Partial recovery of adrenal function in a patient with autoimmune Addison's disease

Future directions for adrenal insufficiency: cellular transplantation and genetic therapies

Primary adrenal insufficiency occurs in 1 in 5-7000 adults. Leading aetiologies are autoimmune adrenalitis in adults and congenital adrenal hyperplasia (CAH) in children. Oral replacement of cortisol is lifesaving, but poor quality of life, repeated adrenal crises and dosing uncertainty related to lack of a validated biomarker for glucocorticoid sufficiency, persists. Adrenocortical cell therapy and gene therapy may obviate many of the shortcomings of adrenal hormone replacement. Physiological cortisol secretion regulated by pituitary adrenocorticotropin, could be achieved through allogeneic adrenocortical cell transplantation, production of adrenal-like steroidogenic cells from either stem cells or lineage conversion of differentiated cells, or for CAH, gene therapy to replace or repair a defective gene. The adrenal cortex is a high turnover organ and thus failure to incorporate progenitor cells within a transplant will ultimately result in graft exhaustion. Identification of adrenocortical progenitor cells is equally important in gene therapy where new genetic material must be specifically integrated into the genome of progenitors to ensure a durable effect. Delivery of gene editing machinery and a donor template, allowing targeted correction of the 21-hydroxylase gene, has the potential to achieve this. This review describes advances in adrenal cell transplants and gene therapy that may allow physiological cortisol production for children and adults with primary adrenal insufficiency.

Heterogeneous natural history of Addison's disease: mineralocorticoid deficiency may predominate

Autoimmune Addison's disease (AAD) is defined as primary adrenal insufficiency due to immune-mediated destruction of the adrenal cortex. This destruction of steroid-producing cells has historically been thought of as an irreversible process, with linear progression from an ACTH-driven compensated phase to overt adrenal insufficiency requiring lifelong glucocorticoid replacement. However, a growing body of evidence suggests that this process may be more heterogeneous than previously thought, with potential for complete or partial recovery of glucocorticoid secretion. Although patients with persistent mineralocorticoid deficiency despite preserved or recovered glucocorticoid function are anecdotally mentioned, few well-documented cases have been reported to date. We present three patients in the United Kingdom who further challenge the long-standing hypothesis that AAD is a progressive, irreversible disease process. We describe one patient with a 4-year history of mineralocorticoid-only Addison's disease, a patient with spontaneous recovery of adrenal function and one patient with clinical features of adrenal insufficiency despite significant residual cortisol function. All three patients show varying degrees of mineralocorticoid deficiency, suggesting that recovery of zona fasciculata function in the adrenal cortex may occur independently to that of the zona glomerulosa. We outline the current evidence for heterogeneity in the natural history of AAD and discuss possible mechanisms for the recovery of adrenal function.

Latent Adrenal Insufficiency: From Concept to Diagnosis

Primary adrenal insufficiency (PAI) is a rare disease and potentially fatal if unrecognized. It is characterized by destruction of the adrenal cortex, most frequently of autoimmune origin, resulting in glucocorticoid, mineralocorticoid, and adrenal androgen deficiencies. Initial signs and symptoms can be nonspecific, contributing to late diagnosis. Loss of zona glomerulosa function may precede zona fasciculata and reticularis deficiencies. Patients present with hallmark manifestations including fatigue, weight loss, abdominal pain, melanoderma, hypotension, salt craving, hyponatremia, hyperkalemia, or acute adrenal crisis. Diagnosis is established by unequivocally low morning serum cortisol/aldosterone and elevated ACTH and renin concentrations. A standard dose (250 µg) Cosyntropin stimulation test may be needed to confirm adrenal insufficiency (AI) in partial deficiencies. Glucocorticoid and mineralocorticoid substitution is the hallmark of treatment, alongside patient education regarding dose adjustments in periods of stress and prevention of acute adrenal crisis. Recent studies identified partial residual adrenocortical function in patients with AI and rare cases have recuperated normal hormonal function. Modulating therapies using rituximab or ACTH injections are in early stages of investigation hoping it could maintain glucocorticoid residual function and delay complete destruction of adrenal cortex.

