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E Matteucci

Publications and source records attributed to E Matteucci.

At least 19 recordsLinked to original sources
PubMed2006

Hepatocyte growth factor differently influences Met-E-cadherin phosphorylation and downstream signaling pathway in two models of breast cells.

E-cadherins are implicated in cell adhesion, and also in cell signaling by associating with tyrosine kinase-receptors such as Met, the hepatocyte growth factor (HGF) receptor. Using two different cellular models, i.e. MCF-7 (breast carcinoma) and MCF-10 (immortalized mammary) cells, we studied the possible mechanism(s) by which E-cadherins modulate the signaling pathways downstream of Met, leading to beta-catenin-TCF transcriptional activity. In MCF-7, but not in MCF-10 cells, E-cadherins were remarkably associated with Met. Moreover, in MCF-7 cells both co-immunoprecipitation with anti-Met antibody and co-localization were increased by 30-min HGF treatment, which caused E-cadherin tyrosine phosphorylation. Also beta-catenin in the co-immunoprecipitate was phosphorylated by HGF, probably favoring TCF activation. Consistently, after HGF treatment, beta-catenin redistributed earlier in MCF-7 than in MCF-10 cells, with nuclear accumulation and activation of TOPFLASH gene reporter. Our results indicate a functional role of Met-E-cadherin interaction in MCF-7 cells through the amplification of the signaling downstream of HGF-Met triggering that involved c-Src and phosphoinositide-3-kinase activities.

Breast Neoplasms↗
PubMed2005

Dietary habits and nutritional biomarkers in Italian type 1 diabetes families: evidence of unhealthy diet and combined-vitamin-deficient intakes.

OBJECTIVE: Nutritional status and lifestyle can have profound effects on health. To analyse behaviour patterns in population subgroups of public health importance, we compared lifestyle, dietary intake of energy and selected nutrients, and nutritional biomarkers of type 1 diabetes (T1DM) patients and nondiabetic first-degree relatives against control subjects with no family history of T1DM. DESIGN: A cross-sectional study. SETTING: Department of Internal Medicine, University of Pisa, Italy. SUBJECTS: A total of 209 individuals including 38 type 1 patients, 76 relatives, and 95 healthy subjects. INTERVENTIONS: We used the European Prospective Investigation of Cancer and Nutrition questionnaires to assess dietary intake and lifestyle. Anthropometric indices and nutritional biomarkers (such as plasma levels of albumin, iron, lipids, homocysteine, vitamin B9 and vitamin B12 as well as urinary outputs of nitrogen, sodium and potassium) were evaluated. RESULTS: Emerging health issues: (1) In total, 45% of controls were overweight. Increasing age was associated with increasing body mass and decreasing activity in sport in front of an unchanged energy intake. (2) The distribution of energy sources was incorrect. The proportion of caloric intake derived from total fat and cholesterol did not match general guidelines. Total dietary fibre consumption was assessed to be adequate (25 g/day) in only 27% of all the participants. (3) Estimated daily intakes of water-soluble vitamin B9 and fat-soluble vitamin D and vitamin E were deficient in comparison with dietary reference intakes. (4) The prevalence of adoption and maintenance of healthful eating and physical activity habits was higher in women and T1DM patients (probably as a consequence of the medical educational intervention). On the contrary, supportiveness of the family in term of changing the undesirable behaviours at home seemed to fail. CONCLUSIONS: This study provides first evidence indicating unhealthy dietary behaviours, which could even predispose to the development of diabetes and cardiovascular complications, in subjects living in Pisa. The combination of vitamin B9 and vitamin E deprivation could be deleterious for endothelial function, since these antioxidants have been implicated in the modulation of nitric oxide and eicosanoid signalling.

Adult↗
PubMed2004

Hepatocyte growth factor-activated NF-kappaB regulates HIF-1 activity and ODC expression, implicated in survival, differently in different carcinoma cell lines.

