Phagocytosis of Candida albicans enhances malignant behavior of murine tumor cells.

Murine tumor cells were induced to phagocytize either Candida albicans or group A streptococcal cells. The presence of microbial particles within the tumor cell cytoplasm had no effect on in vitro tumor cell growth. However, when Candida albicans-infected tumor cells were injected into syngeneic mice, they formed tumors that grew faster, invaded the surrounding normal tissue more rapidly and metastasized more rapidly than control tumor cells. Tumor cells infected with group A streptococcal particles did not grow faster or show increased malignant behavior. These data indicate that the in vivo behavior of malignant tumor cells can be modulated by microbial particles, which are often present in the microenvironment of the growing tumor.

Intraglomerular pressure and mesangial stretching stimulate extracellular matrix formation in the rat.

To define the interplay of glomerular hypertension and hypertrophy with mesangial extracellular matrix (ECM) deposition, we examined the effects of glomerular capillary distention and mesangial cell stretching on ECM synthesis. The volume of microdissected rat glomeruli (Vg), perfused ex vivo at increasing flows, was quantified and related to the proximal intraglomerular pressure (PIP). Glomerular compliance, expressed as the slope of the positive linear relationship between PIP and Vg was 7.68 x 10(3) microns 3/mmHg. Total Vg increment (PIP 0-150 mmHg) was 1.162 x 10(6) microns 3 or 61% (n = 13). A 16% increase in Vg was obtained over the PIP range equivalent to the pathophysiological limits of mean transcapillary pressure difference. A similar effect of renal perfusion on Vg was also noted histologically in tissue from kidneys perfused/fixed in vivo. Cultured mesangial cells undergoing cyclic stretching increased their synthesis of protein, total collagen, and key components of ECM (collagen IV, collagen I, laminin, fibronectin). Synthetic rates were stimulated by cell growth and the degree of stretching. These results suggest that capillary expansion and stretching of mesangial cells by glomerular hypertension provokes increased ECM production which is accentuated by cell growth and glomerular hypertrophy. Mesangial expansion and glomerulosclerosis might result from this interplay of mechanical and metabolic forces.

Thrombospondin-induced adhesion of human keratinocytes.

Human epidermal keratinocytes obtained from normal skin attached and spread on thrombospondin (TSP)-coated plastic dishes but failed to attach and spread on untreated plastic culture dishes or dishes coated with fibronectin or laminin. These cells produced minimal amounts of immunoreactive TSP. Keratinocytes established in culture on MCDB 153 medium and maintained for one to three passages in an undifferentiated state by continued cultivation in this low Ca2+-containing medium attached and spread on plastic dishes as well as on TSP-coated dishes. These cells also secreted significant amounts of TSP into the culture medium. When the keratinocytes were incubated for one day in MCDB 153 medium supplemented with high Ca2+ or in MEM (which also contains high Ca2+), there was decreased secretion of TSP into the culture medium concomitant with a reduction in attachment and spreading on plastic culture dishes. Proteolytic fragments of TSP were examined for stimulation of keratinocyte attachment and spreading. A 140-kd fragment produced by removal of the 25-kd heparin-binding domain had similar activity to the intact molecule while the 25-kd fragment was without effect. Further proteolytic treatment of the 140-kd fragment gave rise to a fragment consisting of 120 kd and 18-D moieties held together in disulphide linkage. This fragment did not support attachment or spreading. This study reveals that normal epidermal keratinocytes grown under conditions that maintain the undifferentiated state are able to produce TSP and utilize it as an attachment factor. When keratinocytes are grown under conditions that promote differentiation, ability to produce and utilize TSP is diminished. Since TSP is present at the dermal-epidermal junction and because TSP promotes keratinocyte attachment and spreading, this molecule may play an important role in maintaining normal growth of the basal cell layer and may also participate in reepithelialization during wound repair.

Overexpression of glucose transporters in rat mesangial cells cultured in a normal glucose milieu mimics the diabetic phenotype.

