folate metabolism were present in nerve cells and glial cells, as well as in pre or postganglionic nerves. In the process of ageing the activity of dihydrofolate reductase gradually decreased and the folic acid concentration in the nerve cells increased. Thus the enzyme — substrate ratio appeared to favour the enzyme in young animals but the substrate in old animals.     

A novel VIP signaling pathway in T cells cAMP-->protein tyrosine phosphatase (SHP-2?)-->JAK2/STAT4-->Th1 differentiation

Vasoactive intestinal peptide (VIP) is a potent anti-inflammatory agent. In addition to the deactivation of macrophages, dendritic cells, and microglia, VIP shifts the Th1/Th2 balance, promoting the preferential differentiation and survival of Th2 cells, to the detriment of the proinflammatory Th1 effectors. Several mechanisms operate in the Th1/Th2 shift induced by VIP. Here we report on a novel mechanism for the effect of VIP on T cell differentiation, and show that VIP inhibits Th1 differentiation by interfering directly with the IL-12Jak2/STAT4 signaling pathway in T cells. The effect of VIP is cAMP-dependent, and appears to be mediated through the activation of protein tyrosine phosphatases (PTP), with SHP-2 as a potential target. The activation of PTPs represents a novel cAMP-downstream target for the immunomodulatory effects of VIP.     

Cecal Ligation Puncture Procedure

Human sepsis is characterized by a set of systemic reactions in response to intensive and massive infection that failed to be locally contained by the host. Currently, sepsis ranks among the top ten causes of mortality in the USA intensive care units ¹. During sepsis there are two established haemodynamic phases that may overlap. The initial phase (hyperdynamic) is defined as a massive production of proinflammatory cytokines and reactive oxygen species by macrophages and neutrophils that affects vascular permeability (leading to hypotension), cardiac function and induces metabolic changes culminating in tissue necrosis and organ failure. Consequently, the most common cause of mortality is acute kidney injury. The second phase (hypodynamic) is an anti-inflammatory process involving altered monocyte antigen presentation, decreased lymphocyte proliferation and function and increased apoptosis. This state known as immunosuppression or immune depression sharply increases the risk of nocosomial infections and ultimately, death. The mechanisms of these pathophysiological processes are not well characterized. Because both phases of sepsis may cause irreversible and irreparable damage, it is essential to determine the immunological and physiological status of the patient. This is the main reason why many therapeutic drugs have failed. The same drug given at different stages of sepsis may be therapeutic or otherwise harmful or have no effect ^2,3. To understand sepsis at various levels it is crucial to have a suitable and comprehensive animal model that reproduces the clinical course of the disease. It is important to characterize the pathophysiological mechanisms occurring during sepsis and control the model conditions for testing potential therapeutic agents. To study the etiology of human sepsis researchers have developed different animal models. The most widely used clinical model is cecal ligation and puncture (CLP). The CLP model consists of the perforation of the cecum allowing the release of fecal material into the peritoneal cavity to generate an exacerbated immune response induced by polymicrobial infection. This model fulfills the human condition that is clinically relevant. As in humans, mice that undergo CLP with fluid resuscitation show the first (early) hyperdynamic phase that in time progresses to the second (late) hypodynamic phase. In addition, the cytokine profile is similar to that seen in human sepsis where there is increased lymphocyte apoptosis (reviewed in ^4,5). Due to the multiple and overlapping mechanisms involved in sepsis, researchers need a suitable sepsis model of controlled severity in order to obtain consistent and reproducible results.     

Reproducible enrichment of extracellular heat shock proteins from blood serum using monomeric avidin

Extracellular heat shock proteins (eHsps) in blood circulation have been associated with various diseases, including cancer. However, the lack of methods to enrich eHsps from serum samples has hampered the characterization of eHsps. This Letter presents our serendipitous finding that the monomeric avidin resin can serve as an affinity resin to enrich eHsps from blood serum. Biochemical mechanism of this eHsp enrichment as well as implications in biomarker discovery is discussed.     

Curdlan microspheres. Synthesis,characterization and interaction with proteins (enzymes,vaccines)

Microparticles of curdlan, synthesized through crosslinking with epichlorohydrin in organic suspension media, were chemically modified with the aim of introducing strongly and/or weakly acidic anionic and palmitoyl hydrophobic groups. Microparticles of both curdlan and curdlan derivatives were physico-chemically characterized. Study of the interaction with enzymes, such as lysozyme, and vaccines, such as tetanus anatoxin, showed a co-operative protein retention effect, induced by electrostatic and hydrophobic forces. The results of the in vitro release studies on support–protein complexes recommend them as potential controlled release systems.     

Arterial smooth muscle cells dysfunction in hyperglycaemia and hyperglycaemia associated with hyperlipidaemia: from causes to effects

Given the important role of smooth muscle cells in arterial wall dysfunction in diabetes, as well as in diabetes associated with accelerated atherosclerosis, we provide a brief review of the recent achievements in identification of signalling molecules underlying their altered cellular responses, and examine the consequences of these pathological insults on smooth muscle cells properties. The original results emerging from the Golden Syrian hamster model (rendered diabetic or simultaneously hyperlipidaemic-diabetic) and from human aortic smooth muscle cells cultured in 25 mM glucose (to mimic diabetic condition) or sera of obese type 2 diabetic patients (to mimic the metabolic syndrome condition) are presented in this context. We conclude this review with several open issues disclosed by the most recent literature that deserve essential attention for targeting the translational medicine.     

