SIRT1: an Intermediator of Key Pathways Regulating Pulmonary Diseases

Silent information regulator type-1 (SIRT1), a nicotinamide adenine dinucleotide+ (NAD+)-dependent deacetylase, is a member of the sirtuins family and has unique protein deacetylase activity. SIRT1 participates in physiological as well as pathophysiological processes by targeting a wide range of protein substrates and signalings. In this review, we describe the latest progress of SIRT1 in pulmonary diseases. We introduce the basic information and summarize the prominent role of SIRT1 in several lung diseases, such as acute lung injury, acute respiratory distress syndrome, chronic obstructive pulmonary disease, lung cancer, and aging-related diseases.

[Epidemiological characteristics and analysis of related infection risk factors for influenza in Anhui Province from 2013 to 2021]

Objective: Analysis of the characteristics of influenza epidemic in Anhui Province and quantification of the impact of different factors on influenza occurrence, providing scientific basis for better influenza prevention and control. Methods: Descriptive analysis and factor analysis were conducted on influenza-like illness (ILI) cases and RT-PCR results in Anhui Province from 2013 to 2021 using data from China's Influenza Monitoring Information System. Results: The percentage of influenza-like illness (ILI%) of sentinel hospitals in Anhui Province from April 1, 2013 to March 31, 2021 was 3.80% (1 209 142/31 779 987), showing an overall increasing trend, with a relatively high proportion in 2017-2018 at 4.30% (191 148/4 448 211). The proportion of ILI cases in infants and young children aged 0-4 years was a relatively high at 54.14% (654 676/1 209 142), and the highest ILI% was observed in Fuyang City, Anhui Province (6.25%, 236 863/3 788 863). Laboratory monitoring results showed that the positive rate of ILI cases in sentinel hospitals in 8 influenza monitoring years was 16.38% (34 868/212 912), showing an increasing trend year by year, with a relatively proportion in 2017-2018 at 26.19% (6 936/26 488). The detection rate of school-age children aged 5-14 years was a relativelyhigh at 28.81% (13 869/48 144), and the positive rate was a relatively high in Wuhu City among the 16 cities, reaching 22.01% (2 693/122 237). Influenza activity showed a single peak in winter-spring and alternating double peaks in winter-spring and summer, with different subtypes alternating, and A (H3N2) was the dominant subtype in summer. The results of a multiple logistic regression model showed that the positive rate was higher in 2017-2018, among children aged 5-14 years, in winter, and in southern Anhui. Conclusions: Influenza epidemic in Anhui Province has a clear seasonal pattern, and the ILI% and detection rate have shown an upward trend from 2013 to 2021. Therefore, it is suggested to ensure vaccine supply before the winter-spring influenza season arrives, and to strengthen vaccine uptake and health education to avoid the risk of infection during the peak period of influenza.

[Investigate the expression of miRNA-203 in papillary thyroid carcinomaand its effect on cell proliferation]

Objective:To investigate the expression of miRNA-203 in papillary thyroid carcinoma（PTC）tissues and its correlation with clinical pathological parameters，explore its effect on cell proliferation of WRO cell. Method:Thirty cases of PTC tissues, paired normal tissues were collected in our hospital during 2013-2016. The expression of miRNA-203 was determined by qRT-PCR，then the relationship of miRNA-203 expression, clinical pathological parameters were analyzed.WRO cells were transfected with miRNA-203 mimics, then cell proliferation, cell cycle and concerned cyclin protein(CyD1,CyB1) were tested by MTT, flow cytometry and western blot. Result:Compared to the paired normal tissues，tumor tissues showed sifnificantly lower expression of miRNA-203. Upregulaion of miRNA-203 in WRO cells effectively reduced cell growth, G₂/M arrest. Mechanistically,in the miRNA-203-mimics-treated groups,cell-cycle-related proteins cyclin B1 was up-regulated, while cyclin D1 was down-regulated. Conclusion:miRNA-203 may play an anticarcinogenic effect in PTC. Upregulation of miRNA-203 is highly correlated with cell prolliferation, and maybe miRNA-203 is a potential targert for the treatment of thyroid carcinoma.

Expression profile of macrophage migration-inhibitory factor in human gingiva and reconstituted human gingival epithelia stimulated by Porphyromonas gingivalis lipopolysaccharide

BACKGROUND AND OBJECTIVE

Macrophage migration-inhibitory factor (MIF) plays crucial roles in the recruitment and activation of macrophages as well as in helping to kill bacteria. This study investigated the expression profile of MIF in human gingiva under different periodontal conditions and its expression patterns induced by Porphyromonas gingivalis lipopolysaccharide (LPS) in gingival epithelia.

MATERIAL AND METHODS

Gingival tissue samples were collected from deep pockets and clinically healthy sites of 22 nonsmoking subjects with chronic periodontitis. The expression of MIF mRNA and protein was evaluated using real-time PCR and immunohistochemistry, respectively. The in vitro study analyzed the effects of P. gingivalis LPS on the expression of MIF in a reconstituted human gingival epithelia (RHGE) model.

RESULTS

In gingival epithelia, MIF protein was diffusely expressed from the basal layer to the granular and spinous layers; whereas, in the underlying connective tissues, MIF was observed around the dilated blood vessels in the deep-pocket tissues. A significantly lower level of expression of MIF mRNA and an increased level of expression of MIF protein were found in deep-pocket tissues compared with clinically healthy tissues. Expression of MIF mRNA in the RHGE model was significantly down-regulated by P. gingivalis LPS.

CONCLUSION

The present study suggests that MIF expression may be related to periodontal conditions and that its expression profile could be modulated by P. gingivalis LPS. MIF may play a role in periodontal pathogenesis.

Multicavity x-ray Fabry-Perot resonance with ultrahigh resolution and contrast

Realization of x-ray Fabry-Perot (FP) resonance in back-Bragg-reflection crystal cavities has been proposed and explored for many years, but to date no satisfactory performance has been achieved. Here we show that single-cavity crystal resonators intrinsically have limited finesse and efficiency. To break this limit, we demonstrate that monolithic multicavity resonators with equal-width cavities and specific plate thickness ratios can generate ultrahigh-resolution FP resonance with high efficiency, steep peak tails, and ultrahigh contrast simultaneously. The resonance mechanism is similar to that of sequentially cascaded single-cavity resonators. The ultranarrow-bandwidth FP resonance is anticipated to have various applications, including modern ultrahigh-resolution or precision x-ray monochromatization, spectroscopy, coherence purification, coherent diffraction, phase contrast imaging, etc.

Kidney-targeting Smad7 gene transfer inhibits renal TGF-β/MAD homologue (SMAD) and nuclear factor κB (NF-κB) signalling pathways, and improves diabetic nephropathy in mice

AIMS/HYPOTHESIS

The TGF-β/MAD homologue (SMAD) and nuclear factor κB (NF-κB) signalling pathways have been shown to play a critical role in the development of renal fibrosis and inflammation in diabetic nephropathy. We therefore examined whether targeting these pathways by a kidney-targeting Smad7 gene transfer has therapeutic effects on renal lesions in the db/db mouse model of type 2 diabetes.

METHODS

We delivered Smad7 plasmids into the kidney of db/db mice using kidney-targeting, ultrasound-mediated, microbubble-inducible gene transfer. The histopathology, ultrastructural pathology and pathways of TGF-β/SMAD2/3-mediated fibrosis and NF-κB-dependent inflammation were evaluated.

RESULTS

In this mouse model of type 2 diabetes, Smad7 gene therapy significantly inhibited diabetic kidney injury, compared with mice treated with empty vectors. Symptoms inhibited included: (1) proteinuria and renal function impairment; (2) renal fibrosis such as glomerular sclerosis, tubulo-interstitial collagen matrix abundance and renal inflammation, including Inos (also known as Nos2), Il1b and Mcp1 (also known as Ccl2) upregulation, as well as macrophage infiltration; and (3) podocyte and endothelial cell injury as demonstrated by immunohistochemistry and/or electron microscopy. Further study demonstrated that the improvement of type 2 diabetic kidney injury by overexpression of Smad7 was associated with significantly inhibited local activation of the TGF-β/SMAD and NF-κB signalling pathways in the kidney.

