Plasma vascular endothelial growth factor and angiogenin are positively related to erythropoietin dose in hemodialysis patients

PURPOSE

Experimental data confirmed that erythropoietin (EPO) administration alters the course of various pathological situations such as heart failure and tumor growth by inducing vascular endothelial growth factor-A (VEGF-A) expression. The effect of EPO dose on plasma VEGF-A level in hemodialysis (HD) patients was evaluated. The effect of EPO dose on plasma angiogenin level in HD patients was also evaluated, since angiogenin is necessary for angiogenesis induced by VEGF-A.

METHODS

Thirty two HD patients (10 diabetics) enrolled into the study. Patients were iron replete and did not suffer from infections, autoimmune diseases or malignancies. Plasma VEGF-A and angiogenin, as well as serum interleukin-6 and tumor necrosis factor-α were measured by means of ELISA.

RESULTS

Weekly EPO dose per kg of dry body weight was positively related to both VEGF-A and angiogenin, whereas no relation was detected among VEGF-A or angiogenin and hemoglobin, inflammation or presence of diabetes mellitus. These relations among EPO dose and VEGF-A or angiogenin remained after adjustment for hemoglobin concentration or inflammation or presence of diabetes mellitus.

CONCLUSIONS

EPO dose may affect plasma VEGF-A and angiogenin concentrations in HD patients.

Lipopolysaccharide and hypoxia significantly alters interleukin-8 and macrophage chemoattractant protein-1 production by human fibroblasts but not fibrosis related factors

Besides extracellular matrix production, fibroblasts are able to produce various cytokines. Their ubiquitous position makes fibroblasts appropriate cells for sensing various noxious stimuli and for attracting immune cells in the affected area. In the present study the effect of lipopolysaccharide (LPS) and cobalt chloride (CoCl(2)) on the above fibroblasts functions were evaluated in primary human skin fibroblasts cultures. Collagen, matrix metalloproteinase-1, tissue inhibitor of metalloproteinases-1, transforming growth factor-β1, interleukin-8 (IL-8) and macrophage chemoattractant protein-1 (MCP-1) were measured in fibroblasts culture supernatants. Fibroblasts proliferation and viability were assessed as well. Hypoxia inducible factor-1α and the phosphorylated p65 portion of NF-κB were assessed in fibroblasts protein extracts. LPS and CoCl(2) had a minor effect on fibrosis related factors in human primary fibroblasts, possibly due to the absence of interplay with other cell types in the used experimental system. On the contrary both LPS and CoCl(2) increased significantly IL-8. LPS also increased considerably MCP-1, but CoCl(2) decreased it. Thus LPS and CoCl(2) induce a sentinel, nevertheless not identical, phenotype in primary human fibroblasts. The last disparity could result in different body response to infectious or hypoxic noxious stimuli.

Pulmonary renal syndrome in an adult patient with Henoch-Shönlein purpura

Henoch-Schönlein purpura (HSP) is a small vessel vasculitis characterized by purpuric skin rash, haematuria, abdominal pain, gastrointestinal bleeding and arthritis. Nephritis is more frequent and severe in adults than in children, with relatively more adults developing renal insufficiency. Another, fortunately rare, manifestation of HSP that increases mortality significantly, is diffuse alveolar haemorrhage. We report a rare case of an adult male patient with full-blown HSP that followed a respiratory tract infection. He successively, but not concurrently, developed all the clinical manifestations of HSP, i.e. arthritis, abdominal pain and bloody stools, a non-thrombocytopenic purpuric rash, and renal involvement; nephrotic range proteinuria first and haemodialysis-requiring nephritic syndrome later. Most interesting he developed life-threatening pulmonary haemorrhage fulfilling the criteria of the pulmonary-renal syndrome. An immunosuppressive regimen consisting of intravenous cyclophosphamide and corticosteroids was administered with success. In conclusion, HSP should be considered in the diagnosis of pulmonary-renal syndrome. In our opinion, the severity of the condition justifies the use of aggressive immunosuppressive treatment, like the one applied successfully to our patient.

