Drug selection and the management of corticosteroid-related diabetes mellitus

The protective effect of imatinib against pancreatic β-cell apoptosis induced by dexamethasone via increased GSTP1 expression and reduced oxidative stress

Glucocorticoids (GCs) are known to stimulate pancreatic beta (β)-cell apoptosis via several mechanisms, including oxidative stress. Our previous study suggested an increase in dexamethasone-induced pancreatic β-cell apoptosis via a reduction of glutathione S-transferase P1 (GSTP1), which is an antioxidant enzyme. Imatinib, which is a tyrosine kinase inhibitor, also exerts antioxidant effect. This study aims to test our hypothesis that imatinib would prevent pancreatic β-cell apoptosis induced by dexamethasone via increased GSTP1 expression and reduced oxidative stress. Our results revealed that dexamethasone significantly increased apoptosis in INS-1 cells when compared to the control, and that imatinib significantly decreased INS-1 cell apoptosis induced by dexamethasone. Moreover, dexamethasone significantly increased superoxide production in INS-1 cells when compared to the control; however, imatinib, when combined with dexamethasone, significantly reduced superoxide production in INS-1 cells. Dexamethasone significantly decreased GSTP1, p-ERK1/2, and BCL2 protein expression, but significantly increased p-JNK, p-p38, and BAX protein expression in INS-1 cells-all compared to control. Importantly, imatinib significantly ameliorated the effect of dexamethasone on the expression of GSTP1, p-ERK1/2, p-JNK, p-p38 MAPK, BAX, and BCL2. Furthermore-6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio) hexanol (NBDHEX), which is a GSTP1 inhibitor, neutralized the protective effect of imatinib against pancreatic β-cell apoptosis induced by dexamethasone. In conclusion, imatinib decreases pancreatic β-cell apoptosis induced by dexamethasone via increased GSTP1 expression and reduced oxidative stress.

Cytoprotective effect of genistein against dexamethasone-induced pancreatic β-cell apoptosis

Steroid-induced diabetes is a well-known metabolic side effect of long-term use of glucocorticoid (GC). Our group recently demonstrated dexamethasone-induced pancreatic β-cell apoptosis via upregulation of TRAIL and TRAIL death receptor (DR5). Genistein protects against pancreatic β-cell apoptosis induced by toxic agents. This study aimed to investigate the cytoprotective effect of genistein against dexamethasone-induced pancreatic β-cell apoptosis in cultured rat insulinoma (INS-1) cell line and in isolated mouse islets. In the absence of genistein, dexamethasone-induced pancreatic β-cell apoptosis was associated with upregulation of TRAIL, DR5, and superoxide production, but downregulation of TRAIL decoy receptor (DcR1). Dexamethasone also activated the expression of extrinsic and intrinsic apoptotic proteins, including Bax, NF-κB, caspase-8, and caspase-3, but suppressed the expression of the anti-apoptotic Bcl-2 protein. Combination treatment with dexamethasone and genistein protected against pancreatic β-cell apoptosis, and reduced the effects of dexamethasone on the expressions of TRAIL, DR5, DcR1, superoxide production, Bax, Bcl-2, NF-κB, caspase-8, and caspase-3. Moreover, combination treatment with dexamethasone and genistein reduced the expressions of TRAIL and DR5 in isolated mouse islets. The results of this study demonstrate the cytoprotective effect of genistein against dexamethasone-induced pancreatic β-cell apoptosis in both cell line and islets via reduced TRAIL and DR5 protein expression.

Glucocorticoids in rheumatoid arthritis: the silent companion in the therapeutic strategy

INTRODUCTION

Glucocorticoids (GCs) are key actors in RA management, despite the increasing number of available drugs. In fact, due to their efficacy and safety, the combination therapy between GCs and conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) is still recommended in the early phase of RA treatment, because improving the long-term results.

AREAS COVERED

In this paper, we reviewed the role of GCs in RA management, focusing on mechanisms of action as well as the benefit/risk ratio of GCs and newer therapeutic formulations. Furthermore, we analyzed GCs DMARDs proprieties on disease activity and their long-term effects on radiographic damage. We designed a narrative review aimed to provide an overview concerning GCs in RA management.

EXPERT OPINION

A large amount of evidence supports the use of GCs in RA, especially in the earliest phases of the disease. Besides GCs symptomatic effects due to their strong anti-inflammatory effects, data from several randomized clinical trials have shown a substantial benefit of low-dose GCs in inhibiting the radiographic damage, thus highlighting GCs DMARDs properties. Besides their recognized role in the treatment of early RA, systematic monitoring of adverse events should be recommended to minimize GCs toxicity.

Effect of different doses and time-courses of corticosteroid treatment in patients with acute respiratory distress syndrome: A meta-analysis

While previous trials have indicated that the use of corticosteroids for patients with acute respiratory distress syndrome (ARDS) is effective, the dosage and time-course for the use of corticosteroids remain a subject of controversy. The present study aimed to address and resolve these problems. PubMed, Embase and the Cochrane Library databases were searched from inception to March 2017 for randomized controlled trials (RCTs), which included patients with ARDS using corticosteroids. Related data were extracted independently by two investigators. The Mantel-Haenszel method was used with random-effects modeling to calculate the pooled odds ratio (OR) and 95% confidence interval (CI) for the mortality of patients with ARDS, and the risk of new infection arising from the use of glucocorticoids. The inverse variance method was used to calculate the mean difference (MD) and 95% CI for the duration of mechanical-free ventilation and the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FIO₂ ratio). The use of low-dose corticosteroids significantly reduced the mortality rate of patients with ARDS (OR: 0.43; 95% CI: 0.24–0.79; P=0.006) while the use of high-dose corticosteroids provided no significant benefit to reducing the mortality rate (OR: 1.33; 95% CI: 0.86–2.04; P=0.20). The present study identified that glucocorticoids reduced the mortality rate of patients during the early stages of ARDS (OR: 0.61; 95% CI: 0.43–0.86; P=0.005). Glucocorticoids significantly reduced the duration of mechanical ventilation (MD: 3.08; 95% CI: 1.49–4.68; P<0.05) and significantly improved the PaO₂/FiO₂ ratio (MD: 66.39; 95% CI: 57.79–74.98; P<0.05). The use of corticosteroids did not significantly increase the rate of infectious complications (OR: 0.60; 95% CI: 0.32–1.12; P>0.05). The use of low-dose corticosteroids may significantly reduce the mortality rate, particularly in the early stages of ARD, shorten the duration of mechanical ventilation and improve the PaO₂/FiO₂ ratio without increasing the risk of a new infection.

A retrospective observational study of glucocorticoid-induced diabetes mellitus with IgA nephropathy treated with tonsillectomy plus methylprednisolone pulse therapy

Aims

To evaluate the incidence of GC-DM among patients with immunoglobulin A nephropathy (IgAN) and to confirm the risk factors for the development of GC-DM.

Methods

The medical records of patients with IgAN newly treated with the protocol of tonsillectomy combined with steroid pulse therapy were reviewed. The primary outcome was the development of GC-DM within the hospitalization period and during one year of follow-up.