CONCLUSIONS/INTERPRETATION

Our results clearly demonstrate that kidney-targeting Smad7 gene transfer may be an effective therapy for type 2 diabetic nephropathy, acting via simultaneous modulation of the TGF-β/SMAD and NF-κB signalling pathways.

C-reactive protein promotes diabetic kidney disease in a mouse model of type 1 diabetes

AIMS/HYPOTHESIS

Although C-reactive protein (CRP) has been implicated as a risk factor in diabetes, its pathogenic importance in diabetic kidney disease (DKD) remains unclear. The present study investigated the potential role of CRP in DKD.

METHODS

Diabetes was induced by streptozotocin in human CRP transgenic and wild-type mice for assessment of kidney injury at 24 weeks by real-time PCR, immunohistochemistry and western blot analysis. In vitro, the pathogenic effect of CRP was investigated using human kidney tubular epithelial cells cultured with high glucose and/or CRP.

RESULTS

We found that CRP transgenic mice developed much more severe diabetic kidney injury than wild-type mice, as indicated by a significant increase in urinary albumin excretion and kidney injury molecule-1 abundance, enhanced infiltration of macrophages and T cells, and upregulation of pro-inflammatory cytokines (IL-1β, TNFα) and extracellular matrix (collagen I, III and IV). Enhanced renal inflammation and fibrosis in CRP transgenic mice was associated with upregulation of CRP receptor, CD32a, and over-activation of the TGF-β/SMAD and nuclear factor κB signalling pathways. In vitro, CRP significantly upregulated pro-inflammatory cytokines (IL-1β, TNFα, monocyte chemoattractant protein-1 [MCP-1]) and pro-fibrotic growth factors (TGF-β1, connective tissue growth factor [CTGF]) via CD32a/64. CRP was induced by high glucose, which synergistically promoted high glucose-mediated renal inflammation and fibrosis.

CONCLUSIONS/INTERPRETATION

CRP is not only a biomarker, but also a mediator in DKD. Enhanced activation of TGF-β/SMAD and nuclear factor κB signalling pathways may be the mechanisms by which CRP promotes renal inflammation and fibrosis under diabetic conditions.

Immunocapture UPPCR combined with DGGE for rapid detection of Shigella species

AIMS

To develop an immunocapture universal primer PCR (iUPPCR) combined with denaturing gradient gel electrophoresis (DGGE) and evaluate it as a method permitting rapid detection of Shigella species and their serotypes.

METHODS AND RESULTS

This method amplifying the conserved regions of bacterial 16S rRNA genes of different species or serotypes of Shigella dysentery bacilli captured and enriched by polyvalent antibodies can detect and distinguish causative pathogens rapidly. Four serotypes from three Shigella species including Shigella dysenteriae serotype 1, Shigella boydii serotype 1, Shigella flexneri serotypes 1a and 3a were examined.

CONCLUSION

Our approach could be adopted for not only axenic bacterial population but also mixed communities and achieve rapid detection of various bacteria from the same genus or species in one sample.

SIGNIFICANCE AND IMPACT OF THE STUDY

The iUPPCR-DGGE method was shown to be more convenient than serotype-specific-antibody-based method of iUPPCR for Shigella species detection and it could be also applied to the quick detection for other kinds of pathogens with many serotypes.

Polarization properties of the retinal nerve fiber layer

Recently developed optical techniques provide quantitative structural measurements of the retinal nerve fiber layer (RNFL). A complete interpretation of these measurements requires understanding of the optical properties of the RNFL. This paper gives a review of the polarization properties and relevant anatomy of the ocular tissues, followed by a thorough discussion of the optical properties of the RNFL. The RNFL reflectance arises from light scattering from cylinders. Microtubules are a major component contributing to the reflectance. The RNFL reflectance exhibits weak intrinsic diattenuation and well preserves polarization. RNFL birefringence varies across the retina; the variation suggests that birefringence depends on the ultrastructure of the nerve fiber bundles, which offers hope that measurement of RNFL birefringence may be able to provide early detection of subcellular changes in glaucoma.

Step-controlled strain relaxation in the vicinal surface epitaxy of nitrides

On-axis and vicinal GaN/AlN/6H-SiC structures grown under identical conditions have been studied by x-ray diffraction and transmission electron microscopy to demonstrate the distinctive features of vicinal surface epitaxy (VSE) of nitrides on SiC. In VSE, the epilayers are tilted from the substrate due to the out-of-plane lattice mismatch (Nagai tilts), and the in-plane mismatch strains are more relaxed. The majority of misfit dislocations (MDs) at the vicinal AlN/6H-SiC interface are found to be unpaired partial MDs that are geometrically necessary to correct the stacking sequences from 6H to 2H. This mechanism indicates that it is possible to develop "step-controlled-epitaxy" strategies to control strain relaxation by adjusting the substrate offcut angles.

Macrophage migratory inhibitory factor (MIF) expression in acute graft-versus-host disease (GVHD) in allogeneic hemopoietic stem cell transplant recipients

Graft-versus-host disease (GVHD) is a major complication after hemopoietic stem cell transplantation (HSCT), but its pathogenesis remains uncertain. Macrophage migratory inhibitory factor (MIF) is an important mediator in the allo-immune reaction during renal transplantation, yet its role in hemopoietic stem cell transplantation (HSCT) remains unexplored. This study investigated the potential role of MIF in acute graft-versus-host disease (aGVHD) following allogeneic HSCT. Forty-six randomly selected patients undergoing autologous or allogeneic HSCT were studied. Immunohistochemistry and in situ hybridization were performed to examine tissue MIF mRNA and protein expression on skin and colonic biopsy specimens. The associated T cell and macrophage activation was also studied by immunohistochemical studies. A semi-quantitative method was used to assess MIF staining, as well as T cell and macrophage staining. Serial blood samples were analyzed by ELISA for serum MIF levels. Immunohistochemistry and in situ hybridization performed in 15 skin and 19 colonic biopsies from 17 patients who developed moderate to severe aGVHD showed a significant increase in MIF mRNA and protein expression compared with normal controls (seven skin and five colonic biopsies). MIF was localized within the epidermis and the vascular area of skin, but diffusely expressed in the entire thickness of colon. Macrophage and T lymphocyte infiltration was confined to areas of strong MIF expression. Serial analysis by ELISA showed that only patients who developed aGVHD (n = 19) exhibited an increase (two- to three-fold) in serum MIF during HSCT, but not in the allogeneic HSCT recipients without aGVHD (n = 7) or those who received autologous HSCT (n = 8). In 14 out of 19 patients, serum MIF peaked before the onset of aGVHD. Local and systemic up-regulation of MIF expression is associated with the occurrence of acute GVHD. Its pathogenetic role remains to be further determined.

Effects of CTLA4-Fc on glomerular injury in humorally-mediated glomerulonephritis in BALB/c mice

The effect of cytotoxic T-lymphocyte-associated molecule 4-immunoglobulin fusion protein (CTLA4-Fc) on humorally-mediated glomerulonephritis was studied in accelerated anti-glomerular basement membrane (anti-GBM) glomerulonephritis induced in BALB/c mice. This strain of mice develops antibody and complement dependent glomerulonephritis under this protocol. Sensitized BALB/c mice developed high levels of circulating autologous antibody titres, intense glomerular deposition of mouse immunoglobulin and complement, significant proteinuria, renal impairment, significant glomerular necrosis and a minor component of crescent formation 10 days after challenge with a nephritogenic antigen (sheep anti-GBM globulin). Early treatment during the primary immune response, or continuous treatment throughout the disease with CTLA4-Fc, significantly suppressed mouse anti-sheep globulin antibody titres in serum, and immunoglobulin and complement deposition in glomeruli. The degree of glomerular necrosis was improved and proteinuria was reduced, particularly in the earlier stages of disease. Late treatment by CTLA4-Fc starting one day after challenge with sheep anti-mouse GBM did not affect antibody production and did not attenuate glomerulonephritis. The low level of crescent formation found in BALB/c mice developing glomerulonephritis was not prevented by the administration of CTLA4-Fc. These results demonstrate that CTLA4-Fc is of benefit in this model of glomerulonephritis by its capacity to attenuate antibody production, without affecting the minor degree of cell-mediated glomerular injury.

