Continuous inhibition of 11β‐hydroxysteroid dehydrogenase type I in adipose tissue leads to tachyphylaxis in humans and rats but not in mice

Background and Purpose

11β‐hydroxysteroid dehydrogenase type I (11β‐HSD1), a target for Type 2 diabetes mellitus, converts inactive glucocorticoids into bioactive forms, increasing tissue concentrations. We have compared the pharmacokinetic‐pharmacodynamic (PK/PD) relationship of target inhibition after acute and repeat administration of inhibitors of 11β‐HSD1 activity in human, rat and mouse adipose tissue (AT).

Experimental Approach

Studies included abdominally obese human volunteers, rats and mice. Two specific 11β‐HSD1 inhibitors (AZD8329 and COMPOUND‐20) were administered as single oral doses or repeat daily doses for 7–9 days. 11β‐HSD1 activity in AT was measured ex vivo by conversion of ³H‐cortisone to ³H‐cortisol.

Key Results

In human and rat AT, inhibition of 11β‐HSD1 activity was lost after repeat dosing of AZD8329, compared with acute administration. Similarly, in rat AT, there was loss of inhibition of 11β‐HSD1 activity after repeat dosing with COMPOUND‐20 with continuous drug cover, but effects were substantially reduced if a ‘drug holiday’ period was maintained daily. Inhibition of 11β‐HSD1 activity was not lost in mouse AT after continuous cover with COMPOUND‐20 for 7 days.

Conclusions and Implications

Human and rat AT, but not mouse AT, exhibited tachyphylaxis for inhibition of 11β‐HSD1 activity after repeat dosing. Translation of observed efficacy in murine disease models to human for 11β‐HSD1 inhibitors may be misleading. Investigators of the effects of 11β‐HSD1 inhibitors should confirm that desired levels of enzyme inhibition in AT can be maintained over time after repeat dosing and not rely on results following a single dose.

Abbreviations

11β‐HSD1

11β‐hydroxysteroid dehydrogenase type I

PK/PD

pharmacokinetic‐pharmacodynamic

AT

adipose tissue

DIO

diet induced obese

IHC

International Conference on Harmonisation

GCP

Good Clinical Practice

b.i.d.

twice daily

u.i.d.

once daily

HPMC

hydroxypropylmethylcellulose

IC₇₀

concentration that delivers 70% of the maximum effect

IC₉₀

concentration that delivers 90% of the maximum effect

fu

fraction unbound

C_max

maximum achieved concentration

C_min

minimum or trough concentration

E₀

baseline

E_max

maximum effect

ANCOVA

analysis of covariance

     

Effect of empiric antiarrhythmic therapy in resuscitated out-of-hospital cardiac arrest victims with coronary artery disease

The effect of empiric antiarrhythmic therapy with quinidine and procainamide on long-term mortality was examined in 209 patients with coronary artery disease resuscitated after out-of-hospital cardiac arrest. The antiarrhythmic agent used was determined by the patient's private physician without knowledge of the study ambulatory electrocardiogram. Of the 209 patients, procainamide was prescribed in 45 (22%), quinidine in 48 (23%) and no antiarrhythmic therapy in 116 (55%). Digoxin therapy was initiated in 101 patients. The 2-year total survival rate for the quinidine, procainamide and nontreated patients was 61, 57 and 71% (p less than 0.05), and for sudden death was 69, 69 and 89% (p less than 0.01), respectively. These observations suggest that empiric antiarrhythmic therapy in survivors of out-of-hospital cardiac arrest did not affect total mortality and was associated with an increased frequency of sudden death.     

Brain bases of recovery following cognitive rehabilitation for traumatic brain injury: a preliminary study

Brain Imaging and Behavior - Many patients with traumatic brain injury (TBI) have persistent cognitive deficits, including decreased attention and working memory. This preliminary study examined...     

Objective discrimination between mandibular open/close excursion patterns: a clinical case report

The purpose of this clinical case report was to describe the kinematic variables of movement that best discriminated between asymmetrical and symmetrical mandibular excursion patterns in a patient with myogenic temporomandibular dysfunction. Two mandibular movements (deemed to be asymmetrical and symmetrical by both patient and physiotherapist) were each recorded six times on three occasions at six, twelve, and 15 weeks after commencement of an exercise programme. The mandibular movements were captured with a 12-camera Motion Analysis System (Motion Analysis Corp., Santa Rosa, CA) with kinematic variables expressed in six degrees-of-freedom. A two-way analysis of variance (ANOVA) for repeated measures was used to analyze the data. The asymmetrical pattern was characterized by increased axial rotation and decreased sagittal rotation but with no differences in translation values when compared to those of the symmetrical pattern. The results support the clinician's and patient's judgment regarding differences in quality of mandibular excursion patterns made over the course of time.     

Original research: Patient ownership of primary biliary cholangitis long-term management

ObjectivePatient ownership of disease is vital in rare diseases like primary biliary cholangitis (PBC). This survey of UK members of the PBC foundation aimed to assess patients’ perception of their disease management, focusing on key biomarkers and problematic symptoms.DesignRegistered PBC foundation members were surveyed on their experiences on their most recent clinic visit, covering the type of hospital and clinician and whether biochemical response and symptom burden were discussed, including who initiated these conversations. Respondents were also asked about their willingness to initiate these conversations.ResultsAcross 633 respondents, 42% remembered discussing alkaline phosphatase, the key biochemical response measure, and the majority of discussions were initiated by the healthcare provider. 56% of respondents remembered discussing itch, a key PBC symptom. There was no distinction between the grade of healthcare professional, but both patients and clinicians were significantly more likely to discuss symptoms over disease progression. Reassuringly, 84% of respondents felt willing to initiate conversations about their illness, regardless of the grade of managing clinician.ConclusionsThis work lays a positive foundation for patient education and empowerment projects, likely to improve clinical outcomes. Key aspects of management (biochemical response to treatment and symptom burden) should be emphasised as topics of discussion to both patients and clinicians managing PBC. We suggest a simple cue card to prompt patient-led discussion.