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C Johnsson

Publications and source records attributed to C Johnsson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Role of hyaluronan in acute pancreatitis.

BACKGROUND: The connective tissue component hyaluronan is accumulated locally in the damaged tissue during various inflammatory conditions. Owing to the strong water-binding capacity of this glycosaminoglycan, increased tissue content of hyaluronan is paralleled by the development of interstitial edema. The aim with the current experiment was to investigate whether hyaluronan is accumulated in acute pancreatitis and if increased levels of hyaluronan can be correlated to the inflammation of the pancreatic tissue. METHODS: Acute pancreatitis was induced in Sprague-Dawley rats by the administration of supramaximal doses of the cholecystokinin analogue caerulein. The animals were followed for 5 hours (n = 4), 24 hours (n = 6), or 48 hours (n = 5), and the pancreata were then investigated for hyaluronan and water content, hyaluronan distribution, general morphology and the presence of CD44-positive cells, macrophages, and T lymphocytes. RESULTS: Hyaluronan accumulated in the edematous interstitium during acute pancreatitis. Twenty-four hours after the induction of pancreatitis, the hyaluronan content of the pancreata had increased by more than 100%. Simultaneously, CD44-positive cells infiltrated the tissue. However, no correlation between hyaluronan and water was seen at any time point. CONCLUSIONS: This study shows that acute pancreatitis is associated with a strong but transient increase in interstitial hyaluronan and an infiltration of CD44-positive cells located mainly in the same region as the accumulated hyaluronan.

Acute Disease↗
PubMed1999

Hyaluronidase ameliorates rejection-induced edema.

Hyaluronan, a glucosaminoglycan with unique water-binding capacity, is accumulated in the interstitial edematous tissue in rejecting organs. We here investigated whether the increased tissue content of water and hyaluronan seen during allograft rejection can be prevented by treatment with the hyaluronan-degrading enzyme hyaluronidase. Heterotopic heart transplantations between PVG and Wistar/Kyoto rats were performed. Recipient rats were treated with hyaluronidase prophylactically or therapeutically, either alone or in combination with cyclosporine. Daily intravenous injections of hyaluronidase induced a significant reduction of the cardiac content of both hyaluronan and water, as evaluated on day six after transplantation. Morphological examination revealed grafts with better preserved morphology and fewer infiltrating mononuclear cells, compared to untreated controls. Hyaluronidase therapy, alone or combined with cyclosporine, resulted in prolonged graft survival times. Hyaluronidase infusion for two hours also reduced already established edema five days after transplantation. This study confirms the hypothesis that hyaluronan accumulation plays a critical role in edema formation, and that hyaluronidase therapy can be used to reduce edema after organ transplantation.

Animals↗
PubMed1999

Ex vivo propagation and characterization of lymphocytes from rejecting rat-kidney allografts.

Today, most clinically used methods for analysis of alloreactivity in organ transplantation are based on humoral immunity. In order to study the cellular alloresponse, a rat kidney transplantation model with culturing of graft infiltrating lymphocytes was developed. Kidney transplantations between inbred rat strains were performed with the animals initially immunosuppressed with cyclosporine. In order to initiate acute cellular rejection, immunosuppression was withdrawn after 10 days. Infiltrating lymphocytes were analysed using an in vitro culture system, allowing cells to propagate from the biopsies to culture medium. The propagated cells were counted and analysed for subtype activation markers and donor-specificity using flow cytometry and a proliferation assay. Syngeneically transplanted animals and animals given constant immunosuppression upon transplantation were used as controls. During rejection, significantly more T lymphocytes were propagating from the biopsies compared to controls. A higher percentage of the propagated T lymphocytes in the rejection group expressed activation markers [CD25 and major histocompatibility complex (MHC) class II antigen] compared to spleen- and peripheral blood T lymphocytes from the same individuals. Propagated mononuclear cells from biopsies in the rejection group were proliferating and showed donor-specific reactivity whereas mononuclear spleen cells from animals in the same group did not show this donor specificity. In conclusion, we have presented a rat kidney allotransplantation model with in vitro propagation of graft-infiltrating, activated and donor-specific T lymphocytes. This technique offers a possibility to study cellular reactivity in allotransplantation.

Animals↗
PubMed1999

Edema treatment during cardiac allograft rejection.