Results

During hospitalization, 19 of the 95 patients developed GC-DM (20.0%), and the patients with GC-DM were significantly older and had a higher rate of family history of diabetes and higher HbA1c levels. The prevalence of hypertension was higher and the eGFR was numerically lower in patients with GC-DM than in those without. Older age (≥45 years) and a family history of diabetes emerged as independent risk factors for the development of GC-DM (odds ratio [OR], 6.3 and 95% confidence interval [CI], 1.6–27.6; OR, 4.4 and 95% CI, 1.2–16.6, respectively). No patients were newly diagnosed with GC-DM during 1-year observation period at out-patient clinic.

Conclusions

Among the patients with IgAN, 20% developed GC-DM during the hospitalization period, confirming the family history of diabetes is clinically necessary before starting GC therapy.

Verification of glycemic profiles using continuous glucose monitoring: cases with steroid use, liver cirrhosis, enteral nutrition, or late dumping syndrome

Glycemic control is often difficult to achieve in patients with diabetes, especially in the presence of comorbid diseases or conditions such as steroid-use or liver cirrhosis, or in patients receiving enteral nutrition. Moreover, reactive hypoglycemia due to late dumping syndrome in people having undergone gastrectomy is also a matter of concern. Empirically and theoretically, the typical glycemic profiles associated with these conditions have been determined; however, what actually happens during a 24-h span is still somewhat obscure. In order to verify and provide information about the 24-h glycemic profiles associated with these conditions, 8 patients with the 4 above-mentioned conditions were monitored using a continuous glucose monitoring system (CGMS). For all 8 patients, CGMS provided detailed information regarding the 24-h glycemic profiles. The CGM results showed typical glycemic patterns for each condition, and we were moreover able to observe the effects of various practical treatments. Based on these cases, we conclude that the CGMS is highly useful for determining the glycemic patterns of patients with the aforementioned conditions in a practical setting; and this system may be used to monitor the treatment success of such cases.

Hepatic serum- and glucocorticoid-regulated protein kinase 1 (SGK1) regulates insulin sensitivity in mice via extracellular-signal-regulated kinase 1/2 (ERK1/2)

Insulin resistance is a major hallmark of metabolic syndromes, including Type 2 diabetes. Although numerous functions of SGK1 (serum- and glucocorticoid-regulated kinase 1) have been identified, a direct effect of SGK1 on insulin sensitivity has not been previously reported. In the present study, we generated liver-specific SGK1-knockout mice and found that these mice developed glucose intolerance and insulin resistance. We also found that insulin signalling is enhanced or impaired in Hep1-6 cells infected with adenoviruses expressing SGK1 (Ad-SGK1) or shRNA directed against the coding region of SGK1 (Ad-shSGK1) respectively. In addition, we determined that SGK1 inhibits ERK1/2 (extracellular-signal-regulated kinase 1/2) activity in liver and Ad-shERK1/2-mediated inhibition of ERK1/2 reverses the attenuated insulin sensitivity in Ad-shSGK1 mice. Finally, we found that SGK1 functions are compromised under insulin-resistant conditions and overexpression of SGK1 by Ad-SGK1 significantly ameliorates insulin resistance in both glucosamine-treated HepG2 cells and livers of db/db mice, a genetic model of insulin resistance.

Use of dexamethasone in patients with high-grade glioma: a clinical practice guideline

BACKGROUND

Dexamethasone is the corticosteroid most commonly used for the management of vasogenic edema and increased intracranial pressure in patients with brain tumours. It is also used after surgery (before embarking on radiotherapy), particularly in patients whose tumours exert significant mass effect. Few prospective clinical trials have set out to determine the optimal dose and schedule for dexamethasone in patients with primary brain tumours, and subsequently, fewer clinical practice guideline recommendations have been formulated.

METHODS

A review of the scientific literature published to November 2012 considered all publications that addressed dexamethasone use in adult patients with brain tumours. Evidence was selected and reviewed by a working group comprising 3 clinicians and 1 methodologist. The resulting draft guideline underwent internal review by members of the Alberta Provincial cns Tumour Team, and feedback was incorporated into the final version of the guideline.

RECOMMENDATIONS

Based on the evidence available to date, the Alberta Provincial cns Tumour Team makes these recommendations: Treatment with dexamethasone is recommended for symptom relief in adult patients with primary high-grade glioma and cerebral edema.After surgery, a maximum dose of 16 mg daily, administered in 4 equal doses, is recommended for symptomatic patients. This protocol should ideally be started by the neurosurgeon.A rapid dexamethasone tapering schedule should be considered where appropriate.Patients who have high-grade tumours, are symptomatic, or have poor life expectancy, can be maintained on a 0.5-1.0 mg dose of dexamethasone daily.Side effects with dexamethasone are common, and they increase in frequency and severity with increased dose and duration of therapy. Patients should be carefully monitored for endocrine, muscular, skeletal, gastrointestinal, psychiatric, and hematologic complications, and for infections and other general side effects.

Glucocorticoid-induced hyperglycemia

OBJECTIVES

Provide treatment guidelines for glucocorticoid-induced hyperglycemia and to understand the clinical implications of glucocorticoid-induced hyperglycemia.

METHODS

The authors analyzed an electronic search (Medline) and a literature review of the pertinent articles published from 1980 to September 2012.

RESULTS

In patients treated with glucocorticoids, the odds ratio for development of new-onset diabetes mellitus has been reported to be 1.36 to 2.31. The prevalence of abnormal glucose metabolism in post renal transplant patients taking glucocorticoids has been reported to be 17% to 32%. Sustained glucocorticoid treatment increases the potential for future cardiovascular disease through multiple pathways, resulting in a trade-off between benefit and harm. Complications related to glucocorticoid treatments are associated with the total glucocorticoid dose and duration of therapy. Other risk factors include age and body mass index. Understanding the pharmacodynamics and clinical implications of glucocorticoid-induced hyperglycemia can promote recognition and improvement of its treatment.

CONCLUSIONS

Glucocorticoid-induced hyperglycemia has significant clinical implications in patients with diabetes mellitus and without diabetes mellitus. Early recognition and proper proactive management of glucocorticoid-induced hyperglycemia should enhance care for patients receiving glucocorticoid treatment. Furthermore, treatment has been effective for both the inpatient and the outpatient settings.

Crude extract of Ceriporia lacerata has a protective effect on dexamethasone-induced cytotoxicity in INS-1 cells via the modulation of PI3K/PKB activity

Excessive and/or long-term glucocorticoid therapy reduces β-cell mass and induces hyperglycemia, which contribute to the development of steroid‑induced diabetes. Ceriporia (C.) lacerata is one of the white‑rot fungi and has been used in bioremediations, such as lignocellulose degradation, in nature. The pharmacologic effect of C. lacerata on steroid-induced β-cell toxicity is not known. In this study, we evaluated the effect of a crude extract from a submerged cultivation of C. lacerata on the survival and apoptosis of INS-1 rat insulin-secreting cells exposed to dexamethasone (Dex), a synthetic diabetogenic glucocorticoid. Treatment with the C. lacerata crude extract (CLCE) largely blocked the Dex-induced reduction in survival and apoptosis of INS-1 cells. Moreover, CLCE treatment inhibited Dex-induced protein kinase B (PKB) dephosphorylation without affecting Dex-induced extracellular signal-regulated protein kinase-1/2 dephosphorylation and MKP-1 upregulation. Importantly, the protective effect of CLCE on Dex-induced cytotoxicity in INS-1 cells was attenuated by LY294002, an inhibitor of PI3K/PKB. CLCE treatment, however, did not protect the INS-1 cells from the cytotoxic effects triggered by other insults, such as interleukin-1β (an inflammatory cytokine), streptozotocin (a diabetogenic drug), thapsigargin (a calcium mobilizing agent), and tunicamycin (an ER stress inducer). Collectively, these findings demonstrate for the first time the ability of CLCE to specifically protect INS-1 cells from Dex-induced cytotoxicity through the modulation of the PI3K/PKB pathway. It is suggested that CLCE may be applied for the prevention and/or treatment of steroid diabetes in which reduction of β-cell survival and induction of β-cell apoptosis play pathogenic roles.

