Catecholamine excess: pseudopheochromocytoma and beyond

Polymorphisms in COMT and OPRM1 Collectively Contribute to Chronic Shoulder Pain and Disability in South African Breast Cancer Survivors'

Chronic shoulder pain and disability is a common adverse effect experienced by >40% of breast cancer survivors (BCS). Pain management protocols for acute and chronic pain include the use of opioids and opioid derivatives. Furthermore, pain-modulating genes, such as COMT and OPRM1, have been linked to the aetiology of chronic pain. This study aimed to investigate the association between genetic variants of major pain modulator genes and chronic pain/disability in BCS. Assessment of pain, disability and combined (pain and disability) symptoms were determined using the Shoulder Pain and Disability Index (SPADI). Participants were grouped according to their scores such as no-low (<30%) and moderate-high (≥30%) groups of pain, disability and combined (pain and disability). Genotyping of the COMT rs6269 (A > G), rs4633 (C > T), rs4818 (C > G) and the functional rs4680(G > A) SNPs within the BCS (N = 252) cohort were conducted using TaqMan^® SNP assays. Genotype, allele, haplotype, and allele-allele combination frequencies were evaluated. Statistical analysis was applied, with significance accepted at p < 0.05. The COMT rs4680:A/A genotype was significantly associated with moderate-high pain (p = 0.024, OR: 3.23, 95% CI: 1.33-7.81) and combined (pain and disability) (p = 0.015, OR: 3.81, 95% CI: 1.47-9.85). The rs4680:A allele was also significantly associated with moderate-high pain (p = 0.035, OR: 1.58, 95% CI: 1.03-2.43) and combined (pain and disability) (p = 0.017, OR: 1.71, 95% CI: 1.07-2.71). For the inferred COMT (rs6269 A > G-rs4680 G > A) haplotype analyses, the G-G (p = 0.026, OR: 0.67, 95% CI: 0.38-1.18) and A-A (p = 0.007, OR: 2.09, 95% CI: 0.89-4.88) haplotypes were significantly associated with reduced and increased likelihoods of reporting moderate-high pain, respectively. The inferred A-A (p = 0.003, OR: 2.18, 95% CI: 0.92-5.17) haplotype was also significantly associated with combined (pain and disability). Gene-gene interaction analyses further showed allele-allele combinations for COMT (rs4680 G > A)-OPRM1 (rs1799971 A > G) and COMT (rs4680 G > A)-OPRM1(rs540825 T > A) were associated with reporting pain and combined (pain and disability) symptoms, p < 0.05. The findings of this study suggest that COMT and OPRM1 SNPs play a role in the development of chronic shoulder pain/disability in BCS in a unique South African cohort from the Western Cape.

Pseudopheochromocytoma: an Uncommon Cause of Severe Hypertension

PURPOSE OF REVIEW

Pseudopheochromocytoma or paroxysmal hypertension is an underrecognized condition that requires a thorough investigation of secondary causes of hypertension. In this review, we aim to provide an overview of pathogenesis, clinical manifestations, biochemical evaluation, and potential therapeutic options to manage patients with pseudopheochromocytoma.

RECENT FINDINGS

The pathogenesis of this condition has not been completely elucidated but certain patients show overactivity of the sympathetic nervous system and present with elevated epinephrine and dopamine levels. Workup should include a proper evaluation of blood pressure in distinct clinical scenarios, including ambulatory blood pressure monitoring. Management should be focused on treatment of acute hypertensive episodes and prevention of paroxysms. Treatment of patients with pseudopheochromocytoma should be individualized. Psychopharmacotherapy and psychotherapeutic interventions play an important role in controlling patients' symptoms.

Series of myocardial FDG uptake requiring considerations of myocardial abnormalities in FDG-PET/CT

Distinct from cardiac PET performed with preparation to control physiological FDG uptake in the myocardium, standard FDG-PET/CT performed with 4-6 h of fasting will show variation in myocardial FDG uptake. For this reason, important signs of myocardial and pericardial abnormality revealed by myocardial FDG uptake tend to be overlooked. However, recognition of possible underlying disease will support further patient management to avoid complications due to the disease. This review demonstrates the mechanism of FDG uptake in the myocardium, discusses the factors affecting uptake, and provides notable image findings that may suggest underlying disease.

β1-Blocker improves survival and ventricular remodelling in rats with lethal crush injury

BACKGROUND

Crush injury/crush syndrome (CI/CS) is the second most common cause of death during earthquakes. Most studies of CI/CS have mainly focused on kidney injury after decompression. Few studies have focused on myocardial injury caused by crush injury and its potential mechanisms.

METHODS

We first verified cardiomyocyte injury during compression in rats with a crush injury. The survival rate, electrocardiographic results, histological results, catecholamine changes and cardiac β1-AR expression were evaluated. Next, we explored the effects of pretreatment with a selective β1-blocker (bisoprolol) with or without fluid resuscitation on rats with a crush injury. In addition to evaluating the survival rates, biochemical and histological analyses and echocardiographic measurements were also performed.

RESULTS

Reduced heart rates, elevated ST segments, and tall-peaked T waves were observed in the rats with a crush injury. The changes in the myocardial enzymes and pathological results demonstrated that myocardial damage occurred during compression in rats with a crush injury. The levels of the catecholamine norepinephrine in both the serum and myocardial tissue were elevated during compression. Pretreatment with a selective β1-blocker combined with fluid resuscitation significantly improved the survival rates of the rats with lethal crush injury. The myocardial enzymes and pathological results showed that the combined therapy decreased myocardial damage. The echocardiography measurements showed that the rats that received the combined therapy exhibited decreased left ventricular mass (LVM), left ventricular volume at end-systole (LVVs) and left ventricular internal diameter (LVID) compared with the rats with a crush injury.

