Hypertrophic remodeling of subcutaneous small resistance arteries in patients with Cushing's syndrome

Microcirculation in Hypertension: A Therapeutic Target to Prevent Cardiovascular Disease?

Arterial hypertension is a common condition worldwide and an important risk factor for cardio- and cerebrovascular events, renal diseases, as well as microvascular eye diseases. Established hypertension leads to the chronic vasoconstriction of small arteries as well as to a decreased lumen diameter and the thickening of the arterial media or wall with a consequent increased media-to-lumen ratio (MLR) or wall-to-lumen ratio (WLR). This process, defined as vascular remodeling, was firstly demonstrated in small resistance arteries isolated from subcutaneous biopsies and measured by micromyography, and this is still considered the gold-standard method for the assessment of structural alterations in small resistance arteries; however, microvascular remodeling seems to represent a generalized phenomenon. An increased MLR may impair the organ flow reserve, playing a crucial role in the maintenance and, probably, also in the progressive worsening of hypertensive disease, as well as in the development of hypertension-mediated organ damage and related cardiovascular events, thus possessing a relevant prognostic relevance. New non-invasive techniques, such as scanning laser Doppler flowmetry or adaptive optics, are presently under development, focusing mainly on the evaluation of WLR in retinal arterioles; recently, also retinal microvascular WLR was demonstrated to have a prognostic impact in terms of cardio- and cerebrovascular events. A rarefaction of the capillary network has also been reported in hypertension, which may contribute to flow reduction in and impairment of oxygen delivery to different tissues. These microvascular alterations seem to represent an early step in hypertension-mediated organ damage since they might contribute to microvascular angina, stroke, and renal dysfunction. In addition, they can be markers useful in monitoring the beneficial effects of antihypertensive treatment. Additionally, conductance arteries may be affected by a remodeling process in hypertension, and an interrelationship is present in the structural changes in small and large conductance arteries. The review addresses the possible relations between structural microvascular alterations and hypertension-mediated organ damage, and their potential improvement with antihypertensive treatment.

State of the Art Review: Vascular Remodeling in Hypertension

Although the gold-standard method for the assessment of structural alteration in small resistance arteries is the evaluation of the MLR by micromyography in bioptic tissues, new, noninvasive techniques are presently under development, focusing mainly on the evaluation of WLR in retinal arterioles. These approaches represent a promising and interesting future perspective. Appropriate antihypertensive treatment is able to prevent the development of microvascular alterations or to induce their regression. Also, conductance arteries may be affected by a remodeling process in hypertension, and a cross-talk may exist between structural changes in the small and large arteries. In conclusion, the evaluation of microvascular structure is ready for clinical prime time, and it could, in the future, represent an evaluation to be performed in the majority of hypertensive patients, to better stratify cardiovascular risk and better evaluate the effects of antihypertensive therapy. However, for this purpose, we need a clear demonstration of the prognostic relevance of noninvasive measures of microvascular structure, in basal conditions and during treatment. Vascular remodeling may be frequently observed in hypertension, as well as in obesity and diabetes mellitus. An increased media to lumen ratio (MLR) or wall to lumen ratio (WLR) in microvessels is the hallmark of hypertension, and may impair organ flow reserve, being relevant in the maintenance and, probably, also in the progressive worsening of hypertensive disease, as well as in the development of hypertension-mediated organ damage/cardiovascular events. The molecular mechanisms underlying the development of vascular remodeling are only partly understood.

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.

Approach to the Patient with Subclinical Cushing's Syndrome

A growing number of patients with adrenal incidentalomas and subclinical Cushing's syndrome (SCS) led to an increasing number of different guidelines, and diagnostic and treatment recommendations. Excess cortisol secretion in patients with SCS is associated with several comorbidities, such as hypertension, dyslipidemia, type 2 diabetes mellitus, and obesity, which in the long-term increase mortality of these patients. Subtle cortisol secretion affects bone health, quality of life and causes depression, but due to the unapparent clinical features, patients with SCS are often at risk between over and under treatment. This narrative review aimed to summarize the latest recommendations on the approach to the patient with subclinical Cushing's syndrome.

Empagliflozin improves chronic hypercortisolism-induced abnormal myocardial structure and cardiac function in mice

Background:

Chronic exposure to excess glucocorticoids is frequently associated with a specific cardiomyopathy. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has beneficial effects as it aids in the reduction of heart failure and cardiovascular mortality in hospitalized patients. The aim of this study was to investigate the effects of empagliflozin on chronic hypercortisolism-induced myocardial fibrosis and myocardial dysfunction in mice.