BACKGROUND: Interstitial edema of rejecting organs can be correlated with the accumulation of hyaluronan in the transplant; since hyaluronan has strong water-binding capacity, treatment with the hyaluronan-degrading enzyme hyaluronidase reduces not only the hyaluronan content but also the water content of the graft. The aim of the present study was to investigate whether a further reduction of the water content would be the result if hyaluronidase was used in conjunction with classic diuretic substances. METHODS: Five days after heterotopic heart transplantation (PVG to Wistar/Kyoto), recipient rats received hyaluronidase as a continuous intravenous infusion over 2 hours together with either a loop-diuretic (furosemide) or an osmotic diuretic (mannitol). RESULTS: Hyaluronidase was found to reduce the hyaluronan contents of the grafts from 586+/-52 microg/g in control animals receiving vehicle infusion to 161+/-48 microg/g (p < 0.001) and the water contents from 81.3+/-0.4 x 10(-2) U to 79.7+/-0.4 x 10(-2) U (p < 0.05). Combined treatment with furosemide or mannitol did not affect the results and neither furosemide nor mannitol had any intrinsic capacity to affect the water or hyaluronan contents of the cardiac grafts. CONCLUSION: This experiment confirms our previous findings of hyaluronidase as an effective edema-reducing drug and indicate that no additive effect is obtained by a combined therapy with diuretics and hyaluronidase.

Animals↗
PubMed1998

Tolerance induction ameliorates allograft vasculopathy in rat aortic transplants. Influence of Fas-mediated apoptosis.

Based on successful induction of donor-specific unresponsiveness by alloantigenic stimulation in several animal models of acute rejection, we hypothesized that similar immune manipulations would also inhibit the evolution of chronic rejection and transplant vasculopathy. To induce immune tolerance, DA rats received a PVG heart allograft and were immunosuppressed with cyclosporine for 30 d. At day 100 the animals were challenged with a PVG aortic allograft after either 1 or 18 h of cold ischemia. 8 wk after the aortic transplantation, the grafts were investigated for morphological changes, infiltrating cells, apoptosis, and Fas-Fas ligand expression. Control allografts showed advanced transplant arteriosclerosis, whereas tolerance-induced aortic allografts displayed reduced neointimal formation, less medial atrophy, fewer apoptotic cells, and fewer Fas- and FasL-expressing cells. Prolonged ischemic storage time did not profoundly alter the morphological changes of the allografts. Fas expression was found in T cells, macrophages, vascular smooth muscle cells, and endothelial cells, whereas FasL was expressed mainly by T cells and macrophages. FasL mRNA expression was evident throughout the entire allograft wall. In conclusion, induction of allospecific tolerance can effectively prevent transplant arteriosclerosis. Cold ischemia damage does not abrogate the beneficial effect of tolerance, but creates a separate identity of mainly endothelial lesions. Furthermore, Fas-mediated apoptosis appears to be involved in the pathological lesions seen in chronic rejection.

Animals↗
PubMed1998

A vitamin D analogue (MC 1288) has immunomodulatory properties and suppresses collagen-induced arthritis (CIA) without causing hypercalcaemia.

The immunomodulatory properties of the vitamin D analogue MC 1288 (20-epi-1alpha,25-dihydroxycholecalciferol) were investigated in CIA in rats. The analogue was administered systemically at three different time points; (i) for 10 consecutive days before collagen (CII) immunization; (ii) for 10 consecutive days after CII immunization; or (iii) for 7 consecutive days from disease onset. Treatment initiated either 10 days before CII immunization or at the day of collagen immunization effectively suppressed the development of arthritis. Treatment initiated at the day of the onset of arthritis reduced the severity of joint inflammation. Significantly, doses which did not induce hypercalcaemia decreased the incidence and severity of arthritis. In vivo treatment with the 20-epi analogue of 1alpha,25-dihydroxycholecalciferol diminished the serum levels of antibodies to rat CII. Similarly, mitogen-induced proliferation of lymph node cells from rat CII-immunized animals was reduced. The experiments demonstrate that the vitamin D analogue MC 1288 has the ability to prevent, and furthermore to suppress, already established CIA by its immunomodulatory properties without inducing hypercalcaemia.

Adjuvants, Immunologic↗
PubMed1998

A morphological sequential study of mouse-to-rat cardiac xenografts.