[Determination of naoning pian by multi-wavelength linear regression method]

Assay of naoning pian was reported by multi-wavelength linear regression method in this paper. The program was edited by BASIC. The recoveries and RSD of pyramidon and caffeine were 98.03%-100.9%, 1.0% and 97.77%-99.39%, 0.61%, respectively. This method could be used for the determination of two components in naoning pian without separation. The method was simple, rapid, and results were satisfactory.

Distribution of distinct vacA, cagA and iceA alleles in Helicobacter pylori in Hong Kong

BACKGROUND

There is a substantial genetic heterogeneity among Helicobacter pylori strains, and certain genotypes have been suggested to be associated with the virulence of this pathogen. The aim of this study was to investigate the distribution of H. pylori vacA, cagA and iceA genotypes and their association with duodenal ulcer disease in Hong Kong.

MATERIALS AND METHODS

Gastric biopsies of 72 H. pylori infected patients were analyzed by specific polymerase chain reactions.

RESULTS

Of the 72 cases, 69 (95.8%) had vacA signal sequence s1c strains, and three (4.2%) had s1a strains. vacA middle region sequences, m1b and m2, were detected in 23 (31.9%) and 46 (63.9%), respectively. Six (8.3%) cases contained multiple vacA subtypes. vacA s2 allele was only observed in three (4.3%) cases, which were also infected with s1c subtype. cagA was present in 64 (88.9%) of 72 patients, and iceA1 subtype was detected in 46 (63.9%) cases. Neither cagA nor vacA and iceA were associated with duodenal ulcer disease.

CONCLUSION

The distribution of vacA, cagA and iceA alleles in H. pylori strains in Hong Kong is similar to that in east Asia. There is a difference in the distribution of genotypes between strains in Hong Kong and those in mainland China, although strains in the two regions exhibit a very close relation. The association of these virulence genes and duodenal ulcer disease needs reappraisal, particularly under geographic considerations.

Tubular phenotypic change in progressive tubulointerstitial fibrosis in human glomerulonephritis

There is much debate over the origins of fibroblast-type cells that accumulate in interstitial fibrosis. A controversial hypothesis, supported by data from animal and cell-culture studies, is that fibroblast-type cells can derive from tubular epithelial cells by a process of epithelial-mesenchymal transdifferentiation. However, to date, no evidence supports this postulate in human glomerulonephritis. This study sought to provide evidence that tubular epithelial cells can undergo phenotypic change toward a fibroblast-like cell in human glomerulonephritis. One hundred twenty-seven open renal biopsy specimens from patients with minimal change disease (MCD), immunoglobulin A (IgA) nephropathy, and rapidly progressive glomerulonephritis (RPGN) were examined for tubular phenotypic change by two-color immunohistochemistry using the criteria of de novo expression of alpha-smooth muscle actin (alpha-SMA), a myofibroblast marker; loss of the epithelial marker cytokeratin; and collagen production. In normal human kidney and MCD, tubular epithelial cells expressed cytokeratin with no evidence of alpha-SMA staining. However, in 36 of 90 cases of IgA nephropathy and 9 of 18 cases of RPGN, small numbers of tubular epithelial cells in areas of fibrosis showed de novo alpha-SMA expression, accounting for 0.4% +/- 0.2% (IgA nephropathy) and 3.8% +/- 1.5% (RPGN) of cortical tubules. An intermediate stage of phenotypic change was observed in some cuboidal epithelial cells that expressed both cytokeratin and alpha-SMA. Tubules containing alpha-SMA-positive (alpha-SMA(+)) cells also stained for collagen types I and III, suggesting that tubular cells undergoing phenotypic change have an active role in the fibrotic process. There also was a marked increase in transforming growth factor-beta1 (TGF-beta1) tubular expression in areas with interstitial fibrosis, including tubules with phenotypic change. There was a highly significant correlation between tubular alpha-SMA expression and interstitial fibrosis, interstitial alpha-SMA(+) myofibroblast accumulation, deposition of collagen types I and III, tubular TGF-beta1 expression, and renal dysfunction. In conclusion, this study provides evidence that tubular epithelial cells can undergo phenotypic change toward a myofibroblast-like phenotype on the basis of de novo alpha-SMA expression, loss of cytokeratin, and de novo collagen staining. These data, although not conclusive, provide the first support for the hypothesis that transdifferentiation of tubular epithelial cells has a role in progressive renal fibrosis in human glomerulonephritis.

Macrophage migration inhibitory factor is an important mediator in the pathogenesis of gastric inflammation in rats

BACKGROUND & AIMS

Macrophage migration inhibitory factor (MIF) has been shown to play a pivotal role in inflammatory and immune-mediated diseases. This study investigates the role of MIF in gastric inflammation.

METHODS

Expression of MIF was examined in a rat gastric ulcer model induced by acetic acid, and the functional role of MIF in acute gastric ulcer was investigated by administration of a neutralizing anti-MIF antibody.

RESULTS

MIF messenger RNA and protein were markedly up-regulated in acute gastric ulcer, which correlated with the accumulation of macrophages (P < 0.001) and neutrophils (P < 0.05) at the site of inflammation. Macrophages, like neutrophils, were the major inflammatory cells infiltrating the ulcer base and they strongly expressed inducible nitric oxide synthase. However, macrophages, not neutrophils, were a rich source of MIF production in acute gastric ulcer. In vivo and in vitro blockade of MIF with the neutralizing anti-MIF antibody significantly inhibited the marked up-regulation of MIF, tumor necrosis factor alpha, inducible nitric oxide synthase, and intercellular adhesion molecule-1. This was associated with the marked inhibition of macrophage (70% reduced) and neutrophil (60% reduced) accumulation and activation, thus reducing ulcer sizes and attenuating ulceration.

CONCLUSIONS

This study has shown that MIF was markedly up-regulated during acute gastric ulcer. Inhibition of acute gastric ulcer by blockade of MIF indicates that MIF is a key inflammatory mediator and plays a pathogenic role in gastric inflammation.

SiCNN--a new stable isomer with Si(triple bond)C triple bonding

To predict potentially stable molecules with Si(triple bond)C triple bonding, theoretical calculations at the B3LYP/ 6-311G(d) and CCSD(T)/6-311G(2df) (single-point) levels were employed to study the structures, energetics, and isomerization of various SiCN2 isomers. A schematic potential energy surface (PES) of SiCN2 was established to discuss the kinetic stability of the isomers. A new isomer SiCNN was found to possess a typical Si(triple bond)C triple bond, as confirmed by comparative calculations at the B3LYP, QCISD, QCISD(T), CCSD, and CCSD(T) levels on the bond lengths of SiCNN and other experimentally or theoretically known species of RSiCH (R = H, F, Cl, OH). Moreover, SiCNN resides in a very deep potential, the stabilization barrier is at least 53.2 kcal mol(-1). Thus, SiCNN may be considered as the most kinetically stable isomer with Si(triple bond)C triple bonding known to date, and it may represent a very promising molecule for future experimental characterization. In addition, the stability of the other isomers, such as the four linear species SiNCN, SiNNC, NSiCN and NSiNC, a three-membered NNC ring isomer with exocyclic C-Si bonding, and a four-membered SiCNN ring isomer is discussed and compared with SiCNN.