A retrospective study comparing neutral protamine hagedorn insulin with glargine as basal therapy in prednisone-associated diabetes mellitus in hospitalized patients

OBJECTIVE

To compare glycemic outcomes in hospitalized patients with or without type 2 diabetes mellitus receiving neutral protamine Hagedorn insulin (NPH) vs glargine as basal insulin for management of glucocorticoid-associated hyperglycemia.

METHODS

We conducted a retrospective review of electronic medical records in prednisone-treated adult patients with hyperglycemia in a university hospital. Consecutive patients were selected in both the NPH and glargine cohorts using inclusion and exclusion criteria. Baseline characteristics were assessed in each cohort. Glycemic outcomes were analyzed by comparing fasting blood glucose, mean daily blood glucose concentration, median daily blood glucose concentration, and the number of hypoglycemic episodes on a prespecified index day.

RESULTS

One hundred twenty patients were included: 60 patients in the NPH cohort and 60 patients in the glargine cohort. The weight-based insulin requirement was lower in the NPH cohort than in the glargine cohort (0.27 ± 0.2 units/kg vs 0.34 ± 0.2 units/kg [P = .04] for basal insulin and 0.26 ± 0.2 units/kg vs 0.36 ± 0.2 units/kg [P = .03] for bolus insulin). NPH and glargine cohorts were similar regarding age, sex, race, body mass index, hemoglobin A1c, serum creatinine, and prednisone dosage. Glycemic outcomes in the NPH cohort compared with outcomes in the glargine cohort were similar regarding mean fasting blood glucose concentration (134 ± 49 mg/dL vs 139 ± 54 mg/dL [P = .63]), mean daily blood glucose (167 ± 46 mg/dL vs 165 ± 52 mg/dL [P = .79]), median blood glucose (160 ± 49 mg/dL vs 159 ± 57 mg/dL [P = .90]), and number of hypoglycemic episodes per day (0.12 ± 0.3 vs 0.10 ± 0.3 [P = .77]).

CONCLUSIONS

NPH and glargine appear to be equally effective as basal insulin in the management of hyperglycemia in hospitalized patients receiving prednisone. However, the total daily insulin doses used were lower in the NPH cohort.

Glucocorticoid-induced suppression of β-cell proliferation is mediated by Mig6

Glucocorticoids can cause steroid-induced diabetes or accelerate the progression to diabetes by creating systemic insulin resistance and decreasing functional β-cell mass, which is influenced by changes in β-cell function, growth, and death. The synthetic glucocorticoid agonist dexamethasone (Dex) is deleterious to functional β-cell mass by decreasing β-cell function, survival, and proliferation. However, the mechanism by which Dex decreases β-cell proliferation is unknown. Interestingly, Dex induces the transcription of an antiproliferative factor and negative regulator of epidermal growth factor receptor signaling, Mig6 (also known as gene 33, RALT, and Errfi1). We, therefore, hypothesized that Dex impairs β-cell proliferation by increasing the expression of Mig6 and thereby decreasing downstream signaling of epidermal growth factor receptor. We found that Dex induced Mig6 and decreased [(3)H]thymidine incorporation, an index of cellular replication, in mouse, rat, and human islets. Using adenovirally delivered small interfering RNA targeted to Mig6 in rat islets, we were able to limit the induction of Mig6 upon exposure to Dex, compared with islets treated with a control virus, and completely rescued the Dex-mediated impairment in replication. We demonstrated that both Dex and overexpression of Mig6 attenuated the phosphorylation of ERK1/2 and blocked the G(1)/S transition of the cell cycle. In conclusion, Mig6 functions as a molecular brake for β-cell proliferation during glucocorticoid treatment in β-cells, and thus, Mig6 may be a novel target for preventing glucocorticoid-induced impairments in functional β-cell mass.

Secondary diabetes associated with 5-fluorouracil-based chemotherapy regimens in non-diabetic patients with colorectal cancer: results from a single-centre cohort study

AIM

The aim of the study was to analyse the prevalence and characteristics of secondary diabetes induced by 5-fluorouracil (5-FU) based chemotherapy in non-diabetic patients with colorectal cancer (CRC).

METHOD

A total of 422 consecutive CRC patients who received 5-FU-based chemotherapy were retrospectively analysed. Fasting plasma glucose (FPG) levels were determined before each cycle of chemotherapy during active treatment and regular follow-up. The prevalence and characteristics of secondary hyperglycaemia were investigated, with special focus on the clinical outcome.

RESULTS

Among the 422 CRC patients, 60 had pre-existing hyperglycaemia. In the remaining 362 with normal FPG levels before chemotherapy, 42 (11.6%) and 41 (11.3%) patients developed diabetes and impaired fasting glucose during the study period. Among the 42 secondary diabetic patients, 22 (52.4%) received anti-diabetes drug therapy, in 7 (16.7%) cases the FPG level returned to normal without any active intervention, and 13 (30.9%) cases received diet control and physiotherapy. Thirty-one (8.6%) patients developed diabetes. Based on the Common Terminology Criteria for Adverse Events, an adverse event over Grade 3 occurred in seven cases during follow-up. Diabetes-related adverse events had a serious negative impact on chemotherapy in six cases. Diabetes-related death occurred in three patients.

CONCLUSIONS

Secondary diabetes associated with 5-FU-based chemotherapy occurs in around 10% of CRC patients, with a significant negative impact on treatment and clinical outcome. 5-FU-related diabetes should be regarded as a common side effect of 5-FU treatment.

"Brittleness" in diabetes: easier spoken than broken

By definition, brittle diabetes (BD) is an unstable condition. Patients with BD suffer chronically from poor metabolic control, characterized by severe instability of glycemic values with frequent and unpredictable hypoglycemic and/or diabetic ketoacidosis episodes that cannot be attributed to failure in management. Quality of life is dramatically compromised because of very frequent acute complications leading to hospital admissions and because of premature chronic complications. It remains difficult to identify all patients with BD as diagnostic criteria are still not well defined. In practice, metabolic instability is manifested most obviously by chaotic glycemic profiles, which show greater and more unpredictable variation than in "stable" patients with diabetes. It is important that patients with BD are not adequately controlled, even by closely supervised, intensive insulin regimens, including continuous subcutaneous and/or intravenous insulin infusion. Their care is often very expensive in terms of time and resources, and their lives are constantly at risk for severe metabolic derangement. Management can also be frustrating and demoralizing for everyone involved, including the patient's family as well as the diabetes care team. Adopting a team approach, involving a broad range of disciplines, is essential in treating patients with BD and helping them to achieve and maintain both normoglycemia and quality of life.

