Interleukin-1-induced cyclooxygenase 2 expression is suppressed by cyclosporin A in rat mesangial cells

The Effects of a High-Fat Diet on Inflammatory Bowel Disease

The interactions among diet, intestinal immunity, and microbiota are complex and play contradictory roles in inflammatory bowel disease (IBD). An increasing number of studies has shed light on this field. The intestinal immune balance is disrupted by a high-fat diet (HFD) in several ways, such as impairing the intestinal barrier, influencing immune cells, and altering the gut microbiota. In contrast, a rational diet is thought to maintain intestinal immunity by regulating gut microbiota. In this review, we emphasize the crucial contributions made by an HFD to the gut immune system and microbiota.

The effect of renin-angiotensin-aldosterone system inhibitors on continuous and binary kidney outcomes in subgroups of patients with diabetes: a meta-analysis of randomized clinical trials

INTRODUCTION

Diabetic nephropathy is the leading cause of kidney failure. Clinical practice guidelines recommend prescribing renin-angiotensin aldosterone system inhibitors (RAASi) to prevent diabetic nephropathy at any stage. We conducted this systematic review and meta-analysis to compare the effects of RAASi with placebo and other antihypertensive agents in adults with diabetes on continuous and binary kidney outcomes to provide a comprehensive review of the class effect of RAASi on several subgroups.

METHODS

A systematic electronic search to identify randomized clinical trials of a duration of ≥ 12 months that recruited ≥ 50 adult participants with type 1 or 2 diabetes with any stage of chronic kidney disease and proteinuria was conducted in MEDLINE, CINAHL, EMBASE, and Cochrane library with no language restriction. Studies were screened against the inclusion and exclusion criteria by two reviewers independently.

RESULTS

In this meta-analysis, evidence was drawn from 26,551 patients with diabetes from 46 studies. Our analysis shows that RAASi were better than placebo in reducing SrCr (the raw mean difference [RMD] = -13.4 μmol/L; 95%CI: -16.78; -10.01) and albuminuria levels (standardized mean difference [SMD] = -1; 95%CI: -1.57, -0.44, I2 = 96%). When compared to other active treatments, RAASi did not reduce SrCr (RMD = 0.03 μmol/L; 95%CI: -6.4, 6.10, I2 = 76%), caused a non-significant reduction of GFR levels (RMD = -1.21 mL/min; 95%CI: -4.52, 2.09, I2 = 86%), and resulted in modest reduction of albuminuria levels (SMD = -0.55; 95%CI: -0.95, -0.16, I2 = 90%). RAASi were superior to placebo in reducing the risks of kidney failure (OR = 0.74; 95%CI: 0.56, 0.97) and doubling of serum creatinine levels (SrCr; OR = 0.71; 95%CI: 0.55, 0.91), but not in promoting the regression of albuminuria (OR = 3.00; 95%CI: 0.96, 9.37). RAASi, however, were not superior to other antihypertensives in reducing the risks of these outcomes. Patients with type 2 diabetes, macroalbuminuria and longer duration of diabetes had less risk of developing kidney failure in placebo-controlled trials, while longer duration of diabetes, normal kidney function, and hypertension increased the probability of achieving regression of albuminuria in active-controlled trials.

CONCLUSION

While our findings revealed the non-superiority of RAASi over other antihypertensives and portrayed a class effect on several subgroups of study participants, it raised a challenging question on whether RAASi deserve their place as first-line therapy in managing diabetic nephropathy.

Human mesenchymal stem cells derived from umbilical cord and bone marrow exert immunomodulatory effects in different mechanisms

BACKGROUND

Mesenchymal stem cells (MSCs) are an attractive tool to treat graft-versus-host disease because of their unique immunoregulatory properties. Although human bone marrow-derived MSCs (BM-MSCs) were the most widely used MSCs in cell therapy until recently, MSCs derived from human umbilical cords (UC-MSCs) have gained popularity as cell therapy material for their ethical and noninvasive collection.

AIM

To investigate the difference in mechanisms of the immunosuppressive effects of UC-MSCs and BM-MSCs.

METHODS

To analyze soluble factors expressed by MSCs, such as indolamine 2,3-dioxygenase, cyclooxygenase-2, prostaglandin E2 and interleukin (IL)-6, inflammatory environments in vitro were reconstituted with combinations of interferon-gamma (IFN-γ), tumor necrosis factor alpha and IL-1β or with IFN-γ alone. Activated T cells were cocultured with MSCs treated with indomethacin and/or anti-IL-10. To assess the ability of MSCs to inhibit T helper 17 cells and induce regulatory T cells, induced T helper 17 cells were cocultured with MSCs treated with indomethacin or anti-IL-10. Xenogeneic graft-versus-host disease was induced in NOG mice (NOD/Shi-scid/IL-2Rγ^null) and UC-MSCs or BM-MSCs were treated as cell therapies.

RESULTS

Our data demonstrated that BM-MSCs and UC-MSCs shared similar phenotypic characteristics and immunomodulation abilities. BM-MSCs expressed more indolamine 2,3-dioxygenase after cytokine stimulation with different combinations of IFN-γ, tumor necrosis factor alpha-α and IL-1β or IFN-γ alone. UC-MSCs expressed more prostaglandin E2, IL-6, programmed death-ligand 1 and 2 in the in vitro inflammatory environment. Cyclooxygenase-2 and IL-10 were key factors in the immunomodulatory mechanisms of both MSCs. In addition, UC-MSCs inhibited more T helper 17 cells and induced more regulatory T cells than BM-MSCs. UC-MSCs and BM-MSCs exhibited similar effects on attenuating graft-versus-host disease.

CONCLUSION

UC-MSCs and BM-MSCs exert similar immunosuppressive effects with different mechanisms involved. These findings suggest that UC-MSCs have distinct immunoregulatory functions and may substitute BM-MBSCs in the field of cell therapy.

Update on blood pressure control and renal outcomes in diabetes mellitus

Diabetic nephropathy (DN) is associated with a high incidence of cardiovascular (CV) morbidity and mortality. Although relationships between hypertension and diabetic nephropathy are complex, blood pressure (BP) control is an important management strategy in the prevention of onset and progression of DN in patients with diabetes mellitus (DM). Recent guidelines recommend less stringent BP targets among patients with type 2 DM and chronic kidney disease. These recommendations are based mostly on lack of benefit in CV outcomes with a low BP target. We review the current information on efficacy of BP control in improving renal outcomes in patients with type 2 DM. Presently, although intensive BP control has been was beneficial in decreasing albuminuria, it has not translated into reductions in risks of hard renal endpoints, such as progression to end-stage renal disease, the need for renal replacement therapy, and mortality from renal causes.

Elevated levels of cyclooxygenase 1 and 2 in human cyclosporine induced gingival overgrowth

OBJECTIVE

This study was carried out to immuno-localize and estimate the levels of cyclooxygenase 1 and 2 in human gingival tissue samples from healthy individuals, chronic periodontitis patients and patients with cyclosporine induced gingival overgrowth.

METHODS

Group I consisted of individuals with healthy gingiva (n=6), Group II - cyclosporine induced gingival overgrowth (n=9) and Group III - chronic periodontitis patients (n=6). Gingival tissue samples were collected from subjects of all the three groups. COX-1, COX-2 levels were estimated in tissue homogenates by enzyme activity assay. Immuno-localization for COX-1 and COX-2 was also done in sections of gingival tissue.

RESULTS

The study results demonstrated a significantly higher mean levels of COX-1 and 2 in drug induced gingival overgrowth samples (p<0.05). COX-1 and COX-2 was localized to epithelium and connective tissue in human gingival tissue sections from cyclosporine induced gingival overgrowth.

CONCLUSION

Cyclooxygenase enzymes appear to be potential mediators involved in the pathogenesis of cyclosporine induced gingival overgrowth.

Novel Therapies of Diabetic Nephropathy

Diabetic nephropathy is currently the most common cause of end stage renal disease not only in the Western hemisphere but also in the developing nations. While the available therapeutic options remain not very effective, there is a strong ongoing effort to understand the pathogenesis better and develop more useful biomarkers. As the pathogenic mediators and signaling pathways get better defined, the scope of novel pharmaceutical agents to address such mediating factors as therapeutic targets is advancing. This review provides, in addition to a brief synopsis of currently used strategies, a comprehensive review of potential therapies that have been evolving in the past decade with a specific focus on the promising agents.