Interleukin-1 induces tubular epithelial-myofibroblast transdifferentiation through a transforming growth factor-beta1-dependent mechanism in vitro

Interleukin-1 (IL-1) has been shown to exert profibrotic activity in a number of disease models, including crescentic glomerulonephritis and pulmonary fibrosis, but the mechanisms by which this operates are poorly understood. Recent studies have identified a novel mechanism promoting renal fibrosis: tubular epithelial-myofibroblast transdifferentiation (TEMT). The present study examined whether IL-1 can stimulate TEMT in vitro. Cells of the normal rat kidney tubular epithelial cell line (NRK52E) were grown to confluence on collagen-coated plates and cultured for 5 days in the presence 1 to 20 ng/mL of IL-1alpha. Doses of 10 to 20 ng/mL of IL-1 caused transdifferentiation of NRK52E cells into myofibroblast-like cells. Scanning electron microscopy identified IL-1-induced morphological changes as a loss of apical-basal polarity and microvilli, cell hypertrophy, and the development of an elongated and invasive appearance. Phenotypically, IL-1-induced TEMT was characterized by de novo messenger RNA and protein expression of the mesenchymal marker alpha-smooth muscle actin, shown by Northern blotting, immunohistochemistry, and Western blotting. This was accompanied by loss of the epithelial marker E-cadherin. The addition of an excess of IL-1-receptor antagonist completely inhibited IL-1-induced TEMT. IL-1 was shown to stimulate the secretion of active transforming growth factor-beta1 (TGF-beta1) by NRK52E cells. Furthermore, the addition of a neutralizing anti-TGF-beta1 antibody inhibited IL-1-induced TEMT. In conclusion, IL-1 is a profibrogenic cytokine capable of inducing TEMT through a TGF-beta1-dependent mechanism. This may represent a novel mechanism by which IL-1 induces renal fibrosis in vivo.

[Esterification of octanoic acid with 1-octanol catalyzed by lipase in W/O microemulsions and in microemulsion-based organogels]

The esterification reactions of octanoic acid with 1-octanol catalyzed by Candida lypolytical (CL) lipase was studied in water-in-oil microemulsions formed by water/bis-(2-ethylhexyl)sulfosuccinate sodium (AOT)/isooctane. The results of kinetic study showed that the reaction follows a Ping-Pong Bi-Bi mechanism. The values of apparent kinetic parameters were determined. Lipase has also been immobilized in gelatin-containing AOT microemulsion-based organogels (MBGs) for retention of catalytic activity. These lipase-containing MBGs proved to be a solid-phase catalysts for use in apolar organic solvents, retaining its higher activity after many runs of esterification reactions.

Forbidden X-ray wavefields of three-beam Bragg reflections from thick crystals

A detailed analysis of a three-beam diffraction dispersion surface is performed to study the forbidden wavefields of thick-crystal Bragg reflections. From the asymptotic transition between two- and three-beam diffraction, it is found that the excitation state of each wavefield can be accurately determined with the two-beam criterion. Consequently, Bragg-case three-beam diffraction from thick crystals is either a four-mode diffraction process for the Bragg-Laue geometry or a two-mode process for the Bragg-Bragg geometry, and the amplitudes of the excited wavefields can be completely determined by the entrance boundary conditions. Based on this picture, the intrinsic mechanisms underlying three-beam Bragg reflections are clearly illustrated.

De novo expression of macrophage migration inhibitory factor in atherogenesis in rabbits

Macrophage migration inhibitory factor (MIF) has been shown to play an important role in macrophage-mediated diseases. We investigate the potential role of MIF in atherogenesis using a hypercholesterolemic rabbit model. New Zealand White rabbits fed with a 2% cholesterol diet developed hypercholesterolemia and early fatty streaks at 1 month. The lesions became advanced at 3 months and were associated with de novo MIF expression by vascular endothelial cells (VECs) and smooth muscle cells (SMCs), as demonstrated by immunohistochemistry, reverse transcriptase-polymerase chain reaction, and in situ hybridization. By contrast, there was no increase in MIF levels in rabbits fed a normal diet. In early atherogenesis, marked upregulation of MIF mRNA and protein by VECs and some intimal cells were closely associated with CD68(+) monocyte adhesion onto and subsequent migration into subendothelial space. Of significance, the accumulation of macrophages was exclusively localized to areas of strong MIF expression, which may be associated with the macrophage-rich fatty streak lesion formation. Upregulation of MIF by SMCs is transient during atherogenesis. Importantly, strong MIF expression by activated macrophages may be responsible for the development of foam cell-rich lesions. Finally, the ability of MIF to induce intercellular adhesion molecule-1 expression by VECs implicates its pathogenic role in atherogenesis. In conclusion, the present study provides the first demonstration that MIF is markedly upregulated during atherogenesis. Upregulation of MIF by VECs and SMCs may play a role in macrophage adhesion, transendothelial migration, accumulation, and, importantly, transformation into foam cells. Furthermore, strong MIF expression by macrophages may both initiate and amplify the atherogenesis process.

Fluorescence property on solutions of zwitterionic surfactant tetradecylbetaine in the presence of macromolecules

The fluorescence property of zwitterionic surfactant tetradecylbetaine (C14BE) solutions in the presence of polyvinylpyrrolidone (PVPk30 and PVPk90), or Xanthan (Xc) have been investigated by steady-state fluorescence probe. The intensity ratio of the first and third peaks (I1/I3) of the monomer and that of the excimer to monomer (Ie/Im), and the aggregation number of the aggregates have been monitored. The results showed that C14BE/PVP and C14BE/Xc interactions mostly occur at the micelle surface. The C14BE clusters or micelles are bound to macromolecule chains by electrostatic force for PVP and by hydrogen-bonding for Xc, respectively.

Osteopontin expression in progressive renal injury in remnant kidney: role of angiotensin II

BACKGROUND

Osteopontin (OPN) is a macrophage chemotactic and adhesion molecule and has been shown to play a role in glomerular and tubulointerstitial injury in several kidney disease models.

METHODS

The present study examined whether OPN expression is involved in the progression of renal disease following subtotal (5/6) nephrectomy (STNx) in rats and whether angiotensin II (Ang II) mediates the up-regulation of renal OPN expression and macrophage accumulation in this model by administering valsartan, an Ang II type I (AT1) receptor antagonist, or ramipril, an angiotensin-converting enzyme (ACE) inhibitor.

RESULTS

In normal and sham-operated rat kidneys, OPN was expressed in a few tubules (<5%) and was absent in glomeruli. Following STNx (weeks 2 to 16), there was substantial up-regulation of OPN mRNA and protein expression in glomeruli [2 to 12 cells/glomerular cross section (gcs)] and tubular epithelial cells (20 to 75% OPN+). The up-regulation of OPN expression was associated with macrophage accumulation within the kidney, severe proteinuria, loss of renal function, and severe histologic damage, including tubulitis and tubulointerstitial fibrosis (all P < 0.001). Treatment with either valsartan or ramipril completely abrogated the up-regulation of OPN mRNA and protein expression in glomeruli and tubules. The reduction in OPN expression was associated with a significant inhibition of macrophage accumulation and progressive renal injury (P < 0.001).

CONCLUSION

An up-regulation of OPN expression may play a role in progressive renal injury following STNx. Inhibition of OPN expression may be one of the mechanisms by which Ang II blockade attenuated renal injury after renal ablation.

Involvement of macrophage migration inhibitory factor (MIF) in experimental uric acid nephropathy

BACKGROUND

Deposition of uric acid in the kidney can lead to progressive tubulointerstitial injury with granuloma formation. We hypothesized that uric acid crystal deposition may induce granuloma formation by stimulating local expression of macrophage migration inhibitory factor (MIF), which is a known mediator of delayed type hypersensitivity (DTH).