Hepatocyte growth factor (HGF)-stimulated Met signaling influences tumor survival, growth and progression, all processes involving the transcription factor NF-kappaB. NF-kappaB plays a complex role in the control of survival due to the influence of cellular factors acting downstream. We undertook a comparative investigation of two human breast carcinoma cells with different grades of malignancy and HepG2 hepatoma cells, which present a biphasic response to HGF (proliferation followed by apoptosis). We found evidence that HGF induced gene patterns characteristic of survival rather than apoptosis depending on the cell type. The ability of NF-kappaB to regulate expression of hypoxia-inducible factor-1alpha (HIF-1alpha), a survival/anti-apoptotic gene in cancer, seemed to be critical. In the HepG2 and MCF-7 (low invasive breast carcinoma) cell lines increased transcription and translation were responsible for HIF-1alpha induction after HGF. The regulation by NF-kappaB was mainly at the level of the 5'-UTR of the HIF-1alpha message. HIF-1 (alpha/beta heterodimer) was likely to transactivate Mcl-1, another anti-apoptotic gene. Opposite results were observed in MDA-MB-231 cells (highly invasive breast carcinoma), which have high NF-kappaB activity, further inducible by HGF, because HIF-1alpha mRNA expression and HIF-1 transactivating capacity were HGF-insensitive while the alpha subunit seemed to be degraded after HGF. However, ornithine decarboxylase (ODC) and heme oxygenase mRNA expression persistently increased. By transiently transfecting two ODC gene reporters we demonstrated that ODC is a target gene of NF-kappaB in HGF-treated tumor cells. By regulating HIF-1 activity and specific gene expression downstream, NF-kappaB may influence the survival threshold, with an impact on the fate of carcinoma cells after prolonged HGF treatment.

Breast Neoplasms↗
PubMed2004

Redox status and immune function in type I diabetes families.

Because abnormalities in redox balance cluster in type I diabetes families and the intracellular thiol redox status seems to modulate immune function, we aimed to investigate the relationship between oxidative stress and immunological features. We measured oxidative markers, serum proinflammatory cytokines, soluble cytokine receptors and subsets of peripheral blood lymphocytes (by varying combinations of CD4, CD8, CD23 or low-affinity IgE receptor, and CD25 or IL-2 receptor) from 38 type I patients, 76 low-risk (i.e. without underlying islet autoimmunity) non-diabetic first-degree relatives of diabetic patients, and 95 healthy subjects. In type I diabetes families, protein and lipid oxidation was confirmed by the presence of reduced sulphhydryl groups, increased advanced oxidation protein products, and increased plasma and erythrocyte malondialdehyde. Relatives had decreased counts of monocytes, of cells co-expressing CD23 and CD25 and of CD25(+) cells in peripheral blood. Patients with TIDM had similar defects and, in addition, showed decreased counts of peripheral CD4(+)CD8(+) lymphocytes and increased serum levels of soluble receptors for interleukin (IL)-6 and IL-2. Abnormal indicators of oxidative stress were related in part to immune abnormalities. In the whole study group, we found a correlation (multiple R 0.5, P < 0.001) of CD23(+)CD25(+) cells with blood counts of monocytes, CD4(+)CD8(+) cells, CD25(+) cells, basal haemolysis and plasma levels of thiols. In type I diabetics, anti-GAD65 antibody levels were associated (multiple R 0.6, P = 0.01) positively with sIL-6R, negatively with duration of diabetes and CD23(+)CD25(+) counts; plasma creatinine correlated positively (multiple R 0.6, P < 0.001) with both sIL-2R and tumour necrosis factor (TNF)-alpha concentration. Our study reports the first evidence that the oxidative stress observed in type I families is related to immunological hallmarks (decreased peripheral numbers of monocytes as well as cells bearing a CD4(+)CD8(+), CD23(+)CD25(+) and CD25(+) phenotype) from which the involvement of some immunoregulatory mechanisms could be suspected. It remains to be elucidated the course of events culminating in the loss of physiological immune homeostasis and disease pathology.

