Torstein Hovig

Compstatin, a peptide inhibitor of C3, prolongs survival of ex vivo perfused pig xenografts

Fiane AE, Mollnes TE, Videm V, Hovig T, Høgåsen K, Mellbye OJ, Spruce L, Moore WT, Sahu A, Lambris JD. Compstatin, a peptide inhibitor of C3, prolongs survival of ex vivo perfused xenografts. Xenotransplantation 1999; 6: 000‐000 ©Munksgaard, Copenhagen

Argyria—tissue deposition of silver as selenide

Generalized argyria was precipitated in a patient by treating gingival erosions with a solution of silver nitrate for several months. High silver concentrations were measured in skin biopsies. treatment with penicillamine did not increase the urinary silver excretion, indicating that silver is deposited in tissues in a chemically stable and apparently inert form. Electron microscopy showed that in the kidney, silver was deposited mainly in the basal membranes as electron-dense particles. These particles were studied by using X-ray emission spectrometry and electron diffraction. the particles consisted of Ag2Se in the low temperature orthorhombic alfaform. The lattice parameters are: a = 0.433 nm, b = 0.693 nm and c = 0.784 nm. This selenide complex seems to be remarkably non-toxic, since the renal function of the patient was unaffected and only negligible reactive changes were observed in kidney biopsies.

Complement activation in early protocol kidney graft biopsies after living-donor transplantation1

Background. To gain insight into complement activation in kidney grafts, we studied the deposition of components from all complement pathways in protocol biopsies from living-donor recipients that were taken 1 week (median 7 days) after transplantation. Methods. Graft protocol biopsies (n=37) were taken consecutively and stained for two-color immunofluorescence, with antibodies to C4d, C3, C1q, factor B, C6, terminal C5b-9 complement complex, mannose-binding lectin (MBL), and MBL-associated serine protease-1, combined with an endothelial marker. Light and electron microscopy were performed in all cases. Clinical acute rejection (AR), graft loss, and long-term kidney function were recorded. Baseline biopsies from 15 of the patients served as controls. Results. Endothelial C4d deposition was demonstrated in peritubular capillaries in 11 of 37 cases (30%), of which 9 of 11 (82%) experienced clinical AR but only 6 of 11 (55%) experienced AR as defined by histopathologic criteria. Biopsies from three patients, two with early graft loss, showed diffuse global C4d in the glomerular endothelium with codeposition of C3 in all patients and MBL-associated serine protease-1 in one patient. Focal peritubular capillary C3 deposition was found in two additional C4d-positive cases with AR. No posttransplant deposition was demonstrated for the other components. Conclusions. Early diffuse C4d deposition in the kidney graft capillaries is closely related to acute humoral rejection, whereas focal staining may occur with mild AR or, rarely, without rejection. Codeposition of C3 indicates early AR with a higher risk of graft loss. In most cases, activation was limited to C4d, indicating efficient in situ regulation of complement activation.

Formation of prostanoids in human umbilical vessels perfused in vitro.

Four major prostanoids (6-keto-PGF1 alpha, PGE2, PGF2 alpha and TXB2) were measured by specific radioimmunoassays in the outputs from human umbilical vessels perfused in vitro. As evaluated by scanning electron microscopy (SEM) only few blood platelets were attached to the vessel wall. After an initial flush with decreasing concentrations of all four prostanoids, a stable stage was reached, lasting for 4-5 hours. During this stage the production could be inhibited by indomethacin and only slightly stimulated with arachidonic acid. The TXA2 synthetase inhibitor UK 38485 depressed the TXB2 production, while only slightly affecting the other three prostanoids at very high concentrations. The arteries produced relatively more 6-keto-PGF1 alpha than did the vein.

Glomerular monocyte/macrophage influx correlates strongly with complement activation in 1-week protocol kidney allograft biopsies.

BACKGROUND The specific role of monocytes/macrophages (MO) in kidney graft rejection is not yet fully elucidated. In a recent protocol biopsy study of living-donor recipients, we demonstrated massive capillary influx of MO, associated with severe complement activation and acute rejection (AR) 1 week after transplantation [Sund et al.]. To gain further insight into the possible relationship between MO and complement activation, we analyzed glomerular and interstitial MO in these biopsies. METHODS Twenty-seven protocol biopsies were stained with antibodies to calprotectin (L1) and CD68 as markers for MO. Cells were counted as an average number per glomerulus and as an average number per defined visual field in the interstitium. Polymorphonuclear leukocytes (PMN) were counted in glomeruli and interstitium by light microscopy. Baseline specimens from 10 of the patients served as controls. The results were compared with data on deposition of complement from the foregoing study, and with histopathologic and clinical data on AR. RESULTS Cases with diffuse C4d deposition in peritubular capillaries consistent with acute antibody-mediated rejection (AbAR) (n = 4) had significantly higher numbers of intraglomerular MO than the other protocol biopsies (L1: median 20.7 vs 3.6, p = 0.0002; CD68: median 10.1 vs. 2.0, p = 0.0008). With a cut-off of 10 L1-positive and 6 CD68-positive MO, the specificity for the diagnosis of AbAR was 96% and 91%, respectively. The number of interstitial MO was significantly higher in patients with AR than in those without, but in contrast to glomerular MO, interstitial MO could not discriminate between complement positive and negative AR. The number of glomerular and interstitial PMNs was significantly higher in the AbAR group than in the other protocol biopsies. CONCLUSIONS The strong correlation between complement activation and early glomerular influx of MO in the kidney allograft suggests a causal relationship between these 2 events. At 1 week after transplantation, a number of 10 L1-positive and 6 CD68-positive MO per glomerulus indicates AbAR.

