Hypertrophic Cardiomyopathy After a Single Dose of Dexamethasone in a Preterm Infant

Cardiac Hypertrophy Associated with Insulin Therapy in Extremely Preterm Infants

BACKGROUND

In the neonatal period, cardiac hypertrophy (CH) has been commonly associated with hyperinsulinemic pathologies, and the first case of CH in an extremely preterm infant treated with insulin infusion has recently been reported. To confirm this association, we report a case series of patients who developed CH after insulin therapy.

METHODS

Infants with gestational age < 30 weeks and birth weight < 1500 g, born from November 2017 to June 2022, were studied if they developed hyperglycemia requiring treatment with insulin and had echocardiographic diagnosis of CH.

RESULTS

We studied 10 extremely preterm infants (24.3 ± 1.4 weeks) who developed CH at a mean age of 124 ± 37 h of life, 98 ± 24 h after the initiation of insulin therapy. All surviving patients had resolution of CH at discharge, while three of four (75%) of the deceased patients had persistent CH.

CONCLUSIONS

Our case series supports the association between the development of CH and insulin therapy in extremely preterm infants and suggests further caution and the need for echocardiographic monitoring when treating these fragile patients with insulin.

Preterm Neonate With Dexamethasone-Induced Acute Hypertrophic Cardiomyopathy and Cardiogenic Shock

This case report describes an extremely low birth weight infant, born at 26-week gestational age, who developed hypertrophic cardiomyopathy (HCM) and cardiogenic shock a few hours after administration of a small dose of dexamethasone. Although cases of steroid-induced cardiomyopathy in preterm neonates are known in literature, their adverse effects are insidious and are transient in occurrence. This is the first report of HCM and cardiogenic shock occurring acutely after administration of small-dose dexamethasone. This neonate received small-dose dexamethasone initially to prevent reintubation, and again to facilitate successful extubation. Both occurrences were associated with acute cardiac decompensation with reduction in ejection fraction within hours of administration. Cardiac function subsequently improved with discontinuation of drug and use of inotropic pharmacotherapy. Studies outlined in this report show that steroid-induced HCM is known and not isolated to dexamethasone alone; however, little is known on the adverse effect of small-dose steroid in resulting acute cardiac decompensation. This case is of educational value in clinical practice by highlighting the potential adverse effects even at the smaller doses of dexamethasone currently recommended in extremely low birth weight infants.

Transient Global Ventricular Hypertrophy in a Patient With Multisystem Inflammatory Syndrome in Children (MIS-C) Correlated With High-Dose Glucocorticoid Treatment: A Case Report

Multisystem inflammatory syndrome in children (MIS-C) following SARS-CoV-2 infection has been shown to lead to depressed cardiac function. Standard treatment includes high-dose glucocorticoids (GC). We present the unusual case of a teenager who developed transient echocardiographic global ventricular hypertrophy following GC administration during his treatment for MIS-C, with the resolution of the hypertrophy after cessation of GC.

Hypertrophic Cardiomyopathy in Infants from the Perspective of Cardiomyocyte Maturation

Hypertrophic cardiomyopathy (HCM) in infancy is rare and many fulminant cases are fatal. Infantile HCM shows a rapid progressive clinical course and different characteristics compared with late-onset HCM presenting during the prepubertal age. There are also spontaneously resolving phenotypes of HCM that are diagnosed in neonates being treated for bronchopulmonary dysplasia with corticosteroids or in those with other problems related to maternal endocrine diseases. The pathophysiology of infantile HCM has not been well described. Therefore, this review updates the pathophysiology of infantile HCM and includes molecular studies on maturation of cardiomyocytes from a clinician's point of view.

