Everyday technology use among people with Parkinson's disease

OBJECTIVES

To explore the relevance of and ability to use everyday technology (ET) among people with Parkinson's Disease (PD) and to explore associations between ET use and global cognition and motor ability.

MATERIALS AND METHODS

Cross-sectional data was collected from 34 people with PD using the Short Everyday Technology Use Questionnaire+ (S-ETUQ+), the Movement Disorder Society-Unified Parkinson's Disease Rating Scale and the Montreal Cognitive Assessment (MoCA).

RESULTS

Out of 41 ETs in the S-ETUQ+, the mean number perceived as relevant was 27.5 (min-max 19-35, SD 3.6). A good ability to use ET was reported where many ETs had a challenge measure below participants' ability to use them. A strong positive correlation between the ability to use ET and global cognition (MoCA) (r = .676, p = <0.01) was shown.

CONCLUSIONS

ET use has become integrated into everyday life and is important for participation. This study showed a high relevance of and good ability to use ET and a correlation between ET use and global cognition among people with mild-moderate PD. Evaluation and support to use ET in PD are important for maintaining independence and participation, especially among those with cognitive decline.

Angiotensin converting enzyme inhibition blocks interstitial hyaluronan dissipation in the neonatal rat kidney via hyaluronan synthase 2 and hyaluronidase 1

A functional renin-angiotensin system (RAS) is required for normal kidney development. Neonatal inhibition of the RAS in rats results in long-term pathological renal phenotype and causes hyaluronan (HA), which is involved in morphogenesis and inflammation, to accumulate. To elucidate the mechanisms, intrarenal HA content was followed during neonatal completion of nephrogenesis with or without angiotensin converting enzyme inhibition (ACEI) together with mRNA expression of hyaluronan synthases (HAS), hyaluronidases (Hyal), urinary hyaluronidase activity and cortical lymphatic vessels, which facilitate the drainage of HA from the tissue. In 6-8days old control rats cortical HA content was high and reduced by 93% on days 10-21, reaching adult low levels. Medullary HA content was high on days 6-8 and then reduced by 85% to 12-fold above cortical levels at day 21. In neonatally ACEI-treated rats the reduction in HA was abolished. Temporal expression of HAS2 corresponded with the reduction in HA content in the normal kidney. In ACEI-treated animals cortical HAS2 remained twice the expression of controls. Medullary Hyal1 increased in controls but decreased in ACEI-treated animals. Urine hyaluronidase activity decreased with time in control animals while in ACEI-treated animals it was initially 50% lower and did not change over time. Cells expressing the lymphatic endothelial mucoprotein podoplanin in ACEI-treated animals were increased 18-fold compared to controls suggesting compensation. In conclusion, the high renal HA content is rapidly reduced due to reduced HAS2 and increased Hyal1 mRNA expressions. Normal angiotensin II function is crucial for inducing these changes. Due to the extreme water-attracting and pro-inflammatory properties of HA, accumulation in the neonatally ACEI-treated kidneys may partly explain the pathological renal phenotype of the adult kidney, which include reduced urinary concentration ability and tubulointerstitial inflammation.

Hormonal regulation of renomedullary hyaluronan

AIM

Hyaluronan (HA) is involved in renomedullary water handling through its water-binding capacity. This study addressed the effect of hormones involved in regulating fluid-electrolyte homeostasis on renomedullary HA content in vivo and in vitro.

METHODS

The kidneys from rats treated with L-NAME, indomethacin, vasopressin (AVP) or methylprednisolone (MP) during euvolaemia or water loading were analysed for HA by RIA, ELISA and histochemical staining. HA was measured in renomedullary interstitial cells treated with AVP, angiotensin II (Ang II) or a combination of AVP and Ang II.

RESULTS

Baseline renal cortical and medullary HA content was unaffected by 2 h of intravenous treatment with L-NAME (NOS inhibitor) or indomethacin (cyclo-oxygenase inhibitor), whereas AVP reduced medullary HA by 33%. During 2 h of acute water loading, diuresis was accompanied by an increase in renomedullary HA (+45%), but cortical HA was unaffected. In both L-NAME- and indomethacin-treated animals, the water loading-induced increase in renomedullary HA was absent, indicating involvement of NO and prostaglandins. After 7 days of MP treatment, medullary HA was reduced by 40%, but the water loading-induced elevation in HA remained. In cultured renomedullary interstitial cells, AVP reduced the HA content in the supernatant by 63%, and simultaneous treatment with Ang II reduced the HA content even further (95%).

CONCLUSION

AVP reduces HA content, and NO and prostaglandins are needed for the increase in HA during water loading.

Renal hyaluronan content during experimental uncontrolled diabetes in rats

With diabetes mellitus, the ability of the kidneys to maintain fluid balance is affected. Hyperglycaemia increases production of hyaluronan in cultured kidney cells implying that diabetes promotes induction of hyaluronan in the kidney. The aim of the present study was to determine if the interstitial matrix component hyaluronan is differently distributed within the kidney in diabetic rats compared to non-diabetic rats. Furthermore, to test if diabetic rats are able to respond with diuresis upon a hypotonic fluid load. The normal heterogeneous intrarenal distribution of hyaluronan was confirmed in non-diabetic control rats, with 60-fold more in the papilla than in the cortex. In diabetic animals, the cortical hyaluronan was unaffected but the papillary hyaluronan content was 3-fold higher than in non-diabetic rats. This increase correlated with a more than three-fold induction of the papillary hyaluronan-synthase 2 mRNA expression. In non-diabetic animals, 2 h water loading increased papillary hyaluronan (+93%) and diuresis (17-fold). In diabetic animals, baseline diuresis was 8-fold higher than in non-diabetic animals, which correlated with hyperglycaemia, glucosuria and proteinuria. Water loading in diabetic animals did not further increase papillary hyaluronan or diuresis: the urine flow rate decreased. To conclude, papillary hyaluronan is elevated in diabetic rats, which coincides with induction of hyaluronan-synthase 2 mRNA, hyperglycaemia, glucosuria, proteinuria and overt diuresis. The inability to respond to a water load with further diuresis may be related to the already elevated papillary hyaluronan and the inability to change hyaluronan during water loading.

Ultrasmall iron oxide particle contrast agent and MRI can be used to monitor the effect of anti-rejection treatment

BACKGROUND

The purpose of the study was to investigate the feasibility of monitoring anti-rejection treatment using a blood pool contrast agent and magnetic resonance (MR) imaging.

METHODS

Allogeneic heterotopic heart transplantations in rats were performed. In one group (treated group), a mild acute rejection was developed and subsequently treated and MR imaging was performed before and after anti-rejection treatment. In the other group (nontreated group), a mild acute rejection was developed and allowed to progress without treatment and MR examinations were performed before and after the advance of the acute rejection. After injecting ultrasmall superparamagnetic contrast agent, the relative change of signal intensity (SI) over time was measured. The SI difference between both radiological investigations for every animal was calculated; hence, every animal served as its own control.

RESULTS

In both treated and nontreated groups, a significant difference over time was found between the two MR examinations seen as a decrease in the treated group and an increase in the nontreatment group.

CONCLUSION

It is concluded that the effect of anti-rejection treatment can be detected using a blood pool agent and MR imaging, as a change in SI corresponding to changes in the vascular permeability.

