Plasma prednisolone levels in man following administration in plain and enteric-coated forms

Prednisolone Alters Endometrial Decidual Cells and Affects Decidual-Trophoblast Interactions

Poor pregnancy outcomes such as recurrent pregnancy loss (RPL) and preeclampsia are associated with impaired decidualization and abnormal trophoblast invasion. Emerging evidence suggests that use of corticosteroids, including prednisolone affects fertility by altering uterine function and may be associated with preeclampsia incidence. In this study, using primary and gestational-age appropriate tissue, we aimed to define the effect of prednisolone on human endometrial stromal fibroblast (hESF) decidualization and determine whether hESF decidualization in the presence of prednisolone would alter hESF regulation of trophoblast function. We found that prednisolone treatment reduced hESF cytokine expression (IL6, IL11, IL18, LIF, and LIFR) but had no effect on hESF expression or secretion of the classic markers of decidualization [prolactin (PRL) and IGFBP1]. Using proteomics we determined that prednisolone altered decidualized hESF protein production, enriching hESF proteins associated with acetylation and mitrochondria. Conditioned media from hESF decidualized in the presence of prednisolone significantly enhanced trophoblast outgrowth and trophoblast mRNA expression of cell motility gene PLCG1 and reduced trophoblast production of PGF. Prednisolone treatment during the menstrual cycle and 1st trimester of pregnancy might alter decidual interactions with other cells, including invasive trophoblast.

Influence of PDLA nanoparticles size on drug release and interaction with cells

Polymeric nanoparticles (NPs) are strong candidates for the development of systemic and targeted drug delivery applications. Their size is a determinant property since it defines the NP-cell interactions, drug loading capacity, and release kinetics. Herein, poly(d,l-lactic acid) (PDLA) NPs were produced by the nanoprecipitation method, in which the influence of type and concentration of surfactant as well as PDLA concentration were assessed. The adjustment of these parameters allowed the successful production of NPs with defined medium sizes, ranging from 80 to 460 nm. The surface charge of the different NPs populations was consistently negative. Prednisolone was effectively entrapped and released from NPs with statistically different medium sizes (i.e., 80 or 120 nm). Release profiles indicate that these systems were able to deliver appropriate amounts of drug with potential applicability in the treatment of inflammatory conditions. Both NPs populations were cytocompatible with human endothelial and fibroblastic cells, in the range of concentrations tested (0.187-0.784 mg/mL). However, confocal microscopy revealed that within the range of sizes tested in our experiments, NPs presenting a medium size of 120 nm were able to be internalized in endothelial cells. In summary, this study demonstrates the optimization of the processing conditions to obtain PDLA NPs with narrow size ranges, and with promising performance for the treatment of inflammatory diseases. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 482-493, 2019.

The effect of acute and short term glucocorticoid administration on exercise capacity and metabolism

OBJECTIVES

Glucocorticoids (GC) are commonly used in the treatment of inflammatory conditions. Chronic GC administration has severe side effects that can decrease exercise capacity and, as a result performance. The side effects of acute (single dose) and short term (<7 days) GC administration are less severe, therefore the impact on exercise performance is unclear. Consequently, it is of interest to determine the influence of acute and short term GC administration on exercise capacity and performance and investigate the relationship with metabolism.

DESIGN

Review article.

METHODS

Included in the review were studies with healthy volunteers that reported exercise capacity and performance outcomes following acute and short term GC ingestion. Additionally, the relationship of exercise, GC ingestion and metabolism was investigated.

RESULTS

Acute GC treatment appears to have minimal effects on exercise performance at intensities between 60 and 90% of VO_2max. Short term GC treatment improved performance in the majority of studies at various exercise intensities. In general, blood glucose values increased whilst insulin and lactate values remained unchanged following GC administration. However, inconsistencies in metabolic results are present and may be due to variations in exercise protocols and the type and dosage of drug treatments.

CONCLUSIONS

Acute GC administration has a minimal effect on exercise capacity and performance while short-term GC administration is likely to improve performance. Future studies should focus on the effects of GC on exercise performance and exercise metabolism during and post exercise to determine the effects on exercise capacity.

Imatinib Triggers Phagolysosome Acidification and Antimicrobial Activity against Mycobacterium bovis Bacille Calmette-Guérin in Glucocorticoid-Treated Human Macrophages