Treatment of diabetic nephropathy with Tripterygium wilfordii Hook F extract: a prospective, randomized, controlled clinical trial

Background

Diabetic nephropathy (DN) is the most common cause of end-stage renal failure. Although angiotensin II receptor blockers (ARBs) can be used to attenuate proteinuria in DN patients, their efficacy remains limited. This clinical trial aimed to evaluate the efficacy of Tripterygium wilfordii Hook F (TwHF) extract in the treatment of type 2 diabetes mellitus (DM)-induced nephropathy.

Methods

A total of 65 DN patients with proteinuria levels ≥ 2.5 g/24 h and serum creatinine levels < 3 mg/dl were enrolled in this six-month, prospective, randomized, controlled study. The patients were randomized into treatment groups that received either 120 mg of TwHF extract per day for three months, followed by 60 mg per day for three more months, or 160 mg of valsartan daily for six months. The urinary protein and estimated glomerular filtration (eGFR) level were measured at one, three, and six months after the commencement of treatment. The primary measure of treatment efficacy was a reduction in the 24-h urine protein level between baseline and the end of the study, and the secondary measure of treatment efficacy was a reduction in the eGFR value.

Results

At the end of the treatment period, the mean urine protein level in the TwHF group was dramatically decreased (4.99 ± 2.25 g/24 h vs 2.99 ± 1.81 g/24 h, p < 0.01), with decreases at one, three, and six months of 32.9%, 38.8%, and 34.3%, respectively. In contrast, the proteinuria in the valsartan group was not significantly attenuated, and the decreases in urine protein levels at treatment months one, three, and six were 1.05%, 10.1%, and -11.7%, respectively. The mean decrease in eGFR in the valsartan group was greater than that in the TwHF group (26.4% vs. 13.7%, respectively; p =0.067).

Conclusions

TwHF extract can reduce the urine protein level of DN patients and represents a novel, potentially effective, and safe drug for the treatment of DN patients with proteinuria.

Trial registration

ClinicalTrials.gov: NCT00518362

Lymphocytic colitis is associated with increased pro-inflammatory cytokine profile and up regulation of prostaglandin receptor EP4

Microscopic colitis (MC) is comprised of two entities, lymphocytic (LC) and collagenous colitis. Up to 20% of patients with chronic diarrhea that have a normal appearing colonoscopy will be diagnosed with MC. Since MC was first described less than 40 years ago, little is known about the mechanisms involved in disease pathogenesis. Nonsteroidal anti-inflammatory drugs are associated with an increased risk of MC and some reports suggest a dysregulation in prostaglandin production. Recent genome wide screens have found an association between prostaglandin receptor EP4 expression and inflammatory bowel disease; however, EP4 expression has never been studied in MC. The aim of this study was to assess colonic mucosal inflammatory cytokine profiles in patients with LC and to assess expression of the prostaglandin receptor EP4. Colonic mucosal biopsies were obtained from patients undergoing colonoscopy for investigation of diarrhea and in those undergoing colon cancer screening. Following histological assessment, expression of cytokines and the prostaglandin receptor EP4 was analyzed using real-time reverse transcriptase-PCR and immunohistochemistry. Patients with LC had markedly increased mRNA expression for TNF-α, IFN-γ and IL-8 compared to normal controls (p<0.001). No significant differences were noted for IL-1β, IL-4, IL-10 or IL-12/23. Interestingly, those with LC had increased EP4 receptor expression, which positively correlated with increased TNF-α expression. This is the first report to demonstrate that LC is associated with increased TNF-α, INF-γ and IL-8 concurrent with a marked up-regulation of EP4. These findings add to our knowledge on the pathogenesis of LC and may give rise to possible new therapeutic and/or diagnostic tools in the management of MC.

Pre-treatment with IL-1β enhances the efficacy of MSC transplantation in DSS-induced colitis

Mesenchymal stem cells (MSCs) have been used experimentally for treating inflammatory disorders, partly due to their immunosuppressive properties. Although interleukin-1β (IL-1β) is one of the most important inflammatory mediators, growing evidence indicates that IL-1β signaling elicits the immunosuppressive properties of MSCs. However, it remains unclear how IL-1β signaling accomplishes this activity. Here, we focus on the therapeutic efficacy of IL-1β-primed MSCs in the dextran sulfate sodium (DSS)-induced colitis model, in addition to the underlining mechanisms. We first found that IL-1β-primed MSCs, without any observable phenotype change in vitro, significantly attenuated the development of DSS-induced murine colitis. Moreover, IL-1β-primed MSCs modulated the balance of immune cells in the spleen and the mesenteric lymph nodes (MLNs) through elevating cyclooxygenase-2 (COX-2), IL-6 and IL-8 expression and influencing the polarization of peritoneal macrophages. Importantly, IL-1β-primed MSCs possessed an enhanced ability to migrate to the inflammatory site of the gut via upregulation of chemokine receptor type 4 (CXCR4) expression. In summary, IL-1β-primed MSCs have improved efficacy in treating DSS-induced colitis, which at least partly depends on their increased immunosuppressive capacities and enhanced migration ability.

A guide to the management of blood pressure in the diabetic hypertensive patient

Diabetes mellitus and hypertension frequently coexist in patients with the insulin resistance syndrome (IRS). Patients with both diabetes and hypertension typically have widespread endothelial dysfunction, increased oxidative stress, an activated sympathoadrenal system, and an elevated systemic burden of inflammatory mediators. Patients with diabetes and hypertension also have concomitant mixed dyslipidemia and obesity with significant frequency, and are at high risk for the development of macro- and microvascular disease, congestive heart failure, and nephropathy. Current data suggest that ACE inhibitors or angiotensin receptor blockers with or without a diuretic are important, if not preferred, initial therapies for the patient with diabetes and hypertension. Other drug classes such as combined alpha-/beta-adrenoceptor antagonists, dihydropyridine calcium channel antagonists (CCAs), and peripheral alpha-adrenoceptor antagonists are also useful therapeutic options in these patients. In order to optimally reduce the risk for cardiovascular events in the patient with diabetes and hypertension, optimal BP control should be coupled with comprehensive lifestyle modification and aggressive management of dyslipidemia and hyperglycemia.

Clostridium difficile infection in HIV-seropositive individuals and transplant recipients

Immunocompromise is a commonly cited risk factor for Clostridium difficile infection (CDI). We reviewed the experimental and epidemiological literature on CDI in three immunocompromised groups, HIV-seropositive individuals, haematopoietic stem cell or bone marrow transplant recipients and solid organ transplant recipients. All three groups have varying degrees of impairment of humoral immunity, a major factor influencing the outcome of CDI. Soluble HIV proteins such as nef and immunosuppressive agents such as cyclosporin, azathioprine and mycophenalate mofetil modify signalling from the key cellular pathways triggered by C. difficile toxin A, although there is a paucity of data on how these factors may interact with pathways activated by toxin B. Despite this, there has been little direct investigation into the effect of immunosuppression on the pathogenesis of CDI. Epidemiological studies consistently show increased rates of CDI in these populations, which are higher in those with greater degrees of immunocompromise such as individuals with advanced AIDS not receiving combination antiretroviral therapy or allogeneic haematopoietic stem cell transplant recipients. Less consistently data suggests immunocompromise in each group also impacts rates of severe, recurrent or complicated CDI. However all these conditions are characterised by high levels of antibiotic use and prolonged hospital stay, both powerful drivers of CDI risk.

