Silent pituitary adenoma and metabolic disorders: obesity, abnormal glucose tolerance, hypertension and dyslipidemia

Improvement of metabolic syndrome and its components in patients who underwent transsphenoidal resection for pituitary adenoma

BACKGROUND

Pituitary adenomas (PA) are neoplasms of pituitary adenohypophyseal cell lineage, which are the third most common cause of brain tumors among adults. Due to hormone secretion, PAs are closely related to metabolic syndrome (MetS). However, the relationship between these two entities has been scarcely studied to date.

PURPOSE

This paper aims to evaluate changes in the metabolic status of patients with PA before and after surgical treatment and to look for differences in metabolic outcomes among patients according to the adenoma type and the surgery success rate.

METHODS

We assessed patients with PA who went through transsphenoidal surgery for its treatment, documenting metabolic parameters before and after surgery, analyzed whole sample changes, and then stratified them according to adenoma type (nonfunctioning, somatotroph, lactotroph, and corticotroph), and surgery success (total resection, near-total resection, partial resection, subtotal resection).

RESULTS

A total of 214 patients were enrolled for this study. The prevalence of MetS with AACE criteria went from 51.52% before surgery to 28.99% after surgery (P < 0.001). Hyperglycemia (HG) was the most beneficial component; it went from 56% pre-surgery to 40.51% post-surgery (P = 0.03). The total resection group had the best improvement, with a significant decrease of prevalence in MetS from 83 to 16% (P < 0.001), and every component, except hypoalphalipoproteinemia (HA): obesity went from 96 to 67% (P < 0.001), arterial hypertension (AH) 59 to 24% (P < 0.001), HG 74 to 23% (P < 0.001), and hypertriglyceridemia (HTG) from 81 to 54% (P < 0.001). According to MetS prevalence, there was no difference in the improvement according to PA type.

CONCLUSION

Surgical treatment in patients with PA is associated with MetS improvement.

PitNETs and the gut microbiota: potential connections, future directions

The role of the gut microbiome has been widely discussed in numerous works of literature. The biggest concern is the association of the gut microbiome with the central nervous system through the microbiome-brain-gut axis in the past ten years. As more and more research has been done on the relationship between the disease of the central nervous system and gut microbes. This fact is being revealed that gut microbes seem to play an important role from the onset and progression of the disease to clinical symptoms, and new treatments. As a special tumor of the central nervous system, pituitary neuroendocrine tumors (PitNETs)are closely related to metabolism, endocrinology, and immunity. These factors are the vectors through which intestinal microbes interact with the central nervous system. However, little is known about the effects of gut microbes on the PitNET. In this review, the relationship of gut microbiota in PitNETs is introduced, the potential effects of the gut-brain axis in this relationship are analyzed, and future research directions are presented.

Glymphatic transport is reduced in rats with spontaneous pituitary tumor

Background and objective

Pituitary tumor in patients induces adverse alterations in the brain, accompanied by cognitive deficits. Dysfunction of glymphatic waste clearance results in accumulation of neurotoxic products within the brain, leading to cognitive impairment. However, the status of glymphatic function in the brain with pituitary tumor is unknown. Using magnetic resonance imaging (MRI) and an advanced mathematical modeling, we investigated the changes of glymphatic transport in the rats carrying spontaneous pituitary tumor.

Methods

Rats (22-24 months, female, Wistar) with and without pituitary tumor (n = 7/per group) underwent the identical experimental protocol. MRI measurements, including T2-weighted imaging and dynamic 3D T1-weighted imaging with intracisternal administration of contrast agent, were performed on each animal. The contrast-induced enhancement in the circle of Willis and in the glymphatic influx nodes were observed on the dynamic images and verified with time-signal-curves (TSCs). Model-derived parameters of infusion rate and clearance rate that characterize the kinetics of glymphatic tracer transport were evaluated in multiple representative brain regions.

Results

Our imaging data demonstrated a higher incidence of partially enhanced circle of Willis (86 vs. 14%; p < 0.033) and a lower incidence of enhancement in glymphatic influx nodes of pituitary (71 vs. 100%) and pineal (57 vs. 86%) recesses in the rats with pituitary tumor than in the rats with normal appearance of pituitary gland, indicating an intensification of impaired peri-vascular pathway and impeded glymphatic transport due to the presence of pituitary tumor. Consistently, our kinetic modeling and regional cerebral tissue quantification revealed significantly lower infusion and clearance rates in all examined regions in rats with spontaneous pituitary tumor than in non-tumor rats, representing a suppressed glymphatic transport in the brain with pituitary tumor.

Conclusion

Our study demonstrates the compromised glymphatic transport in the rat brain with spontaneous pituitary tumor. The reduced efficiency in cerebral waste clearance increases the risk for neurodegeneration in the brain that may underlie the cognitive impairment commonly seen in patients with pituitary tumors.

Pituitary adenomas and cerebrovascular disease: A review on pathophysiology, prevalence, and treatment

Pituitary adenomas (PAs) have been shown to cause excess cardiovascular disease comorbidity and mortality. Cerebrovascular disease (CeVD) is a small subset of cardiovascular disease with high morbidity, and its risk in patients with pituitary adenomas has been sparingly explored. In this review, we examine what is known about the prevalence of cerebrovascular disease in patients with PAs, from its initial discovery in 1970 to present. An abundance of literature describes increased cerebrovascular mortality in patients with acromegaly, while research on other PA subtypes is less frequent but shows a similarly elevated CeVD mortality relative to healthy populations. We also review how cerebrovascular risk changes after PAs are treated, with PA treatment appearing to prevent further accumulation of cerebrovascular risk without reversing prior elevations. While acromegaly-associated CeVD appears to be caused by elevated growth hormone (GH) levels and Cushing disease's elevated glucocorticoids similarly cause durable alterations in cerebrovascular structure and function, less is known about the mechanisms behind CeVD in other PA subpopulations. Proposed pathophysiologies include growth hormone deficiency inducing vessel wall damage or other hormone deficits causing increased atherosclerotic disease. Early diagnosis and treatment of PAs may be the key to minimizing lifetime CeVD risk elevations. More research is needed to better understand the mechanisms behind the increased CeVD seen in patients with PAs. Physicians caring for PA patients must remain vigilant for signs and symptoms of cerebrovascular disease in this patient population.