Methods:

Male C57BL/6J mice (6 weeks old) were randomized to control, corticosterone (CORT), and empagliflozin + CORT groups. After 4 weeks of administration, heart structure and function were evaluated by echocardiography, and peripheral blood and tissue samples were collected. Expressions of Ccl2, Itgax, Mrc1, and Adgre1 mRNA in heart tissue were evaluated by RT-PCR, and signal transducer and activator of transcription 3 (STAT3) and Toll-like receptor 4 (TLR4) protein expression were analyzed by Western blotting.

Results:

Empagliflozin effectively reduced body weight, liver triglyceride, visceral adipose volume, and uric acid in CORT-treated mice. Left ventricular hypertrophy and cardiac dysfunction were improved significantly, phosphorylated STAT3 and TLR4 were alleviated, and macrophage infiltration in the myocardium was inhibited after administration of empagliflozin in CORT-treated mice.

Conclusion:

Empagliflozin has beneficial effects on specific cardiomyopathy associated with CORT, and the results provide new evidence that empagliflozin might be a potential drug for the prevention of this disease.

How Structure, Mechanics, and Function of the Vasculature Contribute to Blood Pressure Elevation in Hypertension

Large conduit arteries and the microcirculation participate in the mechanisms of elevation of blood pressure (BP). Large vessels play roles predominantly in older subjects, with stiffening progressing after middle age leading to increases in systolic BP found in most humans with aging. Systolic BP elevation and increased pulsatility penetrate deeper into the distal vasculature, leading to microcirculatory injury, remodelling, and associated endothelial dysfunction. The result is target organ damage in the heart, brain, and kidney. In younger individuals genetically predisposed to high BP, increased salt intake or other exogenous or endogenous risk factors for hypertension, including overweight and excess alcohol intake, lead to enhanced sympathetic activity and vasoconstriction. Enhanced vasoconstrictor responses and myogenic tone become persistent when embedded in an increased extracellular matrix, resulting in remodelling of resistance arteries with a narrowed lumen and increased media-lumen ratio. Stimulation of the renin-angiotensin-aldosterone and endothelin systems and inflammatory and immune activation, to which gut microbiome dysbiosis may contribute as a result of salt intake, also participate in the injury and remodelling of the microcirculation and endothelial dysfunction. Inflammation of perivascular fat and loss of anticontractile factors play roles as well in microvessel remodelling. Exaggerated myogenic tone leads to closure of terminal arterioles, collapse of capillaries and venules, functional rarefaction, and eventually to anatomic rarefaction, compromising tissue perfusion. The remodelling of the microcirculation raises resistance to flow, and accordingly raises BP in a feedback process that over years results in stiffening of conduit arteries and systo-diastolic or predominantly systolic hypertension and, more rarely, predominantly diastolic hypertension. Thus, at different stages of life and the evolution of hypertension, large vessels and the microcirculation interact to contribute to BP elevation.

Increased oxidative stress, inflammation and fibrosis in perirenal adipose tissue of patients with cortisol-producing adenoma

Although much is known about that corticosteroids affect the functions of adipose tissues, little genetic information is available for perirenal adipose tissue (peri-N) from patients with cortisol-producing adenoma (CPA). We conducted microarray analysis of peri-N from patients with CPA by using an Affymetrix human U133 plus 2.0 array. We also analysed the inflammation, fibrosis and oxidative stress in vitro. Compared with normotension (NT) group, CPA group has significantly higher protein levels of TNFα, IL-6, fibronectin (FN) and collagen I (COLI). The protein level of NADPH oxidase 4 (Nox4) significantly increased, while nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) levels were significantly reduced in the CPA group. Dexamethasone markedly induced fibrosis and adipogenesis-related gene expression in predifferentiated stromal vascular fraction (SVF) cells, 3T3-L1 preadipocytes and brown preadipocytes. Chronic exposure to endogenous glucocorticoids due to CPA increases peri-N oxidative stress, inflammation and fibrosis, which may contribute to the metabolic disturbances associated with hypercortisolism in these patients.