Lymphocyte propagation from biopsies of kidney allografts

Morphological evaluation of transplant biopsies, usually using the Banff classification, is the most important tool to diagnose rejection after kidney transplantation. However, morphological analysis only scores the amount and localisation of infiltrating cells, and studies show that up to 30% of grafts with a stable function display infiltration of lymphocytes consistent with acute cellular rejection. Methods to study the functional properties of the infiltrating lymphocytes are therefore needed. We applied a tissue culture system on biopsies from transplanted human kidneys, allowing infiltrating cells to propagate out from the tissue. Cells were then counted and subtyped by flow cytometry. The results were correlated to morphology. In total, 92 biopsies from 69 patients were analysed. For 14 patients, serial biopsies were available. In grafts with cellular or combined cellular and vascular rejection, the number of ex vivo propagated mononuclear cells was higher than from non-rejecting grafts. A similar pattern was seen for CD3(+) T cells as well as for T cells expressing CD25 or MHC class II antigens. However, the proportion of CD25(+) or MHC class II(+) T lymphocytes was similar in all groups (no rejection, vascular rejection, borderline changes, cellular rejection, combined cellular and vascular rejection). In all groups the number of CD4(+) cells was higher than the number of CD8(+) cells. The results confirm previous experimental studies showing that graft-infiltrating cells are possible to culture in vitro and that lymphocyte propagation correlates to acute cellular rejection. Tissue culturing is easy to perform and evaluate and can be used to determine and analyse the cellular immune response to allografts and may thus be used as a complement to morphological analyses.

T-cell inhibition does not aggravate bacterial translocation from rat small bowel

BACKGROUND

T-cell mediated immunity has been proposed to have an important function in the defence against translocating microbes from the gastrointestinal tract. After small bowel transplantation massive T-cell immunosuppression is necessary to avoid rejection. As a consequence, infections with intestinal bacteria are the main contributors to mortality in this setting. This could further imply that T cells are important in limiting bacterial translocation. In a model for bacterial translocation from small bowel in the rat we examined the outcome of T-cell inactivation.

METHODS

The studies were performed in a model of bacterial translocation from a Thiry-Vella loop of small bowel in the rat. The animals were treated with an anti-alpha/beta T-cell receptor monoclonal antibody (R73). Inhibition of T-cell activation was also made using the immunosuppressive drug cyclosporin A. All animals were sacrificed on day 3 postoperatively and translocation to the mesenteric lymph nodes, liver, spleen, lung and blood was evaluated.

RESULTS

Treatment with R73 resulted in an almost complete labelling of T cells but did not result in any increased bacterial translocation compared to animals treated with saline. Neither did immunosuppression with cyclosporin A.

CONCLUSIONS

In the model of bacterial translocation from a defunctionalised loop of small bowel the inhibition of T cells does not increase bacterial translocation to mesenteric lymph nodes or promote the systemic spread of the translocating bacteria. This indicates that T cells do not have any important protective function against translocating microbes from defunctionalised small bowel.

Antibody responses to xenogenic antigens?a study in the mouse-to-rat system

Antibodies play a crucial role in the rejection of an organ that has been transplanted between different animal species, i.e. xenotransplantation. In previous work, we have induced a state of humoral tolerance where mouse-to-rat heart grafts continued to beat under ciclosporine A monotherapy. Initially, a combined treatment with ciclosporine A and 15-deoxyspergualin was given. This state of tolerance could not be reproduced when the vascularised heart graft was replaced with a free tissue graft or xenogeneic blood transfusions. To gain further insight into the humoral response against mouse antigens, we studied the antibody production in naive rats and rats challenged with heart transplants, heart cells, mononuclear cells (MNC) and erythrocytes from mice. Rats not challenged with any mouse cells or organs had a moderate amount of antibodies targeted against mouse MNC as well as rosette-forming cells in the spleen targeted against mouse erythrocytes. A challenge with either mouse MNC or erythrocytes lead to immunisation with antibodies of both IgM and IgG subtype directed against both MNC and erythrocytes. Antibody titres against mouse erythrocytes in animals challenged with MNC were not detectable until day 7, whereas antibody titres against mouse MNC in animals challenged with erythrocytes were detected on day 1. Immunisation with mouse erythrocytes raised the titre of rosette-forming cells in the spleen compared with naive rats (P < 0.05). Our data indicate that different xenogeneic antigens in the mouse-to-rat system are shared between heart cells, MNC and erythrocytes; however, the immunisation patterns differ regarding the time when antibodies are first detected.

Phenotyping of ex vivo propagated graft-infiltrating cells—A tool to monitor rejection in the early post-operative period

Objective and fast methods to diagnose rejection after organ transplantation are needed. In the present study, the ex vivo propagation technique was evaluated for its ability to detect rejection at two different time-points after experimental heart transplantation. Syngeneic and allogeneic heterotopic heart transplantations were performed using inbred rat strains. After 6 or 15 days, cardiac graft biopsies were put in culture and infiltrating cells isolated by the ex vivo propagation technique. The isolated cells were counted and phenotyped by flow cytometry. In parallel, graft sections were analysed with regard to morphology and the presence of infiltrating cells as determined by immunohistochemical stainings. On day 15 after transplantation, the number of cells possible to isolate through ex vivo propagation reflected the morphological changes of the graft, i.e. considerably more cells were obtained from allogeneic transplants undergoing rejection (1052 +/- 205) than from allogeneic grafts under cyclosporine protection (513 +/- 135; p < 0.05) or from syngeneic grafts (378 +/- 87; p < 0.01). Six days after transplantation the allogeneic grafts were strongly rejected with massive cellular infiltration, still there was no difference between allogeneic and syngeneic grafts as to the number of ex vivo propagated cells. However, the proportion of IL-2-receptor expressing T lymphocytes was increased (15.4 +/- 1.8% vs. 9.5 +/- 1.4%; p < 0.05) and the CD4/CD8 ratio reduced (1.0 +/- 0.1 vs. 2.8 +/- 0.2; p < 0.001) in the allogeneic group as compared with the syngeneic. We conclude that the ex vivo propagation technique can be used to distinguish rejection from non-rejection both early and later after transplantation, provided that not just cell counting but also phenotyping of the graft-infiltrating cells is performed.

Monotherapy with the vitamin D3 analogue MC1288 does not result in prolonged kidney allograft survival in rhesus monkeys

The active form of vitamin D3, 1,25(OH)2D3, has pronounced immunoregulatory properties and is a potential treatment of immune-based disorders. However, the central role of this hormone in calcium and bone metabolism complicates its long-term use as an immunomodulator. Some newly developed vitamin D3-derived analogues, such as MC1288, have an improved immunoregulatory potential and prolong allograft survival in rodent models. Such compounds might be a valuable component of immunosuppressive treatment regimen in transplantation and autoimmunity. The rhesus monkey provides a useful model for the preclinical validation of new therapeutic strategies for transplantation. The present study shows that MC1288 inhibits both proliferation and interferon-gamma production by rhesus peripheral blood mononuclear cells in a mixed lymphocyte reaction. We have tested the maximum tolerated dose of MC1288 in a rhesus monkey model of kidney transplantation. The observed effects on serum calcium and parathyroid hormone confirm the in vivo activity of MC1288. However, as a monotherapy, MC1288 did not cause prolongation of the kidney allograft survival in rhesus monkeys.

Serum hyaluronan--a potential marker of cardiac allograft rejection?

BACKGROUND

The connective tissue component hyaluronan accumulates within the transplanted organ at rejection. Increased tissue content of hyaluronan is seen also in synovial tissue in rheumatoid arthritis and in skin in scleroderma. In these diseases, the elevated hyaluronan levels are reflected by increased concentrations of hyaluronan in serum. The aim of the present study was to study the changes in serum hyaluronan after organ transplantation.