MATERIALS AND METHODS

A model of acute uric acid nephropathy was induced in rats by the administration of oxonic acid (an inhibitor of uricase), together with uric acid supplements. MIF expression and local cellular response were examined by in situ hybridization and immunohistochemistry.

RESULTS

Kidney tissue examined at 35 days posttreatment showed widespread tubulointerstitial damage with intratubular uric acid crystal deposition and granuloma formation. Tubules within the areas of granuloma showed a six-fold increase in MIF mRNA, compared with uninvolved areas by in situ hybridization. Moreover, the areas of increased MIF mRNA expression correlated with sites of dense accumulation of macrophages and T cells, and these cells were activated when assessed by the expression of interleukin-2R (IL-2R) and (MHC) class II. Interestingly, cytoplasmic staining for MIF protein in the uric acid (UA) crystal-associated granulomatous lesions was reduced, indicating a rapid MIF secretion by damaged tubules and macrophages secondary to uric acid crystal stimulation. This was confirmed by the demonstration of a marked increase in urinary MIF protein by Western blot analysis. Control rats fed either a normal diet or only oxonic acid had no discernible evidence of renal disease by routine light microscopy and minimal tubular expression of MIF mRNA and protein.

CONCLUSIONS

These data suggest that intrarenal granulomas in urate nephropathy may be the consequence of a crystal induced DTH reaction mediated by MIF.

Effect of corneal polarization axis on assessment of retinal nerve fiber layer thickness by scanning laser polarimetry

PURPOSE

Scanning laser polarimetry uses an anterior segment compensating device that assumes a fixed axis of corneal birefringence, which we call the corneal polarization axis. The purpose of this investigation was to establish the distribution of corneal polarization axes among a population of normal eyes and to evaluate the relationship between corneal polarization axis and posterior segment retardation.

METHODS

We constructed a noninvasive slit lamp-mounted device incorporating two crossed linear polarizers and an optical retarder in order to measure the slow axis of corneal birefringence. Normal subjects underwent corneal polarization axis measurement. A subset of eyes underwent scanning laser polarimetry of the peripapillary retinal nerve fiber layer (n = 32) and macula (n = 29), and retardation measurements were evaluated in each group.

RESULTS

One hundred eighteen eyes of 63 normal subjects (35 female, 28 male) underwent corneal polarization axis measurement (mean age, 45.5 +/- 17.1 years). Six eyes (5.1%) demonstrated unmeasurable corneal polarization. In the remaining 112 eyes, the mode of the corneal polarization axis distribution was 10 to 20 degrees nasally downward (range, 90 degrees nasally downward to 54 degrees nasally upward). A significant (P <.0001) correlation was observed between fellow eyes (R(2) =.52), with a mean difference of 11.2 +/- 10.5 degrees (range, 0-52 degrees). Corneal polarization axis was significantly associated (R(2) =.52-.84) with retinal nerve fiber layer and macula summary retardation parameters (average thickness, ellipse average, superior and inferior average, superior and total integral; P <.0001 for all groups).

CONCLUSIONS

The mean corneal polarization axis among normal corneas is nasally downward; however, considerable intraindividual and interindividual variability exists. The linear relationship between corneal polarization axis and posterior segment retardation parameters is responsible, in part, for the wide distribution of retinal nerve fiber layer thickness data generated by scanning laser polarimetry.

Endogenous glucocorticoids modulate experimental anti-glomerular basement membrane glomerulonephritis

The influence of endogenous glucocorticoids (GC) on glomerular injury was studied in a rat model of heterologous anti-glomerular basement membrane (GBM) glomerulonephritis (GN). Sprague-Dawley rats underwent adrenalectomy (ADX) or sham-operation 3 days prior to i.v. administration of both nephritogenic (100 microgram/g) and subnephritogenic (50 microgram/g) doses of sheep anti-rat GBM globulin. Administration of a subnephritogenic dose of anti-GBM globulin resulted in GN in adrenalectomized animals only. Similarly, ADX performed prior to administration of anti-GBM in the nephritogenic dose range resulted in exacerbation of GN compared with sham-operated animals (24 h protein excretion: 190.8 +/- 32.8 versus 42.5 +/- 2.6 mg/24 h; P < 0.005). In ADX animals receiving subnephritogenic doses of anti-GBM injury was manifested by abnormal proteinuria (62.7 +/- 5.8 mg/24 h), accumulation of neutrophils which peaked at 6 h (7.2 +/- 1.37 neutrophils per glomerular cross-section (neut/gcs)) and macrophage accumulation in glomeruli at 24 h (6.8 +/- 1.2 macrophages/gcs). Sham-adrenalectomized animals given the same dose of anti-GBM globulin developed minimal or no glomerular injury: urinary protein excretion (8.7 +/- 1.5 mg/24 h, P < 0.001); neutrophils (0.2 +/- 0.04 neutrophils/gcs, P < 0.001); macrophages (1.2 +/- 0.5 macrophages/gcs, P < 0.001). The increased cellular recruitment to glomeruli in adrenalectomized animals was associated with glomerular endothelial P-selectin expression. P-selectin expression was not detected in sham-operated rats after anti-GBM injection. Complement deposition in glomeruli was minimal in both groups. Physiologic GC replacement of ADX rats receiving subnephritogenic-dose anti-GBM reversed the observed susceptibility to GN development, with urinary protein excretion (7.8 +/- 1.12, P < 0.005) and no detectable P-selectin expression or leucocyte accumulation in glomeruli. These results suggest that endogenous GC modulate heterologous anti-GBM nephritis in rats and that this may be attributable, in part, to regulation of P-selectin expression.

Macrophage depletion by albumin microencapsulated clodronate: attenuation of cytokine release in macrophage-dependent glomerulonephritis

A macrophage plays an important role in mediating the inflammatory response. Cytokines released by activated macrophages contribute to inflammation in glomerulonephritis (GN). Clodronate, a biphosphonate, causes macrophage depletion when administered in an encapsulated form in liposomes. We used albumin as the polymer matrix to microencapsulate clodronate to the microspheres (MS) in the 1-micron size range. The purpose of this study was to (a) determine macrophage depletion by clodronate MS, (b) determine the effect of clodronate MS on endotoxin-induced cytokine release in vitro, and (c) assess the effect of clodronate MS on macrophage infiltration in experimental antiglomerular basement membrane nephritis. Macrophage depletion by clodronate MS was assessed by staining for the EDI marker. The results indicate greater than 95% depletion of macrophages from the spleen, liver, kidney, and blood. In the whole blood model, clodronate MS attenuated endotoxin-induced tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) release, and the attenuation by the microencapsulated form of clodronate was also more effective than the free (solution) form of clodronate. Macrophage infiltration into the glomerulus in experimental GN was also blocked very effectively by pretreatment with clodronate MS. In conclusion, macrophage depletion by clodronate MS may be beneficial in reducing cytokine release and renal damage in GN.

Directional and spectral reflectance of the rat retinal nerve fiber layer

PURPOSE

To measure and describe the reflectance properties of a mammalian retinal nerve fiber layer (RNFL) and to determine the mechanisms responsible for the RNFL reflectance.

METHODS

An isolated rat retina suspended across a slit in a black membrane and mounted in a black perfusion chamber provided high quality images of the RNFL. Imaging microreflectometry was used to measure RNFL reflectance at wavelengths from 400 nm to 830 nm and as a function of illumination angle.

RESULTS

The directional reflectance of rat RNFL at all wavelengths was consistent with the theory of light scattering by cylinders; each nerve fiber bundle scattered light into a conical sheet coaxial with the bundle. There was no evidence of a noncylindrical component at any wavelength. Measured reflectance spectra were consistent between animals, similar to ones previously measured in macaque, and varied with scattering angle. All spectra could be described by a two-mechanism cylindrical scattering model with three free parameters.