Microvascular structure as a prognostically relevant endpoint

Remodelling of subcutaneous small resistance arteries, as indicated by an increased media-to-lumen ratio, is frequently present in hypertensive, obese, or diabetic patients. The increased media-to-lumen ratio may impair organ flow reserve. This may be important in the maintenance and, probably, also in the progressive worsening of hypertensive disease. The presence of structural alterations represents a prognostically relevant factor, in terms of development of target organ damage or cardiovascular events, thus allowing us a prediction of complications in hypertension. In fact, media-to-lumen ratio of small arteries at baseline, and possibly their changes during treatment may have a strong prognostic significance. However, new, non-invasive techniques are needed before suggesting extensive application of the evaluation of remodelling of small arteries for the cardiovascular risk stratification in hypertensive patients. Some new techniques for the evaluation of microvascular morphology in the retina, currently under clinical investigation, seem to represent a promising and interesting future perspective. The evaluation of microvascular structure is progressively moving from bench to bedside, and it could represent, in the near future, an evaluation to be performed in all hypertensive patients, to obtain a better stratification of cardiovascular risk, and, possibly, it might be considered as an intermediate endpoint in the evaluation of the effects of antihypertensive therapy, provided that a demonstration of a prognostic value of non-invasive measures of microvascular structure is made available.

PENTRAXIN 3 AS A NEW CARDIOVASCULAR MARKER IN ADRENAL ADENOMAS

OBJECTIVE

Pentraxin 3 (PTX3) is an acute-phase glycoprotein, which is increased in patients with cardiovascular disease (CVD) and considered as a predictor of CVD in the general population. Both functional and nonfunctional adrenal tumors are associated with a higher risk of cardiovascular events and mortality. We aimed to investigate plasma PTX3 levels in patients with functioning and nonfunctioning adrenal tumors and determine its relationship with cardiovascular risk factors.

METHODS

Twenty-one patients with functional adrenal tumors (11 pheochromocytomas, 9 Cushing syndrome, and 1 primary hyperaldosteronism), 28 patients with nonfunctional adrenal incidentalomas, and 40 healthy controls were enrolled in the study. Serum PTX3 levels were measured using a human PTX3 enzyme-linked immunosorbent assay.

RESULTS

PTX3 concentrations were significantly higher in the adrenal tumor group compared with the control group (3,001.64 ± 374.64 pg/mL vs. 1,173.59 ± 168.89 pg/mL; P<.001). PTX3 concentrations were positively correlated with carotid intima media thickness (CIMT) (r², 0.464; P<.001), high-sensitivity C-reactive protein (hsCRP) (r², 0.551; P<.001), diastolic blood pressure (r², 0.334; P = .003), systolic blood pressure (r², 0.312; P = .006), and urinary metanephrine concentrations (r², 0.320; P = .041). Serum PTX3 concentrations in patients with functional adrenal tumors and comorbidities including hypertension, diabetes mellitus, or CVD were higher than in those without comorbidities (3,654.54 ± 447 pg/mL vs. 1,026.96 ± 447.97 pg/mL; P = .008).

CONCLUSION

We found that serum PTX3 concentrations increased in both functional and nonfunctional adrenal tumors. PTX3 levels were correlated with cardiovascular risk factors such as CIMT, hsCRP, and blood pressure.

ABBREVIATIONS

BMI = body mass index; CIMT = carotid intima-media thickness; CRP = C-reactive protein; CT = computed tomography; CVD = cardiovascular disease; FGF2 = fibroblast growth factor 2; hsCRP = high-sensitivity C-reactive protein; PA = primary hyperaldosteronism; PTX3 = pentraxin 3.

Relationship between different subpopulations of circulating CD4+ T lymphocytes and microvascular or systemic oxidative stress in humans

BACKGROUND AND OBJECTIVE

Different components of the immune system, including innate and adaptive immunity (T effector lymphocytes and T regulatory lymphocytes - TREGs) may be involved in the development of hypertension, vascular injury and inflammation. However, no data are presently available in humans about possible relationships between T-lymphocyte subtypes and microvascular oxidative stress. Our objective was to investigate possible relationships between T-lymphocyte subtypes and systemic and microvascular oxidative stress in a population of normotensive subjects and hypertensive patients.

PATIENTS AND METHODS

In the present study we enrolled 24 normotensive subjects and 12 hypertensive patients undergoing an elective surgical intervention. No sign of local or systemic inflammation was present. All patients underwent a biopsy of subcutaneous fat during surgery. A peripheral blood sample was obtained before surgery for assessment of T lymphocyte subpopulations by flow cytometry and circulating indices of oxidative stress.

RESULTS

A significant direct correlation was observed between Th1 lymphocytes and reactive oxygen species (ROS) production (mainly in microvessels). Additionally, significant inverse correlations were observed between ROS and total TREGs, or TREGs subtypes. Significant correlations were detected between circulating indices of oxidative stress/inflammation and indices of microvascular morphology/Th1 and Th17 lymphocytes. In addition, a significant inverse correlation was detected between TREGs in subcutaneous small vessels and C reactive protein.