An environment of high glucose concentration stimulates the synthesis of extracellular matrix (ECM) in mesangial cell (MC) cultures. This may result from a similar increase in intracellular glucose concentration. We theorized that increased uptake, rather than glucose concentration per se is the major determinant of exaggerated ECM formation. To test this, we compared the effects of 35 mM glucose on ECM synthesis in normal MCs with those of 8 mM glucose in the same cells overexpressing the glucose transporter GLUT1 (MCGT1). Increasing medium glucose from 8 to 35 mM caused normal MCs to increase total collagen synthesis and catabolism, with a net 81-90% increase in accumulation. MCs transduced with the human GLUT1 gene (MCGT1) grown in 8 mM glucose had a 10-fold greater GLUT1 protein expression and a 1.9, 2.1, and 2.5-fold increase in cell myo-inositol, lactate production, and cell sorbitol content, respectively, as compared to control MCs transduced with bacterial beta-galactosidase (MCLacZ). MCGT1 also demonstrated increased glucose uptake (5-fold) and increased net utilization (43-fold), and greater synthesis of individual ECM components than MCLacZ. In addition, total collagen synthesis and catabolism were also enhanced with a net collagen accumulation 111-118% greater than controls. Thus, glucose transport activity is an important modulator of ECM formation by MCs; the presence of high extracellular glucose concentrations is not necessarily required for the stimulation of matrix synthesis.

Monocyte killing of human squamous epithelial cells: role for thrombospondin.

Human peripheral blood monocytes maintained in culture for 18 h were examined for killing of normal human keratinocytes and squamous carcinoma cells. Keratinocytes grown under conditions which maintain the undifferentiated state were highly sensitive to killing but these cells became resistant to killing after induction of differentiation. A line of squamous carcinoma cells obtained from an undifferentiated tumor (designated as UM-SCC-11B) was sensitive to killing while a second line obtained from a more well-differentiated tumor (designated as UM-SCC-22B) was resistant. Several observations suggested that interaction of monocytes with the squamous epithelial cells was mediated, in part, through thrombospondin (TSP). Monocytes synthesized TSP and were positive by immunofluorescence for surface TSP. The normal and malignant squamous epithelial cells also expressed surface TSP as well as unoccupied TSP receptors and our previous studies have shown that both TSP and its receptor are much more prominently displayed on the undifferentiated cells than on the differentiated cells. A series of anti-TSP monoclonal antibodies inhibited killing. These included an antibody directed against the Mr 25,000 NH2-terminal region of the molecule which has heparin-binding activity and three antibodies the epitopes of which lie within the Mr 140,000 non-heparin-binding fragment of TSP. High concentrations of exogenously added TSP as well as the recombinant form of the heparin-binding domain from the TSP molecule also partially inhibited killing while laminin and fibronectin were ineffective. Taken together, these data suggest that TSP and TSP receptors on monocytes and squamous epithelial cells play a role in monocyte-mediated killing of the squamous epithelial cells.

Inhibitory effect of gamma interferon on cultured human keratinocyte thrombospondin production, distribution, and biologic activities.

Rapidly proliferating keratinocytes (KCs) maintained in low calcium, serum-free medium produce and utilize thrombospondin (TSP) as an attachment and spreading factor. To begin to understand the modulation of KC TSP metabolism, gamma interferon (IFN-gamma), a product of activated T lymphocytes, was added to KC cultures. IFN-gamma was chosen because activated T cells appear at sites of cutaneous injury. Two additional cytokines including tumor necrosis factor (TNF) and IFN-beta were also examined. IFN-gamma (600 U/ml), but not TNF (500 U/ml) or IFN-beta (10(3) U/ml), as single agents decreased KC TSP biosynthesis, secretion, and utilization as an attachment factor. IFN-gamma alone did not detectably decrease TSP mRNA levels suggesting a post-transcriptional effect in KCs. However, the combination of IFN-gamma (600 U/ml) and TNF (500 U/ml) inhibited TSP mRNA production. These results demonstrate the modulation of KC TSP metabolism and biologic activity.

Phorbol ester binding and phorbol ester-induced arachidonic acid metabolism in a highly responsive murine fibrosarcoma cell line and in a less-responsive variant.