Curcumin and enalapril ameliorate renal failure by antagonizing inflammation in 5/6 nephrectomized rats: role of phospholipase and cyclooxygenase

Previously, we showed that curcumin prevents chronic kidney disease (CKD) development in &frac56; nephrectomized (Nx) rats when given within 1 wk after Nx (Ghosh SS, Massey HD, Krieg R, Fazelbhoy ZA, Ghosh S, Sica DA, Fakhry I, Gehr TW. Am J Physiol Renal Physiol 296: F1146-F1157, 2009). To better mimic the scenario for renal disease in humans, we began curcumin and enalapril therapy when proteinuria was already established. We hypothesized that curcumin, by blocking the inflammatory mediators TNF-α and IL-1β, could also reduce cyclooxygenase (COX) and phospholipase expression in the kidney. Nx animals were divided into untreated Nx, curcumin-treated, and enalapril-treated groups. Curcumin (75 mg/kg) and enalapril (10 mg/kg) were administered for 10 wk. Renal dysfunction in the Nx group, as evidenced by elevated blood urea nitrogen, plasma creatinine, proteinuria, segmental sclerosis, and tubular dilatation, was comparably reduced by curcumin and enalapril, with only enalapril significantly lowering blood pressure. Compared with controls, Nx animals had higher plasma/kidney TNF-α and IL-1β, which were reduced by curcumin and enalapril treatment. Nx animals had significantly elevated kidney levels of cytosolic PLA(2), calcium-independent intracellular PLA(2), COX 1, and COX 2, which were comparably reduced by curcumin and enalapril. Studies in mesangial cells and macrophages were carried out to establish that the in vivo increase in PLA(2) and COX were mediated by TNF-α and IL-1β and that curcumin, by antagonizing the cytokines, could significantly reduce both PLA(2) and COX. We conclude that curcumin ameliorates CKD by blocking inflammatory signals even if it is given at a later stage of the disease.

Critical care issues in patients after liver transplantation

The majority of patients who undergo liver transplantation (LT) spend some time in the intensive care unit during the postoperative period. For some, this is an expected part of the immediate posttransplant recovery period, whereas for others, the stay is more prolonged because of preexisting conditions, intraoperative events, or postoperative complications. In this review, 4 topics that are particularly relevant to the postoperative intensive care of LT recipients are discussed, with an emphasis on current knowledge specific to this patient group. Infectious complications are the most common causes of early posttransplant morbidity and mortality. The common patterns of infection seen in patients after LT and their management are discussed. Acute kidney injury and renal failure are common in post-LT patients. Kidney injury identification, etiologies, and risk factors and approaches to management are reviewed. The majority of patients will require weaning from mechanical ventilation in the immediate postoperative period; the approach to this is discussed along with the approach for those patients who require a prolonged period of mechanical ventilation. A poorly functioning graft requires prompt identification and appropriate management if the outcomes are to be optimized. The causes of poor graft function are systematically reviewed, and the management of these grafts is discussed.

Dual therapy versus monotherapy of trandolapril and telmisartan on diabetic nephropathy in experimentally induced type 2 diabetes mellitus rats

Objective: To investigate the combination of telmisartan with trandolapril therapy versus monotherapy of trandolapril and telmisartan on diabetic nephropathy in type 2 diabetes mellitus rats.

Material and methods: Neonatal rats (2 days old) were used for inducing type 2 diabetes mellitus. Streptozotocin at a dose of 90 mg/kg, in freshly prepared citrate buffer (0.1M, pH 4.5), was injected intraperitoneally. There were five groups: (1) normal control, (2) diabetic control, (3) diabetic treated with telmisartan, (4) diabetic treated with trandolapril and (5) diabetic treated with telmisartan and trandolapril. Albumin excretion rate, total protein excretion rate, plasma fibronectin, transforming growth factor beta 1(TGF-β1), tumour necrosis factor-α (TNF-α) concentration and renal structural changes were measured.

Results: Albumin excretion rate, total protein excretion rate, plasma fibronectin, TGF-β1, TNF-α concentration and renal structural changes increased significantly in untreated diabetic rats compared with normal control rats. Administration of telmisartan, trandolapril, or both decreased these changes.

Conclusions: Addition of the telmisartan to trandolapril was more effective in reducing renal structural changes and improvement of renal function than monotherapy with either drug, possibly due to dual inhibitory effect on the renin— angiotensin system, and thus suppression of TGF-β1, TNF-α.

Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and combined therapy in patients with micro- and macroalbuminuria and other cardiovascular risk factors: a systematic review of randomized controlled trials

BACKGROUND

A recent clinical trial showed harmful renal effects with the combined use of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin-II receptor blockers (ARB) in people with diabetes or vascular disease. We examined the benefits and risks of these agents in people with albuminuria and one or more cardiovascular risk factors.

METHODS

MEDLINE, EMBASE and Renal Health Library were searched for trials comparing ACEI, ARB or their combination with placebo or with one another in people with albuminuria and one or more cardiovascular risk factor.

RESULTS

Eighty-five trials (21,708 patients) were included. There was no significant reduction in the risk of all-cause mortality or fatal cardiac-cerebrovascular outcomes with ACEI versus placebo, ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. There was a significant reduction in the risk of nonfatal cardiovascular events with ACEI versus placebo but not with ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. Development of end-stage kidney disease and progression of microalbuminuria to macroalbuminuria were reduced significantly with ACEI versus placebo and ARB versus placebo but not with combined therapy with ACEI + ARB versus monotherapy.

CONCLUSIONS

ACEI and ARB exert independent renal and nonfatal cardiovascular benefits while their effects on mortality and fatal cardiovascular disease are uncertain. There is a lack of evidence to support the use of combination therapy. A comparative clinical trial with ACE, ARB and its combination in people with albuminuria and a cardiovascular risk factor is warranted.

Interleukin 1 receptor signaling regulates DUBA expression and facilitates Toll-like receptor 9-driven antiinflammatory cytokine production

The interleukin 1 receptor (IL-1R) and the Toll-like receptors (TLRs) are highly homologous innate immune receptors that provide the first line of defense against infection. We show that IL-1R type I (IL-1RI) is essential for TLR9-dependent activation of tumor necrosis factor receptor-associated factor 3 (TRAF3) and for production of the antiinflammatory cytokines IL-10 and type I interferon (IFN). Noncanonical K63-linked ubiquitination of TRAF3, which is essential for type I IFN and IL-10 production, was impaired in Il1r1(-/-) CD11c(+) dendritic cells. In contrast, degradative ubiquitination of TRAF3 was not affected in the absence of IL-1R1 signaling. Deubiquitinating enzyme A (DUBA), which selectively cleaves K63-linked ubiquitin chains from TRAF3, was up-regulated in the absence of IL-1R1 signaling. DUBA short interference RNA augmented the TLR9-dependent type I IFN response. Mice deficient in IL-1RI signaling showed reduced expression of IL-10 and type I IFN and increased susceptibility to dextran sulphate sodium-induced colitis and failed to mount a protective type I IFN response after TLR9 ligand (CpG) administration. Our data identifies a new molecular pathway by which IL-1 signaling attenuates TLR9-mediated proinflammatory responses.

Proteinuria and clinical outcomes in hypertensive patients

This narrative review focuses on outcomes related to proteinuria in hypertension (HT), and also examines the role of current and future therapeutic strategies. Proteinuria is an independent marker of renal and cardiovascular (CV) disease in hypertensive populations, particularly in high-risk groups such as diabetic patients. Effective blood pressure (BP) control and proteinuria management are associated with significant improvements in the risk of key adverse outcomes, although a causative relationship needs careful assessment. Available antihypertensives have varying effects on proteinuria reduction. Drugs affecting the renin system offer antiproteinuric and renoprotective effects that are probably at least partially independent of their BP effects. Economic evaluations of these interventions confirm their cost-saving benefits relative to other antihypertensives, but outcomes-based research is needed in some settings.

Lowering of proteinuria in response to antihypertensive therapy predicts improved renal function in late but not in early diabetic nephropathy: a pooled analysis

In late diabetic nephropathy (DN) the initial lowering of albumin excretion rate (AER) with antihypertensive therapy is proportional to the degree of subsequent preservation of glomerular filtration rate (GFR). Whether a similar relationship exists between AER and GFR in early diabetes is not known. The present analysis has compared AER and GFR responses to antihypertensive therapy in 33 published studies (77 treatment groups) of early and late DN in type 1 (T1) and type 2 (T2) diabetes, analyzed on an intention-to-treat basis. Prospective trials were included if the initial change in AER during the first year of therapy and the change in GFR during at least 2 years of follow-up could be estimated from group mean data. The initial % decreases in AER were 5.9 +/- 4.3 (T1), 10.5 +/- 5.4 (T2, normotensive) and 18.4 +/- 6.2 (T2, hypertensive) in early DN and 7.6 +/- 11.1 (T1) and 20.8 +/- 5.5 (T2) in late DN. The corresponding annual % rates of decline of GFR were 2.0 +/- 0.5 (T1), 1.6 +/- 0.5 (T2, normotensive) and 2.1 +/- 0.3 (T2, hypertensive) in early DN and 9.8 +/- 1.5 (T1) and 9.2 +/- 1.1 (T2) in late DN. AER and GFR responses in each treatment group were closely correlated in late nephropathy (T1, r = -0.67, p = 0.03; T2, r = 0.57, p = 0.02) but not in early nephropathy. In contrast to late DN, the initial decrease in AER with antihypertensive therapy was not shown to predict the subsequent rate of decline of GFR in early DN. It follows that assessment of renoprotection during antihypertensive therapy in early nephropathy should be based not only on albuminuria but also on the GFR response.