Adrenal cortex renewal in health and disease

Resident progenitor and/or stem cell populations in the adult adrenal cortex enable cortical cells to undergo homeostatic renewal and regeneration after injury. Renewal occurs predominantly in the outer layers of the adrenal gland but newly formed cells undergo centripetal migration, differentiation and lineage conversion in the process of forming the different functional steroidogenic zones. Over the past 10 years, advances in the genetic characterization of adrenal diseases and studies of mouse models with altered adrenal phenotypes have helped to elucidate the molecular pathways that regulate adrenal tissue renewal, several of which are fine-tuned via complex paracrine and endocrine influences. Moreover, the adrenal gland is a sexually dimorphic organ, and testicular androgens have inhibitory effects on cell proliferation and progenitor cell recruitment in the adrenal cortex. This Review integrates these advances, including the emerging role of sex hormones, into existing knowledge on adrenocortical cell renewal. An in-depth understanding of these mechanisms is expected to contribute to the development of novel therapies for severe endocrine diseases, for which current treatments are unsatisfactory.

Fast Clinical, but Long-Term, Biochemical Remission after Waterhouse-Friderichsen Syndrome

Background. The Waterhouse–Friderichsen Syndrome (WFS) is a course of bacterial meningitis with a lethality rate that is still high today. One hallmark of the clinical course is intravascular coagulopathy. This causes hemorrhagic infarctions in the adrenal glands, rapidly causing a primary adrenal insufficiency. Only few reports highlight the course of the remaining adrenal insufficiency or adrenal restitution in survivors. Case Presentation. After 3 weeks in an intensive care unit, a 45-year-old male survived WFS with necroses on the legs and forefeet and with primary adrenal insufficiency confirmed by the ACTH stimulation test. The substitution therapy with hydrocortisone and fludrocortisone could be gradually discontinued after nine months due to a further positive clinical course. Although the patient reported good mental and physical performance further on, the cortisol response in ACTH testing showed tiny incremental rises of the stimulated serum cortisol, but to reach a formally normal level, it took about five years. Discussion. The report demonstrates a case with a relatively fast clinical remission. A remission of the corticotrophic response occurred in small increments during an observational period of five years. The data suggest that not only a clinical remission is possible but also a complete biochemical remission, although this process may take a much longer timespan.

MANAGEMENT OF ENDOCRINE DISEASE: Residual adrenal function in Addison's disease

Over the last 10 years, evidence has accumulated that autoimmune Addison's disease (AAD) is a heterogeneous disease. Residual adrenal function, characterised by persistent secretion of cortisol, other glucocorticoids and mineralocorticoids is present in around 30% of patients with established AAD, and appears commoner in men. This persistent steroidogenesis is present in some patients with AAD for more than 20 years, but it is commoner in people with shorter disease duration. The clinical significance of residual adrenal function is not fully clear at the moment, but as it signifies an intact adrenocortical stem cell population, it opens up the possibility of regeneration of adrenal steroidogenesis and improvement in adrenal failure for some patients.

Natural History of Adrenal Steroidogenesis in Autoimmune Addison's Disease Following Diagnosis and Treatment

CONTEXT

The natural history of adrenal function in autoimmune Addison disease once diagnosed and treated has not been systematically studied, but several case reports of recovery from established adrenal failure suggest it may not be uniform.

OBJECTIVE

To ascertain steroidogenic function in autoimmune Addison disease immediately following diagnosis and during prolonged treatment.

DESIGN

We studied peak serum cortisol in response to ACTH1-24 in 20 newly diagnosed autoimmune Addison disease patients at first presentation and then again within a month. We also studied 37 patients with established Addison disease (for between 7 months and 44 years) in a medication-free state, measuring peak serum cortisol responses to ACTH1-24 and the urine LC-MS steroid metabolome.

RESULTS

Adrenal steroidogenesis declined rapidly after steroid replacement treatment for newly diagnosed Addison disease was started, with a peak serum cortisol falling from 138 ± 19 nmol/L (SEM) at presentation to 63 ± 13 nmol/L over 4 weeks (P < 0.003).Six of 37 participants (16%) with established Addison disease had detectable serum cortisol and urine glucocorticoid and mineralocorticoid metabolites during repeat testing, indicating variable degrees of residual adrenal function.

CONCLUSION

Autoimmune Addison disease is a heterogeneous condition, showing a rapid decline in adrenal steroidogenesis during the first few weeks following diagnosis, but low-level residual function in a minority of patients, which appears to persist for many years.

Residual endogenous corticosteroid production in patients with adrenal insufficiency

OBJECTIVE

This study aimed at comparing precursors of endogenous corticosteroid production in patients with primary adrenal insufficiency and in secondary adrenal insufficiency.

DESIGN

Twenty patients with primary adrenal insufficiency and matched controls and 19 patients with secondary adrenal insufficiency participated in this ancillary analysis of two different studies.