CONCLUSIONS

Our data suggest that TREG lymphocytes may be protective against microvascular damage, probably because of their anti-oxidant properties, while Th1-Th17 lymphocytes seem to exert an opposite effect, confirming an involvement of adaptive immune system in microvascular damage.

Endocrine Hypertension: A Practical Approach

Elevated blood pressure resulting from few endocrine disorders (endocrine hypertension) accounts for a high proportion of cases of secondary hypertension. Although some features may be suggestive, many cases of endocrine hypertension remain silent until worked up for the disease. A majority of cases result from primary aldosteronism. Other conditions that can cause endocrine hypertension are: congenital adrenal hyperplasia, Liddle syndrome, pheochromocytomas, Cushing's syndrome, acromegaly, thyroid diseases, primary hyperparathyroidism and iatrogenic hormone manipulation. Early identification and treatment of the cause of endocrine hypertension may help to reduce morbidity and mortality related to these disorders. This article gives a comprehensive and practical approach to the diagnosis and management of endocrine hypertension.

Glucocorticoid-induced fetal origins of adult hypertension: Association with epigenetic events

Hypertension is a predominant risk factor for cardiovascular diseases and a major health care burden. Accumulating epidemiological and experimental evidence suggest that adult-onset hypertension may have its origins during early development. Upon exposure to glucocorticoids, the fetus develops hypertension, and the offspring may be programmed to continue the hypertensive trajectory into adulthood. Elevated oxidative stress and deranged nitric oxide system are not only hallmarks of adult hypertension but are also observed earlier in life. Endothelial dysfunction and remodeling of the vasculature, which are robustly associated with increased incidence of hypertension, are likely to have been pre-programmed during fetal life. Apparently, genomic, non-genomic, and epigenomic factors play a significant role in the development of hypertension, including glucocorticoid-driven effects on blood pressure. In this review, we discuss the involvement of the aforementioned participants in the pathophysiology of hypertension and suggest therapeutic opportunities for targeting epigenome modifiers, potentially for personalized medicine.

Subclinical hypercortisolism: a state, a syndrome, or a disease?

Subclinical hypercortisolism (SH), defined as alterations of the hypothalamus-pituitary-adrenal axis in the absence of clinical signs or symptoms related to cortisol secretion, is a common finding in patients with adrenal incidentalomas. The clinical correlates of this pathological condition have become clearer over the last few years. The aim of this review is to summarize the co-morbidities and the clinical outcomes of patients with SH. According to the analysis of the results of the studies published within the last 15 years, hypertension and type 2 diabetes are a common finding in patients with SH, occurring roughly in 2/3 and 1/3 of the patients respectively. Moreover, several additional cardiovascular and metabolic complications, like endothelial damage, increased visceral fat accumulation and impaired lipid metabolism have been shown to increase the cardiovascular risk of those patients. Accordingly, recent independent reports investigating the natural history of the disease in a long-term follow-up setting have shown that patients with SH have a higher incidence of cardiovascular events and related mortality. Moreover, longitudinal studies have also shown increased incidence of osteoporotic vertebral fractures. Future research is needed to improve the diagnostic performance of hormonal tests, by assessment of the complete steroid profile with more accurate assays, and to define the efficacy of surgical vs medical treatment in a randomized-controlled setting.

Metabolic comorbidities in Cushing's syndrome

Cushing's syndrome (CS) patients have increased mortality primarily due to cardiovascular events induced by glucocorticoid (GC) excess-related severe metabolic changes. Glucose metabolism abnormalities are common in CS due to increased gluconeogenesis, disruption of insulin signalling with reduced glucose uptake and disposal of glucose and altered insulin secretion, consequent to the combination of GCs effects on liver, muscle, adipose tissue and pancreas. Dyslipidaemia is a frequent feature in CS as a result of GC-induced increased lipolysis, lipid mobilisation, liponeogenesis and adipogenesis. Protein metabolism is severely affected by GC excess via complex direct and indirect stimulation of protein breakdown and inhibition of protein synthesis, which can lead to muscle loss. CS patients show changes in body composition, with fat redistribution resulting in accumulation of central adipose tissue. Metabolic changes, altered adipokine release, GC-induced heart and vasculature abnormalities, hypertension and atherosclerosis contribute to the increased cardiovascular morbidity and mortality. In paediatric CS patients, the interplay between GC and the GH/IGF1 axis affects growth and body composition, while in adults it further contributes to the metabolic derangement. GC excess has a myriad of deleterious effects and here we attempt to summarise the metabolic comorbidities related to CS and their management in the perspective of reducing the cardiovascular risk and mortality overall.

