The causes of impaired skeletal muscle mass and strength during aging are well-studied in healthy populations. Less is known on pathological age-related muscle wasting and weakness termed sarcopenia, which directly impacts physical autonomy and survival. Here, we compare genome-wide transcriptional changes of sarcopenia versus age-matched controls in muscle biopsies from 119 older men from Singapore, Hertfordshire UK and Jamaica. Individuals with sarcopenia reproducibly demonstrate a prominent transcriptional signature of mitochondrial bioenergetic dysfunction in skeletal muscle, with low PGC-1α/ERRα signalling, and downregulation of oxidative phosphorylation and mitochondrial proteostasis genes. These changes translate functionally into fewer mitochondria, reduced mitochondrial respiratory complex expression and activity, and low NAD+ levels through perturbed NAD+ biosynthesis and salvage in sarcopenic muscle. We provide an integrated molecular profile of human sarcopenia across ethnicities, demonstrating a fundamental role of altered mitochondrial metabolism in the pathological loss of skeletal muscle mass and function in older people.

Marasmus survivors tend to be less insulin sensitive, but have significantly lower insulin secretion and are more glucose intolerant compared with kwashiorkor survivors and controls. This suggests that poor nutrition in early life causes β-cell dysfunction, which may predispose to the development of diabetes.

No abstract

Ectopic ACTH secretion (EAS) presents in myriad ways. We present five cases of EAS to highlight similarities and differences in presentation and treatment. The first woman with known metastatic lung neuroendocrine tumour (NET) for two years presented with facial fullness, proximal weakness, worsening hypertension and hypokalaemia. Random cortisol of 2742nmol/L (99.39mcg/dL), with adrenocorticotrophic hormone (ACTH) of 201ng/L (5-50), was in keeping with EAS. She received medical treatment followed by bilateral adrenalectomy with EAS resolution and development of adrenal insufficiency. She is doing well. The second woman with proximal weakness was evaluated by neurologists. All neurological tests were normal but facial fullness and easy bruising was noted. Random cortisol was 875nmol/L (31.71mcg/dL) and ACTH was 90 ng/L. Imaging revealed metastatic liver disease with unknown primary and biopsy confirmed NET. Cortisol rose despite medical treatment and she died within fifteen months. The third woman with significant smoking history presented with haemoptysis and breathlessness. A right lung mass was suspected on chest X-ray and confirmed with CT. Endobronchial ultrasound-guided biopsy revealed small cell lung cancer (SCLC). She developed generalised weakness and severe hypokalaemia. Random cortisol of 1645nmol/L (59.63mcg/dL) with ACTH of 282ng/L suggested EAS. Despite medical treatment, she died within two weeks. The fourth woman presented with confusion, hypertension and severe hypokalaemia. Morning cortisol of 8557nmol/L (310.19mcg/dL) and random ACTH of 73ng/L were suggestive of EAS. CT demonstrated left lung mass with widespread metastases. She deteriorated and died within 2 weeks. Our only man had incidentally discovered metastatic liver lesions on ultrasound. Further imaging revealed prostatic mass and biopsy showed small cell neuroendocrine cancer. He presented with severe hypokalaemia. Random cortisol was 1065nmol/L (38.61mcg/dL) and ACTH was 188ng/L. He was commenced on medical treatment but declined rapidly and died. All our patients had profound hypokalaemia and metastatic disease at presentation. Many patients do not exhibit classical cushingoid features as EAS tends to develop acutely and underlying malignancy drives weight loss. A high index of suspicion is required to make a diagnosis. EAS should be considered in patients with proximal myopathy, pigmentation, resistant or severe hypokalaemia or hypertension and known or suspected malignancy. Early and quick control of cortisol excess is essential to minimise cardiometabolic abnormalities, severe infections and thromboembolic complications. Prognosis depends upon age, frailty, comorbidity, nature of neoplasm and extent of hypercortisolaemia. Adrenolytics with or without bilateral adrenalectomy, reduction in tumour burden and management of complications are the mainstay of treatment.

Introduction: Ectopic ACTH secretion (EAS) causes myriad metabolic derangements which may be effectively managed with laparoscopic bilateral adrenalectomy (LBA) in fit-for-surgery candidates. Clinical Case: A 67-year old woman with a remote 12-pack year smoking history presented with unintentional weight loss, cough, fever and chest pain. Imaging revealed a right-sided lung mass with liver lesions. Liver biopsy confirmed a well-differentiated neuroendocrine tumour (NET). Attempt at palliative lung resection was aborted due to disease extent. She was treated with multiple courses of chemotherapy but her disease progressed. Two years later, she presented with hypokalemia of 2.8 mmol/L (3.5 - 5.0 mmol/L) and uncontrolled hypertension. She was treated with spironolactone and oral potassium. She was notably hyperglycaemic with clinical features of cortisol excess. A random cortisol of 2742 nmol/L (<500 nmol/L), corresponding ACTH of 201 ng/L (5 - 50 ng/L) and lack of diurnal variation in cortisol day curve were in keeping with EAS. Metyrapone and spironolactone normalised blood pressure and biochemical derangement. With her initially high cortisol levels and its associated immunocompromised state, she developed pneumocystis jirovecii pneumonia (PCP), and was briefly admitted to the intensive care unit. In hospital, monitoring her response to EAS management necessitated multiple blood investigations, which proved burdensome for the patient. To effect definitive management of EAS and reduce invasive monitoring, she wished to have LBA and underwent an uneventful procedure. She was discharged on fludrocortisone and hydrocortisone along with lanreotide for primary disease management. Metyrapone and spironolactone were stopped. At initial outpatient follow up, she had normal blood pressure and electrolytes. By her report, her quality of life had improved tremendously, given the reduced need for multiple clinic visits and blood investigations. Unfortunately, her primary disease progressed with gradual deterioration of physical function. She died six months after LBA but, as per her desire, spent her final months with loved ones. Clinical Lesson: In patients with EAS who have unresectable primary disease but otherwise good performance status, LBA is a viable alternative to medical management and should be discussed with patients early after diagnosis. References1. Alberda et al., Endoscopic bilateral adrenalectomy in patients with ectopic Cushing’s syndrome. Surgical Endoscopy 2012; 26:1140-1145 2. Reincke et al., A critical reappraisal of bilateral adrenalectomy for ACTH-dependent Cushing’s syndrome. Eur Journal of Endocrinology 2015, 173M23-M32