Interleukin-20 plays a critical role in maintenance and development of psoriasis in the human xenograft transplantation model.

BACKGROUND: Interleukin (IL)-20 is a recently discovered cytokine displaying increased levels in psoriatic lesions. Interestingly, IL-20 levels decrease with antipsoriatic treatment, correlating with clinical improvement. However, the role of IL-20 in the aetiology of psoriasis is unknown. OBJECTIVES: In this study, we investigate the effects both of blocking IL-20 signalling in psoriatic plaques and of adding IL-20 to nonlesional psoriasis skin. METHODS: We employed the human skin xenograft transplantation model in which psoriatic plaques and nonlesional keratome skin biopsies obtained from donors with moderate to severe plaque psoriasis were transplanted on to immuno-deficient mice. The transplanted mice were treated with anti-IL-20 antibodies or recombinant human IL-20. RESULTS: We demonstrate that blocking IL-20 signalling with anti-IL-20 antibodies induces psoriasis resolution and inhibits psoriasis induction. We also demonstrate that continuous IL-20 infusion, together with injection of additional nonactivated leucocytes, promotes induction of psoriasis in nonlesional skin from patients with psoriasis. CONCLUSIONS: The results suggest that IL-20 plays a critical role in the induction and maintenance of psoriasis, and IL-20 is suggested as a new possible specific target in psoriasis treatment.

Regulation of GAD expression in rat pancreatic islets and brain by gamma-vinyl-GABA and glucose.

Glutamic acid decarboxylase (GAD) is an important autoantigen in insulin-dependent diabetes mellitus (IDDM), but little is known about its regulation and function in islet cells. We investigated the effects of the GABA-transaminase inhibitor gamma-vinyl-GABA (GVG) on GAD expression in rat islets and brain in vitro and in vivo. In islets incubated in high glucose culture medium there was an increase in GAD activity, GAD65 and GAD67 protein levels compared to low-glucose conditions; however, even in high glucose, GVG still significantly suppressed GAD activity and GAD67 expression. Our observations suggest that glucose and GVG act on GAD in islets through different mechanisms. Quantitative immunohistochemistry of pancreatic sections from rats treated with GVG in vivo using novel monoclonal antibodies specific for GAD65 and GAD67, showed a decrease in GAD67 expression (p < 0.005) relative to untreated rats. The effects of GVG on rat pancreatic islets were very similar to those observed in brain of rats treated with GVG in vivo. In homogenates of cerebral tissue from GVG treated rats containing both membrane-bound and soluble protein GAD67 levels were significantly decreased while GAD65 levels were not significantly changed compared to untreated rats. In contrast, in homogenates of cerebral tissues containing only soluble cytosolic protein, GVG-treatment was also significantly found to decrease GAD65 levels. Taken together, these results suggest that GVG potentially could be of use to decrease GAD expression in islet cells and consequently to deviate/inhibit the autoimmune response against the beta cells seen in IDDM.

Effects of heparin and aminoguanidine on glomerular basement membrane thickening in diabetic rats.

The effects of heparin and aminoguanidine on glomerular basement membrane thickening were studied in streptozotocin diabetic Sprague-Dawley rats. A placebo-treated group and a non-diabetic group served as controls. All diabetic rats remained severely hyperglycaemic (23 mmol/l) throughout the 8-month study period. At the end of this time relative kidney weight was significantly increased in diabetic control rats (4.9 +/- 0.5 g/kg b.w.) compared with non-diabetic rats (3.3 +/- 0.3 g/kg). This increase was not affected by the intervention treatments. Glomerular basement membrane thickness increased 32% in diabetic control rats (240 +/- 24 nm) compared with non-diabetic rats (182 +/- 20 nm). This increase was prevented by s.c. treatment with both unfractionated and low molecular weight heparins, while basement membrane thickness was the same in animals treated with oral heparins and aminoguanidine and untreated diabetic rats. Macroscopic malignant kidney tumours were seen in three aminoguanidine-treated rats. In conclusion, subcutaneously administered heparin prevents diabetes-induced glomerular basement membrane thickening.

Soluble, fatty acid acylated insulins bind to albumin and show protracted action in pigs.

We have synthesized insulins acylated by fatty acids in the epsilon-amino group of LysB29. Soluble preparations can be made in the usual concentration of 600 nmol/ml (100 IU/ml) at neutral pH. The time for 50% disappearance after subcutaneous injection of the corresponding TyrA14(125I)-labelled insulins in pigs correlated with the affinity for binding to albumin (r = 0.97), suggesting that the mechanism of prolonged disappearance is binding to albumin in subcutis. Most protracted was LysB29-tetradecanoyl des-(B30) insulin. The time for 50% disappearance was 14.3 +/- 2.2 h, significantly longer than that of Neutral Protamine Hagedorn (NPH) insulin, 10.5 +/- 4.3 h (p < 0.001), and with less inter-pig variation (p < 0.001). Intravenous bolus injections of LysB29-tetradecanoyl des-(B30) human insulin showed a protracted blood glucose lowering effect compared to that of human insulin. The relative affinity of LysB29-tetradecanoyl des-(B30) insulin to the insulin receptor is 46%. In a 24-h glucose clamp study in pigs the total glucose consumptions for LysB29-tetradecanoyl des-(B30) insulin and NPH were not significantly different (p = 0.88), whereas the times when 50% of the total glucose had been infused were significantly different, 7.9 +/- 1.0 h and 6.2 +/- 1.3 h, respectively (p < 0.04). The glucose disposal curve caused by LysB29-tetradecanoyl des-(B30) insulin was more steady than that caused by NPH, without the pronounced peak at 3 h. Unlike the crystalline insulins, the soluble LysB29-tetradecanoyl des-(B30) insulin does not elicit invasion of macrophages at the site of injection. Thus, LysB29-tetradecanoyl des-(B30) insulin might be suitable for providing basal insulin in the treatment of diabetes mellitus.