Bone marrow-derived dendritic cells generated in the presence of resolvin E1 induce apoptosis of activated CD4+ T cells

In contrast to the role of dendritic cells (DC) in immunity and tolerance, little is known about their possible role in the resolution of inflammatory processes. In addition to the reduction in the number of infiltrating immune cells, the elimination of effector T cells already present at the inflammatory site represents an essential step toward resolution. Recently, lipid mediators such as the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid and their metabolites, including resolvin E1 (RvE1), have been shown to accumulate in inflammatory foci during the resolution phase. RvE1 has been reported to reduce immune cell infiltration and proinflammatory cytokine production. In this study we report that DC exposed to RvE1, especially during differentiation, acquire the capacity to induce apoptosis of activated T cells through the induction and activity of indoleamine 2,3-dioxygenase. To our knowledge, this study is the first to report on an omega-3 fatty acid derivative inducing indoleamine 2,3-dioxygenase expression in DC. RvE1-exposed DC maintain an immature chemokine receptor expression pattern even following TLR stimulation, with high CCR5 and no CCR7 expression. This effect implies that DC exposed to RvE1 and pathogens remain at the inflammatory site, instead of migrating to lymph nodes, and induce apoptosis in effector T cells infiltrating the inflammatory site. To our knowledge, the DC described in this study represent a new functional DC subtype, whose essential function resides in the resolution of inflammation.     

Beneficial effects of L-arginine supplementation in experimental hyperlipemia-hyperglycemia in the hamster

The objective of this study was to evaluate whether administration of L-arginine, the substrate for nitric oxide synthesis, was able to ameliorate the endothelial dysfunction and the morphological changes induced by the combined insult of hyperlipemia and hyperglycemia. To this purpose, golden Syrian hamsters were rendered simultaneously hyperlipemic and diabetic (HD group) for 24 weeks, and then orally treated with 622.14 mg/kg per day L-arginine, for 12 weeks (HD + L-arg group). The following assays were carried out: (1) spectrophotometric: concentrations of circulating glucose, cholesterol, and creatinine, the activity of angiotensin-converting enzyme (ACE), and the osmotic fragility of erythrocyte plasmalemma; (2) myographic: the endothelium-dependent and -independent relaxation of the resistance arteries (i.d. 210-250 microm) to 10(-8) to 10(-4) M acetylcholine (ACh) or sodium nitroprusside (SNP); and (3) electron-microscopic: the ultrastructure of the resistance arteries, myocardium, and kidney glomeruli, which are main targets of hypertensive complications.The results showed that oral supplementation with L-arginine in simultaneous hyperlipemia-hyperglycemia induced in hamsters had favorable effects on: (1) homeostasis, i.e., diminished the concentration of circulating glucose (by ~63%) and cholesterol (by approximately 10%), reduced the ACE activity (by approximately 45%), and lowered the osmotic fragility of erythrocyte plasmalemma (as marker for the oxidative stress in plasma); (2) mesenteric resistance arteries, which showed (in 10(-4) M ACh) an improved endothelium-dependent relaxation (72.40+/-4.6% in the HD + L-arg group vs 61.90+/-1.45% in the HD group) and a reduced thickness (approximately 1.32-fold) of the smooth muscle cells' extracellular matrix; and (3) the heart, which displayed approximately 16% diminishing of the thickness of the left ventricular wall, and an apparently normal structure of the myocardium; the restoration of the thickness of the pericapillary extracellular matrix to almost normal dimensions was also observed. Administration of L-arginine did not modify the high level of plasma creatinine determined for the HD group (approximately 48% increased vs control group) and had no effect on the thickened, nodular basal lamina of the kidney capillaries. The results indicate that endothelial dysfunction established in combined hyperlipemia-diabetes is distinctive for each vascular bed (mesenteric arterioles, heart capillaries, kidney glomerular capillaries), and there is a reversible stage of the dysfunction in which L-arginine oral supplementation induced beneficial effects.     

The level of interleukin-2 and of soluble interleukin-2 receptor in patients with Balkan nephropathy

Balkan Nephropathy (BN) is defined as a clinical entity with unknown etiology. The involvement of immune system in pathogenesis of BN is not well defined yet. The aim of this study was to gain more insight into the cellular immune mechanisms in BN. We determined some factors implied in cellular immunity, such as the serum level of IL-2 and of IL-2 soluble receptor (sIL-2R), and the presence of IL-2 receptor alpha chain (CD25) on T cells membrane. The study was performed on 15 patients with BN, 15 patients with Chronic Pyelonephritis (CPN), and 10 healthy controls from a non-endemic area. Our study showed no significant differences between IL-2 level and CD25+ cells percentage in CPN compared to controls, but a significantly increased level of sIL-2R. The BN sIL-2R is significantly lower than sIL-2R in CPN, and associates an important T cell activation (high CD25+ presence, elevated IL-2 level) compared to CPN. Our conclusion is that while the high sIL-2R level could down modulate T cell activity in CPN, BN sIL-2R level is ineffective in limiting the activation effects of IL-2 on T cells. The results suggest that cellular immunity could have a role in the pathogenesis of N.