Adult↗
PubMed2002

Blood levels of total homocysteine in patients with type 1 diabetes (with no complications, diabetic nephropathy and/or retinopathy) and in their non-diabetic relatives.

BACKGROUND AND AIM: It has been reported that plasma homocysteine (Hcy) levels in type 1 diabetes (T1DM) patients without renal involvement are higher, similar to or lower than those in healthy controls. METHODS AND RESULTS: We measured plasma Hcy in 60 controls, 79 type 1 diabetics (23 with retinopathy, 22 with nephropathy) and 73 non-diabetic relatives of 30 probands. The female controls had lower levels than their male counterparts: geometric mean 10.5 vs 13.6 mumol/L, p < 0.001. Among the controls, smokers (n = 20) and ex-smokers (n = 12) had higher Hcy levels than non-smokers (n = 28): 13.2 and 13.2 vs 10.9 mumol/L, p < 0.01. Among the diabetics, high plasma Hcy levels were associated with male gender: 11.9 vs 9.1 mumol/L in women, p < 0.01. The patients without complications had higher plasma glucose and hemoglobin A1c (HbA1c) levels (p < 0.001), and lower plasma Hcy (9.2 mumol/L vs 12.2, p < 0.01) and uric acid levels (p < 0.05) than the controls. The patients with nephropathy and higher levels of Hcy (13.0 mumol/L vs 9.0, p < 0.05), and different levels of creatinine (p < 0.01), uric acid (p < 0.01), fibrinogen (p < 0.05), and urinary albumin (p < 0.001) than those with retinopathy. There was no difference in Hcy levels between the patients' relatives and the controls: 11.9 mumol/L in siblings vs 11.6 mumol/L, 13.5 mumol/L in parents vs 12.1 mumol/L. In the control group, plasma Hcy levels were associated with age, gender and smoking; among the diabetics, they correlated with age, gender, smoking, and plasma creatinine and lipoprotein (a) levels. CONCLUSIONS: 1) male gender and smoking are associated with high Hcy levels in healthy people; 2) plasma Hcy levels are lower in T1DM patients than in healthy people (glomerular hyperfiltration and accelerated hepatic transsulfuration?); 3) high Hcy levels are associated with diabetic nephropathy and plasma creatinine levels; and 4) non-diabetic first-degree relatives of type 1 diabetics have normal plasma Hcy concentrations.

Adult↗
PubMed2001

Influence of proteasome and redox state on heat shock-induced activation of stress kinases, AP-1 and HSF.

We studied the pattern of activation of stress kinases and of transcription factors activator protein-1 (AP-1) and heat shock factor (HSF) in FAO cells by combining two treatments, i.e. heating (42 degrees C for 1 h) and proteasome inhibition, each known to cause cellular heat shock response. The co-treatment heat shock (HS) and proteasome inhibitor (a peptidyl aldehyde or lactacystin) showed cumulative effects on the intensity and duration of activation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) at the end of the HS period and during recovery. Similarly, the thiol-reducing agents N-(2-mercaptoethyl)-1,3-diaminopropane and dithiothreitol strongly activated both JNK and p38 MAPK in cells undergoing HS. AP-1 DNA binding activity in response to proteasome inhibitors was so strong that it shadowed the stimulatory effect of HS in the combined treatment, but lactacystin, which is the most potent and specific proteasome inhibitor, decreased the binding late during recovery from HS. Thiol-reducing agents prevented AP-1 DNA binding induced by HS. The combined HS/proteasome inhibitors or HS/thiol-reducing agents treatments cooperatively activated HSF DNA binding. Expression of collagenase I and hsp 70 mRNAs reflects the different behavior of AP-1 and HSF transcription factors in cells exposed to HS and proteasome inhibition. The data seem to indicate that JNK and p38 MAPK activations are not necessarily coupled to DNA binding of AP-1, which can be either increased or inhibited when these kinases are activated. AP-1 and HSF show opposite patterns of response to HS in the presence of proteasome inhibitors or reducing agents.

Animals↗
PubMed2001

Hepatocyte growth factor induces pro-apoptotic genes in HepG2 hepatoma but not in B16-F1 melanoma cells.