Health economic implications of irbesartan treatment versus standard blood pressure control in patients with type 2 diabetes, hypertension and renal disease: a Hungarian analysis

To perform a health economic analysis on treatment with irbesartan in patients with type 2 diabetes and hypertension. A Markov model was adapted to the Hungarian setting to simulate renal deterioration from the development of microalbuminuria to nephropathy, doubling of serum creatinine, end-stage renal disease (ESRD) and all-cause mortality. Outcomes for two treatments were evaluated: (1) a placebo regimen of standard antihypertensive medications, and (2) the addition of irbesartan 300 mg administered daily, with both treatment initiated after developing microalbuminuria. Outcomes were discounted at 5% annually to correspond with national guidelines. Treatment with irbesartan was estimated to improve undiscounted life expectancy by 0.98 +/- 0.05 years, reduce the cumulative incidence of ESRD by 7.5 +/- 0.4%, and reduce lifetime costs by Hungarian Forints (HUF) 519,993 +/- 70,814, compared to placebo. Irbesartan was projected to improved life expectancy and reduce costs compared to placebo in the Hungarian setting in hypertensive patients with type 2 diabetes and microalbuminuria.

Blood pressure lowering for the prevention and treatment of diabetic kidney disease

The current pandemic of diabetes mellitus will inevitably be followed by an epidemic of chronic kidney disease. It is anticipated that 25-40% of patients with type 1 diabetes and 5-40% of patients with type 2 diabetes will ultimately develop diabetic kidney disease. The control of blood pressure represents a key component for the prevention and management of diabetic nephropathy. There is a strong epidemiological connection between hypertension in diabetes and adverse outcomes in diabetes. Hypertension is closely linked to insulin resistance as part of the 'metabolic syndrome'. Diabetic nephropathy may lead to hypertension through direct actions on renal sodium handling, vascular compliance and vasomotor function. Recent clinical trials also support the utility of blood pressure reduction in the prevention of diabetic kidney disease. In patients with normoalbuminuria, transition to microalbuminuria can be prevented by blood pressure reduction. This action appears to be significant regardless of whether patients have elevated blood pressure or not. The efficacy of ACE inhibition appears to be greater than that achieved by other agents with a similar degree of blood pressure reduction; although large observational studies suggest the risk of microalbuminuria may be reduced by blood pressure reduction, regardless of modality. In patients with established microalbuminuria, ACE inhibitors and angiotensin receptor antagonists (angiotensin receptor blockers [ARBs]) consistently reduce the risk of progression from microalbuminuria to macroalbuminuria, over and above their antihypertensive actions. The clinical utility of combining these strategies remains to be established. In patients with overt nephropathy, blood pressure reduction is associated with reduced urinary albumin excretion and, subsequently, a reduced risk of renal impairment or end stage renal disease. In addition to actions on systemic blood pressure, it is now clear that ACE inhibitors and ARBs also reduce proteinuria in patients with diabetes. This anti-proteinuric activity is distinct from other antihypertensive agents and diuretics. Although there is a clear physiological rationale for blockade of the renin angiotensin system, which is strongly supported by clinical studies, to achieve the optimal lowering of blood pressure, particularly in the setting of established diabetic renal disease, a number of different antihypertensive agents will always be needed. In the end, the choice of agents should be individualised to achieve the maximal tolerated reduction in blood pressure and albuminuria. Ultimately, no matter how it is achieved, so long as it is achieved, renal risk can be reduced by agents that lower blood pressure and albuminuria.

Pharmacoepidemiology of antihypertensive drugs in primary care setting of Bahrain between 1998 and 2000

PURPOSE

To compare pattern of antihypertensive drug utilization in 1998 with 2000 following the: (a) publication of 1999 World Health Organization/International Society of Hypertension (WHO/ISH) guidelines for drug management of hypertension; and (b) introducing new antihypertensives to the essential drug list, in primary care, Bahrain.

METHODS

Retrospective prescription-based survey carried out in seven out of 20 primary care health centers in Bahrain. A total of 9272 patients comprising 6543 with uncomplicated hypertension and 2729 with diabetic hypertension were studied.

RESULTS

Between 1998 and 2000, the prescription rate of beta-blockers and methyldopa significantly declined (p < 0.0001) while the rate of angiotensin converting enzyme (ACE) inhibitors and calcium channel blockers (CCBs) increased (p < 0.0001) in uncomplicated hypertension. However, in diabetic hypertension there was a non-significant decline in utilization of beta-blockers, CCBs, methyldopa, and diuretics whereas a significant increase in prescribing of ACE inhibitors (p < 0.0001). Inclusion of Perindopril into the essential drug list resulted in an overall increase in utilization of ACE inhibitors: use of captopril and enalapril declined while lisinopril and perindopril increased. Substitution of immediate-release (IR) indapamide by sustained-release (SR) formulation did not change the overall utilization of diuretics; however, intra-class changes were evident with a significant decline in use of thiazide diuretics and concomitant increase in use of SR indapamide by 2000.

CONCLUSIONS

The antihypertensive prescribing pattern is influenced by WHO/ISH guidelines as well as by introduction of new antihypertensives to primary care essential drug list in primary care. The choice of a drug is also influenced by presence of co-morbidity with diabetes mellitus.

Prevention and treatment of diabetic renal disease in type 2 diabetes: the BENEDICT study

Diabetic nephropathy (DN) is the leading cause of end-stage renal failure in Western countries and carries an increased risk for cardiovascular mortality. Studies have identified a number of factors that play a part in the development of DN. Among them, hypertension and proteinuria are the most important. In the early stages of DN, when albumin is present in the urine in very low quantities (microalbuminuria) and an increase is seen in BP, there is no loss of filtrate and patients respond well to prophylactic measures. Microalbuminuria is considered an early marker of DN. Prevention of the onset of microalbuminuria, therefore, could be considered as the primary means of preventing DN. The Bergamo Nephrologic Diabetes Complication Trial (BENEDICT) was a prospective, randomized, double-blind, parallel-group study that was organized in two phases. Phase A included 1204 patients and was aimed at assessing the efficacy of the angiotensin-converting enzyme (ACE) inhibitor trandolapril, the non-dihydropyridine calcium channel blocker verapamil, and the trandolapril plus verapamil combination as compared with placebo in prevention of microalbuminuria in hypertensive patients with type 2 diabetes and normal urinary albumin excretion rate. Phase B was aimed at assessing the efficacy of the combination as compared with trandolapril alone in prevention of macroalbuminuria in patients with microalbuminuria. The BENEDICT Phase A study showed that DN can be prevented by ACE inhibitor therapy. The beneficial effect of ACE inhibition is not enhanced by combined non-dihydropyridine calcium channel blocker therapy. The apparent advantage of ACE inhibitors over other agents includes a protective effect on the kidney against the development of microalbuminuria, which is a major risk factor for cardiovascular events and death in this population.

Losartan: lessons learned from the RENAAL study

Renal and cardiovascular diseases associated with Type 2 diabetes are increasing at rapid rates, and are significant burdens to patients and healthcare systems. The RENAAL (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) study was conducted from 1996 to 2001. This landmark clinical trial provided the opportunity to study renal and cardiovascular outcomes, as well as risk predictors, in a relatively large number of patients with Type 2 diabetes and nephropathy. The RENAAL study also provided information that will be valuable to those designing future clinical trials in this patient population. This review highlights key findings from the RENAAL study.