Adrenal adenomas, subclinical hypercortisolism, and cardiovascular outcomes

PURPOSE OF REVIEW

Recent evidence has highlighted the link between cardiovascular outcomes and incidentally discovered adrenal masses. The purpose of this review is to summarize the most recent findings on the cardiovascular profile of patients with nonfunctional adrenal adenomas.

RECENT FINDINGS

Nonsecreting adrenal tumors, defined mostly by cortisol levels after dexamethasone suppression test below 1.8 μg/dl, are associated with impairment of markers of subclinical atherosclerosis such as intima-media thickness and flow-mediated vasodilation. The presence of impaired indices of insulin resistance could represent an additional factor that contributes to the worsening of the cardiovascular profile of those patients. No evidence of increased cardiovascular outcomes was found in this group of patients. On the contrary, according to the findings of recent long-term retrospective studies, patients with subclinical hypercortisolism have an increased incidence of cardiovascular outcomes and related mortality with respect to nonsecreting adrenal masses and to the general population.

SUMMARY

An impaired cardiovascular profile is a common finding in patients with apparently nonfunctional adrenal masses. However, the incidence of cardiovascular outcomes and related mortality seems to be increased only in patients with mild cortisol hypersecretion.

Enhanced oxidative stress and platelet activation in patients with Cushing's syndrome

OBJECTIVE

Cushing Syndrome (CS) is implicated by increased cardiovascular risk (CVR) leading to increased morbidity and mortality. Oxidative stress (OS) and platelet activation (PA) are associated with increased CVR. However, scarce data of OS in CS exist. Our objective was to determine the oxidant-antioxidant balance in CS.

DESIGN

Fourteen patients with CS at diagnosis and fourteen healthy subjects (NS) were evaluated OS by measuring plasma 15-F2t -Isoprostane (15-F2t -IsoP), PA by thromboxaneB2 levels (TXB2 ), and antioxidant reserve measuring total antioxidant capacity (TAC) and serum vitamin E.

RESULTS

15-F2t -IsoP and TXB2 levels were significantly higher (P < 0·01) in CS, while vitamin E levels were higher in NS (P < 0·03). 15-F2t -IsoP levels were significantly higher (P < 0·01) in complicated vs not-complicated CS and NS and significantly higher (P < 0·03) in CS not-complicated vs NS. TXB2 levels were significantly reduced (P < 0·03) in NS vs complicated and not-complicated CS. A negative correlation between Vitamin E and UFC was observed in CS (P < 0·05 r = -0·497). TXB2 correlated with glucose, HbA1c and T-score (P < 0·05 r = 0·512, P < 0·03 r = 0·527 and P < 0·01 r = 0·783, respectively) and HDL (P < 0·01 r = -0·651). 15-F2t -IsoP correlated with triglicerides, HbA1c and diastolic pressure (P < 0·01 r = 0·650, P < 0·03 r = 0·571 and P < 0·05 r = 0·498, respectively) and HDL (P < 0·03 r = -0·594).

CONCLUSIONS

This study emphasizes the major role of OS in CS. As our findings demonstrated that enhanced OS and PA take place in this rare metabolic disorder which is associated with increased CVR, it could be suggested that these biochemical alterations can further contribute in the pathogenesis of atherosclerosis, increased CVR and mortality in CS.

Clinical and biochemical manifestations of Cushing's

INTRODUCTION

Cushing's syndrome is associated with a number of clinical manifestations and co-morbidities which may not resolve even after long-term remission leading to excessive mortality.

MATERIALS AND METHODS

This review summarizes the main manifestations of Cushing's syndrome (active or in remission) with particular focus on data from recently published literature.

CONCLUSION

Obesity and metabolic alterations, hypertension and cardio/cerebrovascular complications, hypercoagulability/thromboembolism, neuropsychiatric, muscle/skeletal and immune consequences remain the most challenging. Cardiovascular consequences and immunosuppression determine the main causes of death in Cushing's syndrome necessitating early intervention when possible.