Surface exchange area of the porcine placenta: morphometry of anisotropic interdigitating microvilli.

The pig has a diffuse epitheliochorial placenta. The foeto-maternal surface area (Sv(F), Sv(M)) is enlarged at three levels: level I: macroscopic folds of uterine mucosa covered by foetal membranes; level II: light microscopic folds of uterine epithelium covered by trophoblastic epithelium; level III: ultrastructural formation of both maternal and foetal microvilli in an interdigitating pattern. This study presents a morphometric method, using intersection counting, to estimate the surface area of these interdigitating, highly oriented microvilli at level III, i.e. the 'true' surface exchange area. The method is applied to different stages in pregnancy. The epithelial surfaces are enlarged by a factor 8-11 due to the formation of microvilli. This factor varies during pregnancy, being lower early in gestation and before delivery, and for the first time it is shown to be significantly different for mother and foetus. At level III the foetal surface of placenta is larger than the maternal indicating that the two opposing surfaces are not congruent at the ultrastructural level and that membrane-linked placental transport may be different in mother and foetus. A three-compartment model is suggested for placental exchange with maternal, intermicrovillous and foetal compartments.

Occurrence of Pneumocystis carinii Delanoë & Delanoë, 1912 in dogs and cats in Denmark.

Lungs from 106 normal dogs and 75 normal cats were examined for Pneumocystis carinii by microscopy of toluidine blue O stained imprints. Pneumocysts were demonstrated in 1 dog and 3 cats. It is suggested that these animals may constitute a part of the natural reservoir for this parasite.

Perfusion in vivo of the porcine placenta. Fixation for EM.

A method for vascular perfusion in vivo, especially for EM fixation, was developed with the porcine placenta. The effect of fixation at varying parameters was studied. Nine multiparous Danish Landrace sows ranging in gestation from 33 to 112 days and in body weight from 160 to 257 kg were used. After general and local anaesthesia laparotomy was undertaken on the left flank and the uterine horn was perfused through a. uterina with buffered glutaraldehyde. Local perfusion through a. umbilicalis was undertaken in one case, and installation of concentrated glutaraldehyde into the allantoic cavity was performed in five cases. Perfusion-fixed and fresh tissue samples were fixed in OsO4 and processed for electron microscopy. The osmolarity of the buffer was varied between 470 and 660 mOsm. At high tonicity cytoplasm was well preserved but the intercellular spaces of the uterine epithelium was dilated. At about 575 mOsm the preservation was still good and the spaces were occluded. At lower tonicity damage occurred in the cytoplasm. The trophoblast was generally better preserved than the uterine epithelium. A rapid perfusion flow was beneficial for fixation.

An electron microscopic study of histiotrophe in the interareolar part of the porcine placenta.

Placentae from nine sows covering gestational stages from 33 to 112 days were examined by light and electron microscopy. Deeply stainable electron-dense histiotrophe was demonstrated in the interareolar placenta. Focal accumulations of cell debris with profiles of organelles were demonstrated in the intermicrovillous space between uterine epithelium and trophoblast. In addition, small expansions of amorphous histiotrophe were found between the microvilli. Furthermore, histiotrophe with profiles of cytomembranes was shown in intercellular spaces in columnar trophoblast between the microvillar border and tight junctions. Dense bodies were demonstrated in the uterine epithelium, and endocytic vesicles and branched tubular structures with dense contents were found in the columnar trophoblast. It is concluded that focal accumulations of cell debris are derived from degenerating epithelial cells in the endometrium and chorion, and that amorphous histiotrophe arises by secretory activity of uterine epithelium. It is further concluded that the histiotrophe is absorbed by columnar trophoblast of the chorionic fossae.

The heart production in energy-depleted human erythrocytes induced by glucose, inosine and adenine.

The heat production (HP) of glucose deprived human red blood cells was measured, using glucose, adenine and inosine as substrates. Inosine induced a significantly higher HP than glucose and adenine induced no significant HP. At low pH the HP of glucose decreased more than that of inosine, corresponding to an equally lowered lactate production. The results indicate that it should be possible to use the system developed to study the functional state both of the complete glycolytic system and the lower part of it in intact red blood cells during various clinical conditions.

Perfusion fixation of kidneys in adult pigs for electron microscopy.

In five female pigs, weighing approximately 100 kg, laparotomy was made under surgical anesthesia. One kidney was removed for immersion fixation and enzyme histochemistry, while the other kidney was fixed by vascular perfusion without prior interruption of the blood flow. A step-by-step description is given of the perfusion procedure, which requires three assistant. Prior to perfusion, heparin was given in order to prevent intravascular coagulation. 1% glutaraldehyde in Tyrode's solution was used as perfusion fluid. Polyvinylpyrrolidone 2.5% was added in order to adjust the colloid osmotic pressure of the perfusion fluid to that of the blood. Perfusion was maintained for 5 min. The tubules appeared with open lumina, and the proximal tubular cells had evenly arranged brush borders and both lateral and intercellular spaces were narrow and of constant width.