Long-term survival of a concordant xenograft can be achieved by using cyclosporine (CyA) and deoxyspergualin (DSG) for immunosuppression. We have demonstrated in a mouse-to-rat heterotopic heart transplantation model that DSG treatment can be stopped after 4 weeks with the grafts remaining beating. In this investigation we have sequentially characterized the morphological changes and infiltrating cells in the transplanted hearts. Graft recipients were killed 9 days, 28 days and 56 days after transplantation. At days 9 and 28, the grafts exhibited a well-preserved morphology, with infiltrating cells restricted only to the periphery. These cells stained positive for rat MHC class II antigens, the ED1-macrophage marker and the CD4 antigen, and were thus considered to be macrophages. In comparison, grafts harvested at day 56 had signs of interstitial fibrosis and some arteries showed pronounced intimal thickening. There was a moderate infiltrate of cells both in the peripheral and central parts of the graft, consisting mainly of MHC class II+/ CD4+/ED1+ macrophages. Very few T cells and NK cells were noticed. Termination of DSG after 28 days does not trigger a humoral rejection. However, the grafts exhibit morphological changes equivalent to those seen in chronic allograft rejection. In addition, the characteristics of the infiltrating cells conformed with cellular infiltrates associated with chronic allograft rejection. Hence, this model could in the future prove to be useful for studies of mechanisms involved in chronic xenograft rejection.

Animals↗
PubMed1997

Successful retransplantation of mouse-to-rat cardiac xenografts under immunosuppressive monotherapy with cyclosporine.

The present study was undertaken to investigate whether retransplantation with a second xenograft, from the same species as the primary graft, is possible to achieve using only moderate immunosuppression. Heterotopic mouse-to-rat cardiac transplantations were performed, and the recipients were treated with 15-deoxyspergualin (DSG) and cyclosporine (CsA) at high doses for days -1 to 4 and at moderate doses for days 5 to 28. From day 29 and onward, the immunosuppressive protocol consisted of daily oral administration of CsA 10 mg/kg as monotherapy. Animals that had beating grafts when DSG treatment was stopped were retransplanted 56-154 days after the primary transplantation, either with a vascularized graft (heart) or with nonvascularized graft (pancreatic islets), under continued therapy with CsA. Six of 10 secondary cardiac xenografts functioned for more than 50 days and were harvested beating after 60-100 days. In contrast, nonimmunosuppressed or DSG-treated rats are known to reject a second cardiac mouse graft hyperacutely. The unresponsiveness was confined to cardiac tissue, as the pancreatic islets, transplanted under the kidney capsule, were totally rejected after 14 days. Long-term functioning cardiac xenografts, primary and secondary, had a well-preserved morphology, and infiltrating mononuclear cells were found just in the periphery of the grafts. A majority of these cells were macrophages expressing the ED1, but not the ED2, antigen. No deposition of IgG or complement was seen in any of the graft vessels, whereas a slight deposition of IgM was observed in some vessels of both primary and secondary grafts. In conclusion, we have demonstrated that unresponsiveness can be induced by effective immunosuppression of the recipient at the time of the initial transplantation, so that retransplantation with a second xenograft can be performed successfully under single-drug immunosuppressive therapy with CsA.

Animals↗
PubMed1997

Ex vivo PKH26-labelling of lymphocytes for studies of cell migration in vivo.

A prerequisite for studies of cell migration is that the cells of interest can be appropriately labelled and subsequently easily traced. The use of radioisotopes or fluorescent substances that bind covalently to the cell surface, e.g. fluorescein isothiocyanate (FITC) or rhodamine isothiocyanate (RITC), have limitations such as rapid loss of the labelling, toxicity and interference with cell surface molecules. In the present work the authors labelled rat spleen lymphocytes with the fluorescent labelling molecule PKH26, which is incorporated into the lipid bilayer of cytoplasmic membranes. The labelled lymphocytes were injected intravenously into syngeneic recipients and 2 or 6 days later the lymphocytes were detected in various organs by using flow cytometry and fluorescence microscopy. As could be expected, the lymphocytes homed to lymphoid tissues, preferably the spleen, and no labelled cells were found in non-lymphoid organs such as the heart and the kidney. Membrane labelling proved to be intense, uniform and stable and PKH26 positive cells were easily detectable in fractions less than 0.2% in peripheral blood and the various tissues after 6 days of in vivo circulation. Thus, the PKH26 dye appears to be suitable for labelling cell populations used in the study of cell migration in vivo, both under normal conditions and when specific immunological processes are taking place, such as graft rejection and tumour growth.