Swiss Hypertension and Risk Factor Program (SHARP): cardiovascular risk factors management in patients with type 2 diabetes in Switzerland

The prevalence of hypertension in type 2 diabetics is high, though there is no published data for Switzerland. This prospective cohort survey determined the frequency of type 2 diabetes mellitus associated with hypertension from medical practitioners in Switzerland, and collected data on the diagnostic and therapeutic work-up for cardiovascular risk patients. The Swiss Hypertension And Risk Factor Program (SHARP) is a two-part survey: The first part, I-SHARP, was a survey among 1040 Swiss physicians to assess what are the target blood pressure (BP) values and preferred treatment for their patients. The second part, SHARP, collected data from 20,956 patients treated on any of 5 consecutive days from 188 participating physicians. In I-SHARP, target BP?135/85 mmHg, as recommended by the Swiss Society of Hypertension, was the goal for 25% of physicians for hypertensives, and for 60% for hypertensive diabetics; values >140/90 mmHg were targeted by 19% for hypertensives, respectively 9% for hypertensive diabetics. In SHARP, 30% of the 20,956 patients enrolled were hypertensive (as defined by the doctors) and 10% were diabetic (67% of whom were also hypertensive). Six per cent of known hypertensive patients and 4% of known hypertensive diabetics did not receive any antihypertensive treatment. Diabetes was not treated pharmacologically in 20% of diabetics. Proteinuria was not screened for in 45% of known hypertensives and in 29% of known hypertensive diabetics. In Switzerland, most physicians set target BP levels higher than recommended in published guidelines. In this country with easy access to medical care, high medical density and few financial constraints, appropriate detection and treatment for cardiovascular risk factors remain highly problematic.

Expression of cyclooxygenase-1 and cyclooxygenase-2 in human renal allograft rejection - a prospective study

Cyclooxygenases (COX) are known to be involved in inflammatory kidney diseases. However, there are no data available about the expression of COX-1 and only preliminary reports about the expression of COX-2 in biopsies of patients undergoing acute renal allograft rejection. We conducted this prospective study to analyze the expression, distribution, and cellular localization of COX-1 and -2 and thus to elucidate the role of COX in human kidney transplantation. One hundred forty-four biopsies were included from patients without rejection and unaltered morphology (n = 60), with acute interstitial rejection (n = 7), with acute vascular rejection (n = 21), with chronic allograft nephropathy (n = 16), without rejection but with various other lesions (n = 40). COX-1 and -2 expression was localized in each biopsy by immunohistochemistry. We found a highly significant up-regulation of COX-1 in vessels and in infiltrating interstitial cells of patients with acute allograft rejection compared with biopsies with well-preserved tissue. Also, COX-2 expression was significantly elevated in infiltrating interstitial cells of biopsies with acute rejection. This is the first prospective study demonstrating a significant induction of both COX-1 and -2 in human allograft biopsies with acute rejection after renal transplantation.

The Role of Glycosaminoglycans and Sulodexide in the Treatment of Diabetic Nephropathy

Diabetic nephropathy occurs in 20-40% of diabetic patients, making it one of the most important causes of end-stage renal disease (ESRD). It has a large impact in terms of associated morbidity and mortality for the individual patient and in terms of costs for healthcare. Several studies have demonstrated that micro- and macroalbuminuria predict cardiovascular morbidity and mortality in patients with diabetes mellitus.Current nephroprotective therapies for diabetic nephropathy include the pursuit of normoglycemia and normotension, and a consensus is emerging that there is a necessity to also achieve as low a level of albuminuria as possible. However, the search for innovative and ancillary approaches to the prevention and treatment of this diabetic complication is warranted since strict metabolic control can be difficult, and sometimes dangerous, to achieve and even diabetic patients responding to ACE inhibitors (ACEIs) or angiotensin II receptor antagonists (angiotensin receptor blockers; ARBs) and metabolic control show progressive renal damage and eventually ESRD. A number of drugs are currently being investigated; glycosaminoglycans are particularly interesting since, in theory, they target the generalized endothelial dysfunction and metabolic defect in matrix and basement membrane synthesis which, according to the Steno hypothesis, are responsible for diabetic nephropathy and macroangiopathy.Treatment with glycosaminoglycans, and with sulodexide in particular, significantly improves albuminuria in type 1 and type 2 diabetic patients with micro- or macroalbuminuria. The albuminuria-lowering effect of sulodexide enhances the effect of ACEI/ARB therapy. Most studies have shown that the effect of sulodexide on albuminuria is sustained, strongly suggesting that favorable chemical and anatomic remodeling is induced by exogenous glycosaminoglycans in renal tisues, as observed in the experimental model.

Flow cytometric analysis of the in situ hybridization of cyclooxygenase isoforms in mesangial cells treated with cyclosporine A

BACKGROUND

Cyclosporine A increases oxidative stress in kidney and we hypothesized that cyclooxygenase (COX) may be involved in this effect.

MATERIAL AND METHODS

Mesangial cells of Cyclosporine A-treated (4, 7 or 10 days) rats were obtained to evaluate mRNA expression of COX-isoforms (COX-1, constitutive and COX-2, inducible) by "in situ" hybridization. Probes were labelled using "Gene Image Random Prime Labelling Protocol" and COX expression was measured by flow cytometry.

RESULTS AND DISCUSSION

"In situ" hybridization by flow cytometry is an useful method to detect mRNA. We observed an increased COX-2 expression in a time-dependent manner in parallel with Reactive Oxygen Species synthesis. COX-1 expression increased only at 10 days.

Angiotensin II antagonists--therapeutic benefits spanning the cardiovascular disease continuum from hypertension to heart failure and diabetic nephropathy

BACKGROUND

The cardiovascular benefits of angiotensin II antagonists (AIIAs) have been evaluated not only in terms of their ability to lower blood pressure but also on their ability to prevent strokes, cardiac events, and target organ damage. This review summarizes the body of evidence-based data demonstrating the efficacy of AIIAs across the spectrum of cardiovascular disease.

METHODS

A PubMed/MEDLINE search of English-language articles (1990 to September 2005) was used to identify articles describing clinical studies, particularly outcome trials, or mechanisms of therapeutic action pertinent to the therapy of cardiovascular disease or nephropathy.

FINDINGS

The antihypertensive efficacy of AIIAs is apparent across a wide spectrum of hypertensive patients, including black and Asian patients and patients with isolated systolic hypertension. More importantly, large outcome-based studies have demonstrated the efficacy of AIIAs across the continuum of cardiovascular disease, including hypertension, heart failure, post-myocardial infarction, and diabetic nephropathy. The Losartan Intervention For Endpoint reduction in hypertension study (LIFE), Reduction of Endpoints in Non-insulin-dependent Diabetes Mellitus with the AII Antagonist Losartan (RENAAL), and the Irbesartan Type 2 Diabetic Nephropathy Trial (IDNT) indicate that AIIAs confer cardiovascular and renal protective effects beyond their ability to lower blood pressure. These bloodpressure independent protective benefits of AIIAs may arise not only by blocking the deleterious effects of AII mediated via the AT1-receptor but may also be due to beneficial molecule-specific effects. As a class, AIIAs are well tolerated with an overall adverse event profile generally comparable to placebo and superior to that typically seen with calcium channel blockers, ACE inhibitors, diuretics, and beta-blockers.

CONCLUSIONS

By utilizing the body of clinical trial evidence as a guide to rational prescribing of AIIAs, practitioners can expect to deliver clinical benefits to their patients in terms of survival, prognosis, and quality of life.

Prevention and Treatment of Diabetic Nephropathy: The Program for Irbesartan Mortality and Morbidity Evaluation

Aggressive treatment of hypertension is effective in reducing both microvascular and macrovascular complications in type 2 diabetes, with target BP < 130/80 mmHg being recommended. Angiotensin-converting enzyme inhibitors were found to be more effective than the other traditional agents in reducing the onset of clinical proteinuria in individuals with both type 1 and type 2 diabetes and incipient nephropathy. However, small trials on patients with type 2 diabetes and overt nephropathy failed to demonstrate a specific renoprotective role for this class of drugs. The aim of the Program for Irbesartan Mortality and Morbidity Evaluation was to ascertain whether angiotensin II receptor blockers are effective in both preventing the development of clinical proteinuria and delaying the progression of nephropathy in type 2 diabetes. The Irbesartan in Patients with Type 2 Diabetes and Microalbuminuria (IRMA) Study showed that, as compared with conventional therapy, irbesartan is better at preventing the development of clinical proteinuria and at restoring normoalbuminuria for comparable BP control in patients with incipient nephropathy. The Irbesartan Diabetic Nephropathy Trial showed that irbesartan is more effective than traditional antihypertensive therapies in reducing the progression toward ESRD in patients with type 2 diabetes and overt nephropathy regardless of changes in BP. Moreover, secondary analysis of the Irbesartan Diabetic Nephropathy Trial showed that the achieved systolic pressure as well as baseline and current proteinuria significantly predict renal outcomes. In conclusion, the results of the Program for Irbesartan Mortality and Morbidity Evaluation demonstrate that irbesartan significantly prevents the development of clinical proteinuria in individuals with microalbuminuria and delays the progression of nephropathy in individuals with proteinuria. Moreover, the renoprotective effects of irbesartan go beyond its effect on BP.