Phorbol ester binding was examined in two lines of murine fibrosarcoma cells. The two cell lines were isolated from the same parent tumor but respond differentially to stimulation with phorbol esters. In one of the lines, these agents stimulate a rapid attachment and spreading response and induce directional migration. The other cell line does not migrate in response to stimulation with phorbol esters and the attachment and spreading response is slow. The cell line which responds actively to phorbol ester stimulation is highly malignant when injected into syngeneic animals while the other line is of low tumorigenicity and is virtually non-metastatic. In spite of these differences, both lines were found in the present study to bind [3H]4 beta-phorbol-12 beta, 13 alpha-dibutyrate in a receptor-mediated fashion. The characteristics of binding were virtually identical between the two cell lines. In additional studies, arachidonic acid metabolism was examined in the same two lines. In the highly responsive line, PMA stimulated a rapid release of [3H]arachidonic acid and its conversion into cyclooxygenase and lipoxygenase products. In the less-responsive line, PMA stimulated a slower release of [3H]arachidonic acid from prelabeled cells. The quantity of arachidonic acid metabolites produced was also much less. These studies suggest that the disparity between the two cell lines in their response to phorbol ester stimulation is not the result of differences in the initial interaction between the cells and ligand but may result from alterations in their signal transductance mechanism. This may be the result of inherent differences in capacity for arachidonic acid metabolism.

Characterization of thrombospondin synthesis, secretion and cell surface expression by human tumor cells.

Previous studies have shown that thrombospondin (TSP) is an adhesion factor for some human tumor cells. The previous studies have shown further that tumor cells which utilize TSP as an adhesion factor also synthesize it. This study continues the effort to understand how TSP production and expression are regulated in human tumor cells and the consequences of this for the cells. It is shown that differences among cell lines in their capacity to biosynthesize TSP are associated with differences in TSP specific mRNA levels. This indicates that biosynthesis is regulated at the transcriptional level. There is also a direct relationship between TSP biosynthesis and secretion into the culture medium and expression at the cell surface. The cells which are the most biosynthetically active secrete amounts of TSP into the culture medium that are sufficient to elicit a detectable response in the cell-substrate adhesion assay. The kinetics of TSP secretion by these cells are in accord with the kinetics of attachment and spreading of the same cells in the absence of exogenous adhesion factors. These data are consistent with the idea that endogenously produced TSP promotes the adhesion of the cells which synthesize it in an autocrine manner.

Tissue destruction resulting from the interaction of cytotoxic T cells and their targets.

In vitro and in vivo-generated cytotoxic T lymphocytes (CTL) specific for major and minor histocompatibility antigens evoked antigen-specific full-thickness skin necrosis when injected intradermally into allogeneic mice in a variety of strain combinations. In addition, CTL-target-cell mixtures injected intradermally into hosts syngeneic to the CTL also evoked destruction of host tissue. These "innocent bystander" reactions were evoked with alloreactive CTL as well as with CTL directed against hapten (TNP)-modified and virus (influenza A)-infected target cells. Unlike the direct reactions, the bystander reactions in histocompatibility-antigen systems occurred in spite of H-2 incompatibility of the CTL, admixed target cells, and the hosts. One explanation for these results, currently under investigation, is that some bystander reactions may occur without MHC restriction. In aggregate, our findings indicate that nonspecific as well as antigen-specific reactions initiated by CTL-target-cell interactions may contribute to tissue destruction in allograft rejection, in severe forms of delayed-type hypersensitivity, and in certain viral infections.

Effect of Misoprostol on Mesangial Cell Growth and Collagen Metabolism.

Independent of etiology, progressive chronic renal failure is characterized by accumulation of mesangial matrix and collagenous materials leading to glomerular sclerosis and closure. Pharmacologic intervention aimed at ameliorating this process has significant potential for substantial clinical benefit. We, therefore, assessed the effect of misoprostol on glomerular mesangial cell growth and collagen metabolism. Studies were carried out using a rat glomerular mesangial cell line cloned in our laboratory. At the concentration tested (1 &mgr;M), neither misoprostol nor prostaglandin E(2) had any effect on glomerular mesangial cell proliferation. Misoprostol did not change the absolute synthesis rates for collagen or total protein when measured by (14)C-proline incorporation into protein-associated hydroxyproline and proline respectively. However, the amount of collagen extruded into the medium, as a percentage of protein synthesis, was decreased by 10% in misoprostol-treated cells (p = 0.042). In addition, collagen breakdown was 26% greater in misoprostol-treated cultures (p = 0.044). Misprosotol had no such effects on cell cultures subjected to mechanical stress applied as continuous stretch-relaxation cycles. These results indicate that misoprostol influences mesangial cell collagen metabolism by increasing the rate of endogenous breakdown and decreasing collagen export outside the cell. Misoprostol has no effect on mesangial cell proliferation.

Differential interaction of virulent and attenuated influenza virus strains with ferret alveolar macrophages: possible role in pathogenicity.