Glucocorticoids are extensively used to treat inflammatory diseases; however, their chronic intake increases the risk for mycobacterial infections. Meanwhile, the effects of glucocorticoids on innate host responses are incompletely understood. In this study, we investigated the direct effects of glucocorticoids on antimycobacterial host defense in primary human macrophages. We found that glucocorticoids triggered the expression of cathelicidin, an antimicrobial critical for antimycobacterial responses, independent of the intracellular vitamin D metabolism. Despite upregulating cathelicidin, glucocorticoids failed to promote macrophage antimycobacterial activity. Gene expression profiles of human macrophages treated with glucocorticoids and/or IFN-γ, which promotes induction of cathelicidin, as well as antimycobacterial activity, were investigated. Using weighted gene coexpression network analysis, we identified a module of highly connected genes that was strongly inversely correlated with glucocorticoid treatment and associated with IFN-γ stimulation. This module was linked to the biological functions autophagy, phagosome maturation, and lytic vacuole/lysosome, and contained the vacuolar H(+)-ATPase subunit a3, alias TCIRG1, a known antimycobacterial host defense gene, as a top hub gene. We next found that glucocorticoids, in contrast with IFN-γ, failed to trigger expression and phagolysosome recruitment of TCIRG1, as well as to promote lysosome acidification. Finally, we demonstrated that the tyrosine kinase inhibitor imatinib induces lysosome acidification and antimicrobial activity in glucocorticoid-treated macrophages without reversing the anti-inflammatory effects of glucocorticoids. Taken together, we provide evidence that the induction of cathelicidin by glucocorticoids is not sufficient for macrophage antimicrobial activity, and identify the vacuolar H(+)-ATPase as a potential target for host-directed therapy in the context of glucocorticoid therapy.

Glucocorticoid treatment and endocrine pancreas function: implications for glucose homeostasis, insulin resistance and diabetes

Glucocorticoids (GCs) are broadly prescribed for numerous pathological conditions because of their anti-inflammatory, antiallergic and immunosuppressive effects, among other actions. Nevertheless, GCs can produce undesired diabetogenic side effects through interactions with the regulation of glucose homeostasis. Under conditions of excess and/or long-term treatment, GCs can induce peripheral insulin resistance (IR) by impairing insulin signalling, which results in reduced glucose disposal and augmented endogenous glucose production. In addition, GCs can promote abdominal obesity, elevate plasma fatty acids and triglycerides, and suppress osteocalcin synthesis in bone tissue. In response to GC-induced peripheral IR and in an attempt to maintain normoglycaemia, pancreatic β-cells undergo several morphofunctional adaptations that result in hyperinsulinaemia. Failure of β-cells to compensate for this situation favours glucose homeostasis disruption, which can result in hyperglycaemia, particularly in susceptible individuals. GC treatment does not only alter pancreatic β-cell function but also affect them by their actions that can lead to hyperglucagonaemia, further contributing to glucose homeostasis imbalance and hyperglycaemia. In addition, the release of other islet hormones, such as somatostatin, amylin and ghrelin, is also affected by GC administration. These undesired GC actions merit further consideration for the design of improved GC therapies without diabetogenic effects. In summary, in this review, we consider the implication of GC treatment on peripheral IR, islet function and glucose homeostasis.

Clinical pharmacokinetics of prednisone and prednisolone

The growth of knowledge in the field of the pharmacokinetics of prednisolone/prednisone has been slow for several reasons. First, convenient and specific methods for measuring these steroids only became available with the development of high performance liquid chromatographic methods. Secondly, prednisolone is nonlinearly bound to transcortin and albumin: since the unbound concentrations of prednisolone are biologically relevant, it was necessary to determine the free fraction in each plasma sample. Thirdly, due to the short half-life of prednisolone no steady-state is achieved, and therefore area under the concentration-time curve needed to be determined in all studies. Fourthly, prednisolone and prednisone are interconvertible and prednisolone is given intravenously as an ester prodrug, features which created controversies about the correct interpretation of pharmacokinetic results. Finally, the total body clearances of total and (to a lesser degree) of unbound prednisolone increase with increasing concentrations of prednisolone. Therefore, in order to compare pharmacokinetic results between different subjects, standardised doses had to be administered. The investigations performed so far have revealed that: (1) the dose-dependent pharmacokinetics partly explain the clinical observation that an alternate-day regimen with prednisone yields fewer biological effects; (2) the interconversion of prednisone into prednisolone is not a limiting factor, even in patients with severely impaired liver function; (3) hypoproteinaemia per se does not cause increased unbound concentrations of prednisolone in vivo; (4) patients with liver failure, renal failure or a renal transplant, subjects older than 65 years, women on estrogen-containing oral contraceptive steroids or subjects taking ketoconazole have increased unbound concentrations of prednisolone-whereas hyperthyroid patients, some patients with Crohn's disease, subjects taking microsomal liver enzyme-inducing agents or patients on intravenous prednisolone phthalate (instead of prednisolone phosphate) or on some brands of enteric coated prednisolone tablets have decreased concentrations of prednisolone. The biological relevance of the altered pharmacokinetics is supported in part by altered clinical effects and altered effects on cellular immunofunctions.