L-arginine supplementation does not affect chemically induced carcinogenesis and tumor growth in BALB-c mice

T-cell zeta-chain downregulation is common in various types of cancer and it is proposed as a mechanism of cancer immunosubversion. L-arginine consumption by arginase rich suppressor myeloid cells has been incriminated. The effect of L-arginine supplementation on chemically induced carcinogenesis and tumor growth in mice was evaluated.

METHODS

Eight-week old female BALB-c mice were used. Ten mice were injected i.m. with 0.6 mg methylcholanthrene (MCA) once. Ten mice were injected with MCA once and were receiving L-arginine supplementation (5% in animal drinking water) continuously during the study. Mice with cancer were sacrificed 12 weeks after.

RESULTS

From the 10 MCA injected mice 6 developed sarcoma. From the 10 MCA injected mice that were receiving L-arginine supplementation 7 developed sarcoma. L-arginine supplementation did not affect MCA induced carcinogenesis (p=1.0, Fisher's exact test). The weight of tumors was not different between the tumors derived from mice that were or were not receiving L-arginine supplementation (1088.3+/-590.2 mg vs. 969.6+/-608.1 mg respectively, p=0.729, unpaired t-test).

CONCLUSION

L-arginine supplementation does not affect chemically induced carcinogenesis and tumor growth in BALB-c mice. Although zeta-chain downregulation could be a mechanism of cancer immunosubversion there are enough other cancer immunosubversion mechanisms that were not overwhelmed by L-arginine supplementation. Additionally, except cancer immunosubversion, cancer immunoselection is another, possibly more significant, mechanism of tumor escape from immunosurveillance.

Suppression of humoral immune response to hepatitis B surface antigen vaccine in BALB/c mice by 1-methyl-tryptophan co-administration

BACKGROUND AND THE PURPOSE OF THE STUDY

Indoleamine 2,3-dioxygenase (IDO) suppresses adaptive immune response. The purpose of this study was to determine the effect of the IDO inhibitor namely 1-methyl-DL-tryptophan (DL-1-MT) on antibody production after vaccination with hepatitis B surface (HBs) antigen.

METHODS

Four groups of BALB/c mice were immunized with a HBs antigen vaccine. In the first group the vaccine had no DL-1-MT, whereas in the other three groups the vaccine contained 1 mg, 10 mg and 20 mg DL-1-MT. Blood samples were collected 5 weeks post-vaccination and anti-HBs antibodies in the serum were measured by ELISA.

RESULTS

Compared to the three groups of mice that were immunized with the vaccines containing DL-1-MT, serum anti-HBs level was much higher in the mice that were immunized with the vaccine with out DL-1-MT.

CONCLUSIONS

Inhibition of IDO at the time of vaccination decreased humoral immune response to HBs antigen vaccine. The idea that IDO activity is simply immunosuppressive may need to be re-evaluated.

Infections in hemodialysis: a concise review. Part II: blood transmitted viral infections

Hemodialysis (HD) patients are particularly predisposed to infections. It seems that the HD procedure per se as well as disturbances in both innate and adaptive immunity significantly contribute to this susceptibility. Infections are the major cause of morbidity and the second cause of death following cardiovascular events in HD patients. Episodes of bacteremia and pneumonia account for the majority of severe infections in this population. In addition to these bacterial infections another common problem in HD units is the blood transmitted viral infections, particularly infections caused by hepatitis B virus, hepatitis C virus and Human immunodeficiency virus. A number of safety concerns exist for limiting the spread of these viral infections among HD patients and the staff of the unit. The aim of the present review is to present in a concise albeit practical form the difficult aspect of infections in HD. For practical reasons the review is separated in two parts. The previous first part covered bacteremia and respiratory infections, while the present second part covers blood transmitted viral infections.

Urate crystals induce NLRP3 inflammasome-dependent IL-1β secretion and proliferation in isolated primary human T-cells

BACKGROUND

Urate through NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome-dependent caspase-1 activation stimulates macrophages to secrete inteleukin-1β (IL-1β). Urate also enhances adaptive immunity indirectly through its effect on antigen presenting cells. In this study, the direct effect of urate on isolated primary human T-cells was evaluated.