PATIENTS AND MEASUREMENTS

Patients with primary adrenal insufficiency were on stable hydrocortisone and fludrocortisone therapy. Patients with secondary adrenal insufficiency received two different doses of hydrocortisone in a randomized crossover study. Main outcome measures were concentrations of precursors of cortisol and aldosterone measured by LC-MS/MS RESULTS: Compared to controls, progressively lower concentrations of the glucocorticoid precursors 11-deoxycortisol, 11-deoxycorticosterone and corticosterone concentrations were found in patients with secondary adrenal insufficiency on lower hydrocortisone dose, secondary adrenal insufficiency on higher hydrocortisone dose and primary adrenal insufficiency, respectively. Half of the primary adrenal insufficient patients showed evidence of residual endogenous cortisol or aldosterone synthesis, as determined by quantifiable 11-deoxycortisol, 11-deoxycorticosterone and corticosterone conce ntrations. In secondary adrenal insufficient patients with higher endogenous cortisol production, as indicated by 11-deoxycortisol concentrations above the median, no increased cortisol exposure was observed both by plasma pharmacokinetic parameters and 24-hour free cortisol excretion in urine.

CONCLUSIONS

Adrenal corticosteroid production is likely to continue during treatment in a considerable percentage of patients with both primary and secondary adrenal insufficiency. In patients with secondary adrenal insufficiency, this synthesis appears to be sensitive to the dose of hydrocortisone. However, the residual corticosteroid concentrations were quantitatively low and its clinical significance remains therefore to be determined.

Latent Adrenal Insufficiency: Concept, Clues to Detection, and Diagnosis

In 1855, Thomas Addison described an illness now known as Addison disease (AD) caused by damage to the adrenal cortex and manifesting in weakness, weight loss, hypotension, gastrointestinal disturbances, and brownish pigmentation of the skin and mucous membranes. Corticosteroid supplementation, corticotropin (adrenocorticotropic hormone [ACTH] of medicinal use) test, and anti-adrenal auto-antibodies (AA) have come into use in the 100 years since Addison's death. Following the methodological innovations, 4 disorders which share impaired response to corticotropin in common have been discovered (i.e., partial AD, apigmented adrenal insufficiency [AI], subclinical AI, and the AA-positive state exclusively in subjects proven to have an impaired response to corticotropin). As they are hidden, potentially serious conditions, these disorders are bound together as latent AI (LAI). Diagnosis of AD is often delayed, which may lead to adrenal crisis. If LAI were widely recognized, such delays would not exist and crises would be averted. The 3 existing guidelines do not refer much to LAI patients outside those in acute situations. To address this, information relevant to clinical manifestations and diagnostic tests of LAI was sought in the literature. Signs and symptoms that are useful clues to begin a diagnostic workup are presented for endocrinologists to identify patients with suspected LAI. The utility of 2 corticotropin test protocols is reviewed. To endorse LAI shown by the corticotropin test, monitoring items following corticosteroid supplementation are cited from the guidelines and supplemented with the author's observations.

ABBREVIATIONS

AA = anti-adrenal auto-antibodies; Ab = antibodies; ACA = AA detected by immunofluorescence; ACTH = adrenocorticotropic hormone; AD = Addison disease; AI = adrenal insufficiency; DHEA = dehydroepiandrosterone; GC = glucocorticoid; IFA = immunofluorescence assay; LAI = latent AI; LDT = low-dose test; MC = mineralocorticoid; 21OHAb = anti-21-hydroxylase Ab; ST = standard test; URI = upper respiratory infection.

Autoimmune Addison's disease - An update on pathogenesis

Autoimmunity against the adrenal cortex is the leading cause of Addison's disease in industrialized countries, with prevalence estimates ranging from 93-220 per million in Europe. The immune-mediated attack on adrenocortical cells cripples their ability to synthesize vital steroid hormones and necessitates life-long hormone replacement therapy. The autoimmune disease etiology is multifactorial involving variants in immune genes and environmental factors. Recently, we have come to appreciate that the adrenocortical cell itself is an active player in the autoimmune process. Here we summarize the complex interplay between the immune system and the adrenal cortex and highlight unanswered questions and gaps in our current understanding of the disease.

MANAGEMENT OF ENDOCRINE DISEASE: Regenerative therapies in autoimmune Addison's disease

The treatment for autoimmune Addison's disease (AAD) has remained virtually unchanged in the last 60 years. Most patients have symptoms that are relatively well controlled with exogenous steroid replacement, but there may be persistent symptoms, recurrent adrenal crisis and poor quality of life, despite good compliance with optimal current treatments. Treatment with conventional exogenous steroid therapy is also associated with premature mortality, increased cardiovascular risk and complications related to excessive steroid replacement. Hence, novel therapeutic approaches have emerged in the last decade attempting to improve the long-term outcome and quality of life of patients with AAD. This review discusses the recent developments in treatment innovations for AAD, including the novel exogenous steroid formulations with the intention of mimicking the physiological biorhythm of cortisol secretion. Our group has also carried out a few studies attempting to restore endogenous glucocorticoid production via immunomodulatory and regenerative medicine approaches. The recent advances in the understanding of adrenocortical stem cell biology, and adrenal plasticity will also be discussed to help comprehend the science behind the therapeutic approaches adopted.