CONCLUSIONS

At all wavelengths the reflectance of rat RNFL arises from light scattering by cylindrical structures. The highly directional nature of this reflectance can be an important source of measurement variability in clinical assessment of the RNFL. The reflectance spectra reveal a combination of mechanisms: At wavelengths shorter than approximately 570 nm the reflectance comes from cylinders with diameters much smaller than the wavelength, but at wavelengths longer than approximately 680 nm the reflectance comes from cylinders with effective diameters of 350 nm to 900 nm.

Prominence of cell-mediated immunity effectors in "pauci-immune" glomerulonephritis

The majority of patients with rapidly progressive crescentic glomerulonephritis show histologic features of extensive necrosis and focal and segmental proliferation with fibrin production, but little or absent Ig deposition in the glomerulus. This subcategory of the disease, labeled "pauci-immune" glomerulonephritis, has recently been shown to be associated with the presence of antineutrophil cytoplasmic antibody in the patient's circulation (but not within the glomerulus). The absence of the effectors of humoral immunity at the site of renal injury led to this investigation of the contribution of cell-mediated immunity to the glomerular injury in this form of glomerulonephritis. In 15 patients presenting acutely with pauci-immune glomerulonephritis, CD3-positive T cells (3.7+/-2.5 [mean +/- SD] cells per glomerular cross section, [c/gcs]), CD45RO-positive T cells (2.7+/-1.9 c/cgs), macrophages (7.3+/-6.1 c/gcs), fibrin (3+), and endothelial-associated tissue factor were demonstrated to be prominent in glomeruli. These mediators were absent in a group of 12 patients with thin basement membrane disease and only occasionally observed in a group of eight patients with "humorally mediated"(noncrescentic) glomerulonephritis. Thus, in pauci-immune glomerulonephritis, there is the development of significant cell-mediated immunity with activated T cells, macrophages, tissue factor, and fibrin at the site of glomerular injury, suggesting that this glomerular disease is most likely a manifestation of T cell-directed cognate immune injury.

Visible and near-infrared imaging of the nerve fiber layer of the isolated rat retina

PURPOSE

To develop an isolated rat retina preparation suitable for the study of the reflectance of the mammalian retinal nerve fiber layer (RNFL).

METHODS

A rat retina with a short piece of optic nerve attached was dissected free from the eye and stretched over a slit in a black membrane. The retina was placed in a black chamber perfused with warmed and oxygenated physiologic solution. Imaging microreflectometry was used to acquire images of the RNFL at wavelengths from 400 to 830 nm and over time.

RESULTS

At all wavelengths the isolated retina provided high-contrast images of nerve fiber bundles against a uniform, dark background. The nerve fiber bundles had a speckled texture, especially at long wavelengths. Time-lapse movies showed that over a period of several minutes the speckle pattern slowly changed. Although the general appearance of the bundles was similar at two closely spaced wavelengths (660 and 680 nm), the detailed patterns were completely different.

CONCLUSION

The isolated retina preparation is well suited to the study of the optical properties of the RNFL. The speckled texture of nerve fiber bundles probably results from optical interference in the scattered light. The slow change in pattern implies that the size and/or shape of the scattering structures must change with time.

Crescentic glomerulonephritis in CD4- and CD8-deficient mice. Requirement for CD4 but not CD8 cells

The contribution of CD4 and CD8 cells to crescentic glomerulonephritis (GN) was studied in mice genetically deficient in CD4, CD8, and with combined CD4 and CD8 (CD4/CD8) deficiency. Wild-type (C57BL/6) mice developed GN with mild proliferative changes 7 days after an intravenous dose of sheep anti-mouse glomerular basement membrane globulin. Crescents were observed in 12.5 +/- 6.1% of glomeruli on day 14. On day 21, 51.5 +/- 7.3% of glomeruli were affected by crescents, and mice had marked azotemia and proteinuria. CD4 and combined CD4/CD8-deficient mice developed minimal evidence of GN. On day 21, their glomeruli showed only mild proliferative changes and crescents, azotemia, and proteinuria were absent. In contrast, CD8-deficient mice developed severe crescentic GN with three of five mice dying on day 20 with ascites and edema. The two mice surviving to day 21 had severe azotemia. Crescent development was accelerated (day 14, 51.6 +/- 2.4% of glomeruli; day 20 or 21, 62.0 +/- 4.0% of glomeruli). These studies demonstrate that CD4 cells are crucial for the development of crescentic GN in mice and that genetic absence of CD8 cells accelerates disease. They support the hypothesis that crescent formation is a manifestation of CD4-dependent (and CD8-independent) delayed type hypersensitivity in the glomerulus.

P-selectin requirement for neutrophil accumulation and injury in the direct passive Arthus reaction

The aim of this study was to investigate the role of P-selectin in the accumulation of neutrophils in the direct passive Arthus reaction in rat skin. Direct passive Arthus dermal reaction was induced in male Sprague-Dawley (SD) rats by a single i.v. injection of rat anti-sheep globulin (SG) 1 h before i.d. injection of SG antigen. Anti-P-selectin or irrelevant control antibody was given 1 h before rat anti-SG injection. Complement depletion was also performed in a separate group by pretreatment with cobra venom factor (CVF). In all groups dermal swelling was assessed 4 h after antigen challenge. Four hours after antigen challenge, rats treated with control antibody developed skin swelling (2.29 +/- 0.47 mm), prominent complement deposition and neutrophil accumulation. This response was associated with local up-regulation of endothelial P-selectin. Pre-treatment with anti-P-selectin antibody 1 h before passive Arthus induction prevented skin swelling (0.29 +/- 0.06 mm, P < 0.05, cf with control antibody treatment), neutrophil accumulation and up-regulation of endothelial P-selectin despite complement deposition. CVF treatment prevented complement deposition, neutrophil accumulation and skin swelling (0.13 +/- 0.07 mm, P < 0.05, cf with saline treatment). However, endothelial P-selectin expression was still present. Inhibition of skin swelling and neutrophil accumulation in direct passive Arthus by functional inhibition of P-selectin suggest a pivotal role for this adhesion molecule in this inflammatory process. These results also suggest that multiple steps are involved in the evolution of direct passive Arthus, including both P-selectin expression and complement activation. However, while complement activation is essential for neutrophil accumulation and expression of dermal injury, P-selectin up-regulation initiated by antibody/antigen deposition occurs independently of complement activation.

Interleukin-4 deficiency enhances Th1 responses and crescentic glomerulonephritis in mice

Evidence suggests that crescentic glomerulonephritis (GN) is due to T helper cell 1 (Th1) directed delayed-type hypersensitivity (DTH)-like injury. As endogenous interleukin (IL)-4, (the pivotal cytokine in Th2 responses) may attenuate Th1 responses in this disease, we compared the development of crescentic GN, induced by a planted antigen, in mice genetically deficient in IL-4 (IL-4-/-) with disease in normal mice (IL-4+/+). IL-4-/- mice developed more severe GN with increased renal impairment (CCr 35 +/- 7 microliters/min vs. 133 +/- 14 microliters/min, P < 0.002) and crescent formation (55.7 +/- 8.4% vs. 4.9 +/- 1.2%, P < 0.002). This was associated with increased glomerular fibrin deposition, glomerular CD4+ T cell infiltration and macrophage recruitment. Systemically, IL-4-/- mice showed an increased antigen specific Th1 response indicated by increased skin DTH, and increased IgG3 and IgG2b. Decreased IgG1 levels indicated a reduced Th2 response. These results demonstrate a protective role for endogenous IL-4 in crescentic GN. They show that IL-4 deficiency promotes crescentic glomerular injury and amplifies local and systemic Th1 responses. They support the hypothesis that crescent formation results from Th1 immune responses to antigens in the glomerulus.