Diabetic nephropathy: the proteinuria hypothesis

BACKGROUND/AIMS

Proteinuria, nearly a universal finding in progressive kidney disease, has been the subject of frequent recent analyses in the renal literature. Proteinuria is a hallmark of diabetic nephropathy: microalbuminuria is the principal early predictor for progression of diabetic glomerulopathy, and proteinuria may be viewed as a measure of the severity and promoter of progression of nephropathy.

METHODS

This article critically reviews for the first time the full scope of diabetic proteinuria--complex molecular mechanisms, natural history, and analysis of treatment trials--in order to address the validity of 'the proteinuria hypothesis', i.e., that diabetic proteinuria is a modifiable determinant of renal progression. This hypothesis is analyzed in detail, including recent studies on the primary therapy of diabetic nephropathy, renin-angiotensin blockade.

RESULTS

As fully developed, this hypothesis consists of three postulates: that higher amounts of proteinuria predict progressive loss of function, that proteinuria reduction correlates with slowing progression, and that proteinuria is a surrogate endpoint for clinical trials. The latter postulate has not before been adequately linked to growing information about the first two postulates as they apply to diabetic kidney disease.

CONCLUSION

While diabetic nephropathy is a disease model for the potential use of proteinuria as a surrogate marker for renal progression, this shift in perspective will require prospective data from additional clinical trials, particularly of non-renin-angiotensin blocking drugs, to be complete.

Case-based study: from prediabetes to complications--opportunities for prevention

A 31-year-old man presents with central obesity, hypertension, and abnormal lipids. How would you manage this patient?

The selective cyclooxygenase-2 inhibitor celecoxib modulates the formation of vasoconstrictor eicosanoids and activates PPARgamma. Influence of albumin

BACKGROUND/AIMS

Selective cyclooxygenase (COX)-2 inhibitors do not adversely affect renal function in experimental cirrhosis. In the current study, we investigated the molecular mechanisms underlying the effects of the selective COX-2 inhibitor, celecoxib, and assessed the influence of albumin on its actions.

METHODS

Rat mesangial cells (RMC) were incubated with celecoxib in the absence or presence of albumin, and levels of selected vasoconstrictor eicosanoids, renin release and alpha-smooth muscle actin (alpha-SMA) expression were determined. The effects of celecoxib on PPARgamma were assessed in RMC co-transfected with PPARgamma and luciferase reporter constructs.

RESULTS

Under resting conditions, RMC expressed COX-1, COX-2 and 12/15-lipoxygenase and mainly generated prostaglandin (PG)E2, thromboxane (TX)B2, 12-hydroxyeicosatetraenoic acid (12-HETE) and 8-epi-PGF2alpha. Celecoxib, in addition to reducing PGE2, significantly decreased 8-epi-PGF2alpha formation. In the presence of albumin, celecoxib also reduced TXB2 and 12-HETE. Albumin per se inhibited PGE2 as well as renin release. In trans-activation assays, celecoxib acted as a PPARgamma agonist whereas albumin inhibited PPARgamma as well as 15d-PGJ2-induced PPARgamma activation. Finally, celecoxib and albumin potentiated the inhibitory effect of 15d-PGJ2 on alpha-SMA expression.

CONCLUSIONS

These data provide novel molecular mechanisms of celecoxib and their modulation by albumin, that may be relevant to prevent renal dysfunction in conditions of unbalanced effective blood volume.

Latin American consensus on diabetes mellitus and hypertension

Diabetes mellitus and hypertension, responsible of a major burden of cardiovascular complications, are increasing their incidence in Latin America in similar proportions to the rest of the world. The metabolic syndrome, a strong predictor of both diabetes and hypertension deserves more attention from the primary care physicians. Evidence based and updated guidelines on detection, prevention and treatment of diabetes and hypertension, issued by local experts, are willing to inform and translate these recommendations to the clinical practice of physicians assisting these patients throughout Latin America.

Angiotensin-receptor blockade versus converting-enzyme inhibition in type 2 diabetes and nephropathy

BACKGROUND

Few studies have directly compared the renoprotective effects of angiotensin II-receptor blockers and angiotensin-converting-enzyme (ACE) inhibitors in persons with type 2 diabetes.

METHODS

In this prospective, multicenter, double-blind, five-year study, we randomly assigned 250 subjects with type 2 diabetes and early nephropathy to receive either the angiotensin II-receptor blocker telmisartan (80 mg daily, in 120 subjects) or the ACE inhibitor enalapril (20 mg daily, in 130 subjects). The primary end point was the change in the glomerular filtration rate (determined by measuring the plasma clearance of iohexol) between the baseline value and the last available value during the five-year treatment period. Secondary end points included the annual changes in the glomerular filtration rate, serum creatinine level, urinary albumin excretion, and blood pressure; the rates of end-stage renal disease and cardiovascular events; and the rate of death from all causes.

RESULTS

After five years, the change in the glomerular filtration rate was -17.5 ml per minute per 1.73 m2 (where the minus sign denotes a decrement) in the telmisartan-treated subjects, as compared with -15.0 ml per minute per 1.73 m2 in the enalapril-treated subjects; the treatment difference was thus -2.6 ml per minute per 1.73 m2 (95 percent confidence interval, -7.1 to 2.0 ml per minute per 1.73 m2)[corrected] The lower boundary of the confidence interval, in favor of enalapril, was greater than the predefined margin of -10.0 ml per minute per 1.73 m2, indicating that telmisartan was not inferior to enalapril. The effects of the two agents on the secondary end points were not significantly different after five years.

CONCLUSIONS

Telmisartan is not inferior to enalapril in providing long-term renoprotection in persons with type 2 diabetes. These findings do not necessarily apply to persons with more advanced nephropathy, but they support the clinical equivalence of angiotensin II-receptor blockers and ACE inhibitors in persons with conditions that place them at high risk for cardiovascular events.

Antihypertensive drugs and the kidney

In the United States, 50 million Americans are estimated to have hypertension. Over the past several decades, it has become clear that hypertension is both a cause and a consequence of kidney disease. In contrast to the striking decline in mortality rates from both stroke and coronary heart disease, the prevalence of hypertension as a cause of end-stage renal disease (ESRD) has increased such that it is now the second most common cause of ESRD in the United States. Hypertension and proteinuria occur in most patients with chronic kidney disease and are risk factors for faster progression of kidney disease. Antihypertensive agents reduce blood pressure and urine protein excretion and slow the progression of kidney disease. The level of blood pressure achieved and use of renin-angiotensin-aldosterone system-blocking agents is critical for delaying progression of renal disease in all ethnic groups.

Proinflammatory cytokines enhance COX-1 gene expression in cultured rat glomerular mesangial cells

Glomerular mesangial cells (GMC) exert an essential maintaining effect on hemodynamic integrity and immune competence of the kidney through arachidonate metabolism. To clarify this, cultured rat GMC were measured for the expression and production of cyclooxygenase (COX) and excretion of prostaglandin (PG). The rat GMC spontaneously expressed type 1 cyclooxygenase (COX-1), but not COX-2. The PGE2 and thromboxane B2 (TXB2) were spontaneously produced by the cells. Interleukin (IL)-1beta (25 ng/ml), IL-8 (25 ng/ml), growth-related oncogene-alpha (GRO, 50 ng/ml) and tumor necrosis factor-alpha (TNF-alpha, 25 ng/ml) stimulated the COX-1 protein production as demonstrated by Western blot and enhanced PGE2 synthesis in GMC, beginning on 2 h of incubation, and steadily enhanced TXB2 synthesis over a 24-h period. Lipopolysaccharide (LPS, 100 ng/ml) enhanced both PGE2 and TXB2 syntheses from 2 h to at least 24 h of incubation. Collectively, the proinflammatory cytokines could enhance COX-1 but not COX-2 expression in GMC leading to increased PGE2 and TXB2 production. These biochemical events may be implicated in normal renal physiology as well as in pathogenesis of glomerular diseases.