Hepatocyte growth factor (HGF) exerts a cytostatic effect on HepG2 and B16-F1 cell lines. To evaluate the possible involvement of the apoptotic process in this effect, we performed studies at cellular and molecular levels. HGF induced apoptosis only in HepG2 hepatoma cells at day 3 in about 20% of the cells undergoing growth inhibition, while hallmarks of apoptosis did not occur in B16-F1 melanoma cells. During the first 24 h after HGF treatment, enhanced expression of the pro-apoptotic genes bax and c-Myc was observed at level of mRNA and protein. Concomitant induction of antizyme (AZ) might lower ornithine decarboxylase (ODC) protein level though a huge increase in ODC mRNA level took place. This was suggested as a signal for apoptosis decisional phase. The levels of the proteins examined except that of AZ fell down thereafter when HepG2 cells underwent apoptosis. In B16-F1 cells, only ODC and AZ protein levels were elevated probably in relation to the initial elevated growth rate and the absence of apoptosis involvement in the following cytostatic effect of HGF in melanoma cells. Consistent with this hypothesis, bax mRNA and protein levels were unchanged or even lower relative to control values.

Animals↗
PubMed2001

Erythrocyte sodium/hydrogen exchange inhibition by (-) epicatechin.

Epicatechin, a flavonoid belonging to the group of compounds collectively called catechins, have been reported to possess insulin-like properties. Besides their anti-diabetic properties, catechins also show growth inhibition. Since cytosolic pH (pHi) plays a role in cell proliferation and the Na/H exchanger (NHE) is the major pH (pHi) regulatory mechanism, we undertook in vitro studies with human erythrocytes to examine the effect of (-) epicatechin (EC) on the NHE1 isoform. NHE activity was measured in eight healthy volunteers, eight type 1 diabetics, and nine type 2 diabetics, following 30 min incubations at 37 degrees C with either 1 mM epicatechin, 10(-9) M insulin or solvent alone. NHE activity was elevated in both groups of patients (P< 0.05). Epicatechin caused a 93% decrease in Na/H antiport activity in health controls, 89 and 86% in type 1 and type 2 diabetics, respectively (P< 0.001). Insulin caused a 36% decrease in antiport activity only in the type 2 diabetic group (P< 0.05). The strong inhibition of erythrocyte NHE1 (the ubiquitously present isoform) by epicatechin may have important implications. NHE1 inhibition could be one of the major mechanisms underlying the antiproliferative effects of catechins.

Adult↗
PubMed2001

Advanced oxidation protein products in plasma: stability during storage and correlation with other clinical characteristics.

Proteins are susceptible to free radical damage. We measured advanced oxidation protein products (AOPP) in the plasma of 56 hospitalised patients. Concentrations of AOPP were expressed as chloramine-T equivalents by measuring absorbance in acidic conditions at 340 nm in the presence of potassium iodide. We also determined erythrocyte sedimentation rate (ESR), circulating urea, creatinine, glucose, uric acid, electrolytes, lipids, total proteins and fractions and fibrinogen. Twenty-four samples were processed both immediately and after 7, 15, 30, 90, 180 and 438 days of storage at both at -20 degrees C and -80 degrees C (aliquots were frozen and thawed only once) to evaluate AOPP stability. The remaining 32 samples were also processed for thiobarbituric-acid-reactive substances (TBARS). Mean AOPP concentration in all 56 patients was 48.3+/-37.2 microM. Mean basal concentration of AOPP in the 24 plasma samples (55.0+/-47.1 microM) showed no significant change at each intermediate determination, yet significantly increased after 438 days of storage both at -80 degrees C (96.6+/-83.2, p<0.01) and, markedly, at -20 degrees C (171.3+/-94.6, p<0.001). TBARS concentration was 1.59+/-0.65 micromol/l. Multiple regression analysis evidenced that AOPP concentration was positively correlated (multiple r=0.62, p<0.001) with serum urea and triglycerides, but negatively correlated with patient age (indeed, serum albumin and total proteins decreased with increasing age, r=0.3, p<0.05). TBARS concentration was associated with ESR and serum glucose (multiple r=0.73, p<0.001), yet positively with AOPP (r=0.39, simple p<0.05). We conclude that AOPP remain stable during sample storage both at -20 degrees C and -80 degrees C for 6 months. Renal failure and hypertriglyceridemia probably enhance the in vivo process of AOPP formation. Oxidative damage as measured by TBARS may be increased because of exposure to hyperglycemia causing nonenzymatic glycation of plasma proteins.