Steroid-induced diabetes: is it just unmasking of type 2 diabetes?

Aims. We compared the demographic profile and clinical characteristics of individuals with new onset steroid-induced diabetes (NOSID) to Type 2 diabetes (T2DM) patients with and without steroid treatment. Methods. The demographic profile and clinical characteristics of 60 individuals who developed NOSID were examined and matched to 60 type 2 diabetes patients receiving steroid therapy (T2DM+S) and 360 diabetic patients not on steroids (T2DM) for age, duration of diabetes, HbA1c, gender, and ethnicity. Results. Patients who developed NOSID had less family history of diabetes (P ≤ 0.05) and were less overweight (P ≤ 0.02). NOSID was more commonly treated with insulin. Despite a matching duration of diabetes and glycaemic control, significantly less retinopathy was found in the group of patients with NOSID (P < 0.03). Conclusions. It appears that steroid treatment primarily precipitated diabetes in a group of individuals otherwise less affected by risk factors of diabetes at that point in time, rather than just opportunistically unmasking preexisting diabetes. Furthermore, the absence of retinopathy suggests that patients with NOSID had not been exposed to long periods of hyperglycaemia. However, the impact of the underlying conditions necessitating steroid treatment and concomitant medications such as immunosuppressants on diabetes development remain to be defined.

Glucocorticoid-induced diabetes mellitus in patients with systemic lupus erythematosus treated with high-dose glucocorticoid therapy

The aim of this study was to investigate the prevalence and associated factors of glucocorticoid-induced diabetes mellitus (GDM) in patients with systemic lupus erythematosus (SLE) receiving high-dose glucocorticoid therapy. Patients with SLE who had received high-dose glucocorticoid therapy (prednisolone ≥1 mg/kg/day) at Yonsei University Medical Center, Seoul, Korea, were recruited between January 1999 and June 2009. In total 127 patients with SLE were evaluated. Sixteen (12.6%) of them developed GDM after high-dose glucocorticoid therapy (95% confidence interval, 6.8-18.4%). Univariate analysis showed that old age, family history of diabetes mellitus (DM), hypertension, higher body mass index, higher mean dose of prednisolone before high-dose glucocorticoid therapy, and concurrent use of mycophenolate mofetil (MMF) were factors that would increase the likelihood of GDM. Multivariate analysis determined that age, family history of DM, mean dose of prednisolone before high-dose glucocorticoid therapy and concurrent use of MMF were independent associated factors for GDM. In summary, GDM was developed among 12.6% of patients with SLE after high-dose glucocorticoid therapy. Old age, family history of DM, higher mean dose of prednisolone before high-dose glucocorticoid therapy and concurrent use of MMF were determined to be factors responsible for increasing the risk of developing GDM.

Dynamic regulation of PDX-1 and FoxO1 expression by FoxA2 in dexamethasone-induced pancreatic β-cells dysfunction

Transcription factors forkhead box (Fox)O1 and pancreatic and duodenal homeobox-1 (PDX-1) are involved in dexamethasone (DEX)-induced dysfunction in pancreatic β-cells. However, the molecular mechanism underlying the regulation of FoxO1 and PDX-1 expression in β-cells treated with DEX is not fully understood. In this study, we found that DEX markedly increased FoxO1 mRNA and protein expression, whereas it decreased PDX-1 mRNA and protein expression in a dose- and time-dependent manner. Further study showed that FoxA2 was involved in regulation of FoxO1 and PDX-1 expression in DEX-induced pancreatic β-cells dysfunction. Interestingly, we demonstrated for the first time that FoxA2 could bind to the FoxO1 gene promoter and positively regulate FoxO1 expression. Moreover, we found that DEX increased the activity of FoxA2 binding to the FoxO1 promoter but decreased the activity of FoxA2 binding to the PDX-1 promoter of RINm5F cells. Knockdown of FoxA2 by RNA interference inhibited FoxO1 expression and restored PDX-1 expression in pancreatic β-cells treated with DEX. However, DEX had no effect on the expression of FoxA2. Together, the results of the present study demonstrated that FoxA2 could dynamically regulate FoxO1 and PDX-1 expression in pancreatic β-cells treated with DEX, which provides new important information on the transcriptional regulation of FoxO1 and PDX-1 in DEX-induced pancreatic β-cells. Inhibition of FoxA2 can effectively protect β-cells against DEX-induced dysfunction.

New-onset diabetes after transplantation: risk factors and clinical impact

With improvements in patient and graft survival, increasing attention has been placed on complications that contribute to long-term patient morbidity and mortality. New-onset diabetes after transplantation (NODAT) is a common complication of solid-organ transplantation, and is a strong predictor of graft failure and cardiovascular mortality in the transplant population. Risk factors for NODAT in transplant recipients are similar to those in non-transplant patients, but transplant-specific risk factors such as hepatitis C (HCV) infection, corticosteroids and calcineurin inhibitors play a dominant role in NODAT pathogenesis. Management of NODAT is similar to type 2 diabetes management in the general population. However, adjusting the immunosuppressant regimen to improve glucose tolerance must be weighed against the risk of allograft rejection. Lifestyle modification is currently the strategy with the least risk and the most benefit.

Incidence and risk factors of steroid-induced diabetes in patients with respiratory disease

Glucocorticoids are effective for treating several respiratory diseases. However, they can cause hyperglycemia. This study determined the incidence and risk factors of steroid-induced diabetes mellitus (S-DM) in patients treated with glucocorticoid for respiratory diseases. A retrospective study examined patients with respiratory diseases treated with a prednisolone-equivalent glucocorticoid dose exceeding 20 mg/day for at least 4 weeks between January 2003 and December 2008. Patients whose initial random glucose level exceeded 200 mg/dL or who had pre-existing diabetes were excluded. S-DM was defined as a fasting glucose concentration exceeding 126 mg/dL or a random glucose concentration exceeding 200 mg/dL at least twice after beginning steroid treatment. A total of 231 patients with respiratory diseases met the inclusion criteria. Their median age was 55 yr, and 139 were female. The median cumulative prednisolone-equivalent glucocorticoid dose was 4,965 mg, and the median duration of steroid treatment was 193 days. S-DM was diagnosed in 34 (14.7%) of 231 patients. Multivariate logistic regression identified older age (odds ratio 1.05, 95% confidence interval 1.02-1.09) as a risk factor for S-DM. S-DM is frequent among patients with respiratory diseases treated with glucocorticoid. Clinicians should be aware of the possibility of S-DM, especially among elderly patients.