The ferret provides a unique model for the study of human influenza. The interaction between alveolar macrophages and virus strains with different levels of virulence was examined in vitro. The greater virulence of wild-type A strains over type B and C viruses was reflected in the higher production of infectious virus progeny and subsequent cytopathology, even though the expression of viral antigens was equivalent for all strains tested. These included A/Ann Arbor/6/60 (H2N2) and A/Rochester/1/82 (H3N2), B/Hong Kong/72, and C/Ann Arbor/1/50. The attenuated cold-adapted and temperature-sensitive variant of A/Ann Arbor/6/60 behaved like its parent except that a longer period was needed to reach peak viral release. In contrast, the avirulent host-range reassortant CR-43-3 did not productively replicate, though viral antigen expression was comparable to that of the other strains. Type C virus infected few cells and these continued to release low virus levels in the absence of detectable cytopathology. The results suggest that the ability of certain strains to infect and replicate in alveolar macrophages can be correlated to their in vivo virulence and may play a role in determining the course of viral pathogenesis.

Connective tissue growth factor and its regulation: a new element in diabetic glomerulosclerosis.

Connective tissue growth factor (CTGF), a member of the closely related CCN family of cytokines appears to be fibrotic in skin. To determine whether CTGF is implicated in diabetic glomerulosclerosis we studied cultured rat mesangial cells (MC) as well as kidney cortex and microdissected glomeruli from obese, diabetic db/db mice and their normal counterparts. Exposure of MC to rhCTGF significantly increased fibronectin and collagen type I secretion. Further, unstimulated MC expressed low levels of CTGF message and secreted minimal amounts of CTGF protein (36-38 kDa). However, exposure to TGF-beta, increased glucose concentrations, or cyclic mechanical strain, all causal factors in glomerulosclerosis, markedly induced the expression of CTGF transcripts. With all but mechanical strain there was a concomitant stimulation of CTGF protein secretion. TGF-beta also induced abundant quantities of a small molecular weight form of CTGF (18 kDa). The induction of CTGF protein by a high glucose concentration was mediated by TGF-beta, since a TGF-beta neutralizing antibody blocked this stimulation. In vivo studies using quantitative RT-PCR demonstrated that while CTGF transcripts were low in the glomeruli of control mice, expression was increased 27-fold after approximately 3.5 months of diabetes. These changes occurred early in diabetic nephropathy when mesangial expansion was mild, and interstitial disease and proteinuria were absent. A substantially reduced elevation of CTGF mRNA (2-fold) observed in whole kidney cortices indicted that the primary alteration of CTGF expression was in the glomerulus. These results suggest that CTGF upregulation is an important factor in the pathogenesis of mesangial matrix accumulation in both diabetic and non-diabetic glomerulosclerosis, acting downstream of TGF-beta.

Treatment of mice with anti-asialo-GM1 antibody or poly-I:C: effects on metastasis dissociable from modulation of macrophage antitumor activity.

Treatment of C57BL/6J mice with poly-I:C or antibodies to asialo-GM1 enhances and depresses respectively natural killer (NK) cell activity while inversely altering lung metastasis, suggesting a critical role for these cells in controlling tumor formation. We assessed the effect of these treatments on antitumor activity mediated by macrophage (M phi) populations likely to be important in lung metastasis. Alveolar and lung interstitial M phi were asialo-GM1 positive (98%) and were sensitive to in vitro treatment with the antibody plus complement; however, treatment of mice with antibodies to asialo-GM1 failed to alter their tumoricidal activity in vitro. Few blood monocytes (4%) or spleen M phi (2%) were asialo-GM1 positive and their antitumor activity was similarly unaffected. In contrast, however, this same in vivo treatment resulted in a 14-fold increase in lung metastasis. Intraperitoneal injection of poly-I:C greatly reduced metastasis formation but also failed to significantly affect in vitro cytolytic activity of the M phi populations. These findings suggest that the major metastasis altering effects of these agents result from modulation of NK rather than M phi function.

Modelling the effects of vascular stress in mesangial cells.