Current and emerging therapies for Addison's disease

PURPOSE OF REVIEW

The purpose of this article is to review the current therapy of Addison's disease and to highlight recent developments in this field.

RECENT FINDINGS

Conventional steroid replacement for Addison's disease consists of twice or three-times daily oral hydrocortisone and once-daily fludrocortisone; however, new treatment modalities such as modified-released hydrocortisone and continuous subcutaneous hydrocortisone infusion have recently been developed. These offer the potential for closer simulation of the physiological serum cortisol rhythm. Two studies have also looked at modifying the natural history of adrenal failure using adrenocorticotropic hormone (ACTH) stimulation and immunomodulatory therapies, leading to the concept of residual adrenal function in some Addison's disease patients.

SUMMARY

Following more than 60 years with no significant innovation in the management of Addison's disease, these new approaches hold promise for improved patient health and better quality of life in the future.

Diagnosis and classification of Addison's disease (autoimmune adrenalitis)

Autoimmune adrenalitis, or autoimmune Addison disease (AAD), is the most prevalent cause of primary adrenal insufficiency in the developed world. AAD is rare and can easily be misdiagnosed as other conditions. The diagnosis depends on demonstrating inappropriately low cortisol production and the presence of high titers of adrenal cortex autoantibodies (ACAs), along with excluding other causes of adrenal failure using other tests as necessary. The treatment corticosteroid replacement, and the prognosis following the treatment is the same as the normal population. Spontaneous recovery of adrenal function has been described but is rare.

Therapy of endocrine disease: Perspectives on the management of adrenal insufficiency: clinical insights from across Europe

BACKGROUND

Conventional glucocorticoid (GC) replacement for patients with adrenal insufficiency (AI) is inadequate. Patients with AI continue to have increased mortality and morbidity and compromised quality of life despite treatment and monitoring.

OBJECTIVES

i) To review current management of AI and the unmet medical need based on literature and treatment experience and ii) to offer practical advice for managing AI in specific clinical situations.

METHODS

The review considers the most urgent questions endocrinologists face in managing AI and presents generalised patient cases with suggested strategies for treatment.

RESULTS

Optimisation and individualisation of GC replacement remain a challenge because available therapies do not mimic physiological cortisol patterns. While increased mortality and morbidity appear related to inadequate GC replacement, there are no objective measures to guide dose selection and optimisation. Physicians must rely on experience to recognise the clinical signs, which are not unique to AI, of inadequate treatment. The increased demand for corticosteroids during periods of stress can result in a life-threatening adrenal crisis (AC) in a patient with AI. Education is paramount for patients and their caregivers to anticipate, recognise and provide proper early treatment to prevent or reduce the occurrence of ACs.

CONCLUSIONS

This review highlights and offers suggestions to address the challenges endocrinologists encounter in treating patients with AI. New preparations are being developed to better mimic normal physiological cortisol levels with convenient, once-daily dosing which may improve treatment outcomes.

Recovery of adrenal function in a patient with confirmed Addison's disease

Addison's disease is a condition characterised by immune-mediated destruction of the adrenal glands leading to a requirement of lifelong replacement therapy with mineralocorticoid and glucocorticoid. We present a case of a 53-year-old man who presented at the age of 37 years with nausea, fatigue and dizziness. He was found to have postural hypotension and buccal pigmentation. His presenting cortisol level was 43 nmol/l with no response to Synacthen testing. He made an excellent response to conventional replacement therapy with hydrocortisone and fludrocortisone and then remained well for 16 years. On registering with a new endocrinologist, his hydrocortisone dose was revised downwards and pre- and post-dose serum cortisol levels were assessed. His pre-dose cortisol was surprisingly elevated, and so his dose was further reduced. Subsequent Synacthen testing was normal and has remained so for further 12 months. He is now asymptomatic without glucocorticoid therapy, although he continues on fludrocortisone 50 μg daily. His adrenal antibodies are positive, although his ACTH and renin levels remain elevated after treatment. Addison's disease is generally deemed to lead to irreversible cell-mediated immune destruction of the adrenal glands. For this reason, patients receive detailed counselling and education on the need for lifelong replacement therapy. To our knowledge, this is the third reported case of spontaneous recovery of the adrenal axis in Addison's disease. Recovery may therefore be more common than previously appreciated, which may have major implications for the treatment and monitoring of this condition, and for the education given to patients at diagnosis.