Slowing the Progression of Adult Chronic Kidney Disease

When kidney disease of any aetiology results in substantial loss of nephrons, a common clinical syndrome, characterised by hypertension, proteinuria and a progressive decline in renal function, ensues. This observation suggests that common mechanisms may contribute to progressive renal injury and that therapeutic interventions that inhibit these common pathways may afford renal protection. Research to date has identified several mechanisms that may contribute to progressive renal injury including glomerular haemodynamic changes, multiple effects of angiotensin II and detrimental effects of excessive filtration of plasma proteins by injured glomeruli. Clinical trials over the past decade have identified several interventions that are effective in slowing the rate of progression of chronic kidney disease (CKD). The use of ACE inhibitors, angiotensin receptor antagonists or a combination of the two should be regarded as fundamental to any therapy for slowing the rate of CKD progression. Hypertension should be treated aggressively to achieve a blood pressure target of < 130/80 mm Hg. Reduction of proteinuria to < 0.5 g/day should be regarded as an independent therapeutic goal. Although inconclusive, there is some evidence to support moderate dietary protein restriction to 0.6 g/kg/day in appropriate patients. Hyperlipidaemia may contribute to CKD progression and should be treated to reduce cardiovascular risk and potentially improve renal protection. Smoking cessation should be encouraged and, where necessary, assisted. Among diabetic patients tight glycaemic control should be achieved (glycosylated haemoglobin < 7%). These interventions are simple and relatively inexpensive. If applied to all patients with CKD they will result in substantial slowing of renal function decline in many patients and thereby reduce the number who progress to end-stage renal disease and require renal replacement therapy.

Glutathione mediates LPS-stimulated COX-2 expression via early transient p42/44 MAPK activation

This study examines whether endotoxin (LPS)-stimulated COX-2 is modulated by an interaction between mitogen activated protein kinases (MAPK) and intracellular glutathione. Bovine pulmonary artery endothelial cells (BPAEC) were pretreated for 30 min with the following prior to addition of 0.1 microg/ml endotoxin in 2% FBS in medium 199: 5 mM N-acetylcysteine (NAC) or 5 mM glutathione ethyl ester (GSE) (modulators of intracellular glutathione); 10 microM SB203580 or 25 microM PD98059 (inhibitors of p38 and p42/44 MAPKs, respectively). End-points included assessment of COX-1 and COX-2 gene expression by reverse transcription polymerase chain reaction (RT-PCR); COX-1, COX-2, p38, and p42/44 protein by Western analysis; and measurement of PGE2 and 6-keto-PGF1alpha releases by GC/MS. Both GSE and NAC resulted in significant exacerbation of the LPS-stimulated increase in COX-2 gene and protein expression and prostaglandin release, and suppressed the LPS-induced decrease in COX-1. LPS caused a biphasic activation of p42/44 MAPKs, an early increase peaking at 30 min and a second sustained phase, lasting up to 24 h; LPS also caused an early and sustained increase p38 MAPK activity. Pretreatment of cells with either GSE or NAC increased the early LPS-stimulated activation of p42/44 but had little effect on the sustained phase. Inhibition of either p38 or p42/44 MAPKs suppressed LPS-stimulated COX-2 gene and protein expression, and prostaglandin release (P<0.05) but had little effect on COX-1. We conclude that intracellular glutathione modulates LPS-stimulated COX-2 gene expression and prostaglandin synthesis in BPAEC via early activation of p42/44 MAPKs.

Lessons from trials in hypertensive type 2 diabetic patients

There is incontrovertible evidence that association of type 2 diabetes with hypertension markedly increases the risk of cardiovascular events, death, and nephropathy. In type 2 diabetes, even blood pressure values usually considered below the threshold for hypertension (ie, 140/90 mm Hg) in nondiabetic subjects represent an additional risk of clinical relevance. Evidence that more intensive blood pressure lowering is beneficial in type 2 diabetes over less intensive lowering is also overwhelming. However, most published trials show the need for combination therapy in the great majority of patients, and even with combination therapy it is difficult to attain the expected goal blood pressure, in particular goal systolic blood pressure. It should be recognized that the systolic blood pressure goal of less than 130 mm Hg is a very difficult one to achieve in diabetics. Evidence of the superiority or inferiority of different drug classes is vague and contradictory. Recent evidence concerning angiotensin II receptor antagonists has shown a significant reduction of cardiovascular events, cardiovascular death, and total mortality when losartan was compared with atenolol, but not when irbesartan was compared with amlodipine. If renal endpoints are considered, evidence of the benefit of angiotensin II receptor antagonists in type 2 diabetes is more robust than that available with angiotensin-converting enzyme inhibitors. Primary prevention of development of microalbuminuria seems to be greatly facilitated by strict blood pressure control. However, by attaining normal blood pressure levels (< 130/80 mm Hg), better preservation of glomerular filtration rate does not seem to be insured.

Expression of cyclooxygenase-2 in biopsies obtained from human transplanted kidneys undergoing rejection

BACKGROUND

The inducible cyclooxygenase (COX)-2 is a target of immunosuppressive drugs routinely administered to patients after transplantation. This study investigates a potential involvement of COX-2 in transplant rejection. Therefore, we examined the expression of COX-2 in biopsies obtained for diagnostic purposes.

METHODS

COX-2 was detected by immunohistochemistry and in situ hybridization. Congruent staining was obtained by both methods: in specimens of a kidney explanted as the result of vascular rejection, tubular epithelial cells and endothelial cells stained positively for COX-2. Furthermore, in appendiceal specimens obtained at surgery, epithelial cells of the crypts, interstitial cells, and mesothelial cells were positive by both methods, affirming the specificity of the antibody.

RESULTS

Compared with healthy control subjects, intensive staining of COX-2 was observed in most of the 28 biopsies obtained from patients diagnosed with vascular rejection combined with cellular interstitial rejection and tubulitis. Glomeruli and the macula densa area were essentially negative compared with prominent staining in cortical and medullary epithelial cells of the tubuli. Staining was distinct with individual positive cells in the tubular cross sections. Few arteries expressed COX-2 in intimal cells. Less prominent expression of COX-2 was detected in the biopsies of six kidneys obtained from patients diagnosed with acute tubular necrosis.

CONCLUSION

This is the first report to show the up-regulation of COX-2 in human transplanted kidneys, despite ongoing immunosuppressive treatment. It remains to be established whether the up-regulation of COX-2 is part of the rejection process or has to be considered implicated in renal preservative mechanisms.

Angiotensin-converting enzyme inhibitors and type 2 diabetic nephropathy: a meta-analysis

OBJECTIVE

To perform a meta-analysis on studies evaluating the effect of angiotensin-converting enzyme (ACE) inhibitors on diabetic nephropathy in patients with type 2 diabetes mellitus.

METHODS

A computerized literature search was conducted for articles of studies comparing ACE inhibitors with a control in patients with diabetes, in which measurement of albuminuria or proteinuria was an outcome. Each article was abstracted by two of the authors. Data from the articles were presented as geometric or arithmetic means. The data were summarized separately by using standard techniques for meta-analysis.

MAIN RESULTS

Statistically significant reductions in albuminuria were observed regardless of whether data were described with geometric or arithmetic means. Both were associated with significant heterogeneity. When studies reporting geometric means were stratified and analyzed, the heterogeneity was lost and statistically significant reductions in albuminuria were observed. The same procedure was repeated for studies reporting arithmetic means, but heterogeneity remained.

CONCLUSION

The ACE inhibitors produce statistically significant reductions in albuminuria associated with significant heterogeneity of effect. Stratification reduces the heterogeneity and supports treatment with ACE inhibitors to reduce the progression of nephropathy in patients with type 2 diabetes mellitus.

ACE inhibition or angiotensin receptor blockade: which should we use in diabetic patients?

