Plasma and tissue chromogranin in patients with adrenocortical adenomas

Low catestatin as a risk factor for cardiovascular disease - assessment in patients with adrenal incidentalomas

Background

Catestatin (Cts) is a peptide derived from proteolytic cleavage of chromogranin A, which exhibits cardioprotective and anti-inflammatory properties. Cts has been proposed as a potential biomarker for cardiovascular (CV) disease.

Objectives

examining Cts in patients with incidentally discovered adrenocortical adenomas (AI), and its associations with CV risk factors and blood pressure (BP).

Materials and methods

In this cross-sectional study, 64 AI patients without overt CV disease other than primary hypertension were recruited along with 24 age-, sex-, and body-mass-index (BMI)-matched controls with normal adrenal morphology. Laboratory, 24-h ambulatory BP monitoring, echocardiography, and common carotid artery sonography examinations were performed.

Results

Unadjusted Cts was higher in AI patients (median 6.5, interquartile range: 4.9-37 ng/ml) versus controls (4.5 (3.5 - 28)), p=0.048, however, the difference was insignificant after adjusting for confounding variables. Cts was lower in subjects with metabolic syndrome than in those without it (5.2 (3.9- 6.9) vs. 25.7 (5.8-115) ng/ml, p<0.01), and in men compared to women (4.9 (4-7.4) ng/ml vs. 7 (4.8-100), p=0.015). AI patients in the lower half of Cts levels compared to those in the upper had a higher prevalence of hypertension (OR 0.15, 95% CI: 0.041-0.5, p<0.001) and metabolic syndrome (OR 0.15, 95% CI 0.041-0.5, p<0.001). In AI patients Cts correlated positively with high-density lipoprotein cholesterol (Spearman's r=0.31), negatively with BMI (r=-0.31), and 10-year atherosclerotic CV disease risk (r=-0.42).

Conclusions

Our data indicate associations between CV risk factors and Cts. More clinical research is needed to apply serum Cts as a biomarker.

Chromogranin A - unspecific neuroendocrine marker. Clinical utility and potential diagnostic pitfalls

Chromogranin A, despite a number of limitations, is still the most valuable marker of neuroendocrine tumors (NETs). Granins belong to the family of acidic proteins that constitute a major component of secretory granules of various endocrine and neuroendocrine cells, which are components of both the classical endocrine glands and the diffuse neuroendocrine system. These cells are a potential source of transformation into neuroendocrine tumors. The awareness of potential causes influencing the false results of its concentrations simplifies diagnosis and treatment. One of the disadvantages of this marker is its non-specificity and the existence of a number of pathological processes leading to an increase in its concentration, which often results in confusion and diagnostic difficulties. The molecular structure is characterized by a number of sites susceptible to the proteolytic activity of enzymes, resulting in the formation of a number of biologically active peptides. Presumably they act as precursors of active proteins. Chromogranin expression correlates with the amount of secretory vesicles in neuroendocrine cells. The peptide chain during biochemical changes becomes a precursor of biologically active proteins with a wide range of activities. There are a number of commercially available kits for the determination of chromogranin A, which differ in methodology. We present the evaluation of chromogranin A as a marker of neuroendocrine tumors in clinical practice and the possible factors that may affect the outcome of its concentration.

PREDICTIVE VALUE OF CHROMOGRANIN A IN A DIAGNOSIS TOWARDS PHEOCHROMOCYTOMA IN ADRENAL INCIDENTALOMA

Context

Some adrenal tumors, such as pheochromocytoma, can be life-threatening. Therefore it is crucial to distinguish them from other lesions, especially prior to surgery. Chromogranin A (CgA) seems to potentially be a good marker for tumors of chromaffin origin.

Objective

To assess the differentiating value of CgA in the diagnostic work-up of pheochromocytoma.

Design

Retrospective study of operated patients with adrenal incidentaloma with lesions > 10 Hounsfield's units (HU) on CT.

Subjects and methods

Thirty patients (11 males, 19 females; aged 61.5±21 years) were enrolled in the study. Patients using medications interfering with the assessment of CgA and metanephrines were excluded. Two groups were formed: those with pheochromocytoma (Ph, n=16) and those with non-pheochromocytoma (N-Ph, n=14) lesions. Data included radiological features of masses, serum CgA and 24-hour urine metanephrines (24 - HUM) concentrations.

Results

No difference in 24-HUM level nor tumor size or density was found between groups Ph and N-Ph. Median serum CgA concentration was higher in Ph group compared to the N-Ph: 99.35 (68.12-172.73) vs. 52.92 (34.37-101.26) ng/mL, respectively (P=0.04). In Ph group, the size of the lesion correlated negatively with density (r= -0.53, P=0.042). No significant correlation in CgA, 24-HUM, density or size of the lesion was found. Performed curve receiver operating characteristic (ROC) showed AUC=0.7232 for CgA. Taking into account CgA serum value of ≤ 50 ng/mL (sensitivity: 93.75%, specificity: 50.00%, P=0.012), we proposed an algorithm for management of lesions > 10 HU on CT.

Conclusion

CgA level ≤ 50 ng/mL might be useful in initial screening evidence for the exclusion of pheochromocytoma. It is crucial to eliminate factors interfering with the measurements.