Adult↗
PubMed2001

Hepatocyte growth factor signalling stimulates hypoxia inducible factor-1 (HIF-1) activity in HepG2 hepatoma cells.

Hepatocyte growth factor (HGF), a multifunctional cytokine of mesenchymal origin, activates the DNA binding of hypoxia inducible factor-1 (HIF-1) in the HepG2 cell line: the activated complex contained the inducible alpha subunit. An increased expression of HIF-1alpha (mRNA and nuclear protein levels) was observed. To investigate the molecular basis of the HIF-1 response under this non-hypoxic condition, we evaluated first the expression of putative target genes. We found a time-dependent increase in steady-state mRNA levels of heme oxygenase and urokinase plasminogen activator at 4 h, followed by that of urokinase receptor at 10 h. The enhanced expression of these genes might confer the invasive phenotype, since HGF is a proliferative and scatter factor. Second, we examined some aspects of HIF-1 activity regulation in HGF-treated cells with the following findings: (i) the activation of HIF-1 DNA binding was prevented by proteasome blockade, probably because stabilization of the cytosolic alpha-subunit protein level is not sufficient to generate a functional form: also under these conditions nuclear protein level of HIF-1alpha did not increase; (ii) N-acetylcysteine, a free radical scavenger, strongly decreased HIF-1 activation suggesting a role of reactive oxygen species in this process; (iii) the thiol reducing agent dithiothreitol was ineffective. Third, consistent with these data, N-acetylcysteine reduced the stimulatory effect of HGF on stress kinase activities, while p42/44 mitogen activated kinase (MAPK) was unmodified, suggesting an involvement of c-Jun-N-terminal kinase (JNK) and p38 MAPK in HIF-1 activation. Finally, LY 294002 induced the blockade of phosphatidylinositol 3-kinase (PI3K), one of the principal transducers of HGF/Met receptor signalling, prevented the enhancement of HIF-1 DNA binding and JNK activity, but the inhibition of p42/44 MAPK phosphorylation with PD 98059 was ineffective. In conclusion, we suggest that HGF triggers a signal transduction cascade involving PI3K and ultimately activates HIF-1.

Carcinoma, Hepatocellular↗
PubMed2001

Screening for coeliac disease in families of adults with Type 1 diabetes based on serological markers.

