Biomedical subjects

Alessia Fornoni

Publications and source records attributed to Alessia Fornoni.

15 recordsLinked to original sources

PubMed2007

The l-isoform but not d-isoforms of a JNK inhibitory peptide protects pancreatic beta-cells.

The activation of c-jun N-terminal kinase (JNK) in pancreatic islets is associated with impaired function and viability, and JNK inhibitory peptides (JNKIs) are cytoprotective. In particular, l-isoforms of JNKIs were shown to improve islets viability, while the d-retroinverso isoform of JNKI (RI-JNKI), with a higher therapeutic potential due to longer half-life, has not been studied. We compared the cytoprotective properties of L-JNKI and RI-JNKI. Treatment of murine islets with L-JNKI resulted in preservation of islet equivalents and greater percentage of viable beta-cells in culture. In contrast, RI-JNKI was not protective. We found that L-JNKI but not RI-JNKI prevents endogenous c-jun phosphorylation in insulinoma cells. Moreover, RI-JNKI induced islet cells necrosis and activates the p-38 kinase. In conclusion, L-JNKI directly affects beta-cells and ameliorates islet viability and function, while RI-JNKI has toxic effects, limiting its biological application to islet cell biology.

Animals↗

PubMed2006

Chronic kidney disease care delivered by US family medicine and internal medicine trainees: results from an online survey.

BACKGROUND: Complications of chronic kidney disease (CKD) contribute to morbidity and mortality. Consequently, treatment guidelines have been developed to facilitate early detection and treatment. However, given the high prevalence of CKD, many patients with early CKD are seen by non-nephrologists, who need to be aware of CKD complications, screening methods and treatment goals in order to initiate timely therapy and referral. METHODS: We performed a web-based survey to assess perceptions and practice patterns in CKD care among 376 family medicine and internal medicine trainees in the United States. Questions were focused on the identification of CKD risk factors, screening for CKD and associated co-morbidities, as well as management of anemia and secondary hyperparathyroidism in patients with CKD. RESULTS: Our data show that CKD risk factors are not universally recognized, screening for CKD complications is not generally taken into consideration, and that the management of anemia and secondary hyperparathyroidism poses major diagnostic and therapeutic difficulties for trainees. CONCLUSION: Educational efforts are needed to raise awareness of clinical practice guidelines and recommendations for patients with CKD among future practitioners.

Anemia↗

PubMed2006

Low insulin-like growth factor binding protein-2 expression is responsible for increased insulin receptor substrate-1 phosphorylation in mesangial cells from mice susceptible to glomerulosclerosis.

Mesangial cells (MC) isolated from glomerulosclerosis-prone ragged, olygosyndactilism, pintail (ROP) mice retain a stable phenotype after exposure to elevated glucose concentrations, whereas MC from glomerulosclerosis-resistant C57BL/6 (C) mice do not. In NOD and db/db mice, the stable phenotype induced by diabetes consists of autocrine activation of the IGF-I signaling pathway. We hypothesized that high ambient glucose activates the IGF-I pathway in ROP but not in C MC. MC were propagated in either 6 or 25 mm glucose. Isolated murine glomeruli were used to confirm in vitro experiments. 25 mm glucose induced increased insulin receptor substrate (IRS)-1 phosphorylation in ROP but not C MC. However, IGF-I, IGF-I receptor, and IRS-1 protein levels were induced by exposure to 25 mm glucose in both cell lines. This occurred without a change in IGF-I binding sites, suggesting a role for IGF binding protein (IGFBP). ROP MC and glomeruli expressed less IGFBP-2 than C MC and glomeruli. Addition of exogenous IGFBP-2 partially blunted the effect of 25 mm glucose on IRS-1 phosphorylation in ROP MC. Renal biopsies from patients with diabetic nephropathy also showed markedly decreased IGFBP-2 expression when compared with patients without nephropathy. In summary, glucose induces IRS-1 phosphorylation in MC isolated from ROP mice susceptible to glomerulosclerosis. IGFBP-2 expression was low in ROP MC and glomeruli from patients with diabetic nephropathy, suggesting that this may represent a new marker of susceptibility to diabetic nephropathy. Finally, addition of exogenous IGFBP-2 in ROP MC partially blunted the effect of high glucose on IRS-1 phosphorylation and might have a protective role.

Animals↗

PubMed2006

Nonpharmacologic therapy for hypertension: does it really work?