CONCLUSIONS

Our findings demonstrated the presence of myocardial injury in the early stage of compression in rats with a crush injury. Pretreatment with a β1-blocker (bisoprolol) with fluid resuscitation significantly reduced mortality, decreased myocardial tissue damage, and improved ventricular remodelling in rats with a lethal crush injury.

Cardiovascular Risks and Organ Damage in Secondary Hypertension

Secondary hypertension is associated with increased cardiovascular risk and exaggerated target organ damage, not only due to the higher and more sustained blood pressure values often observed in these patients but also because certain forms of hypertension can increase cardiovascular risk and organ damage by the neurohormonal and/or molecular pathways activation they exert. Early identification of secondary forms of hypertension can help mitigate organ damage and prevent cardiovascular complications. Signs and symptoms distinction among types of secondary hypertension is essential in order to prevent complications.

Pseudopheochromocytoma

Pseudopheochromocytoma manifests as severe, symptomatic paroxysmal hypertension without significant elevation in catecholamine and metanephrine levels and lack of evidence of tumor in the adrenal gland. The clinical manifestations are similar but not identical to those in excess circulating catecholamines. The underlying symptomatic mechanism includes augmented cardiovascular responsiveness to catecholamines alongside heightened sympathetic nervous stimulation. The psychological characteristics are probably attributed to the component of repressed emotions related to a past traumatic episode or repressive coping style. Successful management can be achieved by strong collaboration between a hypertension specialist and a psychiatrist or psychologist with expertise in cognitive-behavioral panic management.

Clonidine suppression testing for pheochromocytoma in neurofibromatosis type 1

Compared with the general population, rates of pheochromocytoma are higher in neurofibromatosis type 1 (NF1) patients. However, pheochromocytoma testing is often plagued by false positive results. Here we present a patient with NF1, elevated urinary metanephrine levels, and an indeterminate adrenal nodule. Clonidine suppression testing aided diagnosis and led to definitive surgical treatment that confirmed a pheochromocytoma. Pheochromocytoma screening and clonidine suppression testing can both aid in the evaluation for catecholamine-secreting tumours.

Labile hypertension: a new disease or a variability phenomenon?

Blood pressure (BP) is a physiological parameter with short- and long-term variability caused by complex interactions between intrinsic cardiovascular (CV) mechanisms and extrinsic environmental and behavioral factors. Available evidence suggests that not only mean BP values are important, but also BP variability (BPV) might contribute to CV events. Labile hypertension (HTN) is referred to sudden rises in BP and it seems to be linked with unfavorable outcomes. The aim of this article was to review and summarize recent evidence on BPV phenomenon, unraveling the labile HTN concept along with the prognostic value of these conditions.

Endocannabinoids modulate Gq/11 protein-coupled receptor agonist-induced vasoconstriction via a negative feedback mechanism

OBJECTIVES

The endocannabinoid (eCB) system centrally and peripherally regulates cardiovascular parameters, including blood pressure, in health and disease. The relationship between G_q/11 protein-coupled receptor activation, regulation of eCBs release (mainly 2-arachidonoylglycerol) and subsequent CB₁ receptor activation was initially observed in the central nervous system. Here, we review the latest findings from systemic physiological studies which include for the first time data from pulmonary arteries. We present evidence for direct CB₁ -dependent cannabinoid ligand-induced vasorelaxation, vascular expression of eCBs along with their degradation enzymes, and indicate the location of the described interaction.

KEY FINDINGS

Endocannabinoids (mainly 2-arachidonoylglycerol), acting via CB₁ receptors, evoke vasodilatory effects and may modulate responses of vasoconstrictors for G_q/11 protein-coupled receptors including angiotensin II, thromboxane A₂ , phenylephrine, noradrenaline in systemic or pulmonary arteries. However, the role of the endothelium in this interaction is not well-established, and the precise vascular location of eCB system components remains unclear, which contributes to discrepancies in the interpretation of results when describing the above-mentioned relationship.

SUMMARY

Endocannabinoid's negative feedback is responsible for diminishing agonist-induced vasoconstriction, which may be clinically important in the treatment of arterial and pulmonary hypertension. Further research is required to establish the importance of the eCB system and its downstream signalling pathways.

Pseudopheochromocytoma Associated with Domestic Assault

Pseudopheochromocytoma has a clinical presentation that is similar to pheochromocytoma. It manifests itself with paroxysmal hypertension crises, associated with various symptoms such as headaches, chest pain, nausea, palpitations, and dizziness. Patients are usually asymptomatic in between the crises. Unlike pheochromocytoma, there is no catecholamines overproduction in this pathology: hypertensive peaks are caused by a hyperactivation of the sympathetic nervous system, which is often triggered by a psychological trauma in the past. Treatment of pseudopheochromocytoma can be challenging due to normal blood pressure values in between the hypertensive peaks; it includes alpha- and beta-blockers for moderate crises and prevention and must be combined with psychopharmacologic agents such as anxiolytics or antidepressant drugs. Psychotherapy and dietetic treatment are also crucial in pseudopheochromocytoma management.