Exenatide improves glucocorticoid-induced glucose intolerance in mice

Exenatide is an incretin mimetic that is recently available in the US for the treatment of diabetes. There is a paucity of information on the effects of exenatide in glucocorticoid (GC)-induced diabetes. Although the effect of continuous intravenous infusion of exenatide on GC-induced glucose intolerance has been investigated before in healthy human males receiving oral prednisolone, we investigated the efficacy of a single subcutaneous dose of exenatide (3 μg/kg) in lowering blood glucose in GC-induced glucose intolerance in C57BL/6 mice. In a longitudinal experiment, the area under the curve (AUC) of oral glucose tolerance tests (OGTT) significantly increased after dexamethasone (P = 0.004), which was subsequently decreased by exenatide (P < 0.001). A cross-sectional experiment showed that exenatide improved glucose tolerance compared with placebo in a mouse model of dexamethasone-induced glucose intolerance. AUC of OGTT in the exenatide group were significantly (P < 0.001) lower than in the placebo group. Insulin tolerance tests (ITT) demonstrated that exenatide decreased the ability of the mice to tolerate insulin compared with placebo. The AUC of ITT in the exenatide group were also significantly (P = 0.006) lower than in the placebo group. In conclusion, a single dose of exenatide was able to decrease glucose intolerance and insulin resistance in these placebo-controlled experiments. Future clinical trials are justified to investigate the role of exenatide in the treatment of GC-induced glucose intolerance/diabetes.

Glucocorticoids differentially regulate the expression of CRFR1 and CRFR2α in MIN6 insulinoma cells and rodent islets

Urocortin 3 (Ucn 3), member of the corticotropin-releasing factor (CRF) family of peptide hormones, is released from β-cells to potentiate insulin secretion. Ucn 3 activates the CRF type-2 receptor (CRFR2) but does not activate the type-1 receptor (CRFR1), which was recently demonstrated on β-cells. While the direct actions of Ucn 3 on insulin secretion suggest the presence of cognate receptors within the islet microenvironment, this has not been established. Here we demonstrate that CRFR2α is expressed by MIN6 insulinoma cells and by primary mouse and human islets, with no detectable expression of CRFR2β. Furthermore, stimulation of MIN6 cells or primary mouse islets in vitro or in vivo with glucocorticoids (GCs) robustly and dose-dependently increases the expression of CRFR2α, while simultaneously inhibiting the expression of CRFR1 and incretin receptors. Luciferase reporters driven by the mouse CRFR1 or CRFR2α promoter in MIN6 cells confirm these differential effects of GCs. In contrast, GCs inhibit CRFR2α promoter activity in HEK293 cells and inhibit the expression of CRFR2β in A7r5 rat aortic smooth muscle cells and differentiated C2C12 myotubes. These findings suggest that the GC-mediated increase of CRFR2α depends on the cellular context of the islet and deviates from the GC-mediated suppression of CRFR1 and incretin receptors. Furthermore, GC-induced increases in CRFR2α expression coincide with increased Ucn 3-dependent activation of cAMP and MAPK pathways. We postulate that differential effect of GCs on the expression of CRFR1 and CRFR2α in the endocrine pancreas represent a mechanism to shift sensitivity from CRFR1 to CRFR2 ligands.

Preventive effect of Sphaeranthus indicus during progression of glucocorticoid-induced insulin resistance in mice

CONTEXT

The whole plant of Sphaeranthus indicus Linn. (Asteraceae) is traditionally used in the treatment of diabetes mellitus.

OBJECTIVE

The present study investigated the effect of the methanol extract of Sphaeranthus indicus whole plant in dexamethasone-induced insulin resistance in mice.

MATERIALS AND METHODS

The mice were treated with dexamethasone for 22 days and effects on plasma glucose level, serum triglyceride level, glucose uptake, levels of hepatic enzymes like glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), lipid peroxidase (LPO), and body weight was observed.

RESULTS

The Sphaeranthus indicus extract (SI) showed significant decrease in plasma glucose and serum triglyceride levels (p <0.01) at doses, of 400 and 800 mg/kg, p.o., and stimulated insulin assisted and non-insulin assisted glucose uptake in skeletal muscle. The levels of antioxidant enzymes GSH, SOD, and CAT were significantly increased (p <0.01) and there was a significant decrease in level of LPO (p <0.01). SI significantly restored (p <0.01) dexamethasone induced body weight loss.

DISCUSSION AND CONCLUSION

Sphaeranthus indicus may prove to be effective in the treatment of type II diabetes mellitus owing to its ability to decrease insulin resistance.

Effect of eplerenone versus spironolactone on cortisol and hemoglobin A₁(c) levels in patients with chronic heart failure

BACKGROUND

It has been reported that mineralocorticoid receptor antagonist improves the prognosis of chronic heart failure (CHF). Recently, hemoglobin A₁(c) (HbA₁(c)) levels have been reported to be an independent risk factor for mortality in CHF, suggesting the important role of insulin resistance in CHF. We compared the metabolic effect of a selective mineralocorticoid receptor blocker eplerenone with spironolactone in CHF patients.

METHODS

One hundred seven stable outpatients with mild CHF, who were already receiving standard therapy for CHF, were randomized (1:2) to spironolactone (25 mg/d) or eplerenone (50 mg/d). Plasma levels of B-type natriuretic peptide, adiponectin, HbA₁(c) and cortisol were measured before and after 4 months treatment with spironolactone or eplerenone.

RESULTS

There were no differences in baseline characteristics including hemodynamic parameters and plasma levels of biomarkers between 2 groups. In both groups, plasma B-type natriuretic peptide levels were significantly decreased and plasma aldosterone levels were significantly increased after 4 months. In patients receiving spironolactone (n = 34), plasma adiponectin levels were significantly decreased (12.6 ± 1.4-11.2 ± 1.3 μg/mL, P < .0001) and HbA₁(c) and cortisol levels were significantly increased (5.61 ± 0.1-5.8 ± 0.1%, P < .0001, 11.3 ± 0.8-14.7 ± 1.3 μg/dL, P = .003, respectively). In patients receiving spironolactone, there was a significant positive correlation between the change in cortisol and the change in HbA₁(c) (r = 0.489, P = .003). In contrast, in patients receiving eplerenone (n = 73), plasma levels of adiponectin, HbA₁(c) and cortisol did not change.

CONCLUSION

These findings indicated that the metabolic effect of eplerenone differed from that of spironolactone and that eplerenone had a superior metabolic effect especially on HbA₁(c) in CHF patients.

Involvement of the cholinergic pathway in glucocorticoid-induced hyperinsulinemia in rats

AIMS

We investigated the contribution of the cholinergic nervous system to dexamethasone-induced insulin resistance and hyperinsulinemia in rats.

METHODS

Seventy-day-old Wistar male rats were distributed in groups: control (CTL), vagotomized (VAG), and sham operated (SHAM). On the 90th day of life, half of the rats were treated daily with 1mg/kg of dexamethasone for 5 days (CTL DEX, VAG DEX, and SHAM DEX).

RESULTS

In the presence of 8.3mM glucose plus 100microM carbachol (Cch), isolated islets from CTL DEX secreted significantly more insulin than CTL. Cch-enhancement of secretion was further increased in islets from VAG CTL and VAG DEX than SHAM CTL and SHAM DEX, respectively. In CTL DEX islets, M3R and PLCbeta1 and phosphorylated PKCalpha, but not PKCalpha, protein content was significantly higher compared with each respective control. In islets from VAG DEX, the expression of M3R protein increased significantly compared to VAG CTL and SHAM DEX. Vagotomy per se did not affect insulin resistance, but attenuated fasted and fed insulinemia in VAG DEX, compared with SHAM DEX rats.