Nondrug therapy of hypertension really does work but requires strong motivation by both patient and physician. In addition to global health benefits, prescription of weight loss, exercise, moderation of salt and alcohol intake, Dietary Approach to Stop Hypertension (DASH) eating plan, and tobacco avoidance can decrease the risk for normotensive and prehypertensive patients of developing fixed hypertension. Initiating and maintaining a healthy lifestyle may be sufficient to avoid pharmacologic therapy for some patients and is a valuable adjunct to drug therapy for most. Blood pressure lowering can be achieved by weight reduction (5-20 mm Hg/10 kg), DASH eating plan (8-14 mm Hg), dietary sodium reduction (2-8 mm Hg), increased physical activity (4-9 mm Hg), and moderation of alcohol consumption (2-4 mm Hg). Combination of two or more modalities may have an additive benefit. Cessation of tobacco abuse not only has global health benefits, but may reduce blood pressure.

Alcohol Drinking↗

PubMed2005

Barriers to successful care for chronic kidney disease.

BACKGROUND: The National Kidney Foundation has formulated clinical practice guidelines for patients with chronic kidney disease (K/DOQI). However, little is know about how many patients actually achieve these goals in a dedicated clinic for chronic kidney disease. METHODS: We performed a cross-sectional analysis of 198 patients with an estimated glomerular filtration rate of less than 30 ml/min/1.73 m2 and determined whether K/DOQI goals were met for calcium, phosphate, calcium-phosphate product, parathyroid hormone, albumin, bicarbonate, hemoglobin, lipids, and blood pressure. RESULTS: We found that only a small number of patients achieved K/DOQI targets. Recent referral to the nephrologist, failure to attend scheduled clinic appointments, African American ethnicity, diabetes, and advanced renal failure were significant predictors of low achievement of K/DOQI goals. CONCLUSION: We conclude that raising awareness of chronic kidney disease and K/DOQI goals among primary care providers, early referral to a nephrologist, the exploration of socioeconomic barriers and cultural differences, and both patient and physician education are critical to improve CKD care in patients with Stage 4 and 5 CKD.

Black or African American↗

PubMed2005

Metabolic syndrome and endothelial dysfunction.

The incidence of metabolic syndrome is rapidly increasing in the United States. Metabolic syndrome is associated with increased cardiovascular morbidity and mortality, and endothelial dysfunction is an early pathogenetic event in the metabolic syndrome. Endothelial dysfunction of either the coronary, the peripheral, or the cerebral vasculature is a predictor of vascular events and appears to be a marker of uncontrolled atherosclerotic risk that adds to the burden of the genetic predisposition to cardiovascular disease. Clinically and experimentally, endothelial dysfunction can be restored by several agents, including blockers/inhibitors of the renin-angiotensin-aldosterone system, as well as statins. Nevertheless, it would be premature, and most likely inappropriate, to use improvement of endothelial function as a surrogate end point to predict reduction in cardiovascular morbidity and mortality. However, a clear understanding of the mechanisms of endothelial dysfunction in the metabolic syndrome may allow the development of preventive and early therapeutic measures targeting cardiovascular disease.

Angiotensin II Type 1 Receptor Blockers↗

PubMed2005

Defining the role of mycophenolate mofetil in the treatment of proliferative lupus nephritis.

Systemic lupus erythematosus, which predominantly affects young women, is frequently complicated by renal involvement. The presence of acute glomerulonephritis significantly adds to morbidity and mortality. Cyclophosphamide has become the mainstay of treatment in patients with proliferative forms of lupus nephritis. However, adverse events such as severe infections and infertility have spurred the search for novel treatment regimens and agents. Sequential therapy has significantly reduced adverse events. In several pilot studies, mycophenolate mofetil (MMF) has emerged as a promising therapeutic approach for both the induction and maintenance phase in patients with lupus nephritis, delivering equal efficacy and a better adverse effect profile; however, these studies had a limited power, and a large, multicentre and probably multinational clinical trial will be needed to discern the optimal therapeutic approach. On the basis of the currently available literature, sequential therapy with cyclophosphamide induction followed by azathioprine or MMF maintenance can be recommended for most patients. In selected populations, induction with MMF is a reasonable option to reduce adverse events.

Azathioprine↗

PubMed2004

Autocrine activation of the local insulin-like growth factor I system is up-regulated by estrogen receptor (ER)-independent estrogen actions and accounts for decreased ER expression in type 2 diabetic mesangial cells.