The prevalence of coeliac disease (CD) in the adult population is unknown because silent and latent stages do exist. Type 1 diabetes mellitus may be associated with CD because of common genetic background and/or shared pathogenetic mechanisms. We investigated 74 adults with type 1 diabetes (32+/-11 yr, disease duration 13+/-9 yr), 69 parents of diabetic probands (56+/-10 yr), 59 siblings (30+/-11 yr) and 50 healthy controls (35+/-10 yr) for the presence of circulating islet cell antibodies (ICA), anti-glutamic acid decarboxylase antibodies (GADA65), anti-gliadin immunoglobulins A and G (IgA- and IgG-AGA). All patients with raised AGA, performed also IgA anti-endomysium antibody (EmA) indirect immunofluorescence assay. Samples were positive for ICA in 19 diabetics (26%), 4 parents (6%), 4 siblings (7%), 0 controls (p<0.001); for GADA in 34 diabetics (46%), 4 parents (6%), 1 sibling (2%), 0 controls (p<0.001). Twenty-five diabetic patients (34%), 10 parents (14%), 5 siblings (8%), 3 controls (6%) (p<0.001) had raised IgA-AGA (>4.4 mg/l). Four diabetic patients (5%), 5 parents (7%), 0 siblings (0%), 4 controls (8%) had raised IgG-AGA (>18 mg/l). Both IgA- and IgG-AGA were detected in 1 diabetic and 2 parents. The prevalence of ICA, GADA, and IgA-AGA positivity in Type 1 diabetes patients was significantly higher than in controls (p<0.001). Finally, 50 AGA-positive subjects performed EmA test: only 2 of them resulted EmA-positive, a diabetic patient and a sibling. The patient with Type 1 diabetes had a small-bowel biopsy specimen consistent with CD and, as sole evidence of malabsorption, sideropenic anaemia. EmA-positive sibling also showed severe iron deficiency, yet refused endoscopy. We conclude that: 1) CD cannot be diagnosed on the basis of associated IgA- and IgG-AGA alone. Nevertheless, detection of such antibodies is useful, in combination with EmA, in screening for endoscopic biopsy; 2) too high rate of detection of IgA-AGA in Type 1 diabetic patients in comparison with other groups excludes a false positivity of the test itself, while suggests a pathogenetic association of both immunological disorders, perhaps related to abnormal gammadelta TCR-bearing intraepithelial lymphocytes.

Adult↗
PubMed2001

Glycated hemoglobin measurement: intermethod comparison.

Clinical interpretation of changes in serial measurements of patients' HbA1c ought to be based on the knowledge of pre-analytical, analytical and intra-individual sources of variation that affect the results. The detectable change in HbA1c percentage depends on total analytical error. Since we have previously evidenced major problems in the routine use of HPLC, we compared a highly automated glycohemoglobin assay with the reference HPLC to solve the problem. The within- and between-run coefficients of variations ranged from 0.86 to 0.93%, and 2.51 to 2.12%, respectively, for the HPLC, and from 1.07 to 0.95, and 1.61 to 0.99% for the immunoturbidimetric assay. After HbA1c-assay calibration, the quality-control survey report of duplicate determinations performed on 20 consecutive days by both the HPLC and the immunologic method provided the expected mean values of control materials. The assay of 106 blood samples showed a minor yet significant bias of the immunoturbidimetric assay toward lower HbA1c. values (p 0.0001), as previously observed, although the two determination series resulted significantly correlated (r=0.96,p=0.0001). We conclude that the immunoturbidimetric assay is surely accurate, precise, and reproducible, and represents a valid alternative to the reference HPLC assay.

Autoanalysis↗
PubMed2001

Sodium/hydrogen exchange activity in type 1 diabetes mellitus: the never-ending story.

The amiloride-sensitive Na+/H+ exchanger (NHE) mediates uphill H+ extrusion and thus causes intracellular alkalinization. The NHE plays a major role in pH homeostasis, Na+ absorption, cell volume regulation, and cell proliferation; it is activated by growth factors, mitogens, neurotransmitters, tumor promoters, and others. At intracellular pH (pHi)>7.2-7.4, the system is quiescent; when pHi falls, the rate of H+ - efflux increases in an allosteric manner to reach a maximum around pHi=6.0. The kinetics for external Na+ follows the Michaelis-Menten model with a single, binding site. The effect of intracellular H+ best fits an allosteric model with at least two binding sites. According to the postulate that erythrocyte sodium-lithium countertransport (NLCT) might be one mode of operation of the ubiquitous NHE, and following the trail of previous investigations of NLCT association with hypertension and diabetic nephropathy, several studies have confirmed elevated NHE activity in different cell types in patients with essential hypertension. However, the relation between NHE and either NLCT or hypertension remains unclear and the usefulness of NLCT activity as a risk marker for the development of essential hypertension has been now excluded. On the contrary, few publications have dealt with the physiologic NHE in diabetic nephropathy, and contrasting results have been reported. We have observed an accelerated NHE in essential hypertension and in Type 1 diabetes, however without any relationship with urinary albumin excretion rate. Furthermore, NHE activity increased in non-diabetic first-degree relatives of Type 1 diabetic patients, yet no difference could be observed between relatives of probands with diabetic nephropathy and relatives of probands with normoalbuminuria. Unlike erythrocyte NHE activity, abnormal albumin excretion was a distinctive feature of non-diabetic first-degree relatives of Type 1 diabetic patients with nephropathy. The lack of agreement among Authors, even using both the same cell and the same method, testifies to the difficulty in performing a correct patient selection and uniformly reproducible NHE measurement. We compare individual clinical characteristics among different study populations confirming previous conclusions regarding NLCT in essential hypertension: main determinant for the flux values of NHE seems to be patient selection rather than methodology. A common effort is advisable to collaborate, standardise, compare methodologies, and unify criteria of subject recruitment.

