Intramembranous fine deposit disease associated with collagen disorders: a new morphological entity?

Summary A distinct, hitherto unknown renal histopathological appearance, consisting of diffuse thickening of the glomerular basement membrane (GBM) with fine intramembranous electron-dense deposits, was observed in the renal biopsies from three patients with collagen diseases. In each case, proteinuria was mild with normal urinary sediment. On light microscopy there were no particular abnormalities but a mild thickening of the glomerular capillary wall. Immunofluorescence studies revealed faint linear or extremely fine granular IgG deposition along the capillary wall. On electron microscopy, the GBM was diffusely thickened with fine intramembranous electron-dense deposits without spike formation. No other deposits were seen in the glomerulus. These histological features resembled those of membranous glomerulonephritis (MGN), although the possibility of the early change of MGN is excluded by specific findings in these cases. Other GBM-thickening diseases such as diabetic glomerulosclerosis were ruled out clinically and histologically. Our cases have a singular renal histopathology which differs from any of the previously established classifications of glomerular lesions. It may be a specific change associated with some type of collagen disease.     

Fibroblasts from recurrent fibrotic overgrowths reveal high rate of proliferation in vitro - findings from the study of hereditary and idiopathic gingival fibromatosis

ABSTRACT

Purpose: Investigate the content of fibrotic fibrils in gingival tissue and the proliferation of fibroblasts collected from recurrent and non-recurrent hereditary gingival fibromatosis (HGF) and idiopathic gingival fibromatosis (IGF).

Methods: Gingival biopsies were collected from HGF (n = 3) and IGF (n = 3) donors with recurrent and non-recurrent gingival overgrowths and from a control group (Ctrl, n = 3). Hematoxylin staining was performed to evaluate the histomorphology of gingival tissue. Heidenhain’s AZAN trichrome staining served for visualization of fibrotic fibrils in gingiva. Quantitative analysis of the content of fibrotic fibrils in gingival tissue was performed using a polarized light microscope. Proliferation was evaluated at 24 h, 48 h, and 72 h in fibroblast cultures using a cell proliferation ELISA assay based on 5-bromo-2?-deoxyuridine (BrdU).

Results: Numerous blood vessels and fibroblasts were observed in recurrent overgrowths, whereas moderate blood vessels and moderate to scanty fibroblasts were detected in non-recurrent overgrowths. Heidenhain’s staining revealed numerous collagen fibers in both recurrent and non-recurrent overgrowths. Quantitative analysis in a polarizing microscope showed significant accumulation of fibrotic fibrils exclusively in the overgrowths with the recurrence. In all time-points, increased proliferation of cells from all recurrent overgrowths was observed, but not from overgrowths which do not reoccur.

Conclusions: The study revealed that recurrent gingival overgrowths consist of highly fibrotic and dense connective tissue with numerous blood vessels and abundant fibroblasts. We also demonstrated that unlike fibroblasts derived from overgrowths, which did not present recurrence, fibroblasts derived from highly fibrotic and recurrent overgrowths maintain high rate of proliferation in vitro.     

Age-related changes in the articular cartilage of human sacroiliac joint

 Iliac and sacral articular cartilage of 25 human sacroiliac joints (1–93 years) are examined by light microscopy and immunohistochemistry in order to gain further insight into the nature and progress of degenerative changes appearing during aging. These changes can already be seen in younger adults as compared to cartilage degeneration known in other diarthrodial joints. Structural differences between sacral and iliac cartilage can already be observed in the infant: the sacral auricular facet is covered with a hyaline articular cartilage, reaching 4 mm in thickness in the adult and staining intensely blue with alcian blue at pH1. Iliac cartilage of the newborn is composed of a dense fibrillar network of thick collagen bundles, crossing each other at approximately right angles. A faint staining with alcian blue suggests a low content of acidic glycosaminoglycans. In the adult, iliac cartilage becomes hyaline and its maximal thickness reaches 1–2 mm. Both articular facets exhibit morphological changes during aging that are more pronounced in the iliac cartilage and resemble osteoarthritic degeneration; the staining pattern of the extracellular matrix becomes inhomogenous, chondrocytes are arranged in clusters and the articular surface develops superficial irregularities and fissures. Sometimes fibrous tissue fills up these defects. Nevertheless, large areas of iliac cartilage remain hyaline in nature. Sacral articular cartilage often remains largely unaltered until old age. The sacral subchondral bone plate is usually thin and shows spongiosa trabeculae inserted at right angles, suggesting a perpendicular load on the articular facet. Iliac subchondral spongiosa shows no definite alignment and joins the thickened subchondral bone plate in an oblique direction. The iliac cartilage therefore seems to be stressed predominantly by shearing forces, arising from the changing monopodal support of the pelvis during locomotion. The subchondral bone plate on both the iliac and sacral auricular facet is penetrated by blood vessels that come into close contact with the overlying articular cartilage. These vessels may contribute to the high incidence of rheumatoid and inflammatory diseases in the human sacroiliac joint. Immunolabelling with an antibody against type II collagen reveals a diminished immunoreactivity in the upper half of adult sacral cartilage and only a faint and irregular labelling in the iliac cartilage. Type I collagen can be detected in a superficial layer on the sacral articular surface and around chondrocyte clusters in iliac cartilage, as in dedifferentiating chondrocytes during the development of osteoarthritis. Accepted: 22 April 1998     