Autocrine activation of the IGF-I system in mesangial cells (MC) promotes glomerular scarring in a model of type 1 diabetes. Although estrogens protect against progressive nondiabetic glomerulosclerosis (GS), women with diabetes seem to loose the estrogen-mediated protection against cardiovascular disease. However, little is known about the local IGF-I system and its interactions with estrogens in the pathogenesis of type 2 diabetic GS. Therefore, we examined db/db B6 (db/db) mice, a model of type 2 diabetes and diabetic GS. The IGF-I system was activated in the glomeruli and MC of female diabetic db/db mice, but not in nondiabetic db/+ littermates. We found increased IGF-I receptor (IGFR) expression and activation, including activation of MAPK. Surprisingly, estrogens, via an estrogen receptor (ER)-independent mechanism(s), increased IGFR expression, IGFR and insulin receptor substrate phosphorylation, and extracellular signal-regulated kinase activation in db/db MC. In contrast, ER expression was decreased in MC and glomeruli of db/db mice. Treatment with a neutralizing antibody to IGF-I or the MAPK inhibitor PD98059 increased ER expression and transcriptional activity. This suggests that the local prosclerotic IGF-I system is activated in type 2 diabetes and diminishes ER-mediated protection against GS. Although estrogens may stimulate protective ER signaling, they also activate the IGF-I system via ER-independent mechanisms in db/db MC. The later estrogen effects appear to outweigh the antisclerotic effects of ER activation. This may in part account for loss of estrogen protection against the progression of diabetic GS in women with type 2 diabetes.

Animals↗

PubMed2004

Aging exacerbates neointimal formation, and increases proliferation and reduces susceptibility to apoptosis of vascular smooth muscle cells in mice.

OBJECTIVES: In response to injury, aging mediates exaggerated neointimal formation, the pathologic hallmark of obliterative vascular diseases. We assessed the development of neointima in a model of mechanical vascular injury in aging mice (18 months old) and young mice (2 months old). To investigate the mechanisms by which aging affects neointimal formation, we also carried out a set of in vitro studies to characterize the biologic properties of vascular smooth muscle cells (VSMCs) derived from aging and young mice. METHODS: Aging and young mice were subjected to wire injury to the carotid artery. Four weeks later injured arteries were harvested, and neointimal formation was histologically assessed. The profiles of angiogenesis-related genes between aortic VSMCs derived from aging and young mice were compared with complementary DNA arrays. Expression of platelet-derived growth factor receptor-alpha (PDGFR-alpha) and proliferation in response to platelet-derived growth factor-BB (PDGF-BB) by VSMCs were assessed. Susceptibility to apoptosis in aging and young VSMCs in response to nitric oxide and serum starvation was investigated. In addition, the level of apoptosis in neointimal VSMCs (by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay) was compared between aging and young animals. RESULTS: When compared with young mice, aging mice exhibited exaggerated neointimal formation (intima-media ratio, 1.17 +/- 0.57 vs 0.49 +/- 0.16; P < .0001). Aging VSMCs expressed higher levels of PDGFR-alpha (12.0% +/- 2.7% vs 3.2 +/- 0.67%; P = .034) and greater proliferative response (4-fold increase) to PDGF-BB, compared with young VSMCs. However, aging VSMCs were less susceptible to apoptosis when subjected to serum starvation (75% less) and exposure to nitric oxide (50% less). Furthermore, there was more apoptosis in the neointima of young arteries than in their aging counterparts (8.75% +/- 3.3% vs 2.8% +/- 1.9; P = .021). CONCLUSIONS: Age-dependent increases in PDGFR-alpha may alter VSMC proliferation, and when coupled with resistance to apoptosis could contribute to exaggerated neointima formation in aging animals. Of significance, our findings in the mouse will enable application of abundant molecular tools afforded by this species to further dissect the mechanisms of exaggerated neointimal formation associated with aging. CLINICAL RELEVANCE: Neointimal formation is the pathologic hallmark of obliterative vascular diseases, including primary atherosclerosis, post stent restenosis, graft occlusion after vascular bypass procedures, and transplant allograft vasculopathy. Aging is an independent risk factor for development of cardiovascular diseases, and aging exaggerates neointimal formation after vascular injury. Understanding the mechanisms responsible for this phenomenon may facilitate prevention or provide new therapies for vascular occlusive diseases, which are so prevalent in the aging population. Our ability to reproduce the model in the mouse will no doubt facilitate such understanding.