METHODS

The experiments were performed in a rat model of heterotopic heart transplantation. Serum hyaluronan was assessed at various times after allogeneic (rejection) and syngeneic (non-rejection) transplantation and correlated with tissue hyaluronan. In addition, serum hyaluronan in animals who had long-term-surviving allogeneic grafts was studied.

RESULTS

The hyaluronan concentration in serum was significantly higher in the rejecting than in the non-rejecting group 4 and 6 days after transplantation (p < 0.01). On Day 6, serum hyaluronan had increased by 400% in animals with an allogeneic transplant and by 100% in those with a syngeneic transplant. There was a positive correlation between serum hyaluronan and tissue hyaluronan (p < 0.05). Animals with long-term-surviving grafts displayed normal serum hyaluronan levels.

CONCLUSIONS

Rejection of rat heart transplants is associated with strongly increased serum hyaluronan that parallels the hyaluronan accumulation within the transplant.

Macrophage uptake of ultra-small iron oxide particles for magnetic resonance imaging in experimental acute cardiac transplant rejection

PURPOSE

To discriminate between acutely rejecting and non-rejecting transplanted hearts using a blood pool contrast agent and T2* magnetic resonance imaging (MRI) in a clinical 1.5T scanner.

MATERIAL AND METHODS

Allogeneic and syngeneic heterotopic heart transplantations were performed in rats. One allogeneic and one syngeneic group each received either the ultra-small iron oxide particle (USPIO), at two different doses, or no contrast agent at all. MRI was performed on postoperative day 6. Immediately after the MR scanning, contrast agent was injected and a further MRI was done 24 h later. Change in T2* was calculated.

RESULTS

No significant difference in change in T2* could be seen between rejecting and non-rejecting grafts in either of the doses, or in the control groups. There was a difference between the allogeneic group that received the higher contrast agent dose and the allogeneic group that did not receive any contrast agent at all.

CONCLUSION

In our rat model, measurements of T2* after myocardial macrophage uptake of AMI-227 in a clinical 1.5T scanner were not useful for the diagnosis of acute rejection.

Regulation of fibroblasts by activated and non-activated immune cells

BACKGROUND

Rejection of transplanted tissue is characterized by cell infiltration and interstitial edema. Graft fibroblasts and fibroblast products are partly involved in the regulation of both these phenomena. Knowledge about the mechanisms behind fibroblast activation may lead to new strategies to prevent rejection. This study investigated whether cells of the immune system have the capacity to regulate fibroblast activation.

METHODS

Fibroblasts isolated from rejecting heart transplants or from normal heart tissue were cultured in the presence of supernatants of stimulated or non-stimulated immune cells. The immune cells were challenged either in vitro (incubation with phytohemagglutinin) or in vivo (organ transplantation). Fibroblast proliferation and hyaluronan production were measured.

RESULTS

Normal, sub-confluent heart fibroblasts showed an increased proliferation rate in the presence of supernatants of activated immunocompetent cells, irrespective of if these cells had been stimulated in vitro or in vivo. As expected, proliferation rate and hyaluronan production were upregulated in fibroblasts isolated from rejecting tissue. However, supernatants of biopsy specimens obtained from non-rejecting organs (syngeneic transplants or normal hearts) had an inhibitory effect on the growth rate of confluent fibroblasts isolated from rejecting tissue.

CONCLUSIONS

We conclude that graft-infiltrating cells and immune cells activated in vitro have the capacity to stimulate fibroblasts, most probably as a result of the production and secretion of fibroblast-stimulating factors.

Impact of consumption of freshwater fish on mercury levels in hair, blood, urine, and alveolar air

Human exposure to methylmercury occurs mainly via consumption of fish. The aim of the study was to investigate the influence of freshwater fish consumption on mercury levels in hair, blood, urine, and end-exhaled air. Twenty subjects without dental amalgam fillings were recruited from sport-fishing societies. They ranged in age from 61 to 87 yr. Six individuals ate freshwater fish at least once a week and were categorized as high consumers. Eight individuals were classified as medium consumers and ate freshwater fish at least once a month but less than once a week. Six individuals were categorized as low consumers and had not eaten freshwater fish in the past 3 mo. Among the high consumers, median concentrations of mercury were 8.6 microg/L in blood, 2.4 microg/g in hair, 10 pg/L in end-exhaled air, and 1.1 microg/g creatinine in urine. The relationship between freshwater fish consumption and mercury was significant in all biological media. The high-consumption group had much higher mercury levels in blood (9-fold), hair (7-fold), alveolar air (3-fold), and urine (15-fold) than the low-consumption group. The latter finding may be explained by demethylation of methylmercury in the body. The ratio between mercury concentration in blood and hair was 1:270. This implies that the typical blood-hair ratio of 1:250, specified by the World Health Organization (WHO) in 1990, is valid also for exposure to low amounts of methylmercury.

Hair mercury levels versus freshwater fish consumption in household members of Swedish angling societies

Hair mercury levels were determined in 143 individuals from households of members in angling societies in an area of Sweden with many lakes that have freshwater fish with relatively high mercury levels. Thus, the individuals had a potentially high intake of methyl mercury. The mean mercury concentration of pike and perch was approximately 0.7 microg/g. One-third of the subjects consumed these freshwater fish at least once a week. As could be expected, there was a clear increase in hair Hg with reported freshwater fish consumption (P < 0.001). The median mercury level in hair was 0.9 microg Hg/g for the whole group, and for those who reported consumption of freshwater fish at least once a week it was 1.8 microg/g. The highest hair mercury level was 18.5 microg/g, in a man who consumed pike and perch several times per week. Men had higher hair Hg than women, also when stratified for fish consumption. This was verified in 32 couples, of which the man and woman consumed the same fish and reported the same consumption. The median hair mercury level in these 32 couples was 1.3 microg/g for men and 0.8 microg/g for women (P = 0.002). About half of the subjects had hair mercury exceeding 1 microg/g, corresponding to the reference dose (RfD) of 0.1 microg of mercury per kilogram body weight set by the US Environmental Protection Agency. Although the RfD applies to all populations, the most at-risk group at these levels is pregnant women. There were only 2 women (of 12) of fertile age with hair mercury above 1 microg/g. In Sweden pregnant women are advised not to eat perch and pike at all during pregnancy. Since fish is rich in many important nutrients, it is unsatisfactory that fish consumption must be restricted, and thus there is a need to reduce mercury levels in fish.

Effects of commonly used immunosuppressants on graft-derived fibroblasts

In acute rejection of transplanted organs intragraft fibroblasts increase their production of hyaluronan. Hyaluronan has strong water binding capacity and an increased tissue content of hyaluronan thus contributes to the development of interstitial oedema. The present study examined the effects of commonly used immunosuppressants (prednisolone, cyclosporin, tacrolimus, mycophenolic acid and sirolimus) on fibroblast proliferation, hyaluronan production and cell surface receptor expression. Fibroblasts isolated from rejecting tissue and from normal, non-transplanted tissue were studied in parallel. All substances investigated, except tacrolimus, were found to affect fibroblasts in one way or another. The most striking effect was the almost total inhibition of fibroblast proliferation in the presence of mycophenolic acid. Cyclosporin reduced the proliferation by about 50% and prednisolone had an inhibiting effect on hyaluronan production (50% reduction). These effects were observed on fibroblasts isolated from rat cardiac allografts undergoing rejection as well as on fibroblasts obtained from normal heart tissue. In contrast, sirolimus was found to stimulate the proliferation of fibroblasts from rejecting tissue (100% increase), but not that of normal fibroblasts. The majority of the fibroblasts expressed the hyaluronan receptor CD44, with a more intense expression in cultures of fibroblasts derived at rejection. None of the immunosuppressants affected the staining pattern (number of positive cells or intensity). The inhibitory effects of prednisolone, cyclosporin and mycophenolic acid on fibroblasts may contribute to the overall beneficial effects of these drugs when used for prevention or treatment of rejection.