CONCLUSION

These data indicate an important participation of the cholinergic nervous system through muscaric receptors in dexamethasone-induced hyperinsulinemia in rats.

Glucocorticoid-induced hyperglycemia

OBJECTIVE

To review the current literature on glucocorticoid-induced hyperglycemia and provide a strategy for its treatment.

METHODS

We undertook an electronic (MEDLINE) and a library review of the existing pertinent literature published from 1950 to March 2009.

RESULTS

Glucocorticoid-induced hyperglycemia is common in patients with and without diabetes. The odds ratio for new-onset diabetes mellitus in patients treated with glucocorticoids ranges from approximately 1.5 to 2.5. Total glucocorticoid dose and duration of therapy are strong predictors of diabetes induction. Other risk factors include age and body mass index. Failure to treat glucocorticoid-induced hyperglycemia is related to the presumed short duration of administration of glucocorticoid treatment and the emphasis on fasting plasma glucose only. Understanding the pharmacodynamics of glucocorticoids can lead to increased recognition and improved treatment of the condition. Recent demonstrations that even shortterm elevations in blood glucose level may be associated with adverse sequelae argue for greater attention to the condition.

CONCLUSION

Glucocorticoid-induced hyperglycemia is an important clinical finding that, if recognized, can be effectively treated. We propose a relatively simple schema for the proactive management of corticosteroid-induced hyperglycemia that has been effective and easily adaptable to both the inpatient and the outpatient setting.

Glycemic control and organ transplantation

A discussion of hyperglycemia during organ transplantation is a broad topic that includes patients with a known history of diabetes pretransplant, those at risk for post-transplant diabetes, those with stress-induced hyperglycemia, those with hyperglycemia related to immunosuppressive therapy, and hyperglycemia in the deceased organ donor. In contrast to the plethora of articles and studies describing perioperative and critical care management of hyperglycemia in cardiac, trauma, and medical/surgical intensive care unit patients, relatively few published articles in the field of organ transplantation can be found. This article consists of a review of available literature in the form of publications and abstracts, and a preliminary report of the authors' work with liver transplantation and deceased organ donors.

Inhibition of forkhead box O1 protects pancreatic beta-cells against dexamethasone-induced dysfunction

Forkhead Box O1 (FoxO1) is a key transcription regulator of insulin/IGF-I signaling pathway, and its activity can be increased by dexamethasone (DEX) in several cell types. However, the role of FoxO1 in DEX-induced pancreatic beta-cell dysfunction has not been fully understood. Therefore, in this study, we investigated whether FoxO1 could mediate DEX-induced beta-cell dysfunction and the possible underlying mechanisms in pancreatic beta-cell line RINm5F cells and primary rat islet. We found that DEX markedly increased FoxO1 mRNA and protein expression and decreased FoxO1 phosphorylation through the Akt pathway, which resulted in an increase in active FoxO1 in RINm5F cells and isolated rat islets. Activated FoxO1 subsequently inhibited pancreatic duodenal homeobox-1 expression and induced nuclear exclusion of pancreatic duodenal homeobox-1. Knockdown of FoxO1 by RNA interference restored the expression of pancreatic duodenal homeobox-1 and prevented DEX-induced dysfunction of glucose-stimulated insulin secretion in rat islets. Together, the results of present study demonstrate that FoxO1 is integrally involved in DEX-induced inhibition of pancreatic duodenal homeobox-1 and glucose-stimulated insulin secretion dysfunction in pancreatic islet beta-cells. Inhibition of FoxO1 can effectively protect beta-cells against DEX-induced dysfunction.

Increased pancreatic islet mass is accompanied by activation of the insulin receptor substrate-2/serine-threonine kinase pathway and augmented cyclin D2 protein levels in insulin-resistant rats

It is well known that glucocorticoids induce peripheral insulin resistance in rodents and humans. Here, we investigated the structural and ultrastructural modifications, as well as the proteins involved in beta-cell function and proliferation, in islets from insulin-resistant rats. Adult male Wistar rats were made insulin resistant by daily administration of dexamethasone (DEX; 1mg/kg, i.p.) for five consecutive days, whilst control (CTL) rats received saline alone. Structure analyses showed a marked hypertrophy of DEX islets with an increase of 1.7-fold in islet mass and of 1.6-fold in islet density compared with CTL islets (P < 0.05). Ultrastructural evaluation of islets revealed an increased amount of secreting organelles, such as endoplasmic reticulum and Golgi apparatus in DEX islets. Mitotic figures were observed in DEX islets at structural and ultrastructural levels. Beta-cell proliferation, evaluated at the immunohistochemical level using anti-PCNA (proliferating cell nuclear antigen), showed an increase in pancreatic beta-cell proliferation of 6.4-fold in DEX islets compared with CTL islets (P < 0.0001). Increases in insulin receptor substrate-2 (IRS-2), phosphorylated-serine-threonine kinase AKT (p-AKT), cyclin D(2) and a decrease in retinoblastoma protein (pRb) levels were observed in DEX islets compared with CTL islets (P < 0.05). Therefore, during the development of insulin resistance, the endocrine pancreas adapts itself increasing beta-cell mass and proliferation, resulting in an amelioration of the functions. The potential mechanisms that underlie these events involve the activation of the IRS-2/AKT pathway and activation of the cell cycle, mediated by cyclin D(2). These adaptations permit the maintenance of glycaemia at near-physiological ranges.

The Etiology of Steroid Cataract

Steroid-induced posterior subcapsular cataracts (PSCs) exhibit three main distinctive characteristics: (i) association only with steroids possessing glucocorticoid activity, (ii) involvement of aberrant migrating lens epithelial cells, and (iii) a central posterior location. The first characteristic suggests a key role for glucocorticoid receptor activation and subsequent changes to the transcription of specific genes. Glucocorticoid receptor activation is associated in many cell types with proliferation, suppressed differentiation, a reduced susceptibility to apoptosis, altered transmembrane transport, and enhancement of reactive oxygen species activity. Glucocorticoids may be capable of inducing changes to the transcription of genes in lens epithelial cells that are related to many of these cellular processes. This review examines the various mechanisms that have been proposed to account for the development of PSC in the context of recent DNA array studies. Additionally, given that the glucocorticoid receptor can also engender wide-ranging indirect activities, glucocorticoids could also indirectly affect the lens through the responses of other cells within the ocular compartment and/or through effects on cells at more remote locations. These indirect mechanisms, which, for example, could be mediated through alterations to the intraocular levels of growth factors that normally orchestrate lens development and maintain lens homeostasis, are also discussed. Although the mechanism of steroid cataract induction remains unknown, glucocorticoid-induced gene transcription events in lens epithelial cells, and also other intraocular or systemic cells, likely interact to generate steroid cataracts. Finally, although evidence for glucocorticoid-protein adduct formation in the lens is inconclusive, the generation of such adducts cannot yet be discounted as a contributing factor and must necessarily be retained in discussions of the etiology of steroid cataract.