Aging↗

PubMed2004

Development of albuminuria and glomerular lesions in normoglycemic B6 recipients of db/db mice bone marrow: the role of mesangial cell progenitors.

The pathologic hallmarks of diabetic nephropathy are excess mesangial extracellular matrix (ECM) and mesangial cell proliferation. We previously showed that mesangial cell phenotypic changes play an important role in the pathogenesis of diabetic nephropathy. We concluded that phenotypic changes were present in bone marrow (BM)-derived mesangial cell progenitors, as transplantation of BM from db/db mice, a model of type 2 diabetic nephropathy, transferred the db genotype and a nephropathy phenotype to naive B6 mice recipients. The recipients did not develop diabetes; however, they did develop albuminuria and glomerular lesions mirroring those in the donors (i.e., glomerular hypertrophy, increased ECM, and increased cell number with cell proliferation). We found that matrix metalloproteinase 2 (MMP-2) facilitated invasion of the mesangial cells into ECM and proliferation in vitro. Thus, increased MMP-2 activity in db/db mesangial cell progenitors may partially explain increased mesangial cell repopulation and proliferation in B6 recipients of db/db BM. In summary, BM-derived mesangial cell progenitors may play a crucial role in the development and progression of ECM accumulation and mesangial cell proliferation in this model of diabetic nephropathy in type 2 diabetes.

Albuminuria↗

PubMed2003

Glucose induces clonal selection and reversible dinucleotide repeat expansion in mesangial cells isolated from glomerulosclerosis-prone mice.

Clonal selection has been proposed as a pathogenetic mechanism in various chronic diseases, such as scleroderma, hypertension, pulmonary fibrosis, interstitial fibrosis of the kidney, atherosclerosis, and uterine leiomyomatosis. We previously found that mesangial cells from ROP mice prone to develop glomerulosclerosis changed their phenotype in response to high glucose concentrations. Here, we investigate whether clonal selection might contribute to this phenotype change. We found that in ROP mice at least two distinct mesangial cell clones exist. They are characterized by a different length of the d(CA) repeat in the MMP-9 promoter and exhibit a significantly different gene expression profile. Exposure of ROP mesangial cells to 25 mmol/l glucose for 35 days induces both clonal selection and reversible dinucleotide repeat expansion. None of these findings were present in mesangial cells isolated from C57BL/6 mice, which are not sclerosis-prone. We conclude that mesangial cell michrochimerism may be a marker for the susceptibility to glomerulosclerosis, that dinucleotide repeat expansion may be a novel mechanism for glucose-induced changes in gene expression, and that clonal selection may partially explain the change in mesangial cell phenotype in diabetes.

Alleles↗

PubMed2002

Association of a decreased number of d(CA) repeats in the matrix metalloproteinase-9 promoter with glomerulosclerosis susceptibility in mice.

The genetic background plays an important role in the development of progressive glomerulosclerosis. However, no marker is available for the reliable prediction of genetic susceptibility to glomerulosclerosis. Because matrix metalloproteinase-9 (MMP-9) levels are decreased in models of glomerulosclerosis and MMP-9 promoter polymorphism has been observed among patients with diabetic nephropathy, MMP-9 could be one such marker. The object of this study was to determine whether MMP-9 promoter polymorphism was associated with altered MMP-9 expression in mesangial cells (MC) from two mouse strains, i.e., ROP (glomerulosclerosis prone) and B6SJL (glomerulosclerosis resistant). ROP MC expressed 12-fold less MMP-9 mRNA. The MMP-9 promoter in ROP MC contained fewer d(CA) repeats, which was associated with lower MMP-9 expression and activity. Phorbol-12-myristate-13-acetate (3 to 60 ng/ml) increased MMP-9 expression in both MC types (3- to 4.5-fold), but the level in ROP MC never reached that in B6SLJ MC. Although reciprocal transfection of ROP and B6SJL MMP-9 promoter constructs into B6SJL and ROP cells revealed that the promoters were functional in both cell types, the B6SJL promoter was less responsive to phorbol-12-myristate-13-acetate stimulation when transfected into ROP MC, suggesting a role for other factors. In conclusion, the MMP-9 promoter exhibits a decreased number of d(CA) repeats in the sclerosis-prone strain. Because fewer d(CA) repeats associated with decreased MMP-9 expression in MC, it might be a genetic marker for glomerulosclerosis.

Animals↗

PubMed2002

Upregulation of type I collagen by TGF-beta in mesangial cells is blocked by PPARgamma activation.

