The Relationship of Mitochondrial Dysfunction and the Development of Insulin Resistance in Cushing’s Syndrome

Authors Ježková J, Ďurovcová V, Wenchich LHansíková H, Zeman J, Hána V, Marek J, Lacinová Z, Haluzík M, Kršek M

Received 18 March 2019

Accepted for publication 13 June 2019

Published 19 August 2019 Volume 2019:12 Pages 1459—1471

DOI https://doi.org/10.2147/DMSO.S209095

Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Melinda Thomas

Peer reviewer comments 3

Editor who approved publication: Dr Antonio Brunetti

 

Jana Ježková,1 Viktória Ďurovcová,1 Laszlo Wenchich,2,3 Hana Hansíková,3 Jiří Zeman,3Václav Hána,1 Josef Marek,1 Zdeňka Lacinová,4,5 Martin Haluzík,4,5 Michal Kršek1

1Third Department of Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic; 2Institute of Rheumatology, Prague, Czech Republic; 3Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic; 4Institute of Medical Biochemistry and Laboratory Diagnostic, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic; 5Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic

Correspondence: Jana Ježková
Third Department of Medicine, First Faculty of Medicine, Charles University and General University Hospital, U Nemocnice 1128 02 Praha 2, Prague, Czech Republic
Tel +420 60 641 2613
Fax +420 22 491 9780
Email fjjezek@cmail.cz

Purpose: Cushing’s syndrome is characterized by metabolic disturbances including insulin resistance. Mitochondrial dysfunction is one pathogenic factor in the development of insulin resistance in patients with obesity. We explored whether mitochondrial dysfunction correlates with insulin resistance and other metabolic complications.

Patients and methods: We investigated the changes of mRNA expression of genes encoding selected subunits of oxidative phosphorylation system (OXPHOS), pyruvate dehydrogenase (PDH) and citrate synthase (CS) in subcutaneous adipose tissue (SCAT) and peripheral monocytes (PM) and mitochondrial enzyme activity in platelets of 24 patients with active Cushing’s syndrome and in 9 of them after successful treatment and 22 healthy control subjects.

Results: Patients with active Cushing’s syndrome had significantly increased body mass index (BMI), homeostasis model assessment of insulin resistance (HOMA-IR) and serum lipids relative to the control group. The expression of all investigated genes for selected mitochondrial proteins was decreased in SCAT in patients with active Cushing’s syndrome and remained decreased after successful treatment. The expression of most tested genes in SCAT correlated inversely with BMI and HOMA-IR. The expression of genes encoding selected OXPHOS subunits and CS was increased in PM in patients with active Cushing’s syndrome with a tendency to decrease toward normal levels after cure. Patients with active Cushing’s syndrome showed increased enzyme activity of complex I (NQR) in platelets.

Conclusion: Mitochondrial function in SCAT in patients with Cushing’s syndrome is impaired and only slightly affected by its treatment which may reflect ongoing metabolic disturbances even after successful treatment of Cushing’s syndrome.

Keywords: Cushing’s syndrome, insulin resistance, mitochondrial enzyme activity, gene expression

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Recovery of HPA Axis Can Occur Late After Transsphenoidal Adenomectomy

Recovery of the hypothalamus-pituitary-adrenal (HPA) axis can occur as late as 12 months after transsphenoidal adenomectomy (TSA), according to study results published in The Journal of Clinical Endocrinology & Metabolism. These findings emphasize the need to periodically assess these patients to avoid unnecessary hydrocortisone replacement.

The primary treatment for most pituitary lesions is TSA. After pituitary surgery, the recovery of pituitary hormone deficits may be delayed; limited data are available regarding the postsurgical recovery of hormonal axes or predictors of recovery. The goal of this study was to assess HPA axis dysfunction and predictive markers of recovery following TSA, as well as time to recovery, to identify subgroups of patients who may be more likely to recover.

This single-center observational retrospective study enrolled 109 patients in the United Kingdom (71 men; mean age, 56 years; range, 17 to 82 years) who underwent TSA between February 2015 and September 2018 and had ≥1 reevaluation of the HPA axis with the short Synacthen (cosyntropin) test. The primary outcome was recovery of HPA axis function 6 weeks, 3 months, 6 months, and 9 to 12 months after TSA.

In 23 patients (21.1%), there was no evidence of pituitary hormone deficit before TSA. In 44 patients (40.4%), there was 1 hormone deficiency and in 25 patients (22.9%), preoperative evaluation showed >1 hormone deficiency.

Of the 23 patients with abnormal HPA function before surgery, 8 patients (34.8%) had recovered 6 weeks after the surgery. Patients who recovered were younger (mean age, 50±14 vs 70±9 years; P =.008) compared with patients who did not respond. Of the 15 remaining patients, 2 (13.3%) recovered at 3 months and 3 (20%) recovered at 9 to 12 months.

With regard to HPA function in the entire cohort 6 weeks after surgery, 32 patients (29.4%) did not pass the short Synacthen test. Of this group, 5 patients (15.6%) recovered at 3 months, 4 (12.5%) at 6 months, and 2 (6.2%) recovered 9 to 12 months after the surgery.

Predictors of future adrenal recovery at 6 weeks included having preoperative 30-minute cortisol >430 nmol/L (P <.001) and a day 8 postoperative cortisol >160 nmol/L (P =.001). With these cutoffs, 80% of patients with preoperative 30-minute cortisol >430 nmol/L (odds ratio [OR], 7.556; 95% CI, 2.847-20.055) and 80% of patients with day 8 postoperative cortisol >160 nmol/L (OR, 9.00; 95% CI, 2.455-32.989) passed the short Synacthen test at 6 weeks postsurgery. In addition, a 6-week baseline short Synacthen test cortisol level above or below 180 nmol/L (P <.001) predicted adrenal recovery at that time point.

None of the patients with all 3 variables below the aforementioned cutoffs recovered HPA axis within 1 year. On the other hand, 91.8% of patients with all 3 variables above those cutoffs had normal adrenal function at 6 weeks (OR, 12.200; 95% CI, 5.268-28.255).

In addition to the retrospective design, the study had other limitations, including the potential for selection bias, a heterogeneous patient cohort, and no data beyond 12 months after the surgery.

“[T]hese data offer the opportunity for patients who may have been given life-long replacement, to safely come off therapy and therefore avoid unnecessary glucocorticoid exposure,” wrote the researchers.

Reference

Pofi R, Gunatilake S, Macgregor V, et al. Recovery of the hypothalamo-pituitary-adrenal axis following transsphenoidal adenomectomy for non-ACTH secreting macroadenomas [published online June 21, 2019]. J Clin Endocrinol Metab. doi:10.1210/jc.2019-00406

From https://www.endocrinologyadvisor.com/home/topics/adrenal/recovery-of-hpa-axis-can-occur-late-after-transsphenoidal-adenomectomy/

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