The role of reactive oxygen species in microvascular remodeling

The microcirculation is a portion of the vascular circulatory system that consists of resistance arteries, arterioles, capillaries and venules. It is the place where gases and nutrients are exchanged between blood and tissues. In addition the microcirculation is the major contributor to blood flow resistance and consequently to regulation of blood pressure. Therefore, structural remodeling of this section of the vascular tree has profound implications on cardiovascular pathophysiology. This review is focused on the role that reactive oxygen species (ROS) play on changing the structural characteristics of vessels within the microcirculation. Particular attention is given to the resistance arteries and the functional pathways that are affected by ROS in these vessels and subsequently induce vascular remodeling. The primary sources of ROS in the microcirculation are identified and the effects of ROS on other microcirculatory remodeling phenomena such as rarefaction and collateralization are briefly reviewed.

Impairment of Arterial Compliance in Cushing's Syndrome

Arterial stiffness may be useful for stratifying cardiovascular risk in individuals suffering from a number of pathologies, such as hypertension, diabetes, obesity, dyslipidaemia and coronary artery disease. Cushing's syndrome is underpinned by a complex metabolic syndrome, which is potentially implicated in the onset of blood vessel alterations and the increase in arterial wall stiffness. The aim of this paper was to perform a review about the most important studies conducted in order to evaluate the arterial distensibility profile of subjects affected by Cushing's syndrome. Increased arterial stiffness may persist even after successful cure of this disease. It is therefore of fundamental importance to identify the presence of early vascular alterations in these patients, in order to commence their treatment and thus attempt to prevent the subsequent onset of adverse cardiovascular events.

Diameters and wall-to-lumen ratio of retinal arterioles in patients with retinal vein occlusion before and after treatment with dexamethasone intravitreal implants

BACKGROUND

To evaluate the diameters and wall-to-lumen ratio (WLR) of retinal arterioles in patients with retinal vein occlusion (RVO) before and after a 0.7 mg dexamethasone (DEX) intravitreal implant and compare it with a matched control group of normal eyes.

METHODS

This was a single-site, multi-investigator, prospective, open-label, observational study in 15 patients with vision loss due to branch or central RVO treated with a single injection of DEX implant. An age-matched control group of 16 normal eyes was recruited. External and internal arteriolar diameters, WLR, and wall thickness were assessed in vivo using scanning-laser Doppler flowmetry. Visual acuity (VA) and central macular thickness (CMT) were evaluated.

RESULTS

Mean internal diameter showed a significant reduction in post-treatment RVO patients compared with pre-treatment RVO patients (56.0±18.0 μm vs. 67.9±16.9 μm, respectively; P=0.02). Mean WLR in pre-treatment RVO patients was 0.47±0.19, showing an increase to 0.63±0.23 3 months after treatment (P=0.037). No significant difference was found in arteriolar external diameter between normotensive, pre-treatment, and post-treatment subjects.

CONCLUSION

Treatment with a DEX implant in RVO patients led to significant improvements in both VA and CMT. These changes were accompanied by reductions in arteriolar lumen diameter, which could contribute to decreased capillary leakage and macular swelling.

Persistent Comorbidities in Cushing’s Syndrome after Endocrine Cure

It was assumed that resolution of hypercortisolism in Cushing syndrome (CS) was followed by normalization of morbidity; however, in the last decade evidence is accumulating that patients with cured CS still have increased morbidity and mortality after the biochemical control of hypercortisolism. Patients with CS have an increased cardiovascular and metabolic risk and persistent accumulation of central fat, with an unfavorable adipokine profile, not only during the active phase of the disease but also long after biochemical remission. Clinical management should be particularly careful in identifying global cardiovascular risk, as a primary goal during the followup of these patients, aimed at improving global vascular morbidity. Moreover bone mass is reduced not only due to the endogenous hypercortisolism but also due to duration and dose of exogenous glucocorticoid (GC) replacement therapy after surgery. Thus, therapy in operated patients with inhibition of the hypothalamic-pituitary-adrenal axis should be reduced to the lowest dose and duration possible. Specific treatments should be considered in patients with decreased bone mass, aimed at reducing the increased fracture incidence. Finally, cognitive and health related quality of life impairments, described in active disease, are still abnormal after endocrine cure. Thus, residual morbidity persists in cured CS, suggesting irreversibility of GC-induced phenomena, typical of chronic hypercortisolism.