Lactogens promote beta cell survival through JAK2/STAT5 activation and Bcl-XL upregulation

One of the goals in the treatment for diabetes is to enhance pancreatic beta cell function, proliferation, and survival. This study explores the role of lactogenic hormones, prolactin (PRL) and placental lactogen (PL), in beta cell survival. We have previously shown that transgenic mice expressing mouse placental lactogen-1 (mPL1) in beta cells under the rat insulin II promoter (RIP) are resistant to the diabetogenic and cytotoxic effects of streptozotocin (STZ) in vivo. The current study demonstrates that lactogens protect rat insulinoma (INS-1) cells and primary mouse beta cells against two distinct beta cell death inducers, STZ and dexamethasone (DEX), in vitro. Further, we identify the mechanism through which lactogens protect beta cells against DEX-induced death. The signaling pathway mediating this protective effect is the janus-activated-kinase-2/signal transducer and activator of transcription-5 (JAK2/STAT5) pathway. This is demonstrated in INS-1 cells and primary mouse beta cells using three separate approaches, pharmacological inhibitors, JAK2-specific siRNAs and a dominant-negative STAT5 mutant. Furthermore, lactogens specifically and significantly increase the anti-apoptotic protein Bcl-XL in insulinoma cells and mouse islets. Bcl-XL-specific siRNA significantly inhibits lactogen-mediated protection against DEX-induced beta cell death. We believe this is the first direct demonstration of lactogens mediating their protective effect through the JAK2/STAT5 pathway in the beta cell and through Bcl-XL in any cell type.

Dexamethasone-induced insulin resistance is associated with increased connexin 36 mRNA and protein expression in pancreatic rat islets

Augmented glucose-stimulated insulin secretion (GSIS) is an adaptive mechanism exhibited by pancreatic islets from insulin-resistant animal models. Gap junction proteins have been proposed to contribute to islet function. As such, we investigated the expression of connexin 36 (Cx36), connexin 43 (Cx43), and the glucose transporter Glut2 at mRNA and protein levels in pancreatic islets of dexamethasone (DEX)-induced insulin-resistant rats. Study rats received daily injections of DEX (1 mg/kg body mass, i.p.) for 5 days, whereas control rats (CTL) received saline solution. DEX rats exhibited peripheral insulin resistance, as indicated by the significant postabsorptive insulin levels and by the constant rate for glucose disappearance (KITT). GSIS was significantly higher in DEX islets (1.8-fold in 16.7 mmol/L glucose vs. CTL, p < 0.05). A significant increase of 2.25-fold in islet area was observed in DEX vs. CTL islets (p < 0.05). Cx36 mRNA expression was significantly augmented, Cx43 diminished, and Glut2 mRNA was unaltered in islets of DEX vs. CTL (p < 0.05). Cx36 protein expression was 1.6-fold higher than that of CTL islets (p < 0.05). Glut2 protein expression was unaltered and Cx43 was not detected at the protein level. We conclude that DEX-induced insulin resistance is accompanied by increased GSIS and this may be associated with increase of Cx36 protein expression.

Dexamethasone increases Na+/K+ ATPase activity in insulin secreting cells through SGK1

Glucocorticoids blunt insulin release, an effect partially due to activation of Kv channels. Similar to those channels Na+/K+ ATPase activity repolarizes the plasma membrane. The present study explored whether glucocorticoids increase the Na+/K+ ATPase activity in pancreatic beta-cells. The glucocorticoid dexamethasone (100 nmol/l for 1 day) significantly increased Na+/K+ ATPase alpha1/beta1-subunit transcript levels and ouabain-sensitive outward current reflecting Na+/K+ ATPase activity in INS-1 cells, effects blunted by glucocorticoid-receptor-blocker RU487 (1 micromol/l). Dexamethasone (100 nmol/l) increased K+ current in beta-cells from wild type mice but not from knockout mice lacking functional serum and glucocorticoid inducible kinase SGK1. Thus, glucocorticoids indeed up-regulate Na+/K+ ATPase activity, an effect requiring SGK1.

Glucocorticoid-induced diabetes mellitus: prevalence and risk factors in primary renal diseases

BACKGROUND/AIMS

In patients with primary renal diseases the current knowledge of hyperglycemia associated with corticosteroid therapy is limited. We therefore examined the prevalence and risk factors of glucocorticoid-induced diabetes mellitus (DM) in primary renal diseases.

METHODS

Patients were recruited with primary renal diseases who were started on corticosteroids between April 2002 and June 2005. In patients with DM, an impaired fasting glucose level and/or positive urinary glucose analyses before corticosteroids therapy were excluded.

RESULTS

During corticosteroid therapy (initial dose: prednisolone 0.75 +/- 0.10 mg/kg/day), DM was newly diagnosed in 17 (40.5%) of 42 patients. All of the 17 patients were diagnosed as having DM by postprandial hyperglycemia at 2 h after lunch, although they had normal fasting blood glucose levels. Age (OR 1.40, 95% CI 1.06-1.84) and body mass index (OR 1.87, 95% CI 1.03-3.38) were determined as independent risk factors for glucocorticoid-induced DM.

CONCLUSION

Over 40% of patients with primary renal disease developed DM during treatment with corticosteroids. A high age and high body mass index are the independent risk factors for glucocorticoid-induced DM. 24-hour urinary glucose analyses and postprandial plasma glucose are useful for detecting glucocorticoid-induced DM.

Prevalence and predictors of corticosteroid-related hyperglycemia in hospitalized patients

OBJECTIVE

To investigate the prevalence of and risk factors for hyperglycemia in hospitalized patients receiving corticosteroids, which have been identified as an independent predictor of hyperglycemia.

METHODS

We conducted a retrospective review of electronic medical records of patients admitted to the general medicine service at a university hospital during a 1-month period. Pharmacy charges were used to identify patients receiving high doses (> or = 40 mg/day of prednisone or the equivalent) of corticosteroids for at least 2 days. Occurrence of hyperglycemia and the presence of risk factors, including history of diabetes, duration of corticosteroid therapy, concurrent parenteral nutrition, antibiotic therapy, use of medications associated with hyperglycemia, severity of illness scores, and hospital length of stay, were determined. Patients experiencing multiple episodes of hyperglycemia (glucose levels > or = 200 mg/dL) were compared with those who had < or = 1 hyperglycemic episode. Patients without a history of diabetes were assessed separately.

RESULTS

During the 1-month study period, 66 of 617 patients received high doses of corticosteroids, but only 50 of the 66 had glucose measurements. Hyperglycemia was documented in 32 of these 50 patients (64%), and multiple hyperglycemic episodes occurred in 26 (52%). A history of diabetes was documented in 12 of 26 patients who experienced multiple episodes, in comparison with 4 of 24 patients with < or = 1 episode of hyperglycemia (P = 0.035). Among patients without a history of diabetes, 19 of 34 (56%) had hyperglycemia at least once. Patients with multiple episodes of hyperglycemia had more comorbid diseases, longer duration of corticosteroid therapy, and longer duration of hospital stay.

CONCLUSION

Hyperglycemia occurs in a majority of hospitalized patients receiving high doses of corticosteroids. In light of the poor outcomes associated with hyperglycemia, protocols targeting its detection and management should be available for patients who receive corticosteroid therapy.