It has recently been shown that mesangial cells are subjected to multiple forms of mechanical strain (fluid shear, hydrostatic pressure, and triaxial stretch) as a result of forces exerted by the vasculature. Nevertheless, the exact nature and the relative response to these stimuli have not been clarified. Although it is now well established that cyclic stretching of mesangial cells in culture results in the overproduction of extracellular matrix, indicating how intraglomerular hypertension may lead to glomerular scar formation, the contribution of different intracellular signalling mechanisms and extracellular mediators of the response are only now being identified. Recent studies point to a role for high glucose concentrations, transforming growth factor beta and its receptors, vascular endothelial growth factor, and connective tissue growth factor as important mediators, or modifiers of the response to mechanical strain. Although evidence exists for a role for protein kinase C, recent studies also implicate the mitogen-activated protein kinases along with enhanced DNA-binding activity of AP-1 as part of the signalling cascade altering matrix synthesis and cell proliferation in response to stretch. Finally, recent studies examining the effects of oscillating hyperbaric pressure demonstrate similarities, as well as differences, in comparison to those of cyclic stretch.

Thrombospondin binding by human squamous carcinoma and melanoma cells: relationship to biological activity.

Human squamous carcinoma cells attach and spread on thrombospondin (TSP)-coated culture dishes but exhibit significant variability among individual cell lines in their degree of responsiveness. Using a highly responsive squamous carcinoma line and a cell line which is much less responsive (as well as a human melanoma cell line which does not respond at all in the adhesion assay), we have examined binding of exogenous radiolabeled TSP. The cells which were the most responsive to TSP in the adhesion assay bound the greatest amount of radiolabeled ligand. Binding was time- and dose-dependent, saturable, inhibitable with excess unlabeled TSP, reversible, and specific. The less-responsive squamous carcinoma cells bound only 25-30% of the amount of TSP bound by the highly responsive cells while the nonresponsive melanoma cells bound less than 10% of the amount bound by the highly responsive squamous carcinoma cells. Our previous studies (J. Varani et al. (1986) Exp. Cell Res. 167, 376) have shown that the highly responsive squamous carcinoma cells also synthesized the greatest amount of TSP as indicated by biosynthetic labeling studies. The less-responsive squamous carcinoma cells were intermediate in synthetic activity and no synthetic activity was seen with the melanoma cells. These findings suggest that the amount of ligand bound may determine the degree of biological responsiveness and that endogenously synthesized TSP may be the source of that ligand.

Modulation of keratinocyte motility. Correlation with production of extracellular matrix molecules in response to growth promoting and antiproliferative factors.

Normal human epidermal keratinocytes (KC) grown under conditions that maintain the undifferentiated state are highly motile. Migration of these cells as measured in two different assays (migration out of an agarose drop explant, and into micropore filters in a modified Boyden chamber), is stimulated by fibronectin (FN) and to a lesser extent by thrombospondin (TSP). In contrast, laminin (LN) inhibits KC migration. Cultivation of the cells for 1 day under conditions that induce differentiation (ie, in the presence of 1.4 mM Ca2+) suppresses KC motility. A number of soluble growth modulating polypeptide factors also influence KC migration. Transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF) stimulate KC motility. These factors simultaneously induce KC production of FN and a significant portion of the stimulated motility can be inhibited with antibodies to FN. EGF and somatomedin-C (SM-C), but not TGF-beta, also stimulate TSP production while EGF and SM-C (but not TGF-beta) induce KC proliferation. In contrast to these factors, interferon-gamma (INF-gamma) inhibits KC production of both FN and TSP and concomitantly inhibits both motility and proliferation. These data suggest that KC properties essential for normal wound healing (ie, motility and proliferation) are regulated by both extracellular matrix molecules and soluble peptide factors. Finally, these effects of various growth promoting and antiproliferative factors on KCs may, in part, be mediated through alteration in the endogenous production of extracellular matrix molecules by KCs.

Role of glomerular mechanical strain in the pathogenesis of diabetic nephropathy.

Glomerular rigidity limits the glomerular expansion and mesangial cell (MC) stretch induced by variations in intracapillary pressure. In tissue culture, MC stretch stimulates synthesis of extracellular matrix components (ECM). Therefore, altered glomerular rigidity in diabetes may influence ECM accumulation by modulating the glomerular distention and MC stretch associated with glomerular hypertension. An ambient of high glucose concentration per se also enhances MC formation of ECM, possibly altering the cellular response to mechanical stretch. In this study, compliance was measured in isolated perfused glomeruli from streptozotocin-injected rats at four days (4d-D), five weeks (5w-D) and six months (6m-D) after induction of diabetes. In addition, collagen metabolism induced by stretch was investigated in MC cultured in 8 and 35 mM glucose concentrations. Glomerular compliance was normal in 5w-D rats and moderately increased in 4d-D (16%) and 6m-D animals (14%). As compared to static cultures. MC stretch increased total collagen synthesis (8 mM, 50%; 35 mM, 27%) and catabolism. However, while the fraction of newly formed collagen being catabolized increased in 8 mM-stretched cultures, in 35 mM-stretched it was unchanged. This resulted in marked increase in the net collagen accumulated in the incubation medium (4 vs. 24%) and cell layer 5 vs. 15%) only in the latter. In diabetes, the largely unaltered glomerular stiffness renders hypertension-induced MC stretch unopposed. More importantly, the accumulation of ECM caused by any degree of mechanical strain is greatly aggravated in a milieu of high glucose concentration.