The graft content of hyaluronan is increased during xenograft rejection

BACKGROUND

Hyaluronan, a macromolecule with strong water binding capacity, is associated with interstitial oedema during rejection of allogeneic transplants. However, the involvement of hyaluronan during xenograft rejection has previously not been investigated. The aims of this study were to characterize hyaluronan content and distribution during rejection of concordant mouse-to-rat cardiac xenografts, and to explore the effects of hyaluronidase (HAse) on xenograft survival.

METHODS

Graft recipients were treated with 15-deoxyspergualin (DSG) or both HAse and DSG. Grafts were removed on day 5 from some of the animals to analyse hyaluronan and water content, while other animals were used to investigate graft survival. The hyaluronan content was measured by a radiometric assay and the distribution was analysed by histochemical staining.

RESULTS

In xenografts undergoing rejection (the DSG group) there was a strong increase of the hyaluronan [555 +/- 93 microg/g dry weight (dw)] and water (82.7 +/- 0.4%) contents compared with normal mouse heart tissue (166 +/- 10 microg/g dw; P < 0.01 and 78.6 +/- 0.5%; P < 0.001, respectively). The combined use of HAse and DSG reduced the accumulation of hyaluronan (284 +/- 43 microg/g dw; P < 0.05 vs. DSG) but did not affect the average water content. The average graft survival time did not differ between the groups; however, three grafts in the HAse + DSG-treatment group survived much longer than the longest-surviving grafts in the DSG group.

CONCLUSIONS

These data suggest that the graft content of hyaluronan considerably increases during xenograft rejection. HAse effectively reduces this accumulation, but does not affect the average water content.

Effects of increased intra-abdominal pressure and volume expansion on renal function in the rat

BACKGROUND

The effects of increased intra-abdominal pressure (IAP) and volume expansion on renal function in the rat were studied to gain more knowledge of the oliguria seen during laparoscopic procedures and to reduce the detrimental renal effects of IAP.

METHODS

IAP was elevated to 5 or 10 mmHg by insufflation of CO(2) and maintained for 2 h in anaesthetized and mechanically ventilated rats. Rats with normal IAP served as controls. An angiotensin II receptor I antagonist, candesartan, was given as a bolus injection and a 5% volume expansion was achieved by i.v. saline infusion. An angiotensin-converting enzyme (ACE) inhibitor was also given. Renal parameters were the glomerular filtration rate (GFR), urine production, the urinary concentrations of sodium and potassium and the osmolality in the urine. The arterial acid-base balance and blood pressure were also monitored.

RESULTS

The GFR deteriorated by 70% during pneumoperitoneum (PP) of 10 mmHg. There was a dramatic drop in sodium excretion (88-97%). With candesartan and elevated IAP, there was a drop in mean arterial pressure (from 90 to 55 mmHg) and the negative renal effects were very pronounced. Renal function was better preserved during elevated IAP in combination with volume expansion.

CONCLUSIONS

Capnoperitoneum suppresses renal function, especially in combination with angiotensin II receptor 1 blockade and ACE inhibition. Volume expansion reduces the deleterious effects of PP on renal function during elevated IAP. The results suggest that patients should not be given pharmaceuticals blocking the renin-angiotensin-aldosterone system prior to procedures that may increase IAP. It may be beneficial, however, to reduce angiotensin II tension by volume expansion.

ORAL ADMINISTRATION OF XENOGENEIC ERYTHROCYTES INDUCES PRODUCTION OF ANTIBODIES THAT ARE CAPABLE OF INDUCING HYPERACUTE REJECTION OF CONCORDANT VASCULARIZED XENOGRAFTS

Oral tolerance induction has proven to be an effective approach for inducing antigen-specific unresponsiveness in several models for allogeneic transplantation and autoimmune diseases. The authors' preliminary studies, however, indicated that xenospecific antibodies are produced when rats are given mouse erythrocytes orally. This response was further examined. Mouse erythrocytes were administered to rats orally or intravenously during one or two episodes, and sera were obtained on day 9 or day 29, respectively. Rat sera containing a positive hemagglutinating titer against mouse antigens were injected into rats that had recently undergone xenotransplantation to study graft survival. Oral administration of xenogeneic cells induced a powerful antibody response consisting mainly of xenospecific immunoglobulin (Ig) M and IgG. This antibody response also induced hyperacute rejection as powerfully as sera from intravenously immunized rats. The authors' study thus indicates that oral administration of xenogeneic cells is a powerful immunization pathway that induces an antibody response capable of rejecting concordant vascularized xenografts.

Renal hyaluronan accumulation and hyaluronan synthase expression after ischaemia-reperfusion injury in the rat

BACKGROUND

Hyaluronan (HA) is a connective tissue component with unique water binding and pro-inflammatory properties. It has been suggested that HA is involved in normal renal water handling but also in several pathological conditions such as organ rejection and ischaemia-reperfusion (IR) injury.

METHODS

In anaesthetized normal rats we investigated if renal cortical HA accumulation and the intrarenal distribution and expression of HA synthases (Has 1, 2 and 3) correlate with renal dysfunction after renal IR injury. After 20, 30 or 45 min of unilateral renal ischaemia and 72 h of reperfusion, renal function and cortical HA content were measured. Has 1, 2 and 3 mRNA were determined in control and IR kidneys subjected to 45 min ischaemia and 72 h reperfusion.

RESULTS

IR kidneys had reduced urine concentrating ability, potassium excretion, glomerular filtration rate (GFR) and renal blood flow. On average, IR kidneys had more than 10 times higher amounts of cortical HA than the contralateral control kidney and their water content was elevated while medullary HA was largely unaffected. Has 2 expression in the cortex was heavily up-regulated in IR kidneys while Has 3 remained at control levels. Has 1 could never be detected. There was a direct correlation between the amount of cortical HA and the time period of ischaemia and also between the cortical amount of HA and depression of functional parameters.

CONCLUSIONS

IR injury depresses parameters of renal function, which coincides with an elevated cortical HA content and Has 2 expression. The enhanced Has 2 expression indicates that the cortical HA accumulation is primarily dependent on increased HA synthesis and not impaired degradation/elimination. The water binding and pro-inflammatory properties of HA may contribute to renal dysfunction after IR.

COX-2 inhibitors prolong trauma-induced elevations of iris hyaluronan

PURPOSE

To investigate whether and how treatment with COX-2 inhibitors influences hyaluronan responses to a standardized trauma, argon laser induced iritis, in rabbits.

METHODS

Two different COX-2 inhibitors were used, SC-236 and rofecoxib. The drugs were administered orally, 6 mg/kg/day and 1.5 mg/kg/day respectively. Iris and aqueous humor hyaluronan concentrations were measured with a radiometric assay at different time points after laser irradiation.