Diabetes Mellitus, Type 1↗
PubMed2000

Hepatocyte growth factor signal coupling to various transcription factors depends on triggering of Met receptor and protein kinase transducers in human hepatoma cells HepG2.

Hepatocyte growth factor (HGF) regulates a wide variety of biological activities by binding to the tyrosine kinase receptor Met. In HGF-treated hepatocarcinoma cells, we observed a biphasic activation of AP-1 and AP-2 transcription factors. For NF-kappaB complex the p50-p50 homodimer was activated before the p50-p65 heterodimer, and c-Myc/Max DNA-binding activity increased thereafter. Since these transcription factors are responders to mitogenic stimulation through protein kinase transducers, we tested the effects of inhibitors of these enzymes on the DNA binding after HGF treatment. Inhibition of protein kinase C (PKC) with H7 strikingly activated NF-kappaB above the values observed after HGF alone. Under this inhibitory condition, Met tyrosine phosphorylation was elevated as though the phosphorylation-dependent activity of the receptor was partially blocked by activation of PKC due to HGF. NF-kappaB DNA binding seems to be related to Met triggering by HGF since it was largely prevented by genistein treatment, which blocks receptor activity. Phosphatidylinositol 3-kinase seems to be involved in AP-1 binding activity stimulated by HGF. It is noteworthy that Met is responsive to HGF stimulating postreceptor signaling, which converges on the activation of transcription factors acting coordinately to regulate target gene expression.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2000

Transmembrane electron transfer in diabetic nephropathy.

OBJECTIVE: Erythrocytes (red blood cells [RBCs]) reduce extracellular ferricyanide by transmembrane transfer of reducing equivalents involving ascorbate recycling. RESEARCH DESIGN AND METHODS: Because ascorbate regeneration is glutathione (GSH) dependent and cells may be depleted of GSH in diabetes, we measured RBC GSH, plasma sulfhydryl (SH) groups, and RBC-mediated ferricyanide reduction in 30 type 1 diabetic patients (age 34 +/- 10 years, disease duration 20 +/- 8 years; no complications, n = 10; retinopathy, n = 10; nephropathy, n = 10), their 36 siblings (age 39 +/- 13 years), and matched healthy volunteers. RESULTS: Fasting plasma glucose was 15 +/- 7 mmol/l (vs. 5 +/- 1 in control subjects, P < 0.001), HbA1c 8.4 +/- 1.5% (vs. 5.4 +/- 0.3, P < 0.001), GSH 0.76 +/- 0.12 mg/ml packed RBCs (vs. 0.88 +/- 0.18, P < 0.01), SH groups 401 +/- 72 micromol/l (vs. 444 +/- 56, P < 0.05), and ferrocyanide generation 15 +/- 5 micromol/ml RBC per h (vs. 13 +/- 5, NS). In comparison with 10 normoalbuminuric diabetic subjects with retinopathy, 10 patients with diabetic nephropathy had similar fasting plasma glucose, HbA1c, and SH groups; lower RBC GSH (0.73 +/- 0.08 vs. 0.85 +/- 0.11, P < 0.05); and higher ferrocyanide generation (18 +/- 4 vs. 14 +/- 5, P < 0.05). The 10 patients without complications differed from the 10 healthy volunteers in glycemic control and RBC GSH. RBC electron transfer correlated with plasma lactate (r = 0.8, P = 0.01) only in the uncomplicated group. No difference was detected between siblings and healthy control subjects or between siblings of subjects in the nephropathy and retinopathy groups. Among diabetic patients, the rate of ferrocyanide generation was associated with urinary albumin excretion, plasma creatinine, and SH groups (multiple r = 0.6, P < 0.01). CONCLUSIONS: Transmembrane electron transfer is selectively increased in diabetic nephropathy, where RBC GSH is also depleted. The abnormality is peculiar to the nephropathy group and not contributed by familial or hereditary components because the electron flow was normal in siblings. The close relationship between cytosolic NADH and RBC electron transfer observed in diabetic patients without complications seems to be lost in the microangiopathic patients. Whereas patients with retinopathy alone still had normal activity of the RBC-reducing system, patients with nephropathy showed significantly increased activity, unrelated to metabolic parameters or plasma lactate concentration and correlated with renal function parameters and plasma thiols.