We found that peroxisome proliferator-activated receptor-gamma (PPARgamma) mRNA was reduced by 77% in glomeruli of diabetic mice. Because mesangial cells play an important role in diabetic nephropathy, we examined regulation of type I collagen expression by PPARgamma and transforming growth factor-beta(1) (TGF-beta(1)) in mouse mesangial cells in the presence of 6 and 25 mM glucose. Mesangial cells contained functionally active PPARgamma. Exposure to 25 mM glucose resulted in reduced PPARgamma expression and transcriptional activity, accompanied by increased type I collagen expression. Restoration of PPARgamma activity to normal levels in cells cultured in 25 mM glucose, by transfection with a PPARgamma expression construct and treatment with the PPARgamma agonist troglitazone, returned type I collagen levels toward normal values. Activation of PPARgamma by troglitazone also decreased type I collagen mRNA and blocked TGF-beta(1)-mediated upregulation of type I collagen mRNA and protein. Moreover, PPARgamma activation suppressed basal and activated TGF-beta(1) responses in mesangial cells. This action was blocked by transfection of cells with a dominant-negative PPARgamma construct. In summary, PPARgamma suppresses the increased type I collagen mRNA and protein expression mediated by TGF-beta(1) in mesangial cells.

Animals↗

PubMed2002

Reversibility of glucose-induced changes in mesangial cell extracellular matrix depends on the genetic background.

Adequate glycemic control protects most patients with diabetes from nephropathy, but a substantial fraction of patients develop progressive disease despite lowering glycemia. We isolated mesangial cells (MC) from the glomeruli of mouse strains that model these two outcomes in patients with diabetes, namely those that have the propensity (ROP) or resistance (B6) to develop progressive diabetic nephropathy. We determined the nature and reversibility of changes in selected extracellular matrix-related molecules after chronic exposure to elevated glucose concentration. MC were exposed to 25 mmol/l glucose for 5 weeks followed by 6 mmol/l glucose and 19 mmol/l mannitol for an additional 5 weeks. Matrix metalloproteinase-2 (MMP-2) and transforming growth factor-beta(1) (TGF-beta(1)) levels increased in B6 MC exposed to 25 mmol/l glucose but returned to baseline levels when the glucose concentration was reduced to 6 mmol/l. MMP-2 and TGF-beta(1) were higher in ROP MC at baseline and increased in response to 25 mmol/l glucose, but remained elevated when glucose concentration was reduced. Type I collagen expression and accumulation increased in a reversible manner in B6 MC exposed to 25 mmol/l glucose. However, type I collagen expression was higher in ROP MC at baseline and remained unaffected by changes in glucose concentration. Thus, 25 mmol/l glucose induced reversible changes in MMP-2, TGF-beta(1), and type I collagen in MC of sclerosis-resistant mice but not in MC from sclerosis-prone mice. Therefore, progressive diabetic nephropathy may be secondary to stable alterations in the phenotype of MC as a result of the interplay between the genetic background and elevated glucose concentrations.

Animals↗

PubMedDate not supplied

Overutilization of central venous catheters in incident hemodialysis patients: reasons and potential resolution strategies.

Even after adjusting for comorbidities, the outcomes in hemodialysis (HD) patients using a central venous catheter (CVC) as dialysis access are worse than in those with a permanent vascular access. In spite of this, nationwide data suggest that only about 25% of incident HD patients initiate dialysis with an arteriovenous fistula. We conducted a retrospective study to identify reasons and resolution strategies for CVC use in patients who initiated HD at an academic medical center with a well-established chronic kidney disease (CKD) clinic and a dedicated vascular surgeon. Estimated glomerular filtration rate (eGFR) loss over time to record progression of patients to HD was also examined. The charts of 170 consecutive patients were reviewed. Ninety-two percent were found to initiate HD using a CVC. Three factors explained 93% of all CVC in our cohort: absence of adequate predialysis care (45%), acute illness with failure to recover from an episode of acute renal failure (31%), and patient's failure to adhere to scheduled clinic or surgical appointments (17%). In addition, analyses of eGFR suggest that the velocity of GFR loss rather than a defined degree of renal function might be a better trigger for vascular access referral. We conclude that early referral, a close follow up of CKD patients who initiate dialysis due to acute illness, and patient education may have a positive impact to counteract overutilization of CVCs for dialysis. The rate in eGFR decline might also be used to calculate the referral time adequate for fistula creation.

Acute Kidney Injury↗