Hypertrophic cardiomyopathy (HCM) is characterized by ventricular wall hypertrophy with diastolic dysfunction. Pediatric HCM is distinguished from the adult in many aspects. Most children with HCM do not present clinically until the adolescent period, even when they are born with genetic mutations. Some infants with early-onset HCM present with massive progressive myocardial hypertrophy in the first few months of life, which is often fatal. The mortality of pediatric HCM peaks during the infantile and adolescent periods. These periods roughly correlate with children's growth spurt. Non-sarcomeric causes of HCM are more frequent in pediatric HCM, while sarcomeric causes are more common in adults. From the perspective of cardiac development, the fetal heart has immature cardiomyocytes, which are characterized by proliferation and exit their cell cycles with a decreased regenerative property after birth. In the perinatal period, there is a dynamic change in maturation of cardiomyocytes from immature to mature cells. Infants who are treated with steroids or born to mothers with diabetes or hyperthyroidism often show phenotypes of HCM, which gradually resolve. With remarkable advancement of molecular biology, understanding on maturation of cardiomyocytes has increased. Neonates undergo abrupt environmental changes during the transitional circulation, which is affected by oxygen, metabolic and hormonal fluctuations. Derangement in physiological transition to the normal postnatal environment may influence maturation of proliferative immature cardiomyocytes during early infancy. This article reviews updates of infantile HCM and recent molecular studies related to maturation of cardiomyocytes from the clinical point of view of identifying distinct characteristics of infantile HCM.

Dexamethasone inhibits regeneration and causes ventricular aneurysm in the neonatal porcine heart after myocardial infarction

AIMS

Recently, we demonstrated that the hearts of neonatal pigs (2-day old) have regenerative capacity, likely driven by cardiac myocyte division, but this potential is lost immediately after postnatal day 3. However, it is unknown if corticosteroid, a broad anti-inflammatory agent, will abrogate the regenerative capacity in the hearts of neonatal pigs. The aim of the current study is to evaluate the effect Dexamethasone (Dex), a broad anti-inflammatory agent, on heart regeneration, structure, and function of the neonatal pigs' post-myocardial infarction (MI).

METHODS AND RESULTS

Dex (0.2 mg/kg/day) was injected intramuscularly into the neonatal pig (age: 2 days postnatal) during the first week post-MI. Myocardial scar and left ventricular function were determined by cardiac magnetic resonance (CMR) imaging. Bromodeoxyuridine (BrdU) pulse-chase labeling, histology, immunohistochemistry, and flow cytometry were performed to determine inflammatory cell infiltration, CM cytokinesis, and myocardial fibrosis. Dex injection during the first-week suppressed acute inflammation post-MI in the pig hearts. It inhibited BrdU incorporation to pig CMs and CM cytokinesis via inhibiting aurora-B protein expression which was associated with mature scar formation and thinned walls at the infarct site. CMR imaging showed Dex caused left ventricular aneurysm and poor ejection fraction.

CONCLUSIONS

Dex inhibited CM cytokinesis and functional recovery and caused ventricular aneurysm in the hearts of 2-day old pigs post-MI.

RGD(F/S/V)-Dex: towards the development of novel, effective, and safe glucocorticoids

Dexamethasone (Dex) is an effective glucocorticoid in treating inflammation and preventing rejection reaction. However, the side effects limit its clinical application. To improve its druggable profile, the conjugates of RGD-peptide-modified Dex were presented and their enhanced anti-inflammation activity, minimized osteoporotic action, and nanoscaled assembly were explored. (RGD stands for Arg-Gly-Asp. Standard single letter biochemical abbreviations for amino acids have been used throughout this paper.) In respect of the rejection reaction, the survival time of the implanted myocardium of the mice treated with 1.43 µmol/kg/d of the conjugates for 15 consecutive days was significantly longer than that of the mice treated with 2.5 µmol/kg/d of Dex, and the conjugates, but not Dex, exhibited no toxic action. At a single dose of 14.3 µmol/kg (100 times minimal effective dose, 0.143 µmol/kg), the conjugates induced no liver, kidney, or systemic toxicity. At the dose of 1.43 µmol/kg, the conjugates, but not Dex, prolonged the bleeding time of the mice, and inhibited the thrombosis of the rats. In water and rat plasma, the conjugates formed nanoparticles of 14-250 and 101-166 nm in diameter, respectively. Since the nanoparticles of ~100 nm in size cannot be entrapped by macrophages in the circulation, RGDF-Dex would particularly be worthy of development, since its nanoparticle diameter is 101 nm.