Adult↗
PubMed2000

Oxidative stress in families of type 1 diabetic patients.

OBJECTIVE: The link between hyperglycemia and the complications of diabetes is unknown. It is still discussed whether oxidative stress precedes or merely reflects diabetic complications. To search for a familial predisposition to oxidative stress, we investigated indexes of glucose and lipid metabolism, markers of plasma and cell lipid oxidation, a marker of oxidant-induced protein damage, and the effects of oxygen radicals on erythrocytes (or red blood cells [RBCs]) of patients with type 1 diabetes and their relatives. RESEARCH DESIGN AND METHODS: We recruited 30 type 1 diabetic subjects (10 without diabetic complications, 10 with retinopathy, and 10 with nephropathy), 36 nondiabetic siblings, 37 nondiabetic parents of type 1 diabetic subjects, and 3 control groups of healthy subjects without a family history of diabetes. Levels of blood creatinine, glucose, HbA(1c), cholesterol, triglycerides, lipoprotein(a) (Lp[a]), fibrinogen, malondialdehyde (MDA), and advanced oxidation protein products were determined. The RBC response to oxidative stress (3-h incubation at 37 degrees C with or without a radical generating system) was evaluated by measuring RBC glutathione (GSH), RBC-MDA, and hemolysis. RESULTS: Diabetic patients had higher levels of blood glucose (P < 0.001), HbA(1c) (P < 0.001), Lp(a) (P < 0.01), and fibrinogen (P < 0.05) than control subjects. Siblings of diabetic patients had higher Lp(a) levels (P < 0.001). Parents had higher levels of plasma glucose (P < 0.05) and Lp(a) (P < 0.01). Plasma and RBC-MDA were significantly elevated in diabetic subjects and relatives compared with control subjects. Basal RBC-GSH was lower in diabetic subjects (P < 0.01). In diabetic subjects, incubations of cells caused a decrease in RBC-GSH of a lesser degree than that in control subjects, but they caused a significant increase in hemolysis. Among relatives, hemolysis was increased both at baseline and after incubation. Plasma MDA levels were associated with blood glucose, creatinine, and fibrinogen levels (multiple r = 0.5, P < 0.001), and basal RBC-MDA levels were associated with plasma Lp(a), fibrinogen, and plasma MDA levels (r = 0.6, P < 0.001). Basal RBC-GSH content correlated with serum glucose and RBC-MDA production (r = 0.3, P < 0.01). CONCLUSIONS: Our study is the first to present evidence that markers of lipoprotein metabolism (Lp[a]), oxidative stress (plasma and RBC-MDA), and cellular fragility (hemolysis) are abnormal in nondiabetic relatives of type 1 diabetic subjects, thereby supporting the view that familial elements of diabetes even precede the onset of diabetes. It seems reasonable that the same biological markers considered major predictors of cardiovascular disease can also trace familial susceptibility to type 1 diabetes, just as they have been associated with the development of type 2 diabetes.

Adult↗