Adrenal steroidogenesis after B lymphocyte depletion therapy in new-onset Addison's disease

CONTEXT

A diagnosis of Addison's disease means lifelong dependence on daily glucocorticoid and mineralocorticoid therapy and is associated with increased morbidity and mortality as well as a risk of unexpected adrenal crisis.

OBJECTIVE

The objective of the study was to determine whether immunomodulatory therapy at an early stage of autoimmune Addison's disease could lead to preservation or improvement in adrenal steroidogenesis.

DESIGN AND INTERVENTION

This was an open-label, pilot study of B lymphocyte depletion therapy in new-onset idiopathic primary adrenal failure. Doses of iv rituximab (1 g) were given on d 1 and 15, after pretreatment with 125 mg iv methylprednisolone.

PATIENTS AND MAIN OUTCOME MEASURES

Six patients (aged 17-47 yr; four females) were treated within 4 wk of the first diagnosis of idiopathic primary adrenal failure. Dynamic testing of adrenal function was performed every 3 months for at least 12 months.

RESULTS

Serum cortisol levels declined rapidly and were less than 100 nmol/liter (3.6 μg/dl) in all patients by 3 months after B lymphocyte depletion. Serum cortisol and aldosterone concentrations remained low in five of the six patients throughout the follow-up period. However, a single patient had sustained improvement in both serum cortisol [peak 434 nmol/liter (15.7 μg/dl)] and aldosterone [peak 434 pmol/liter (15.7 ng/dl)] secretion. This patient was able to discontinue steroid medications 15 months after therapy and remains well, with improving serum cortisol levels 27 months after therapy.

CONCLUSION

New-onset autoimmune Addison's disease should be considered as a potentially reversible condition in some patients. Future studies of immunomodulation in autoimmune Addison's disease may be warranted.

Autoimmune Addison disease: pathophysiology and genetic complexity

Autoimmune Addison disease is a rare autoimmune disorder with symptoms that typically develop over months or years. Following the development of serum autoantibodies to the key steroidogenic enzyme, 21-hydroxylase, patients have a period of compensated or preclinical disease, characterized by elevations in adrenocortocotropic hormone and renin, before overt, symptomatic adrenal failure develops. We propose that local failure of steroidogenesis, causing breakdown of tolerance to adrenal antigens, might be a key factor in disease progression. The etiology of autoimmune Addison disease has a strong genetic component in man, and several dog breeds are also susceptible. Allelic variants of genes encoding molecules of both the adaptive and innate immune systems have now been implicated, with a focus on the immunological synapse and downstream participants in T lymphocyte antigen-receptor signaling. With the exception of MHC alleles, which contribute to susceptibility in both human and canine Addison disease, no major or highly penetrant disease alleles have been found to date. Future research into autoimmune Addison disease, making use of genome-wide association studies and next-generation sequencing technology, will address the gaps in our understanding of the etiology of this disease.

Does recovery of adrenal function occur in patients with autoimmune Addison's disease?

OBJECTIVE

We earlier discovered partial recovery in a patient with autoimmune Addison's disease. The aim of this study was to assess the occurrence of adrenocortical recovery in patients with autoimmune adrenalitis.

DESIGN

Cross-sectional study.

PATIENTS

Twenty-seven adult patients with autoimmune Addison's disease on stable glucocorticoid and mineralocorticoid replacement therapy (RT) attending the Department of Endocrinology of a university teaching hospital were included in this study.

METHODS

Adrenocortical function was assessed by performing an adrenocorticotrophic hormone (ACTH) (250 μg Synacthen) stimulation test (SST) after interruption of current glucocorticoid and mineralocorticoid RT. A normal adrenal response was defined as a serum cortisol concentration ≥500 nm 30 or 60 min after stimulation. Partial recovery was defined as a cortisol concentration ≥100 and ≤500 nm after stimulation.

RESULTS

In 17 patients (63%), serum cortisol concentrations remained undetectable 30 and 60 min after the administration of ACTH. None of the remaining 10 participants had a normal response. Only one patient reached a cortisol concentration of 100 nm after 60 min, but this could not be confirmed during a second SST.

CONCLUSIONS

In this cross-sectional study among 27 patients with autoimmune adrenalitis, no new cases of adrenocortical recovery were found.