Immunogold localization of high-affinity glucose transporter isoforms in normal rat kidney.

BACKGROUND: Facilitative glucose transporters (GLUT) have unique kinetic characteristics and distributions suited to the functions of the tissues in which they reside. However, little is known about their individual roles in renal glucose metabolism, and previous investigations of renal GLUT expression have been extensive only with respect to their mRNA levels. We provide here a complete analysis of three GLUT isoforms along the nephron using a sensitive immunodetection method. EXPERIMENTAL DESIGN: Normal rat kidneys were harvested, fixed in paraformaldehyde, and embedded in either paraffin or resin as required for immunogold labeling of individual GLUT Isoforms 1, 3, and 4. Samples were evaluated by light microscopy and selected regions analyzed by high resolution optical scanning with computer-assisted detection of immunogold-labeled GLUT at the subcellular level. We describe, compare, and related to the local patterns of glucose metabolism the cellular and subcellular expression patterns of these GLUT along the nephron. RESULTS: GLUT1 was most intensely labeled in the medullary thick ascending limbs of Henle, cortical collecting ducts, and inner medullary collecting ducts. In contrast, GLUT3 was most prominent in the inner medullary collecting ducts and GLUT4 in medullary thick ascending limbs of Henle. All three GLUT were detected in glomerular tufts, and GLUT1 was also detected in parietal epithelial cells. The predominant subcellular distributions in tubule cells were: basolateral and basolateral/cytoplasmic for GLUT1; basolateral and cytoplasmic for GLUT3; and perinuclear/cytoplasmic for GLUT4. GLUT 1 and 3 expressions were confirmed in specific regions by immunoblotting. CONCLUSIONS: 1) GLUT 1, 3, and 4 are expressed in both glomeruli and renal tubules. 2) The unique GLUT expression patterns along the renal tubules suggests unique functional roles for these isoforms. 3) The renal cortex demonstrates lesser labeling intensity for the high-affinity GLUT compared with the medulla, where higher rates of glucose oxidation and glycolytic metabolism are paralleled by higher GLUT labeling intensities.

Mechanical strain of glomerular mesangial cells in the pathogenesis of glomerulosclerosis: clinical implications.

Due to their elasticity, glomeruli will undergo excessive expansion and repetitive cycles of distension contraction under conditions of impaired glomerular pressure autoregulation and systemic arterial hypertension. These alterations in glomerular volume are associated with mesangial cell stretch which in turn stimulates the synthesis and deposition of ECM with eventual mesangial expansion and glomerulosclerosis. Hyperactivity of growth factors with prosclerotic activity is an important component in the translation of cellular mechanical strain into the abnormal metabolism of ECM components. Although mesangial cell mechanical strain is expected to occur in both remnant glomeruli and in glomeruli of diabetic kidneys, quantitatively different factors will determine the resultant metabolic consequences. In remnant glomeruli, the mechanical stretch is intense, being accounted for largely by the marked glomerular hypertrophy and increased glomerular compliance. In diabetic glomeruli, however, the mechanical stretch is less prominent but its effect on ECM synthesis is markedly aggravated by the presence of hyperglycaemia. There are presently no methods clinically available to diminish the prosclerotic action of growth factors at the glomerular level. In addition, there are no effective means to specifically improve glomerular pressure autoregulation. Therefore, current therapies must be aimed at decreasing systemic arterial pressure, blocking angiotensin II action and reducing glomerular hypertrophy. While there are effective drugs for the treatment of hypertension and for angiotensin II inhibition, protein restriction is the only measure available to diminish glomerular hypertrophy. Finally, in diabetes correction of systemic and glomerular hypertension should be coupled with strict glycaemic control to correct both glomerular autoregulation and increased ECM deposition.