Effects of prednisolone on angiotensin converting enzyme activity

Plasma angiotensin converting enzyme was measured in 23 asthmatic subjects before and after administration of prednisolone, 20 mg daily, for seven days. Plasma specimens from seven patients with asthma, seven with sarcoidosis and 14 normal subjects were also assayed before and after the addition of prednisolone in vitro. A plasma free extract of normal lung was also prepared and assayed before and after prednisolone treatment. Mean angiotensin converting enzyme activity was significantly greater in the asthmatic patients (40.3 nmol min-1 ml plasma-1) than in the control population (35.1 nmol min-1 ml plasma-1), though remaining within the 95% reference range. A fall in plasma angiotensin converting enzyme levels was seen after the addition of prednisolone in asthmatics both in vivo and in vitro. Similar in vitro falls were seen in patients with sarcoidosis but not in controls or in normal lung extract. No changes in angiotensin converting enzyme activity were seen after a single dose of 20 mg prednisolone in normal volunteers. Patients with asthma therefore appear to have higher mean angiotensin converting enzyme activities than the normal population and these fall after the addition of prednisolone whether this is added in vivo or in vitro.

Hepatotoxic effects of anti-rheumatic drugs in cultured rat hepatocytes

Drug-induced liver injury has been suggested as a possible mechanism for the liver damage in rheumatic diseases. To evaluate the role of direct toxic action of drugs on hepatocytes, the effects of salicylate, chloroquine, prednisolone and indomethacin on LDH leakage from cultured rat hepatocytes were studied. Exposure for 24 h to the first two drugs induced liver damage, as reflected by LDH release, at concentrations 2-10 times as high as the therapeutic plasma levels in humans. Indomethacin and prednisolone at concentrations approx 50-100-fold higher than the therapeutic plasma levels, were not toxic to cultured hepatocytes. The data suggest that direct a toxic effect on hepatocytes is one possible mechanism of hepatotoxicity for salicylate and chloroquine, especially since the exposure time is much longer in humans than in the experimental model used here.

Serious renal transplant rejection and adrenal hypofunction after gradual withdrawal of prednisolone two years after transplantation

Ten patients with stable renal function two years after transplantation had their sole immunosuppressive treatment (oral prednisolone 10 mg daily) withdrawn by reducing the daily dose by 1 mg at monthly intervals. Plasma prednisolone concentration, cortisol concentration, creatinine clearance, and serum creatinine concentration were measured in all patients, and the adrenal response to corticotrophin was determined in five by measuring plasma cortisol concentrations before and after tetracosactrin injection. No episodes of rejection occurred in patients taking over 7 mg prednisolone daily. Although three patients apparently required only minimal immunosuppressive treatment (less than 5 mg daily) the remainder suffered episodes of rejection at daily doses below 7 mg. There was a tenuous association between rejection and low plasma cortisol concentration, but neither the pattern of plasma prednisolone concentrations nor the response to tetracosactrin were related to episodes of rejection. Reducing the daily dose of oral prednisolone to under 7 mg should not be attempted in patients with renal transplants unless there are extenuating circumstances.

Variation in plasma prednisolone concentrations in renal transplant recipients given enteric-coated prednisolone

Renal transplant recipients receiving intermittent haemodialysis and kept under normal ward conditions showed appreciable differences in plasma prednisolone concentrations after therapeutic doses of enteric-coated prednisolone tablets. This gross day-to-day variation occurred irrespective of the dosage used. Breakfast given before prednisolone tended to reduce the rate of absorption of the drug, the effect being quantitatively most pronounced with large doses. Haemodialysis had no apparent effect on the elimination of prednisolone from plasma. Such erratic blood concentrations of prednisolone as observed in these patients, possibly resulting from variable absorption, may be potentially hazardous. Hence use of enteric-coated tablets in renal transplant recipients should be viewed with caution.

The effect of food and tablet formulation on plasma prednisolone levels following administration of enteric-coated tablets

1 Plasma prednisolone levels have been compared following the administration of enteric-coated prednisolone to fasted and non-fasted subjects. The effect on plasma levels of altering the formulation of the enteric-coating has also been studied. 2 The presence of food in the stomach at the time of administration does not affect the absorption of enteric-coated prednisolone tablets. 3 There was considerable inter-subject variation in plasma prednisolone levels after administration of shellac based enteric-coated tablets. However, plasma levels were more consistent when a preparation whose formulation was based upon cellulose acetate phthalate (CAP) was given. 4 It is concluded that the pattern of absorption and plasma prednisolone levels depend on the formulation of the enteric coating. The bioavailability of the CAP based preparation is similar to that of plain prednisolone.

Plasma levels, half-life values, and correlation with physiologic assays for growth and immunity

Plasma prednisolone levels have been measured hourly in children receiving a single dose of oral prednisone. Peak prednisolone levels occurred one to two hours after ingestion; half-life studies gave a mean value of 132 minutes in most children. Some children had marked variability in absorption and metabolism of prednisone. Somatomedin activity and cell-mediated immunity were inhibited by plasma prednisolone values which were achieved by single doses of prednisone of 0.5 mg/kg or higher. Monitoring prednisolone levels may be of value in identifying those children who accumulate excessively high levels on moderate dosage regimens.