Hydrocortisone and indomethacin negatively modulate EGF-R signaling in human fetal intestine

Clinical and echocardiography predictors of response to first-line acetaminophen treatment in preterm infants with hemodynamically significant patent ductus arteriosus

OBJECTIVE

To assess clinical and echocardiography predictors of acetaminophen response for the treatment of patent ductus arteriosus (PDA) in preterm neonates.

STUDY DESIGN

Retrospective cohort study of preterm infants born <30 weeks, with a diagnosis of hemodynamically significant PDA, who received 1st line treatment with intravenous acetaminophen during the first 2 postnatal weeks. Response was defined by PDA closure or improvement in PDA score of >50%.

RESULTS

A total of 100 infants were included whose median weight and gestational age at birth were 663 grams and 24.6 weeks respectively. In total, 66 infants were classified as responders and were more likely to have intrauterine growth restriction, exposure to maternal hypertension and chorioamnionitis. Non-response was more common among infants with thrombocytopenia and anemia.

CONCLUSION

Responders were more likely to be IUGR with echocardiography indices of lower preload. Response to 1st line intravenous acetaminophen therapy is comparable to non-steroidal drugs in preterm infants. Relationship of response to acetaminophen to perinatal characteristics requires further characterization.

Acetaminophen Therapy for Persistent Patent Ductus Arteriosus

Persistence of a left-to-right shunt caused by a patent ductus arteriosus (PDA) leads to significant sequelae in extremely premature infants as a result of pulmonary overcirculation and systemic steal. Although timing and duration of treatment for a persistent clinically significant PDA differ among institutions, standard pharmacologic interventions are the nonsteroidal anti-inflammatory drugs indomethacin and ibuprofen. Acetaminophen has emerged as an alternative to indomethacin and ibuprofen with less significant adverse effects, but there is no consensus regarding its use. This review summarizes the most recent evidence for the use of acetaminophen in PDA treatment.

The Protective Effect of Testosterone on Indomethacin Induced Gastric Ulcer in Female Sprague Dawley Rats

Gastric ulcer has shown association with changes in sex hormones, with impact exacerbated in males. Also, males are known to be more exposed to ulcer risk factors. This study investigates the effect of testosterone on indomethacin induced gastric ulcers in adult female rats. Eighteen female rats (225 ± 25 g body weight) were randomly assigned to 3 groups under standard laboratory condition. After acclimatization, animals fasted for 40 hrs but were given water ad libitum. Group A served as control while group B served as the ulcer control, in which ulcer was induced without treatment using indomethacin (40 mg/kg single orally dose). Group C was pretreated with testosterone (1 mg/kg IM) eight hours before ulcer induction. Eight hours after ulcer induction, animals were sacrificed and the stomach was harvested for analysis. Results showed a significant reduction in mucus content in groups C (0.79±0.11 g) and B (0.87±0.02 g) compared to A (1.11±0.03 g). Gastric mucus pH was significantly acidic in group B (4.40±0.55) compared to C (5.20±0.45) and A (5.80±0.45). There was a significantly higher ulcer index in group B (4.60±0.55 mm) compared to C (3.60±0.89 mm) and testosterone pretreatment resulted in a 21.74% ulcer inhibition. Although weak, the findings suggest that testosterone might protect the gastric mucosa against NSAIDs in females.

Prolidase directly binds and activates epidermal growth factor receptor and stimulates downstream signaling

Prolidase, also known as Xaa-Pro dipeptidase or peptidase D (PEPD), is a ubiquitously expressed cytosolic enzyme that hydrolyzes dipeptides with proline or hydroxyproline at the carboxyl terminus. In this article, however, we demonstrate that PEPD directly binds to and activates epidermal growth factor receptor (EGFR), leading to stimulation of signaling proteins downstream of EGFR, and that such activity is neither cell-specific nor dependent on the enzymatic activity of PEPD. In line with the pro-survival and pro-proliferation activities of EGFR, PEPD stimulates DNA synthesis. We further show that PEPD activates EGFR only when it is present in the extracellular space, but that PEPD is released from injured cells and tissues and that such release appears to result in EGFR activation. PEPD differs from all known EGFR ligands in that it does not possess an epidermal growth factor (EGF) motif and is not synthesized as a transmembrane precursor, but PEPD binding to EGFR can be blocked by EGF. In conclusion, PEPD is a ligand of EGFR and presents a novel mechanism of EGFR activation.