Proliferation and Osteogenic Differentiation of Mesenchymal Stem Cells Cultured onto Three Different Polymers <Emphasis Type="Italic">In Vitro</Emphasis>

In this study, the osteoinductive and cell-binding properties of three different resorbable polymers were evaluated by human mesenchymal stem cells (MSCs). MSCs were isolated, expanded, and cultivated onto resorbable D,D,L,L-polylactide (PLLA), collagen I/III, and polygalactin-910/polydioxanone (PGPD) scaffolds in vitro. To evaluate the influence of dexamethasone, ascorbic acid, and beta-glycerolphosphate (DAG) on osteoblast differentiation, MSCs were incubated in a DAG-enriched medium. After a 28-day period in vitro, the cellular loaded polymers were digested enzymatically by papain and HCl. The Ca(2+) content of the biomembranes was evaluated by an o-kresolphthalein-complexon reaction via photometer. A PicoGreen assay was performed for dsDNA quantification. Significant differences between the number of adherent MSCs were documented (collagen > PLLA > PGPD). Compared to the initial number of adherent cells, all biomaterials induced a significant decrease in cellular adherence after 28 days in vitro. The presence of DAG-enriched culture medium stimulated the cellular proliferation for PLLA and slightly for PGPD, whereas cell proliferation was inhibited when MSCs were cultivated onto collagen I/III. In comparison with the control groups, all biomaterials (PLLA, PGPD, and collagen I/III) showed a significant increase in local Ca(2+) accumulation under DAG stimulation after 28 days in vitro. Furthermore, collagen I/III and PLLA scaffolds showed osteoinductive properties without DAG stimulation. These results were verified by immunocytochemical stainings against osteoblast-typical markers (osteopontin and alkaline phosphatase) and completed by calcified matrix detection (von Kossa staining). MSCs were identified by CD105 and CD13 antigen expression. Corresponding to an absence of CD34, CD45, and collagen II expression, we found no chondrogenic or hematopoietic cell differentiation. The results indicate significant differences for the proliferation, differentiation, adherence, and Ca(2+) accumulation between the tested polymers in a MSC culture.     

FT-IR study for hydroxyapatite/collagen nanocomposite cross-linked by glutaraldehyde

FT-IR analysis was performed for the hydroxyapatite (HAp)/collagen (COL) nanocomposite cross-linked by glutaraldehyde (GA). The amide bands I, II and III from COL matrix, and phosphate and carbonate bands from HAp were identified. The amide B band arising from C–H stretching mode showed a sensitive conformation by the degree of cross-linking. The amide I band showed a complicate conformational change by the degree of cross-linking. The characteristic amide I band at 1685 cm⁻¹, which is known as an aging parameter in the biological bone, did not show a monotonous tendency by the degree of cross-linking. The relative contents of the organics in the cross-linked HAp/COL nanocomposite were evaluated as an integration ratio between the amide I band at 1600–1700 cm⁻¹ and PO₄³⁻ band at 900–1200 cm⁻¹. The increase of the organics content by the cross-linking is enabled by the further organization of Ca²⁺ ions of HAp crystals in HAp/COL nanocomposite. The complicate conformational behavior in the amide I, II and III bands seems to be affected by the cross-linking induced directional arrangement of HAp/COL nanocomposite fibrils.     

Scanning electron microscopic studies of reticular framework in the rat mesenteric lymph node

Background: The reticular framework in the lymph node has in the past been studied mainly by light microscopy of silver-impregnated specimens. The aim of the present study is to understand three-dimensionally the ultrastructure and organization of the reticular framework better than before. Methods: The mesenteric lymph nodes of the rat were prepared either an alkali-water maceration method or a conventional method and were observed in a scanning electron microscope (SEM). Results: The SEM study of alkali-water macerated tissues visualized directly the reticular fiber network in the lymph node. The reticular fibers consisted of thin bundles of collagem fibrils. They were continuous with the collagen fibriliar sheaths of blood vessels and lymphatic sinuses as well as with the fibrous capusule, thus acting as a skeleton of the lymph node. The arrangement of the reticulum was variable, depending on individual compartments. The SEM study of conventionally treated tissues, on the other hand, clarified the shape of reticular cells and their relationship with the reticular fibers. The sinus reticular cells connected with the sinus lining cells but separated from the parenchymal reticular cells, indicating that the former two originate from lymphatic endothelial cells. The parenchymal reticular cells varied in shape depending on their locations but essentially shared features with fibroblasts. Conclusions: The arrangements of the reticular fibers in the parenchyma were closely related to the associated reticular cells, showing the possibility that the reticular cells maintain the shape of the reticular framework suitable for each compartment of the lymph node. © 1995 Wiley-Liss, Inc.     