RESULTS

The hyaluronan concentration in the iris increased 3-4-fold with a peak concentration of 129.1 microg/g wet weight 2 days after laser irradiation. It then decreased to normal values after 1 week. In eyes treated with either of the COX-2 inhibitors, iris hyaluronan concentrations did not decrease as rapidly and were significantly higher at day 4 and 7 when compared to drug untreated eyes.

CONCLUSION

Treatment with COX-2 inhibitors prolongs trauma induced elevation of iris content of endogenous hyaluronan. This may be, at least partly, due to an inhibition of interstitial fluid pressure regulation.

Intragraft cytokine mRNA expression in rejecting and non-rejecting vascularized xenografts

BACKGROUND

The aim of the present study was to further investigate the characteristics of both graft-infiltrating cells and splenocytes during acute vascular rejection (AVR), cell-mediated rejection and non-rejection of vascularized concordant xenografts, by analysing both proinflammatory [interleukin-1beta (IL-1beta) and tumour necrosis factor (TNF-alpha)] and more specific [(IL-2, IL-4, IL-10, IL-12p40 and interferon-gamma (IFN-gamma)] cytokines. A parallel investigation was made of the antibody response of IgM and IgG to the xenografts.

METHODS

Mouse hearts were heterotopically transplanted to the neck vessels of recipient rats. Grafts, spleens and sera were collected from untreated (AVR) and cyclosporin A (CyA) treated animals on day 2 after transplantation. Organs from rats treated with 15-deoxyspergualin (DSG) or CyA and DSG in combination were harvested on both day 2 and day 8. Grafts from DSG-treated rats undergo cell-mediated rejection and stop beating on day 9 and forth, while CyA + DSG treatment results in long-term graft survival. Real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was applied for analysis of intragraft and splenic cytokine messenger RNA (mRNA) expression. The phenotypes of the graft infiltrating cells were characterized by immunohistochemistry. The antibody response was investigated by means of immunofluorescence, haemagglutination and flow cytometry.

RESULTS

All the studied cytokines (IL-1beta, IL-2, IL-4, IL-10, IL-12p40, IFN-gamma and TNF-alpha) were up-regulated in the grafts from rejecting untreated (day 2) and DSG-treated animals (day 8) in comparison with grafts from CyA + DSG treated animals (day 8). On day 2 under immunosuppression with CyA, DSG or CyA + DSG no or low cytokine mRNA levels were found. The mRNA levels of IL-2, IL-4 and IFN-gamma in the spleens were suppressed under both DSG- and CyA + DSG treatment on day 8. Immunofluorescence showed deposits of both IgM and IgG in grafts from untreated, CyA-treated (day 2) and DSG-treated (day 8) animals, while CyA + DSG treatment diminished these deposits on both day 2 and day 8. No circulating antibodies were identified in either group.

CONCLUSION

We hereby conclude that both AVR on day 2 and cell-mediated rejection on day 8 (under DSG treatment) in a concordant cardiac mouse-to-rat xenotransplantation model are associated with an increase of proinflammatory cytokines, T helper 1 (Th1)-associated cytokines as well as IL-10, while immunosuppression with CyA + DSG diminishes the levels of all examined cytokines. Grafts undergoing AVR or cellular rejection are subjected to deposits of both IgM and IgG, although circulating donor specific antibodies are undetectable in serum.

Pretransplant xenogeneic blood transfusions reduce the humoral response in a mouse-to-rat heart transplantation model

A mouse heart transplanted to a rat is rejected promptly 3 days after transplantation, independent of whether cyclosporin A (CyA) is used as an immunosuppressant or not. Adding a short course of deoxyspergualin (DSG) initially, in addition to continuous CyA treatment, results in long-term graft survival and permits retransplantation during CyA monotherapy. In this paper, we have explored the possibility of substituting the initial heart transplant with blood transfusions. Lymphocyte-enriched blood transfusions combined with CyA and an initial course of DSG proved to lower or eliminate the haemagglutinating antibody titre normally seen in acute vascular xenorejection. The therapy, however, did not prolong the mean survival of the cardiac xenograft, but the same treatment protocol could result in either hyperacute rejection or prolonged survival of up to 11 days. In conclusion, this and earlier studies propose that a humoral unresponsiveness can be induced if the recipient vascular circulation is exposed to a xenoantigen in a mouse-to-rat combination.

Characterization of fibroblasts from rejecting tissue: the hyaluronan production is increased

BACKGROUND

Interstitial edema of rejecting tissue can be partly attributed to the local accumulation of hyaluronan, which has strong water-binding capacity. The aim of the present study was to isolate fibroblasts from rejecting tissue and compare them, in terms of hyaluronan production and proliferation rate, with fibroblasts obtained from nontransplanted tissue. Furthermore, the fibroblast response to various cytokines involved in the rejection process was studied.

METHODS

Fibroblasts were isolated from normal rat heart tissue and from cardiac allografts undergoing rejection. The various preparations were characterized with regard to hyaluronan production (radiometric assay) and cell proliferation ( H-thymidine incorporation). In addition, the effects of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-2 on these parameters were studied.

RESULTS

Fibroblasts isolated from rejecting hearts displayed strongly up-regulated hyaluronan production and proliferation rate as compared with fibroblasts obtained from normal tissue. In the presence of TNF-alpha, the proliferation of nonconfluent cells was augmented, whereas in confluent cultures of fibroblasts from rejecting tissue, the proliferation was inhibited. IFN-gamma stimulated both hyaluronan secretion and proliferation in confluent fibroblasts from rejecting hearts but had no effect on fibroblasts from normal tissue. IL-2, finally, reduced the hyaluronan production of nonconfluent cells.

CONCLUSIONS

The activation of fibroblasts is increased in rejecting tissue. As a result, the hyaluronan concentration is elevated which, in vivo, contributes to the formation of an interstitial edema and a subsequently increased tissue pressure. Several cytokines present at rejection are involved also in the regulation of fibroblast activity.

Acute cardiac transplant rejection: detection and grading with MR imaging with a blood pool contrast agent--experimental study in the rat

PURPOSE

To investigate the possibility of detecting cardiac transplant rejection and determining its degree of severity with magnetic resonance (MR) imaging with a blood pool contrast agent.

MATERIALS AND METHODS

Rat allogeneic (PVG to Wistar/Kyoto, n = 9) and syngeneic (Wistar/Kyoto to Wistar/Kyoto, n = 6) heterotopic heart transplantations were performed. On the 2nd and 6th postoperative days, an ultrasmall superparamagnetic iron oxide, or USPIO, contrast agent was injected intravenously at a dose of 2 mg of iron per kilogram of body weight. The injection was followed by three-dimensional T1-weighted MR imaging of the heart grafts with an imaging time of approximately 2 minutes for each image for 44 minutes. The signal intensity (SI) was measured in the myocardium over time, and the relative enhancement was calculated. After the 6th day, the rats were sacrificed, and the morphology of the transplanted hearts was assessed histologically. The CIs for the difference of the means on day 2 and day 6 were calculated by using a bootstrap technique, and the correlation between the relative SI change and the histologically determined degree of rejection were calculated with the Spearman rank order correlation coefficient.