Long-term effects of neonatal hydrocortisone treatment for chronic lung disease on the developing brain and heart

Despite modern perinatal intensive care techniques, chronic lung disease remains a problem in preterm-born infants. The most commonly and almost exclusively prescribed drug to treat this disorder is dexamethasone. Corticosteroids improve short-term respiratory function; however, many side-effects have been reported and the adverse long-term effects of dexamethasone on neurodevelopment are particularly alarming. Hydrocortisone could be a suitable alternative for dexamethasone, if equally effective with fewer side-effects. This review evaluates the current literature on neonatal hydrocortisone treatment for chronic lung disease with regards to long-term neurodevelopmental outcome and cardiovascular effects. The neurodevelopmental studies do not show any adverse effects of hydrocortisone on neurocognitive and motor outcome, nor on incidence of brain abnormalities on magnetic resonance imaging or on long-lasting programming effects on the hypothalamus-pituitary-adrenal axis. At school age, cardiovascular stress response was the same in hydrocortisone-treated children compared with a reference group. Hydrocortisone seems a safe alternative to dexamethasone, but more double-blind randomised studies are needed.

Understanding intestinal vulnerability to perforation in the extremely low birth weight infant

Spontaneous intestinal perforation (SIP) occurs commonly in extremely low birth weight (ELBW) infants. Our understanding of its etiologies has improved dramatically over the last decade. Included in this comprehension is an ongoing reconciliation of the iatrogenic risk factors, the microbiology, and the histopathology. The latter shows focal perforations with necrosis of the muscularis externa and no sign of ischemic damage (typically characterized by mucosal necrosis in the preterm bowel). Associations include extreme prematurity, early postnatal steroids (EPS), early use of indomethacin (EUI), and two common pathogens (Candida and Staphylococcus epidermis). Animal models of SIP suggest that all risk factors converge on a common collection of signaling pathways: those of nitric oxide synthases (NOS), insulin-like growth factors (IGFs), and epidermal growth factors (EGFs). Many of these factors skew trophism of the ileum (defined as thinning of the submucosa concomitant with hyperplasia of the muscosa). Global depletion of NOS is associated with disturbed intestinal motility and diminished transforming growth factor-alpha (TGF-alpha) in the muscularis externa. This constellation of insults seems to make the distal intestine vulnerable to perforation during recovery of motility.

Prostaglandins, NSAIDs, and gastric mucosal protection: why doesn't the stomach digest itself?

Except in rare cases, the stomach can withstand exposure to highly concentrated hydrochloric acid, refluxed bile salts, alcohol, and foodstuffs with a wide range of temperatures and osmolarity. This is attributed to a number of physiological responses by the mucosal lining to potentially harmful luminal agents, and to an ability to rapidly repair damage when it does occur. Since the discovery in 1971 that prostaglandin synthesis could be blocked by aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), there has been great interest in the contribution of prostaglandins to gastric mucosal defense. Prostaglandins modulate virtually every aspect of mucosal defense, and the importance of this contribution is evident by the increased susceptibility of the stomach to injury following ingestion of an NSAID. With chronic ingestion of these drugs, the development of ulcers in the stomach is a significant clinical concern. Research over the past two decades has helped to identify some of the key events triggered by NSAIDs that contribute to ulcer formation and/or impair ulcer healing. Recent research has also highlighted the fact that the protective functions of prostaglandins in the stomach can be carried out by other mediators, in particular the gaseous mediators nitric oxide and hydrogen sulfide. Better understanding of the mechanisms through which the stomach is able to resist injury in the presence of luminal irritants is helping to drive the development of safer anti-inflammatory drugs, and therapies to accelerate and improve the quality of ulcer healing.