Cardiovascular events and mortality in patients with adrenal incidentalomas that are either non-secreting or associated with intermediate phenotype or subclinical Cushing's syndrome: a 15-year retrospective study

BACKGROUND

Incidental discovery of adrenal masses has increased over the past few years. Mild alterations in cortisol secretion without clinical signs of overt hypercortisolism (subclinical Cushing's syndrome) are a common finding in patients with these tumours. Although metabolic alterations and increased cardiovascular risk have been noted in patients with subclinical Cushing's syndrome, incidence of cardiovascular events and mortality in the long term have not been assessed. We aimed to ascertain the frequency of new cardiovascular events and mortality in patients with non-secreting adrenal incidentalomas, tumours of intermediate phenotype, or those causing subclinical Cushing's syndrome.

METHODS

From January, 1995, to September, 2010, consecutive outpatients with adrenal incidentalomas who were referred to the endocrinology unit of S Orsola-Malpighi Hospital, Bologna, Italy, were enrolled into our study. Individuals were assessed every 18-30 months for the first 5 years (mean follow-up 7·5 [SD 3·2] years, range 26 months to 15 years). Cortisol concentrations after the 1 mg dexamethasone suppression test (DST) were used to define non-secreting (+50 nmol/L) and intermediate phenotype (50-138 nmol/L) adrenal incidentalomas and subclinical Cushing's syndrome (+138 nmol/L). At the end of follow-up, patients were reclassified as having either unchanged or worsened secreting patterns from baseline.

FINDINGS

198 outpatients were assessed; at the end of follow-up, 114 patients had stable non-secreting adrenal incidentalomas, 61 had either a stable intermediate phenotype or subclinical Cushing's syndrome, and 23 had a pattern of secretion that had worsened. By comparison with patients with stable non-secreting adrenal incidentalomas, the incidence of cardiovascular events was higher in individuals with a stable intermediate phenotype or subclinical Cushing's syndrome (6·7% vs 16·7%; p=0·04) and in those with worsened secreting patterns (6·7% vs 28·4%; p=0·02). Cardiovascular events were associated independently with a change (from baseline to the end of follow-up) in cortisol concentrations post DST (hazard ratio 1·13, 95% CI 1·05-1·21; p=0·001). Survival rates for all-cause mortality were lower in patients with either stable intermediate phenotype adrenal incidentalomas or subclinical Cushing's syndrome compared with those with stable non-secreting masses (57·0% vs 91·2%; p=0·005). Factors associated with mortality were age (hazard ratio 1·06, 95% CI 1·01-1·12; p=0·03) and mean concentrations of cortisol post DST (1·10, 1·01-1·19; p=0·04). Compared with patients with stable non-secreting adrenal incidentalomas, unadjusted survival for cardiovascular-specific mortality was lower in patients with either a stable intermediate phenotype or subclinical Cushing's syndrome (97·5% vs 78·4%; p=0·02) and in those with worsened secreting patterns (97·5% vs 60·0%; p=0·01). Cancer mortality did not differ between groups.

INTERPRETATION

Even when clinical signs of overt hypercortisolism are not present, patients with adrenal incidentalomas and mild hypercortisolism have an increased risk of cardiovascular events and mortality.

FUNDING

None.

[Telomeres, aging and Cushing's syndrome: are they related?]

Cushing's syndrome is due to excess cortisol secretion and is associated to increased mortality and severe morbidity that are not fully reversible despite biochemical control. The syndrome consists of a set of systemic manifestations similar to those found in aging. Chronic stress, which also causes hyperstimulation of the hypothalamic-pituitary-adrenal axis, has been related to accelerated telomere shortening, oxidative damage, and cell aging. Although premature aging in patients with Cushing's syndrome could be related to environmental factors, the possibility that chronic exposure to hypercortisolism causes telomere shortening, and thus premature aging, cannot be ruled out. This review discusses the available evidence supporting a link between Cushing's syndrome and cell aging.

Advances in the epidemiology, pathogenesis, and management of Cushing's syndrome complications

Cushing's syndrome (CS) is a clinical condition resulting from chronic exposure to glucocorticoid excess. As a consequence, hypercortisolism contributes significantly to the early development of systemic disorders by direct and/or indirect effects. Complications such as obesity, hypertension, diabetes, dyslipidemia, and hypercoagulability cause premature atherosclerosis and increase cardiovascular mortality. Impairment of the skeletal system is a relevant cause of morbidity and disability in these patients especially due to the high prevalence of vertebral fractures. In addition, muscle weakness, emotional lability, depression, and impairment of quality of life are very common. Clinical management of these patients is complex and should be particularly careful in identifying global cardiovascular risks and aim at controlling all complications. Although the primary goal in the prevention and treatment of complications is the correction of hypercortisolism, treatment does not completely eliminate these comorbidities. Given that cardiovascular risk and fracture risk can persist after cure, early detection of each morbidity could prevent the development of irreversible damage. In this review we present the various complications of CS and their pathogenetic mechanisms. We also suggest the clinical management of these patients based on our extensive clinical experience and on the available literature.