Animals↗
PubMed1997

Alterations in mucosal immune cell distribution in septic rats.

A reduced cell-mediated immunity in the intestinal mucosa might promote gut barrier failure and bacterial translocation in shock. This study was performed to investigate changes from the normal distribution of cellular components of the immune system within the intestine during sepsis. Intra-abdominal sepsis was induced by cecal ligation and puncture. After 24 h, the animals were killed and specimens were taken from the small bowel. Immunohistochemical stainings were performed on frozen sections using monoclonal antibodies reactive with MHC class II positive cells (OX6), the alpha/beta antigen receptor on T lymphocytes (R73), CD4+ T lymphocytes (W3/25), CD8+ T lymphocytes (OX8), and macrophages (ED1). There was a significant reduction in the number of pan T lymphocytes as well as both CD4+ and CD8+ subsets in the mucosa of the septic rats as compared with sham operated rats (p < .01). In contrast, the populations of MHC class II positive cells and macrophages increased in sepsis (p < .01). We conclude that 24 h after the induction of peritonitis, there is an altered pattern of immunocompetent cells within the intestinal mucosa.

Animals↗
PubMed1997

Renal accumulation and distribution of hyaluronan after ureteral obstruction.

In a unilateral ureteral obstruction model, a progressive accumulation of hyaluronan (HA) was observed in the renal papilla during the first 11 days of obstruction, after which the amount of HA decreased until the last day of observation, i.e. day 22. The initial accumulation of HA in the obstructed kidney probably reflects the attempts of the kidney to maintain osmotic balance. Consequently, when filtration ceases, HA synthesis decreases and the concentration of HA falls. In the papilla of the contralateral kidney, that had not been exposed to any mechanical damage, the HA content was found to vary in a similar way to that in the obstructed kidney. The explanation for this could be that the mesenchymal cells within the papilla increase their production of HA in order to meet the requirements of increased function necessary to also shoulder the function of the damaged kidney. In short similar variations in the HA content of the renal papilla was observed in both healthy and obstructed kidneys in a unilateral ureteral obstruction model.

Animals↗
PubMed1997

Elevation of cyclosporin A blood levels during carvedilol treatment in renal transplant patients.

In a consecutive study of 21 renal transplant patients suffering from chronic vascular rejection (CVR) we added the beta-receptor-blocking drug carvedilol to their regular medication. The purpose was to investigate possible pharmacokinetic interactions between carvedilol and cyclosporine (CsA), since carvedilol will soon be used in clinical trials in renal transplant patients with CVR. On the first day of the study the patients received 6.25 mg of carvedilol added to their daily medication. The dose was increased stepwise to 50 mg while the doses of other beta-blocking drugs were decreased. The goal was to exchange atenolol with carvedilol at a ratio of 2:1 when substituting atenolol with carvedilol. The patients' blood pressure was the final determinant of the dose of carvedilol. The trough levels of CsA were measured on days 1, 14, 30, 90 and 180. It was found that the blood levels of CsA increased when carvedilol was introduced. Thus, the doses of CsA had to be reduced in order to keep the blood levels within the therapeutic range. At 90 d, the daily doses of CsA had been reduced from 3.7 +/- 0.3 to 3.0 +/- 0.2 mg/kg BW (p < 0.001). The present results suggest an interaction between carvedilol and CsA that demands a 20% average reduction of CsA doses to maintain the CsA blood levels within the therapeutic range. However, the interaction shows a great interindividual variation, calling for careful monitoring of the CsA blood levels.

Adrenergic beta-Antagonists↗
PubMed1996

Recipient-reactive antibodies occur during development of acute graft-versus-host reaction after small bowel transplantation.

After small bowel transplantation, not only rejection but also graft-versus-host reaction (GVHR) may occur. Donor T lymphocytes, transferred together with the graft, are a prerequisite for the development of GVHR. So far, however, little is known about the effector mechanisms in acute GVHR. It can be assumed that not only T lymphocytes but also other cells, i.e., B lymphocytes, monocytes/macrophages, and NK cells, together with inflammatory cytokines, are responsible for the lesions of recipient tissue. In the present study, the occurrence of recipient-reactive antibodies after semisyngeneic small bowel transplantation was investigated to elucidate the role of B lymphocytes in GVHR development. No antibodies reactive with recipient cells were detectable in serum from untreated, nontransplanted rats. Five days after transplantation, recipient-reactive antibodies started to appear in recipient serum. At the same time, a deposition of IgM antibodies became visible in the liver and native intestine, which are target organs for GVHR. No antibodies directed against either the donor strain or a third-party strain were detectable in serum. We conclude that a synthesis of antibodies against recipient tissue occurs during the development of GVHR. Whether these antibodies contribute to the disease remains unclear.

