Tissue regenerates of adrenal cortex with a physiological function twelve years after bilateral total adrenalectomy for Cushing's syndrome

Unilateral or bilateral adrenalectomy in PPNAD: six cases from a single family followed up over 40 years

The most frequent endocrine Carney complex manifestation is a bilateral primary pigmented nodular adrenocortical disease and bilateral adrenalectomy (BA) is therefore its main treatment. In this study, a 40 years follow-up of six members of the same family with heterozygous PRKAR1A germline mutation, is reported over two generations. The first cases, two sisters with severe hyperandrogenism and Cushing syndrome (CS) diagnosed in 1972 at age 14 and 25, were successfully treated with unilateral adrenalectomy (UA). Their two brothers were then diagnosed, one with a CS-related severe osteoporosis treated with BA and the other with CS treated with UA. The second generation was diagnosed with CS signs at 7 and 21 years of age and were treated with BA and UA respectively. Out of the four patients treated with UA, the only event possibly related to CS was spontaneous episode of pulmonary embolism, 30 years after surgery. Hormonal evaluation revealed either eucortisolism in one patient or partial adrenal deficiency in two and mild hypercortisolism in one patient. For the two patients with BA, one of them accidentally died. The second one, surprisingly, recovered progressively normal cortisol secretion and circadian variation. Steroid substitution was stopped 6 years after her surgery and we demonstrated by iodocholesterol scintigraphy the presence of bilateral adrenal remnants. In conclusion, our results of long term evolution of PPNAD patients show that UA in this subset of patients could be considered to treat CS.

Stem cells, evolutionary aspects and pathology of the adrenal medulla: A new developmental paradigm

The mammalian adrenal gland is composed of two main components; the catecholaminergic neural crest-derived medulla, found in the center of the gland, and the mesoderm-derived cortex producing steroidogenic hormones. The medulla is composed of neuroendocrine chromaffin cells with oxygen-sensing properties and is dependent on tissue interactions with the overlying cortex, both during development and in adulthood. Other relevant organs include the Zuckerkandl organ containing extra-adrenal chromaffin cells, and carotid oxygen-sensing bodies containing glomus cells. Chromaffin and glomus cells reveal a number of important similarities and are derived from the multipotent nerve-associated descendants of the neural crest, or Schwann cell precursors. Abnormalities in complex developmental processes during differentiation of nerve-associated and other progenitors into chromaffin and oxygen-sensing populations may result in different subtypes of paraganglioma, neuroblastoma and pheochromocytoma. Here, we summarize recent findings explaining the development of chromaffin and oxygen-sensing cells, as well as the potential mechanisms driving neuroendocrine tumor initiation.

Regeneration of Functional Adrenal Tissue Following Bilateral Adrenalectomy

It is assumed that after complete bilateral adrenalectomy (ADX), no adrenal tissue will redevelop and adrenal hormone levels will remain low and unaffected by stress. However, anecdotal observations in animals and in patients suggest that under some unknown circumstances the opposite can occur. Herein, we studied whether adrenalectomized rats can develop an alternative source of systemic corticosterone after complete bilateral ADX with minimal replacement therapy. Male and female rats underwent either a standard ADX, in which the glands were removed with minimal surrounding adipose tissue, or an extensive ADX, in which glands were removed with most surrounding adipose tissue. Excised glands were histologically tested for completeness, and corticosterone replacement was nullified within 1 to 3 weeks postoperatively. In four experiments and in both excision approaches, some rats gradually reestablished baseline corticosterone levels and stress response in a time-dependent manner, but differences were observed in the reestablishing rates: 80% in standard ADX vs 20% in extensive ADX. Upon searching for the source of corticosterone secretion, we were surprised to find functional macroscopic foci of adrenocortical tissue without medullary tissue, mostly proximal to the original location. Chronic stress accelerated corticosterone level reestablishment. We hypothesized that underlying this phenomenon were preexisting ectopic microscopic foci of adrenocortical-like tissue or a few adrenal cells that were pre-embedded in surrounding tissue or detached from the excised gland upon removal. We concluded that adrenalectomized animals may develop compensatory mechanisms and suggest that studies employing ADX consider additional corticosterone supplementation, minimize stress, and verify the absence of circulating corticosterone.