Interleukin-4 and interleukin-10 attenuate established crescentic glomerulonephritis in mice

Crescentic glomerulonephritis (GN) has immunopathological features of delayed type hypersensitivity (DTH) and results from a T helper cell 1 (Th1) dependent immune response. The current study examined the capacity of Th2 cytokines, interleukin (IL)-4 and IL-10, to alter the outcome of crescentic GN, after injury is established. Sensitized, control treated mice developed crescentic GN with functional renal injury (117 +/- 20 microliters/min, normal mouse 182 +/- 8 microliters/min, P < 0.05) 10 days after an i.v. dose of sheep anti-mouse glomerular basement membrane globulin. Combined treatment with IL-4 and IL-10 starting three days after initiation of disease significantly reduced glomerular crescent formation (5.3 +/- 3.2%, control treatment 23.3 +/- 6.4%, P < 0.02) and preserved renal function (165 +/- 15 microliters/min, P = 0.57 compared to normal mice). Treatment with IL-4 alone did not reduce crescent formation or protect renal function. Mice treated with IL-10 showed trends to decreased crescent formation and preservation of renal function. In all cytokine treated groups, the accumulation of effectors of glomerular injury (CD4+ positive T cells, macrophages and fibrin) was reduced, with the combination treatment having the greatest effect. Administration of Th2 cytokines, IL-4 and IL-10 to mice with established GN attenuates the development of glomerular crescent formation and protects renal function.

Th2 responses induce humorally mediated injury in experimental anti-glomerular basement membrane glomerulonephritis

Acute autologous phase anti-glomerular basement membrane glomerulonephritis was compared in Th1-prone (C57BL/6) and Th2-prone (BALB/c) mice. Sensitized BALB/c mice, given a subnephritogenic intravenous dose of anti-mouse glomerular basement membrane globulin, developed acute glomerulonephritis characterized by marked proteinuria and glomerular deposition of mouse immunoglobulin and complement. A significant glomerular neutrophil influx was observed, but few T cells and macrophages were present. C57BL/6 mice, given the same dose of disease-inducing globulin, also developed acute glomerulonephritis, although their proteinuria was significantly less. Glomerular deposition of mouse immunoglobulin and complement and the influx of neutrophils were also significantly less than in BALB/c mice. However, their glomerular accumulation of macrophages and T cells was significantly greater. Complement depletion attenuated neutrophil influx and proteinuria in BALB/c mice but did not affect T cell or macrophage accumulation or proteinuria in C57BL/6 mice. CD4+ T cell depletion significantly reduced glomerular macrophage, T cell influx, and proteinuria in C57BL/6 mice, but had no effect on proteinuria or neutrophil influx in BALB/c mice. Thus, immune responses to planted glomerular antigens in Th2-prone mice induce acute injury as a result of antibody deposition, complement activation, and neutrophil influx, whereas immune responses to the same antigen in Th1-prone mice induce delayed-type hypersensitivity-like lesions in affected glomeruli.

Mechanisms of T cell-induced glomerular injury in anti-glomerular basement membrane (GBM) glomerulonephritis in rats

The effector mechanisms of T cell-dependent acute glomerular injury were studied in autologous phase anti-GBM glomerulonephritis (GN) in rats. Acute proliferative GN was induced in sensitized rats by a subnephritogenic dose of sheep anti-rat GBM antibody. Injury was manifested by proteinuria and glomerular leucocyte infiltration composed predominantly of macrophages but also CD4+ and CD8+ T cells. T cell depletion, using an anti-CD5 MoAb, demonstrated that glomerular leucocyte infiltration and proteinuria were T cell-dependent. Inhibition of T helper cell function using an anti-CD4 MoAb prevented proteinuria and glomerular macrophage and CD4+ T cell influx, but not accumulation of CD8+ T cells. Depletion of CD8+ T cells also prevented proteinuria and the influx of macrophages and CD8+ T cells, but not accumulation of CD4+ T cells. Macrophage depletion, using micro-encapsulated clodronate, prevented proteinuria and glomerular macrophage infiltration, but not the accumulation of CD4+ or CD8+ T cells, indicating that macrophages are the common cellular effectors for both CD4 and CD8 T cell-dependent injury. Evidence for cytotoxic mechanisms of injury (increased numbers of apoptotic cells or accumulation of natural killer (NK) cells in glomeruli) could not be demonstrated. These data suggest that acute glomerular injury in anti-GBM GN is the result of macrophage recruitment, which is dependent on both CD4 and CD8 T cells, and that direct T cell-mediated injury (cellular cytotoxicity) is not involved.

Immune modulation with interleukin-4 and interleukin-10 prevents crescent formation and glomerular injury in experimental glomerulonephritis

Crescentic glomerulonephritis (GN) demonstrates immunopathological features of a T helper (Th)1-directed delayed-type hypersensitivity (DTH) response. The capacity of Th2 cytokines to attenuate crescentic glomerular injury in this disease was examined by administering interleukin (IL)-4 and IL-10, singly and in combination. GN was induced by i.v. administration of sheep anti-mouse glomerular basement membrane (GBM) globulin to mice sensitized to sheep globulin 10 days earlier. Treatment (2.5 microg, i.p.) with IL-4, IL-10, or both IL-4 and IL-10 (IL-4 + 10), was started 1 h before sensitization and continued daily until the end of the study (10 days after administration of anti-GBM globulin). Control mice treated with PBS developed GN with glomerular accumulation of T cells and macrophages, crescents in 42.5 +/- 4.5 % of glomeruli (normal 0 %), proteinuria (8.3 +/- 0.9 mg/24 h, normal 0.74 +/- 0.08 mg/24 h, p <0.001) and renal impairment (creatinine clearance [cr/cl]: 93 +/- 12 microl/min, normal 193 +/- 10 microl/min, p < 0.001). Treatment with either IL-4, IL-10, or IL-4 + 10 prevented crescent formation (crescentic glomeruli: 0.8 +/- 0.5, 1.2 +/- 0.9, and 1.4 +/- 1.0 %, respectively, all p < 0.01 compared to control) and attenuated proteinuria (3.6 +/- 1.0, 2.2 +/- 0.5, and 2.9 +/- 0.5 mg/24 h, respectively, all p < 0.01 compared to control). IL-4 + 10 prevented development of renal impairment (cr/cl: 183 +/- 22 microl/min); IL-10 given alone limited the decline in renal function (cr/cl: 150 +/- 20 microl/min), but IL-4 alone did not provide any significant protection (cr/cl: 121 +/- 17 microl/min). All treatments markedly diminished glomerular T cell and macrophage accumulation, reduced interferon-gamma production by splenic T cells, prevented cutaneous DTH to the disease-initiating antigen and reduced antigen-specific immunoglobulin of the IgG2a and IgG3 isotypes. These data demonstrate that crescentic GN and renal impairment can be prevented by administration of Th2 cytokines and that this effect is associated with attenuation of the Th1 response to the disease-initiating antigen.

Th1 responsiveness to nephritogenic antigens determines susceptibility to crescentic glomerulonephritis in mice

The pattern of glomerulonephritis (GN) developing in response to a planted antigen (sheep anti-mouse GBM globulin) was compared in two strains of mice which demonstrated either a predominant Th1 (C57BL/6) or Th2 (BALB/c) response to this antigen. GN was induced with a subnephritogenic i.v. dose of sheep anti-mouse GBM globulin in mice presensitized to sheep globulin. Sensitized C57BL/6 mice showed pronounced cutaneous delayed-type hypersensitivity (DTH) following the challenge with sheep globulin, low titers of circulating anti-sheep globulin antibody and high interferon gamma (IFN-gamma) and low interleukin 4 (IL-4) production by splenic T cells, consistent with a predominant Th1 pattern of immune response. Sensitized BALB/c mice did not develop DTH following cutaneous challenge with sheep globulin, had higher circulating anti-sheep globulin antibody titers, and showed high IL-4 and low IFN gamma production by splenic T cells compared with C57BL/6 mice, consistent with a predominant Th2 response. In C57BL/6 mice, GN developing in response to sheep globulin exhibited a severe crescentic pattern with prominent glomerular T cell and macrophage influx and fibrin deposition. In vivo depletion with a monoclonal anti-CD4 antibody demonstrated that this injury was T helper cell dependent. Treatment with monoclonal anti-mouse IFN gamma antibody significantly reduced glomerular injury and crescent formation and attenuated the cutaneous DTH response. GN induced by the same protocol in BALB/c mice exhibited pronounced glomerular IgG and complement deposition. Crescent formation, fibrin deposition, and glomerular T cell and macrophage infiltration were significantly less than observed in C57BL/6 mice, and injury was not T cell dependent in the effector phase. These data suggest that the pattern of glomerular injury induced by a planted antigen can be determined by the balance of T helper cell subset activation. A Th1 response induces a severe crescentic pattern of GN, which like cutaneous DTH, is T helper cell and IFN gamma dependent.