Prolongation of Ex Vivo-Perfused Pig Xenograft Survival by the Complement Inhibitor Compstatin

HE COMPLEMENT system has been shown to play a central pathophysiologic role in hyperacute rejection (HAR) 1 and to contribute to the inflammation and organ injury associated with transplantation. 2 Recently, a novel phage-displayed C3-binding peptide (Compstatin) has been identified that suppresses complement activation and therefore may be of therapeutic value in clinical situations such as xenotransplantation that involve complement-mediated tissue damage. This peptide binds reversibly to the C3c portion of native C3 and inhibits both the classical and alternative pathways of complement activation. 3 Our results

Attachment, spreading and growth in vitro of highly malignant and low malignant murine fibrosarcoma cells

Highly malignant cell lines and low-malignant cell lines isolated from three different methylcholanthrene-induced murine fibrosarcomas were examined for their ability to attach to plastic dishes and collagen-coated dishes under serumfree conditions and in the presence of serum. Most of the cells from the three highly malignant lines attached and spread under all conditions. By 72h, there was a significant increase in the number of cells indicating that at least some of the cells had undergone division (even in the absence of serum). In contrast, fewer of the cells from the three low-malignant lines attached and spread on the plastic or collagen substrates in the absence of serum or in the presence of 0.1 per cent serum. However, when 15μg laminin per dish was added along with the lowmalignant cells, they then attached and spread on the plastic and collagen-coated dishes. Previous studies have indicated that the highly malignant lines express cell surface antigens that cross-react with laminin while the low-malignant cell lines do not. We speculate that the differences between the high- and low-malignant cells in the expression of cell surface laminin-like antigens contribute to the dissimilarities in attachment and spreading capacity. These differences may also contribute to the dissimilarity between these cells in malignant potential.

Familial Lecithin: Cholesterol Acyltransferase Deficiency: Ultrastructural Studies on Lipid Deposition and Tissue Reactions

Ultrastructural observations of biopsy material from three patients with LCAT deficiency revealed characteristic deposition of membranes and membrane-bound vesicles or particles in the kidneys, spleen, liver, aorta, and muscular arteries. The deposited material, which it is suggested is composed of phospholipids and cholesterol, was in the kidneys observed especially in the glomeruli, both within the capillary lumina, the capillary wall, and in mesangial regions. In the liver it was noted especially in perivascular regions. Phagocytic cells in the spleen and Kuppfer cells of the liver contained numerous granules often composed of membranes, or vacuoles surrounded by layered membranes. It is suggested that the reticuloendothelial system may take up pathological lipoproteins, resulting in abnormal storage of lipids. Furthermore, filtration of the lipoproteins into the vessel wall may occur, and vascular damage may be a part of the LCAT-deficiency syndrome.

Characterization of a new malignant human T-cell line (PFI-285) sensitive to ascorbic acid

Abstract: A new malignant human T‐cell line‐labelled PFI‐285‐has been isolated from a boy with malignant lymphoma. Morphologically, the cells had characteristics of malignant lymphoid cells. The cells presented surface antigens as early cortical lymphocytes and proliferated non‐adherently as single cells, independent of T‐cell growth factor (IL‐2), in liquid culture. The cells had undetectable levels of receptors for IL‐2, were not clonogenic in soft agar, but did form tumors in nude mice. Their establishment and continuous growth in vitro was dependent on the number of cells inoculated and on the growth medium used. Cytogenetic alteration, HTLV‐1 or reverse transcriptase activity were not detected. The production of known T‐cell derived lymphokines such as IL‐2, B‐cell growth factor(s), α‐interferon or granulocyte/macrophage colony stimulating or inhibiting factor(s) was not detected. The cells had 5–8% natural killer (NK)‐cell activity against NK‐cell sensitive target cells (K562) and were not sensitive for NK cells. A most unusual characteristic was the pronounced sensitivity of the cells to ascorbic acid. Concentrations down to 50 μmol/l killed the cells within hours.

Peritoneal, benign, cystic mesothelioma with free-floating cysts, re-examined by new methods

A histologically‐confirmed, multicystic, benign mesothelioma, with free‐floating, thin‐walled cysts, in the abdominal cavity of a 27‐year‐old woman was reported in 1954. After removal of all visible cysts by laparotomy, the patient was healthy and well for 29 years, when she was surgically treated for cholecystitis and gall bladder stones in 1982. The whole peritoneum was found covered with small cysts lined by mesothelial cells. The patient is (April 1987) well, with no complaints. Sections from the old paraffin blocks were studied by means of scanning, transmission electron microscopy and immunohistochemistry. These methods confirmed the histological diagnosis. The authors discuss whether such a lesion really is a benign tumor or should rather be otherwise classified.