Pathogenesis of vascular complications in Cushing's syndrome

Chronic exposure to high glucocorticoid levels in Cushing's syndrome (CS) is often associated with alterations in the hemostatic system and the expression of prothrombotic phenotypes. Increased frequency of both atherothrombotic and venous thromboembolic events (VTE) has been reported in patients with CS. In general, cardiovascular complications in these patients cause a five-fold increase in mortality compared to the normal population. Although numerous abnormalities in the hemostatic system have been detected in patients with CS, the underlying mechanisms of the prothrombotic state are not fully elucidated. High levels of factor VIII and von Willebrand factor, with evidence of enhanced thrombin generation and decreased fibrinolytic activity, have been documented in several studies. However, it is not clear to what extent these changes contribute to the shift of hemostatic balance towards the hypercoagulable state and expression of thrombophilic phenotypes. Thrombosis is usually a multicausal disease, and all three components of the so-called Virchow triad, namely 1) vascular abnormalities and endothelial dysfunction, 2) hypercoagulability and 3) stasis, may play a variable role in the pathogenesis of the prothrombotic state in CS patients. Larger studies are needed to establish strategies for prevention of cardiovascular complications in patients with Cushing's syndrome.

Impaired endothelium mediated vascular reactivity in endogenous Cushing's syndrome

Endogenous Cushing's syndrome (CS) is associated with a high incidence of cardiovascular morbidity and mortality resulting from the co-existence of multiple cardiovascular risk factors which probably induce a state of endothelial dysfunction. Recently, studies conducted in vitro as well as in normal human subjects suggest a direct role of cortisol in the causation of vascular dysfunction in this disorder. We non-invasively assessed the vascular reactivity and its potential association with elevated cortisol levels in patients of CS. A single time point observational study was conducted in 18 patients of CS and 15 age and gender matched healthy subjects. Vascular reactivity was assessed non-invasively by measuring the peripheral pulse wave form changes during reactive hyperemia (RH) using digital photoplethysmography (PPG). Parameters measured were pulse wave form amplitude (PWA), slope and pulse transit time (PTT). Maximal percentage changes in PWA during RH with reference to baseline were significantly lower in the patients as compared to controls [23.19% (13.19-53.54) vs 61.71% (38.21-95.36); p=0.0079]. Normalized PTT responses during the 1(st) minute of RH were blunted in the patients as compared to controls (1.036 ± 0.026 vs 1.056 ± 0.029; p=0.0425). Percentage changes in PTT during the 2(nd) minute of RH were negatively correlated to the morning cortisol levels in patients (r = -0.6328; p=0.0064). The present study showed that endothelium mediated vascular reactivity along with myogenic regulation of vascular tone is impaired in CS. Hypercortisolism possibly plays an important role in the causation of impaired vascular reactivity and endothelial dysfunction in CS.

Increased arterial rigidity in children affected by Cushing's syndrome after successful surgical cure

BACKGROUND

Complications, such as secondary hypertension, probably related to the loss of arterial elasticity, frequently arise in Cushing's syndrome, and may persist even beyond cure. This study aimed at demonstrating that arterial compliance, evaluated by automated recording of the QKd interval, was lower in children after a successful surgery for Cushing's syndrome than in a control group of healthy subjects.

METHODS

In all, 23 young girls aged between 11 and 18 years who had undergone a surgical cure for Cushing syndrome - 18 with a pituitary adenoma, three with a primary adrenal disease, and two suffering from ectopic adrenocorticotrope hormone secretion - were enrolled. Arterial stiffness was measured by the standardised non-invasive QKd 100-60 method. A 24-hour ambulatory blood pressure monitoring and a transthoracic echocardiography were also performed.

RESULTS

The children operated for Cushing's syndrome showed disadvantageous differences in 24-hour ambulatory blood pressure monitoring and in QKD 100-60 value, with p less than 0.01, compared with the control group.

CONCLUSIONS

In spite of its successful surgical cure, Cushing's syndrome results in a significantly decreased arterial distensibility when compared with the control group, which might explain these differences in blood pressure levels. It underlines a significantly higher cardiovascular risk, notwithstanding both the normalisation of cortisol secretion and the very early age of the patients.