P-selectin directs T lymphocyte-mediated injury in delayed-type hypersensitivity responses: studies in glomerulonephritis and cutaneous delayed-type hypersensitivity

The role of P-selectin in T-lymphocyte accumulation and injury was studied in delayed-type hypersensitivity (DTH) responses in the skin and glomeruli of rats. Sprague Dawley rats were sensitized to sheep globulin and challenged 5 days later in the skin by subcutaneous injection and simultaneously in glomeruli by intravenous injection of a subnephritogenic dose of sheep anti-rat glomerular basement membrane globulin. This resulted in cutaneous and glomerular T lymphocyte-dependent macrophage influx and injury characteristic of DTH. Up-regulation of P-selectin expression on endothelial cells was observed in both inflammatory lesions. Treatment of rats with anti-CD5 antibody immediately prior to antigen challenge prevented the development of injury as assessed by measurement of proteinuria and skin swelling, as well as local T cell and macrophage accumulation in the glomerulus and in the skin, but did not block up-regulation endothelial cell P-selectin. Treatment with anti-CD4 antibody produced similar results. Blocking P-selectin in vivo with a functionally inhibitory antibody prevented development of proteinuria and skin swelling following antigen challenge. Local accumulation of T cells and macrophages was markedly attenuated in glomeruli and the skin and up-regulation of endothelial cell P-selectin was prevented. These data demonstrate that P-selectin is locally up-regulated on endothelial cells in T cell-dependent glomerular and cutaneous inflammation and suggests a pivotal functional role for P-selectin in local T cell recruitment and subsequent injury in DTH.

Evidence for delayed-type hypersensitivity mechanisms in glomerular crescent formation

The role of CD4-positive T cells in glomerular crescent formation was examined in WKY rats. Glomerulonephritis (GN) was induced by a subnephritogenic intravenous dose of sheep anti-rat GBM antibody in rats previously sensitized to sheep globulin. This resulted in a severe proliferative and crescentic GN, with marked proteinuria [143 +/- 40 mg/24 hr (mean +/- SD), normal 1.6 +/- 0.7 mg/24 hr] and crescent formation involving 59 +/- 8% of glomeruli at day 10 (normal 0%). Humoral immunity to sheep globulin was evident systemically by high titers of circulating anti-sheep globulin and locally by linear deposition of rat immunoglobulin in glomeruli and cell mediated immunity by cutaneous delayed-type hypersensitivity (DTH) to intradermal injection of sheep globulin. Glomerular accumulation of CD5 positive T cells [2.45 +/- 0.21 cells per glomerular cross section (c/gcs), normal 0.18 +/- 0.10 c/gcs], CD4 positive T cells, (1.87 +/- 0.46 c/gcs, normal 0.14 +/- 0.08 c/gcs), and macrophages (22.7 +/- 5.9 c/gcs, normal 0.05 +/- 0.05 c/gcs), together with the appearance of multinucleated giant cells (0.42 +/- 0.15 c/gcs, normal 0 c/gcs) suggested a DTH-like reaction in glomeruli. Sensitized rats given anti-GBM globulin were treated with monoclonal anti-CD5 or anti-CD4 antibodies in a protocol which prevented cutaneous DTH to sheep globulin without altering the humoral immune response. Both treatments significantly reduced glomerular accumulation of CD5 and CD4 positive T cells at day 10. Crescent formation was significantly reduced (CD5 treated, 13 +/- 4% of glomeruli affected; P < 0.001; CD4 treated 13 +/- 3% of glomeruli affected, P < 0.001) compared to rats treated with an isotype-matched irrelevant monoclonal antibody. Glomerular macrophage accumulation, multinucleated giant cell formation and proteinuria were also significantly reduced by both treatments. These studies demonstrate a functional role for CD4 positive T cells as effector cells within glomeruli, separate from their role in humoral immunity, in the development of crescentic GN. The local participation of CD4 positive T cells, macrophages and multinucleated giant cells in crescent formation, and the attenuation of these features by functional T helper cell depletion suggest that local DTH-like mechanisms may contribute to glomerular crescent formation.

A role for P selectin in complement-independent neutrophil-mediated glomerular injury

Neutrophil recruitment and lung injury following complement activation have been demonstrated to be dependent on endothelial expression of P selectin. In anti-glomerular basement membrane antibody-induced glomerulonephritis (anti-GBM GN) in mice, acute glomerular injury results from complement-independent neutrophil accumulation. The signals for neutrophil recruitment in this model are unknown. Expression of P selectin on glomerular endothelium was demonstrated within 30 minutes of administration of anti-GBM antibody to C57/BL10 mice. This was associated with rapid accumulation of neutrophils in glomeruli which peaked at one hour (6.2 +/- 0.5 neutrophils per glomerular cross section [neut/gcs], normal 0.34 +/- 0.06 neut/gcs, P < 0.01) and significant proteinuria after 16 hours (3.6 +/- 0.5 mg/16 hr, control 0.62 +/- 0.13 mg/16 hr, P < 0.01). Complement depletion with cobra venom factor, which reduced serum C3 levels to less than 5% of normal, did not alter expression of P selectin, reduce glomerular neutrophil accumulation (6.7 +/- 0.8 neut/gcs) or proteinuria (3.7 +/- 0.5 mg/16 hr). Platelet depletion also failed to alter glomerular expression of P selectin, neutrophil accumulation or the development of proteinuria. Mice were treated with an affinity purified anti-human P selectin antibody, which cross reacted with mouse P selectin and blocked P selectin-dependent binding of thrombin-activated mouse platelets to HL60 cells and did not bind to mouse neutrophils. Treatment, one hour prior to the administration of anti-GBM antibody, markedly inhibited glomerular neutrophil accumulation (0.94 +/- 0.12 neut/gcs) and prevented proteinuria (1.0 +/- 0.2 mg/16 hr), and did not alter binding of anti-GBM globulin in the kidney. These data strongly suggest that the rapid up-regulation of P selectin expression in glomeruli following binding of anti-GBM antibody is an essential signal for neutrophil recruitment in this complement independent model of glomerular injury.

Isolation and identification of hepatitis E virus in Xinjiang, China

This paper describes isolation and identification of a virus (termed strain 87A) which has the cytopathic effect and haemagglutination properties of hepatitis E virus (HEV). This virus was isolated by tissue culture from the faeces of a patient with acute non-A, non-B enteric hepatitis in Xinjiang, China. The isolated virus was neutralized by acute phase sera obtained from other patients with acute non-A, non-B enteric hepatitis. The virus particles also could be specifically aggregated with acute phase sera from patients with known HEV hepatitis in China, Burma, India and the U.S.S.R., and with acute and convalescent sera from an HEV-infected chimpanzee. Crystalline arrangements of virus particles in the cytoplasm were observed by electron microscopy in ultrathin sections of infected cells. The sedimentation coefficient of the strain 87A virus particles in sucrose gradients was 176S. Purified virus particles revealed a protein band of about 76K on SDS-PAGE and Western blotting. The evidence indicates that the strain 87A virus is an HEV. Our ability to propagate HEV in cell culture should facilitate research on this hepatotropic virus.