RESULTS

On day 6, a statistically significant difference between the groups was found at 4 minutes after injection of the contrast agent and increased with increasing time after injection. The mean percentage change in SI at the last time point for the allogeneic group on day 2 was -8.7% (SD, 8.5) and for the syngeneic group was -6.6% (SD, 6.0). On day 6, the allogeneic group had a relative SI change of 17.7% (SD, 8.7), whereas the syngeneic group had a change of -7.4% (SD, 2.6). There was a significant difference between only the two groups on day 6 (P <.001). Furthermore, in the allogeneic group the histologically determined degree of rejection correlated positively with the relative SI enhancement (r = 0.89, P <.005).

CONCLUSION

Acutely rejecting heart transplants can be distinguished from nonrejecting ones in an animal model with MR imaging and a blood pool contrast agent. In addition, the relative SI enhancement reflects the histologically determined degree of rejection.

Renomedullary and intestinal hyaluronan content during body water excess: a study in rats and gerbils

Our previous studies in rats have suggested a role for renomedullary hyaluronan (HA) in water homeostasis. The gerbil is known for its unique ability to conserve water. In the present study renal papillary and intestinal HA were compared between groups of anaesthetized gerbils and rats before and after up to 6 h of I.V. water loading. Baseline papillary HA in gerbils was only 37 % of that in the rat. Water loading in rats increased the papillary HA content. Elevation was maximal (+27 %, P < 0.05) after 2 h of water loading and then declined to control levels after 6 h of water loading (+3 %, n.s.). In contrast, the gerbil responded with a decreased papillary HA content during water loading. The depression was maximal after 2 h (-49 %, P < 0.05) and was still 41 % below the control values after 6 h (P < 0.05). The urine flow rate increased rapidly in the rat and its maximum, 21 times above the control level (P < 0.05), occurred at the HA peak, i.e. after 2 h of water loading while in the gerbil, the urine flow rate increased slowly and slightly and was only six times above control values after 6 h of water loading (P < 0.05). The HA content along the intestine was similar in the two species: lowest in the duodenum and jejunum and highest in the distal colon. To conclude, in the rat, the elevation of papillary interstitial HA during acute water loading would counteract water reabsorption by changing the physico-chemical characteristics of the interstitial matrix favouring rapid water diuresis. This would work as a complement to the powerful regulation by ADH. The gerbil has a diametrically different regulation of papillary HA turnover during water loading. The decreased papillary HA level during water loading and the slow and small diuretic response may represent a genetic difference in adaptation to enhance the ability to conserve water in an arid environment.

Effects of sympathetic denervation on the hyaluronan content of the anterior segment in the normal and traumatized rabbit eye

PURPOSE

To determine whether there is any involvement of sympathetic nerves in the regulation of ocular hyaluronan production in the normal and traumatized rabbit iris.

METHODS

Unilateral sympathetic denervation was performed by removing the right superior cervical ganglion. Hyaluronan concentrations in the iris and aqueous were measured with a radiometric assay at various time intervals after denervation. Peripheral iridectomy was also performed in both denervated and non-denervated eyes.

RESULTS

Hyaluronan concentrations in the iris tissue after denervation were observed to have increased after 1 day, reaching a peak of 129.6 +/- 5.7 microg/g wet weight at day 3. Two weeks later, hyaluronan concentrations had fallen back to normal levels. Ocular trauma with peripheral iridectomy in denervated eyes caused an increase of hyaluronan content of up to 253.5 +/- 30.5 microg/g wet weight, which was not significantly different from hyaluronan concentrations observed after the same trauma in non-denervated eyes.

CONCLUSION

Cervical sympathetic denervation results in a moderate increase of the hyaluronan content in the rabbit iris and does not appear to influence the hyaluronan response of the iris to trauma.

Quantification of lymphocytes propagating from rat-kidney allografts--a tool to monitor anti-rejection treatment

BACKGROUND

Morphological evaluation of kidney biopsies applying the Banff Classification is closely correlated to clinical parameters of rejection. However, this classification is insufficient for monitoring the effect of instituted anti-rejection therapy. The objective of the present study was to develop a diagnostic tool enabling rapid assessment of the effects of an attempted anti-rejection treatment.

MATERIALS AND METHODS

A kidney allotransplantation model in the rat was applied. All animals were initially maintained on cyclosporine A (CsA). In order to induce an episode of acute cellular rejection, CsA was withdrawn for 5 days. Thereafter, the immunosuppressive treatment was restarted. Core biopsies were taken before, and at various times after, the introduction of anti-rejection therapy. Infiltrating cells were isolated using an in vitro culture system, allowing cells to propagate from the biopsies to culture medium. Propagated cells were counted and analysed for subtype and activation markers using flow cytometry. The results were compared with immunohistochemical and morphological analyses of the grafts.

RESULTS

By applying the in vitro culture system it was possible to demonstrate a reduction in outgrowth of mononuclear cells from core biopsies as early as 2 days after the start of anti-rejection therapy. At this time-point, as well as 2 days later, morphological and immunohistochemical analyses of biopsies showed ongoing acute cellular rejection, with no differences between biopsies taken before and after restart of CsA-therapy. The percentage of propagating T lymphocytes expressing the activation markers CD25 or MHC class II did not differ between grafts with ongoing rejection and grafts obtained from CsA-treated rats, neither did the ratio of CD4/CD8-positive cells.

CONCLUSION

Our findings indicate that the ex vivo propagation method could function as a complement to routine histology, not only in the diagnosis of cellular rejection but also in order to rapidly reveal a failure of an anti-rejection therapy to halt the rejection process.

Isolation of mouse-to-rat cardiac xenograft-infiltrating cells by ex vivo propagation

Ex vivo propagation of graft infiltrating lymphocytes has become a useful method for the examination of the cellular response after allogeneic transplantation. The aim of the present study was to investigate if this method can be used also for isolation of xenograft infiltrating cells, and, if so, to further characterize these cells. The concordant mouse-to-rat heart transplantation model was used for the experiments. Recipient rats were treated either with 15-deoxyspergualin (DSG) or with a combination of DSG and cyclosporine A (CyA) or left untreated. Transplants were removed beating on day 2 (untreated) or day 8 (DSG and CyA + DSG) and biopsies were incubated in culture medium for 48 h, resulting in propagation of cells from the biopsies into culture medium. The propagated cells were counted and phenotyped using flow cytometry. In parallel, the transplants were examined morphologically and immunohistochemically. Infiltrating cells could be isolated from all grafts in all groups. The number of propagated T lymphocytes during cellular rejection (DSG-treatment) was about 3.5 times higher than during 'non-rejection' (CyA + DSG) and six times higher than during acute vascular rejection (untreated). These findings were supported both by the morphological and the immunohistochemical findings. In conclusion, we have shown that graft infiltrating lymphocytes can be isolated from xenogeneic heart transplants by incubation of biopsies for 48 h, resulting in spontaneous propagation of immune cells into culture medium. Propagated cells could be further characterized by flow cytometry. Thus, the technique presented here can be used as a tool for studies of xenogeneic cellular rejection.

Synthesis and biological evaluation of technetium(III) mixed-ligand complexes with high affinity for the cerebral 5-HT(1A) receptor and the alpha1-adrenergic receptor

Tc(III) and Re(III) complexes [M(NS(3))(CNR)] (M = Re, 99mTc, NS(3) = 2,2',2"-nitrilotris(ethanethiol), CNR = functionalized isocyanide bearing a derivative of WAY 100635) have been synthesized and characterized. Re was used as Tc surrogate for chemical characterization and in vitro receptor-binding studies. For two representatives subnanomolar affinities for the 5-HT(1A) as well as for the alpha1-adrenergic receptor were reached. Biodistribution studies in rats of the 99mTc complexes showed brain uptakes between 0.3 and 0.5% ID/organ (5 min p.i.). In vitro autoradiography of one 99mTc representative in sections of post mortem human brain indicate its accumulation in 5-HT(1A) receptor-rich brain regions. However, addition of the specific 5-HT(1A) receptor agonist 8-OH-DPAT as well as the alpha1-adrenoceptor antagonist prazosin could not substantially block this tracer accumulation. A preliminary SPET study in a monkey showed negligible brain uptake.