Age- and training-related changes in the collagen metabolism of rat skeletal muscle

Summary The effects of ageing and life-long endurance training on the collagen metabolism of skeletal muscle were evaluated in a longitudinal study. Wistar rats performed treadmill running 5 days a week for 2 years. The activities of collagen biosynthesis enzymes, prolyl-4-hydroxylase and galactosylhydroxylysyl glucosyltransferase, were highest in the muscles of the youngest animals, decreased up to the age of 2 months and from then on remained virtually unchanged. The enzyme activity in young animals was higher in the slow collagenous soleus muscle than in the rectus femoris muscle. The enzyme activity in the soleus muscle was higher for older trained rats than older untrained rats. The relative proportion of type I collagen increased and that of type III collagen decreased with age, suggesting a more marked contribution by type I collagen to the agerelated accumulation of total muscular collagen. The results show that collagen biosynthesis decreases with maturation and that life-long endurance training maintains a higher level of biosynthesis in slow muscles.     

中药赤芍对球囊损伤术后血管重构的干预研究

目的 观察中药赤芍防止球囊损伤术后血管重构作用。方法 新西兰白兔随机分为对照组、单纯高脂组、赤芍高剂量组、低剂量组。高脂喂养6周建立动脉粥样硬化模型,行颈动脉球囊损伤术,8周时取材作病理形态学检查。结果(1)与高脂组比较,赤芍高、低剂量组增生内膜面积、中层面积,内膜、中膜、外膜PCNA阳性着色均显著减少(P<0.05或P<0.01)。(2)各组内皮增生成分主要为平滑肌细胞;巨噬细胞阳性着色主要分布在外膜,与高脂组比较,赤芍高、低剂量组阳性着色较少。(3)高脂组动脉损伤侧外膜Ⅰ型胶原增多,赤芍组Ⅰ型胶原增加较少。结论 赤芍对高脂喂养兔颈动脉球囊损伤术后血管重构有显著防止作用。     

类风湿性关节炎患者关节滑膜液浸润的T细胞表达特性

目的 :为研究类风湿性关节炎 (RA)患者关节滑膜液浸润的淋巴细胞介导自身免疫病的特性 ,分析了 2 2例RA患者滑膜液中淋巴细胞的免疫表型、对II型胶原的反应频率及IL 10、IL 12的分泌格局。方法 :用流式细胞术分别测定滑膜液和外周血淋巴细胞表型 ,并采用国际标准半有限稀释法分析了关节滑膜液中浸润的淋巴细胞对II型胶原 (CII)的反应频率 ,同时用ELISA方法检测了滑膜液与外周血中IL 10与IL 12含量。结果 :滑膜液中的T淋巴细胞的表型分别为CD4 (39 6 %±10 5 % )和CD8细胞 (36 4 %± 16 4 % ) ,CD4 CD8细胞比值显著低于外周血 ,且同时表达CD16和CD5 6的活化NK细胞占15 5 %± 11 1%。T细胞受体谱取用表明仍以αβTCR为主 (6 9 6 %± 15 7% )。有意义的是 :滑膜液中的T细胞对CII的反应频率为 15 2× 10 - 6 ,远远高于外周血 (4 0× 10 - 6 )。IL 12含量为 (4 19 9± 89 2 )pg ml,IL 10含量为 (187 7± 34 5 )pg ml,与外周血中这 2种细胞因子的含量〔分别为IL 12 :(6 5 32± 34 2 )pg ml和IL 10 :(85± 12 7)pg ml〕比较 ,具有显著的统计学差异。结论 :上述实验结果表明这种具有表达特性的浸润T细胞介导了RA患者关节滑膜组织的免疫损伤。     

Functional associations between collagen fibre orientation and locomotor strain direction in cortical bone of the equine radius

A novel technique for determining the collagen fibre orientation pattern of cross-sections of cortical bone was used to study mid-diaphyseal sections from the equine radius. Several in vivo strain gauge studies have demonstrated that this bone is loaded in bending during locomotion in such a way that the cranial cortex is consistently subjected to longitudinal tensile strains and the caudal cortex to longitudinal compressive strains. Twenty-three radii from 17 horses were studied. All the bones obtained from adult horses exhibited a consistent pattern of collagen fibre orientation across the cortex. The cranial cortex, subjected to intermittent tension, and the lateral and medial cortices, through which the neutral axis passes, contained predominantly longitudinally oriented collagen fibres. The caudal cortex, subjected to longitudinal compression during life, contained predominantly oblique/transverse collagen. This pattern was less evident in bones from foals. Microscopic analysis of the bones studied showed that primary lamellar bone was composed of predominantly longitudinal collagen fibres, irrespective of cortex. However, there was a strong relationship between cortical location and fibre orientation within remodelled bone. Secondary osteons which formed in the caudal (compressive) cortex contained predominantly oblique/transverse collagen, while those which formed elsewhere contained longitudinal collagen. This observation explained the developmental appearance of the characteristic macroscopic pattern of collagen fibre orientation across the whole cortex in the adult. These findings provide evidence for the existence of a relationship between the mechanical function of a bone with its architecture, and now demonstrate that it extends to the molecular level.