Revisiting the Toxicity of Low-Dose Glucocorticoids: Risks and Fears

We have recently participated in a careful literature search and critical evaluation of glucocorticoids, and we have revised the side-effects data of four recent controlled trials of low-dose glucocorticoids (GCs) in rheumatoid arthritis. The toxicity profile stands out as remarkably more benign than expected from most textbook recommendations. Data regarding low-dose therapy are scarce and of low quality, as no controlled trials have been designed to specifically address toxicity. Common fears of GC toxicity seem to originate from an excessive weight on anecdotal data and observations with high doses, as in organ transplantation. There is now evidence that mechanisms of action of GCs vary considerably according to the dose, thus allowing the possibility of a different toxicity profile. Data from recent controlled trials are quite reassuring, overall. Certainly, risks and benefits of GCs need to be carefully weighed in every patient. But we need to make a clear distinction between established risks and unchecked fears while trying to get the best result for our patient. Clearly, there is a need for studies that are appropriately designed to address the toxicity of GCs and to avoid the risk of "throwing out the baby with the bath water."

Dexamethasone induces cell death in insulin-secreting cells, an effect reversed by exendin-4

Glucocorticoid excess induces hyperglycemia, which may result in diabetes. The present experiments explored whether glucocorticoids trigger apoptosis in insulin-secreting cells. Treatment of mouse beta-cells or INS-1 cells with the glucocorticoid dexamethasone (0.1 micromol/l) over 4 days in cell culture increased the number of fractionated nuclei from 2 to 7 and 14%, respectively, an effect that was reversed by the glucocorticoid receptor antagonist RU486 (1 micromol/l). In INS-1 cells, dexamethasone increased the number of transferase-mediated dUTP nick-end labeling-staining positive cells, caspase-3 activity, and poly-(ADP-) ribose polymerase protein cleavage; decreased Bcl-2 transcript and protein abundance; dephosphorylated the proapoptotic protein of the Bcl-2 family (BAD) at serine155; and depolarized mitochondria. Dexamethasone increased PP-2B (calcineurin) activity, an effect abrogated by FK506. FK506 (0.1 micromol/l) and another calcineurin inhibitor, deltamethrin (1 micromol/l), attenuated dexamethasone-induced cell death. The stable glucagon-like peptide 1 analog, exendin-4 (10 nmol/l), inhibited dexamethasone-induced apoptosis in mouse beta-cells and INS-1 cells. The protective effect of exendin-4 was mimicked by forskolin (10 micromol/l) but not mimicked by guanine nucleotide exchange factor with the specific agonist 8CPT-Me-cAMP (50 micromol/l). Exendin-4 did not protect against cell death in the presence of cAMP-dependent protein kinase (PKA) inhibition by H89 (10 micromol/l) or KT5720 (5 micromol/l). In conclusion, glucocorticoid-induced apoptosis in insulin-secreting cells is accompanied by a downregulation of Bcl-2, activation of calcineurin with subsequent dephosphorylation of BAD, and mitochondrial depolarization. Exendin-4 protects against glucocorticoid-induced apoptosis, an effect mimicked by forskolin and reversed by PKA inhibitors.

Safety of low dose glucocorticoid treatment in rheumatoid arthritis: published evidence and prospective trial data

Adverse effects of glucocorticoids have been abundantly reported. Published reports on low dose glucocorticoid treatment show that few of the commonly held beliefs about their incidence, prevalence, and impact are supported by clear scientific evidence. Safety data from recent randomised controlled clinical trials of low dose glucocorticoid treatment in RA suggest that adverse effects associated with this drug are modest, and often not statistically different from those of placebo.

Developments in Glucocorticoid Therapy

Recent evidence for a disease-modifying potential of low-dose glucocorticoids (GCs) in the treatment of rheumatoid arthritis has renewed the debate on the risk benefit ratio with this therapy. Two recent developments are described that might have a positive influence on these risk benefit ratios. One is the improvement in new GC compounds--designer GCs, alterations in bioactivity, and alterations in formulations. The other is a better understanding and management of the toxicity of GCs.

Corticosteroid use in the treatment of neuromuscular disorders: empirical and evidence-based data

Corticosteroids have been used to treat neuromuscular disorders for many years. With few randomized, controlled trials, efficacy has been established primarily from empirical data. This has led to a range of treatment regimens varying in terms of initial dosing, dosing schedules, and taper rates. The goals of this review were to examine the literature for data concerning corticosteroid pharmacokinetics and for evidence-based treatment regimens in several prototypic neuromuscular disorders. The results provide a number of sound principles for corticosteroid use, but also indicate that corticosteroid regimens and patient management are largely based on empirical clinical experiences.

Postoperative management of the diabetic patient

Diabetic patients are at increased risk for adverse outcomes of surgery. These adverse outcomes are related to pre-existing complications of diabetes, especially atherosclerotic disease, nephropathy (and perhaps increased susceptibility to other renal toxins), and peripheral and autonomic neuropathy. Hyperglycemia is associated with likely risks for poorer wound healing, increased susceptibility to infection, and probable loss of administered nutrients through glycosuria. Insulin use has the flexibility of timing and dose in the postoperative management of most diabetic patients. The combinations of intermediate-acting and long-acting insulins and short-acting insulins usually are related to the experience and preferences of the treating physicians and allied health professionals. Intravenous insulin (always R) may be limited to administration in the ICU because of the need for frequent blood glucose monitoring and rapidity of glucose response to intravenous insulin. The use of short-acting insulin analogues has been shown to work well as premeal insulin or for rapidly treating marked hyperglycemia in the outpatient setting. Meal delivery in the hospitalized patient may not be timed as precisely as in the home situation. Nurses may be responsible for many patients. The rapid-acting analogues may be associated with increased risk for hypoglycemia in the hospitalized patient if insulin cannot be given immediately before a meal. These rapid-acting insulin analogues usually are limited to circumstances in which the patient can determine the dose and self-administer just before ingestion of the meal. The long-acting insulin analogues may not afford enough flexibility in many situations in which daily dosages changes are occurring in intermediate-acting and long-acting insulins. Oral glucose-lowering agent use in the postoperative state usually is limited to selected patients, including patients who have been on such agents before surgery, who have only mild elevations of blood glucose, who are able to ingest oral medications, and who do not have significant comorbid conditions (or significant risk for such conditions) that may be contraindications to use of such agents (see Table 3). Sulfonylureas and other insulin secretagogues (e.g., meglitinide, nateglinide) lower glucoses acutely. The risk for hypoglycemia is slightly less with the nonsulfonylurea agents. Efficacy and side effects limit the use of carbohydrase inhibitors for hospitalized patients. The glucose-lowering effects of biguanides and thiazolidinediones usually are not rapid enough for hospitalized patients who have never taken these medications. For patients who have been on a biguanide or thiazolidinedione before admission, these agents often are restarted in the postoperative period when oral intake of medications is possible and hepatic and renal function are stable. The hospital period affords an opportunity to review long-term management issues related to diabetes and its complications. Instruction on the importance of medical nutrition therapy, glycemic control, management of hypertension, dyslipidemia, and aspirin use as well as basic guidelines for foot care should be carried out during the hospitalization and at the time of discharge. Similarly, appropriate arrangements for medical nutrition therapy, general diabetes education (especially for newly diagnosed diabetic patients), and regular medical follow-up are important to ensure long-term, excellent surgical and medical outcomes.