The effect of mesenteric lymphadenectomy and Kupffer cell depletion on bacterial translocation

BACKGROUND

Infectious complications are associated with high morbidity in patients with short bowel syndrome and after small bowel transplantation. Bacterial translocation from the intestine is probably an essential factor in the genesis of these infections. In a model for bacterial translocation in the rat we examined the consequence of mesenteric lymphadenectomy and the depletion of Kupffer cells.

MATERIALS AND METHODS

The effect of mesenteric lymphadenectomy was studied in two different models; in rats where a Thiry-Vella loop had been created from small bowel and in rats that had received a syngeneic small bowel transplant. To study the role of the Kupffer cells, rats with Thiry-Vella loops were treated intravenously with the Kupffer cell inhibitor gadolinium chloride. All animals were sacrificed on Day 3 postoperatively and the bacterial translocation to the mesenteric lymph nodes, liver, spleen, lung, and blood was evaluated.

RESULTS

Removal of the mesenteric lymph nodes did not result in any increased bacterial translocation in animals with a Thiry-Vella loop. However, the inactivation of Kupffer cells with gadolinium chloride produced a more severe translocation to the liver, spleen, and lungs. After small bowel transplantation the bacterial translocation to the spleen was increased in animals without mesenteric lymph nodes.

CONCLUSIONS

In the model of bacterial translocation from a defunctionalized loop of small bowel the inhibition of Kupffer cells will promote the systemic spread of the translocating bacteria. This indicates an important protective function of the Kupffer cells against translocating microbes.

Renal cortical accumulation of hyaluronan in adult rats exposed neonatally to angiotensin-converting enzyme inhibition

Neonatal inhibition of the renin-angiotensin system [angiotensin-converting enzyme (ACE) inhibition] in the rat results in long-term abnormal renal morphology and function, including interstitial inflammation and fibrosis. Hyaluronan (hyaluronic acid, HA) has pathological implications in inflammatory diseases and renal ischaemia-reperfusion injury. The present study aimed at determining if renal cortical HA in the adult rat is correlated to the abnormal morphology and function in rats treated neonatally with the ACE inhibitor enalapril. In adult control rats (23 weeks old), the cortical HA content was very low [about 5 microg g(-1) dry weight (d.w.)] and about 1% of the papillary HA content. In rats treated neonatally with enalapril (days 3-13), the cortical HA level was 15 times that in control rats already at 21 days after birth, and it persisted at this level during adulthood (at 23 weeks). At 13 weeks the enalapril-treated animals showed markedly reduced ability (-53%) to concentrate urine during 24-h thirst provocation. At 21 days as well as at 23 weeks the enalapril-treated kidneys displayed morphological changes, such as papillary atrophy, dilation of the tubules and cellular infiltration of the cortical tissue. Histochemical staining confirmed the HA quantification assay and revealed a patchy staining for HA located in the same regions as the infiltrating cells. In conclusion, neonatal treatment with the ACE inhibitor enalapril results in renal morphological and functional abnormalities during adulthood. Cortical HA levels are already seriously elevated at day 21 and coexist with infiltrating cells. Besides the known effects of angiotensin II in development, the accumulation of HA in these kidneys may be involved in the genesis of at least the cortical abnormalities in enalapril-treated animals because of the proinflammatory effects and water-binding properties of HA.

Influence of laser irradiation on endogenous hyaluronan in rabbit iris and aqueous humor

PURPOSE

To monitor changes of endogenous hyaluronan in the iris tissue and aqueous humor after an isolated trauma to the iris by argon laser irradiation of the anterior surface of the iris.

METHODS

Iris and aqueous hyaluronan concentrations in rabbit were measured with a radiometric assay at different time points after laser irradiation.

RESULTS

Total hyaluronan content in iris tissue increased 3-fold to a peak concentration of 71-72 microg/g at 1 and 2 days after laser treatment. Aqueous hyaluronan increased to a maximum of about 1.6 microg/ml at 2 h and 12 h after laser irradiation of the iris.

CONCLUSIONS

The iris tissue responds with increased hyluronan synthesis to an isolated iris argon laser irradiation and it seems to be the most important source of aqueous hyaluronan.

Bacterial translocation from defunctionalized rat small bowel

Bacterial translocation from the intestine may cause severe infectious complications in a number of clinical situations, including the short bowel syndrome and after small bowel transplantation. The aim of the present study was to develop a simplified model for the study of bacterial translocation from a defunctionalized intestine. An ileal segment from untreated or cyclosporine-treated rats was exteriorized as a Thiry-Vella loop. After 1, 3. or 7 days, bacterial translocation and distribution of immunocompetent cells were assessed. The data obtained were compared with data from animals subjected to intestinal transplantation. Translocation to the mesenteric lymph nodes was detected in 60% of the Thiry-Vella loop animals on day 1. in 100% on day 3, and in 83% on day 7: concomitantly, the number of macrophages and T-cells in the mesenteric lymph nodes increased from day I until day 7. The degree of bacterial translocation on days 3 and 7 in animals with a Thiry-Vella loop was comparable with that observed 7 days after intestinal transplantation. Furthermore, treatment with cyclosporine A enhanced the number of translocating bacteria. In the model presented here bacterial translocation occurs from the small bowel to the mesenteric lymph nodes. The model offers possibilities to study the mechanisms and immunological phenomena associated with microbial translocation.

Renomedullary interstitial cells in culture; the osmolality and oxygen tension influence the extracellular amounts of hyaluronan and cellular expression of CD44

Our previous studies have suggested a role for renomedullary interstitial cells (RMICs) and renal medullary hyaluronan (HA) in water homeostasis. In the present study, cultured rat RMICs were used to examine the relationship of osmolality and oxygen tension on the extracellular amount of HA in the culture and to the cellular immunoreactivity to CD44, a HA binding protein. Under isotonic (330 mOsm(.)kg(-1) H(2)O), normoxic (20% O(2)) conditions, supernatant from sub-confluent RMICs contained 120+/-37 pg 10(4) cells(-1) 24 h(-1) of HA. Under hyperosmotic conditions (630 mOsm kg(-1) H(2)O), HA in the supernatant was decreased by 42% and under hypoosmotic conditions (230 mOsm kg(-1) H(2)O) it was doubled. Under hypoxic, iso-osmolar conditions (5% and 1% O(2), 330 mOsm kg(-1) H(2)O) this HA content was decreased by 56 and 48%, respectively, compared with normoxic, iso-osmolal conditions. Expression of CD44 on sub-confluent cells increased with increasing osmolality, as shown by immunostaining and flow cytometric analysis. The increases in CD44 from 330 to 630, 930 and 1230 mOsm kg(-1) H(2)O amounted to 5, 142 and 212%, respectively. Low oxygen tension (5% O(2)) decreased the intensity of CD44 immunofluorescence by 31%. Cell viability was similar at all conditions studied. In summary, these data indicate that cultured RMICs produce HA and are immunoreactive to CD44. In the supernatant of RMICs, the HA content decreases under hyperosmotic, hypoxic conditions. Conversely, CD44 immunoreactivity increases under hyperosmotic conditions. These results may explain our previous in vivo findings of a decreased renal papillary HA content during anti-diuresis and an increased content during water diuresis. The results support the concept that RMICs play an important role in renal water handling.