Blockade of the effects of angiotensin II (Ang II) by using an angiotensin-converting enzyme (ACE) inhibitor has been proven to be of value in Type 1 diabetic nephropathy and in non-diabetic renal disease. Evidence in favour of Ang II blockade in Type 2 diabetic patients with renal damage is still lacking for ACE inhibitors (ACE-Is), while recent data indicate that angiotensin receptor blockers (ARBs) could be the drugs of choice in this situation. On the other hand, renal damage from the onset of disease is accompanied by a very significant increment in global cardiovascular risk. This fact, as well as that of simultaneous renal and cardiovascular protection, have to be considered for drug selection. In this sense, ACE-Is have been shown to be the drugs of choice when secondary cardiovascular prevention is required, while the evidence in primary prevention in hypertensive patients has been shown with losartan in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study. All these facts led to the conclusion that both ACE-Is and ARBs can be considered when both renal and cardiovascular protection are aimed for in Type 2 diabetic patients.

Treatment of diabetic nephropathy in its early stages

Diabetic nephropathy is one of the most frequent causes of end-stage renal disease (ESRD), and, in recent years, the number of diabetic patients entering renal replacement therapy has dramatically increased. The magnitude of the problem has led to numerous efforts to identify preventive and therapeutic strategies. In normoalbuminuric patients, optimal glycemic control (HbA(1c) lower than 7.5%) plays a fundamental role in the primary prevention of ESRD [weighted mean relative risk reduction (RRR) approximately 37% for metabolic control versus trivial renoprotection for intensive anti-hypertensive therapy or ACE-inhibitors (ACE-I)]. In the microalbuminuric stage, strict glycemic control probably reduces the incidence of overt nephropathy (weighted mean RRR approximately 50%), while blood pressure levels below 130/80 mmHg are recommended according to the average blood pressure levels obtained in various studies. In normotensive patients, ACE-I markedly reduce the development of overt nephropathy almost regardless of blood pressure levels; in hypertensive patients, ACE-I are less clearly active (weighted mean RRR approximately 23% versus other drugs), whereas angiotensin-receptor blockers (ARB) appear strikingly renoprotective. Once overt proteinuria appears, it is uncertain whether glycemic control affects the progression of nephropathy. In type 1 diabetes, various anti-hypertensive treatments, mainly ACE-I, are effective in slowing down the progression of nephropathy; in type 2 diabetes, two recent studies demonstrate that ARB are superior to conventional therapy or calcium channel blockers (CCB). In clinical practice, pharmacological tools are not always used to the best benefit of the patients. Therefore, clinicians and patients need to be educated regarding the renoprotection of drugs inhibiting the renin-angiotensin system (RAS) and the overwhelming importance of achieving target blood pressure.

Failure of cyclosporin A to induce transforming growth factor beta (TGF-beta) synthesis in activated peripheral blood lymphocytes

Induction of transforming growth factor beta (TGF-beta) by the immunosuppressive drug cyclosporin A (CsA) in activated lymphocytes has been claimed to add to the renal pro-fibrotic effects of CsA. The aim of this study was to evaluate CsA-mediated TGF-beta induction in a larger number of lymphocyte preparations from different donors. Peripheral blood lymphocytes (PBL) were obtained from healthy blood donors. The cells were stimulated with phytohemagglutinin E (PHA) and phorbol ester (tetradecanoyl phorbol acetate, TPA) in the presence or absence of CsA. TGF-beta, interleukin-2 (IL-2) and cyclooxygenase-2 (Cox-2) mRNA were detected by Northern blot analysis or by real time reverse transcriptase-polymerase chain reaction (RT-PCR). TGF-beta and IL-2 protein were determined in the cellular supernatants by enzyme-linked immunosorbent assay. TGF-beta mRNA and protein were up-regulated when the cells were stimulated with PHA/TPA. Cyclosporin A at high concentrations (500 ng/mL) caused a transient increase in TGF-beta mRNA which was significant after 2 h. CsA did not induce sustained TGF-beta protein expression (24-72 h) in any of the preparations (n = 14), whereas the up-regulation of IL-2 mRNA and protein was prevented by CsA in the same preparations. Furthermore, up-regulation of Cox-2 mRNA was inhibited by CsA. Taken together, there was no evidence for TGF-beta as a clinically relevant mediator being induced by CsA in activated peripheral blood T-lymphocytes.

Antihypertensive treatment in patients with type-2 diabetes mellitus: what guidance from recent controlled randomized trials?

BACKGROUND

Patients with type-2 diabetes have a high prevalence of hypertension and show an elevated incidence of cardiovascular events and nephropathy.

OBJECTIVES

Recent randomized trials of antihypertensive therapy providing information about cardiovascular and renal risk in diabetes, blood pressure goals and best suitable drugs were reviewed.

FINDINGS

Evidence that association of type-2 diabetes with hypertension markedly increases cardiovascular and renal risk is incontrovertible: even blood pressure values in the high-normal range represent a more relevant risk than in non-diabetics. More versus less intensive blood pressure lowering or active versus placebo treatment can significantly prevent cardiovascular and renal events, with a particularly consistent reduction of proteinuria and microalbuminuria. Although several of the trials showing significant reduction of cardiovascular or renal risk achieved diastolic blood pressure (DBP) between 75 and 82 mmHg, systolic blood pressure (SBP) 140 mmHg was never achieved in trials showing cardiovascular benefits and SBP 130 mmHg was only achieved in two trials in normotensive subjects showing proteinuria reduction. The recommendation given by all major guidelines to lower SBP 130 mmHg appears to be difficult to comply with. Evidence of the superiority or inferiority of different drug classes (angiotensin-converting enzyme inhibitors, calcium antagonists, diuretics and beta-blockers) is rather vague, especially for cardiovascular protection. As to angiotensin-receptor antagonists, losartan has shown significant cardiovascular protection over a beta-blocker, and irbesartan, although not showing cardiovascular benefits over a calcium antagonist, was significantly better in retarding renal dysfunction and failure.

CONCLUSIONS

In most trials on hypertensive diabetics, the large majority of patients were on two, three and even four-drug therapy. Therefore, it appears reasonable that all effective and well tolerated antihypertensive agents can be used in association to achieve DBP 80 mmHg and, whenever possible, SBP 130 or 135 mmHg, with the regular inclusion of an angiotensin-receptor antagonist for its proven renoprotective action. Hopefully, better guidance will be provided by further trials.

Renal and cardiovascular protection in type 2 diabetes mellitus: angiotensin II receptor blockers

Aggressive treatment of hypertension is effective in reducing both microvascular and macrovascular complications in type 2 diabetes, and target BP less than 130/85 or 130/80 mmHg are now recommended. Inhibition of renin angiotensin aldosterone system (RAAS) plays an essential role in the treatment of hypertension and diabetes-related complications. Studies focusing on renal end-points suggest that angiotensin-converting enzyme inhibitors (ACE-I) are more effective than other traditional agents in reducing the onset of clinical proteinuria in both type 1 and type 2 diabetic patients with incipient nephropathy, mainly in normotensive ones (secondary prevention). However, several small trials in type 2 diabetic patients with overt nephropathy (tertiary prevention) failed to demonstrate a specific renoprotective role for ACE-I, at variance with type 1 diabetes. Three recent large trials address the question of whether angiotensin II receptor blockers (ARB) prevent the development of clinical proteinuria or delay the progression of nephropathy in type 2 diabetes. The IRMA study showed that irbesartan is more effective than conventional therapy in preventing the development of clinical proteinuria and in favoring the regression to normoalbuminuria for comparable BP control in patients with incipient nephropathy. The IDNT and RENAAL trials showed that ARB are more effective than traditional antihypertensive therapies in reducing progression toward end-stage renal failure (ESRF) in type 2 diabetic patients with overt nephropathy independently of changes in BP. Moreover, a reduction in hospitalizations for heart failure was demonstrated for ARB-treated patients compared with placebo. Furthermore, the LIFE study showed that losartan is more effective than conventional therapy in reducing cardiovascular morbidity and mortality in a cohort of diabetic patients with hypertension and left ventricular hypertrophy. In conclusion, ARB seem to be effective in both preventing renal damage and reducing progression toward ESRF in type 2 diabetic patients. Thus, the guidelines for the prevention and treatment of diabetic nephropathy are now changed. In type 1 diabetes ACE-I are the first-choice drug; in type 2 diabetes, ARB are considered first-choice drugs in secondary prevention as well as ACE-I and have been now elected the unique first-choice drug in tertiary prevention of ESRF. Finally, ARB should be considered as the first-choice drug in cardiovascular prevention too, as well as ACE-I.