METHODS

Isolated T-cells were cultured with or without monosodium urate crystals in the presence or not of the NLRP3 inflammasome inhibitor glyburide. Activated cleaved caspase-1 was assessed by means of western blotting, whereas caspase-1 activity was measured colorimetrically in the cell lysates. IL-1β was measured in the supernatants by means of enzyme-linked immunosorbent assay. T-cell proliferation was assessed by means of bromodeoxyuridine labelling and immunoenzymatic detection.

RESULTS

Urate induced caspase-1 activation and IL-1β release by T-cells. It also induced proliferation of T-cells. Glyburide inhibited urate-induced caspase-1 activation, IL-1β secretion and proliferation.

CONCLUSIONS

Urate, a well defined danger signal, stimulates directly human T-cells in a NLRP3 infmmasomela-dependent way. The subsequent IL-1β secretion could enhance inflammation, whereas expansion of T-cell clones could facilitate a subsequent adaptive immune response. Hippokratia 2015, 19 (1): 41-46.

Infections in hemodialysis: a concise review - Part 1: bacteremia and respiratory infections

Hemodialysis (HD) patients are particularly predisposed to infections. It seems that the HD procedure per se as well as disturbances in both innate and adaptive immunity significantly contribute to this susceptibility. Infections are the major cause of morbidity and the second cause of death following cardiovascular events in HD patients. Episodes of bacteremia and pneumonia account for the majority of severe infections in this population. In addition to these bacterial infections another common problem in HD units is the blood transmitted viral infections, particularly infections caused by hepatitis B virus, hepatitis C virus and Human immunodeficiency virus. A number of safety concerns exist for limiting the spread of these viral infections among HD patients and the staff of the unit. The aim of the present review is to present in a concise albeit practical form the difficult aspect of infections in HD. For practical reasons the review is separated in two parts. The present first part covers bacteremia and respiratory infections, while the second part will cover blood transmitted viral infections.

Differential diagnosis of hyperkalemia: an update to a complex problem

Hyperkalemia is a relative common and sometimes life threatening electorlyte disorder. Although its symptomatic treatment is relatively easy, since precise therapeutic algorithms are available, its differential diagnosis is more complicated. The present review aims to unfold the differential diagnosis of hypekalemia using a pathophysiological, albeit clinically useful, approach. The basic elements of potassium homeostasis are provided, the causes of hyperkalemia are categorized and analysed and finally the required for the diferrential diagnosis laboratory tests are mentioned.

Uric acid induces caspase-1 activation, IL-1β secretion and P2X7 receptor dependent proliferation in primary human lymphocytes

BACKGROUND

Urate through Nacht Domain, Leucine-Rich Repeat, and pyrin domain-containing protein 3 (NALP3) dependent caspase-1 activation stimulates macrophages to secrete inteleukin-1β (IL-1β). Purinergic receptor P2X7 plays a role in the urate induced NALP3 activation. Urate also enhances adaptive immunity indirectly through its effect on antigen presenting cells. In this study, the direct effect of urate on primary human lymphocytes was evaluated.

METHODS

Lymphocytes were cultured with or without monosodium urate crystals in the presence or not of a P2X7 inhibitor. Caspase-1 activity was assessed colorimetrically in cell lysates and IL-1β was measured in supernatants with ELISA. Whole lymphocyte viability and proliferation, as well as T-cell proliferation were assessed by means of 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and of flow cytometry respectively.

RESULTS

Urate induced caspase-1 activation and IL-1β release by lymphocytes. It also induced proliferation of whole lymphocytes and T-cells as well. P2X7 inhibitor abrogated lymphocyte proliferation.

CONCLUSIONS

Urate, a well defined danger signal, stimulates directly human lymphocytes in a P2X7 dependent way. The subsequent IL-1β secretion could enhance inflammation, whereas expansion of lymphocyte clones could facilitate a subsequent adaptive immune response.