Characterization of Forssman and other antigen/antibody systems in vascularized mouse heart to rat xenotransplantation

In the present study, the nature of hyperacute xenograft rejection was closely studied in a vascularized mouse-to-rat transplantation model. Antibodies against mouse heart, erythrocytes and lymphocytes and against the Forssman antigen were raised in the rat. Upon heterotopic heart transplantation the respective antisera were intravenously (i.v.) injected. Passive transfer of antiheart, antierythrocyte or antilymphocyte serum resulted in hyperacute rejection of the transplanted mouse heart. Subfractionation of the antiheart serum showed that the capacity to induce hyperacute rejection was carried by the immunoglobulin (Ig)G fraction. When antierythrocyte serum adsorbed with mouse erythrocytes was administered the cardiac grafts remained beating. To the contrary, antilymphocyte serum adsorbed with erythrocytes still had the capacity to induce hyperacute rejection. None of the rats that had previously been challenged with the Forssman antigen rejected their grafts hyperacutely. Subsequent investigations by electron microscopy revealed that the Forssman antigen is expressed on dendritic cells (DC) adjacent to the vessels, but not on the vascular endothelium, thus explaining the inability of the anti-Forssman serum to induce hyperacute rejection. Taken together, we have demonstrated the existence of several xenoantigens that can be targets for antibody-mediated rejection, suggesting that more than one relevant xenoantigen exists also in more distantly related combinations, such as the pig-to-human combination.

Monitoring of intragraft pressure of rejecting organs: increased tissue pressure can be reduced by hyaluronidase therapy

BACKGROUND

The present study was undertaken in order to: (a) develop a new technique for measurement of interstitial pressure, (b) study the intragraft pressure of rejecting and non-rejecting organs, and (c) study the effect of treatment with the hyaluronan-degrading enzyme hyaluronidase on intragraft pressure. Treatment with hyaluronidase has previously been demonstrated to result not only in reduction of tissue hyaluronan but also in ameliorated interstitial edema, and we suggested that the diminished edema would lead to a reduced interstitial pressure as well.

METHODS

At day 5 after syngeneic or allogeneic rat heterotopic heart transplantation, the interstitial pressure of the cardiac grafts was measured using a microtip pressure sensor. Subsequently, the allogeneically grafted animals received a continuous intravenous infusion of either hyaluronidase (total dose: 60,000 U/kg) or vehicle during 2 hr; meanwhile, the interstitial pressure was monitored.

RESULTS

The intragraft pressure measurement technique was found to give reproducible results. The interstitial pressure of the rejecting (allogeneic) grafts was considerably higher than that of the non-rejecting (syngeneic), i.e., 12.3+/-1.6 mmHg vs. 1.1+/-0.6 mmHg (P<0.001). Hyaluronidase infusion effectively reduced the interstitial pressure as compared with vehicle treatment. By 20 min, the pressure had been reduced by 28% (P<0.01 compared with vehicle treatment); after 1 hr, by 49% (P<0.001); and after 2 hr, by 68% (P<0.01).

CONCLUSIONS

By using modern technology for tissue pressure measurements, we found that the strongly increased interstitial pressure of rejecting organs can be instantly reduced by intravenous administration of the hyaluronan-degrading enzyme hyaluronidase.

Hyaluronidase can be used to reduce interstitial edema in the presence of heparin

BACKGROUND

Treatment with the hyaluronan-degrading enzyme, hyaluronidase, reduces rejection-induced interstitial edema of transplanted organs. Hyaluronidase has also been demonstrated to reduce tissue necrosis after experimentally induced myocardial infarction, but its clinical use has been limited by an observed interaction between heparin and hyaluronan. In the present work, we investigated whether it is also possible to retain the effect of the enzyme in heparinized animals.

METHODS

Day 5 after heterotopic heart transplantation, recipient rats received a 2-hour intravenous infusion of hyaluronidase, either of ovine or of bovine origin. Concomitantly, the animals received intravenous heparin, either as 2 bolus doses or as a constant infusion.

RESULTS

Both hyaluronidase preparations effective reduced the hyaluronan content as well as the water content of the rejecting cardiac grafts. The concomitant use of heparin did not hamper the positive results, neither when heparin was administered intermittently nor when it was given continuously.

CONCLUSIONS

Our results in the transplantation model clearly demonstrate that hyaluronidase can be successfully used in heparinized individuals, provided that sufficient doses of the enzyme are given.

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.

Concordant xenotransplantation--non-vascularized pancreatic islets are more difficult to regraft than the vascularized heart

We have previously demonstrated that it is possible to perform retransplantation of a xenogeneic heart (mouse-to-rat) using cyclosporine A as monotherapy, provided that the first heart is transplanted under a short course of deoxyspergualin (DSG). If DSG is omitted, the first heart is rejected within four days and the second heart succumbs to hyperacute rejection within minutes. A mouse heart as first graft does not protect a consecutive pancreatic islet graft, although the heart continues to function after rejection of the cellular graft. One explanation for this discrepancy may be the fact that cellular grafts, as pancreatic islets, lack an endothelial lining. We have, therefore, further investigated possible differences between vascularized and non-vascularized xenografts regarding their capacity to induce unresponsiveness. The use of pancreatic islets as primary graft neither accelerated nor decelerated the speed of rejection of the vascularized heart used as secondary graft. Furthermore, hemagglutinating and cytotoxic antibody titres responded in the same manner as in naive rats transplanted with a mouse heart. Retransplantation with pancreatic islets also resulted in complete rejection of both the primary and secondary grafts. Thus, the lack of unresponsiveness cannot simply be explained by differences, between the pancreatic and cardiac tissues, in antigen expression. In addition, intraperitoneal transplantation of mouse heart cells as primary graft resulted in rejection of a secondary cardiac graft after three days. However, it cannot be totally excluded that the time of antigen exposure had an impact on these results. In conclusion, our previous and present studies suggest that the presence of an intact vascular bed, both in the first and second graft, is necessary to create a state of unresponsiveness. Because the pancreatic islets lack an endothelial lining, they do not benefit from an unresponsiveness of the immune system. Neither are they able to induce such an unresponsiveness.

An observation instrument for assessment of work technique in patient transfer tasks

The aim of the study was to construct an observation instrument for description and assessment of nursing personnel's work technique in patient transfer tasks with regard to musculoskeletal health and safety, and to evaluate the validity and reliability of the instrument. The instrument consists of 24 items arranged in three phases of a transfer: the preparation phase, the starting position and the actual performance. Observations are made from video recordings. A detailed description of the individual's work technique, including actions taken to prepare the transfer, the interaction with the patient and any assistant co-worker, and the motor performance of the nurse, is provided. An attempt was made to quantify the assessments, by calculating an overall score of the work technique with regard to the level of musculoskeletal hazard and safety. The validity and reliability of the instrument were evaluated on 35 video-recorded patient transfers from hospital wards. The validity and reliability were mostly satisfactory, both when evaluating the agreements between the observations of each item (i.e. kappa values > 0.40), and when evaluating the agreements between the overall scores (i.e. intraclass correlation coefficients 0.71-0.90). Further improvements to enhance the agreements are suggested.

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.

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.

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.