Acute Disease↗
PubMed1996

Experimentally-induced warm renal ischemia induces cortical accumulation of hyaluronan in the kidney.

An accumulation of the connective tissue component, hyaluronan (HA), is known to occur in both syngeneic and allogeneic kidney grafts during the early postoperative period. The presence of HA in the interstitial tissue of the grafts is paralleled by an increased water content, suggesting a role for HA in the development of the transplantation edema. In the present work, the kidney content and distribution of HA was studied in a model of warm renal ischemia in the rat to investigate whether renal ischemia is associated with HA accumulation. Seventy-two hours after a period of warm renal ischemia (30 or 60 min) significantly higher amounts of HA were observed in the left kidney that had been exposed to ischemia, than in the right, healthy kidney. The most pronounced increase was found to occur in the cortex (20 to 40 times), a structure where there normally is almost no presence of HA. In addition, there was a correlation between the relative water content of the kidney and the amount of HA possible to extract from the tissue. The renal accumulation of HA and water was prevented by daily intravenous administration of hyaluronidase. We conclude that renal ischemia induces an accumulation of HA that may increase the risk for the development of interstitial edema, a situation that may be circumvented by hyaluronidase treatment.

Animals↗
PubMed1995

Simultaneous occurrence of rejection and graft-versus-host reaction after allogeneic small bowel transplantation.

Small bowel transplantation may be complicated not only by rejection but also by graft-versus-host reaction (GVHR). So far, little is known about the association between these two immunological reactions, partly because of the lack of standardized, reproducible experimental models for such studies. In this work, a rat model in which GVHR and rejection occur simultaneously was established. When transplanting small bowel grafts from BN donors to Lewis recipients and thereafter treating the grafts locally with the immunomodulating substance LS-2616, a clinically visible GVHR occurred on day 6, at the same time the first signs of rejection became visible. The GVHR was confirmed by immunohistochemical staining for MHC class II-positive cells in liver and ear skin biopsy specimens. An obvious quantitative difference in the number of positive cells in both organs was observed when local treatment was compared with oral LS-2616 treatment or with findings in organs from untreated animals. We conclude that GVHR and rejection are not mutually exclusive and thus may occur simultaneously, and that this pharmacological model might facilitate further studies of the impact of GVHR on graft rejection and recipient survival.

Adjuvants, Immunologic↗
PubMed1995

The effects of combined treatment with the novel vitamin D analogue MC 1288 and cyclosporine A on cardiac allograft survival.

The efficacy of combined treatment with the novel vitamin D analogue MC 1288 (20-epi-1 alpha,25-dihydroxycholecalciferol) and cyclosporine A (CyA) in preventing rejection following organ transplantation was evaluated in the heterotopic cardiac allograft model. Wistar/Kyoto rats received hearts from PVG donors and were subsequently treated with MC 1288 and CyA in various dose combinations. Administration of MC 1288 0.1 microgram/kg together with CyA 5 mg/kg produced significantly prolonged graft survival times as compared with single therapy with MC 1288 0.1 microgram/kg (p < 0.01) or CyA 5 mg/kg (p < 0.001). MC 1288 and CyA were tested also in combination with the immunomodulating drug LS-2616, which, in several laboratories, is used as a model for the evaluation of new combinations of immunosuppressive drugs. LS-2616 abolishes the immunosuppressive effect of CyA and the transplanted hearts are thus rejected at the same time as grafts of untreated recipients, i.e. on day 8. The immunosuppressive effect of MC 1288 is also counteracted by LS-2616, but the effect is not absolute and the median graft survival time is 11.0 days. Combined treatment with MC 1288 and CyA in the presence of LS-2616 resulted in a median graft survival time of 14.0 days. The results obtained in our experiments indicate at least an additive effect of MC 1288 and CyA thus suggesting that in the future MC 1288, or other vitamin D analogues, might be used to control rejection, either alone, in combination with CyA or in combination with other immunosuppressive drugs with other mechanisms of action.

Adjuvants, Immunologic↗