Association of aldosterone and arginine vasopressin concentrations and clinical markers of hypoperfusion in neonatal foals

Endothelial glycocalyx degradation in critically ill foals

BACKGROUND

Endothelial glycocalyx (EG) degradation occurs in septic humans and EG products can be used as biomarkers of endothelial injury. Information about EG biomarkers and their association with disease severity is lacking in hospitalized foals.

OBJECTIVES

Measure serum syndecan-1 (SDC-1), heparan sulfate (HS), angiopoietin-2 (ANG-2), aldosterone (ALD), and plasma atrial natriuretic peptide (ANP) concentrations and to determine their association with disease severity and death in hospitalized foals.

ANIMALS

Ninety foals ≤3 days old.

METHODS

Prospective, multicenter, longitudinal study. Foals were categorized into hospitalized (n = 74; 55 septic; 19 sick nonseptic) and 16 healthy foals. Serum ([SDC-1], [HS], [ANG-2], [ALD]) and plasma (ANP) were measured over 72 hours using immunoassays.

RESULTS

Serum ([SDC-1], [HS], [ANG-2], [ALD]) and plasma (ANP) were significantly higher in hospitalized and septic than healthy foals (P < .05). Serum (ANG-2) and plasma (ANP) were significantly higher in hospitalized nonsurvivors than in survivors (P < .05). On admission, hospitalized foals with serum (HS) > 58.7 ng/mL had higher odds of nonsurvival (odds ratio [OR] = 6.1; 95% confidence interval [CI] = 1.02-36.7). Plasma (ANP) >11.5 pg/mL was associated with the likelihood of nonsurvival in hospitalized foals (OR = 7.2; 95% CI = 1.4-37.4; P < .05). Septic foals with serum (ANG-2) >1018 pg/mL on admission had higher odds of nonsurvival (OR = 6.5; 95% CI =1.2-36.6; P < .05).

CONCLUSION AND CLINICAL IMPORTANCE

Critical illness in newborn foals is associated with EG degradation and injury, and these biomarkers are related to the severity of disease on admission and the outcome of sick foals.

Dynamics of androgens in healthy and hospitalized newborn foals

Background

Information on steroids derived from the adrenal glands, gonads, or fetoplacental unit is minimal in newborn foals.

Objective

To measure androgen concentrations in serum and determine their association with disease severity and outcome in hospitalized foals.

Animals

Hospitalized (n = 145) and healthy (n = 80) foals.

Methods

Prospective, multicenter, cross‐sectional study. Foals of ≤3 days of age from 3 hospitals and horse farms were classified as healthy and hospitalized (septic, sick nonseptic, neonatal maladjustment syndrome [NMS]) based on physical exam, medical history, and laboratory findings. Serum androgen and plasma ACTH concentrations were measured with immunoassays. Data were analyzed by nonparametric methods and univariate analysis.

Results

Serum dehydroepiandrosterone (DHEA), androstenedione, testosterone, and dihydrotestosterone (DHT) concentrations were higher upon admission in hospitalized foals (P <  .05), were associated with nonsurvival, decreased to 4.9‐10.8%, 5.7‐31%, and 30.8‐62.8% admission values in healthy, SNS, and septic foals, respectively (P < .05), but remained unchanged or increased in nonsurviving foals. ACTH:androgen ratios were higher in septic and NMS foals (P < .05). Foals with decreased androgen clearance were more likely to die (odds ratio > 3; P < .05).

Conclusions and Clinical Importance

Similar to glucocorticoids, mineralocorticoids, and progestagens, increased serum concentrations of androgens are associated with disease severity and adverse outcome in hospitalized newborn foals. In healthy foals, androgens decrease over time, however, remain elevated longer in septic and nonsurviving foals. Androgens could play a role in or reflect a response to disorders such as sepsis or NMS in newborn foals.

Hypernatraemia in 39 hospitalised foals: clinical findings, primary diagnosis and outcome

OBJECTIVE

To evaluate hypernatraemia in foals presenting as medical emergencies to an intensive care unit (ICU) to determine the prevalence, clinical findings, primary diagnosis and outcome.

METHODS

Retrospective case study of records from Thoroughbred foals aged less than 3 months that presented to an ICU as medical emergencies in 2002-12. Data retrieved included signalment, clinical findings, laboratory results, primary diagnosis and outcome. Foals with hypernatraemia (serum sodium > 145 mmol/L) on admission laboratory data were identified and further evaluated.

RESULTS

A total of 39 of 1718 foals (2.3%) were diagnosed with hypernatraemia; all foals were less than 7 days of age. The most common primary diagnoses in the foals with hypernatraemia were neonatal syndrome (19/39, 48.7%) and sepsis (15/39, 38.5%). Foals with hypernatraemia at presentation were more likely to die or be euthanased during their hospitalisation than foals with a normal serum sodium concentration on ICU admission (33.3% vs 16.1%; odds ratio, 2.3; 95% confidence interval, 1.2-4.6; P = 0.02).

CONCLUSION

Admission hypernatraemia was an uncommon but important electrolyte abnormality in this population of hospitalised foals. Although the short-term outcome in survivors was most likely dependent on the underlying disease process, hypernatraemia was negatively associated with outcome in hospitalised foals.

Distinct neurohumoral biomarker profiles in children with hemodynamically defined orthostatic intolerance may predict treatment options

Studies of adults with orthostatic intolerance (OI) have revealed altered neurohumoral responses to orthostasis, which provide mechanistic insights into the dysregulation of blood pressure control. Similar studies in children with OI providing a thorough neurohumoral profile are lacking. The objective of the present study was to determine the cardiovascular and neurohumoral profile in adolescent subjects presenting with OI. Subjects at 10-18 yr of age were prospectively recruited if they exhibited two or more traditional OI symptoms and were referred for head-up tilt (HUT) testing. Circulating catecholamines, vasopressin, aldosterone, renin, and angiotensins were measured in the supine position and after 15 min of 70° tilt. Heart rate and blood pressure were continuously measured. Of the 48 patients, 30 patients had an abnormal tilt. Subjects with an abnormal tilt had lower systolic, diastolic, and mean arterial blood pressures during tilt, significantly higher levels of vasopressin during HUT, and relatively higher catecholamines and ANG II during HUT than subjects with a normal tilt. Distinct neurohumoral profiles were observed when OI subjects were placed into the following groups defined by the hemodynamic response: postural orthostatic tachycardia syndrome (POTS), orthostatic hypotension (OH), syncope, and POTS/syncope. Key characteristics included higher HUT-induced norepinephrine in POTS subjects, higher vasopressin in OH and syncope subjects, and higher supine and HUT aldosterone in OH subjects. In conclusion, children with OI and an abnormal response to tilt exhibit distinct neurohumoral profiles associated with the type of the hemodynamic response during orthostatic challenge. Elevated arginine vasopressin levels in syncope and OH groups are likely an exaggerated response to decreased blood flow not compensated by higher norepinephrine levels, as observed in POTS subjects. These different compensatory mechanisms support the role of measuring neurohumoral profiles toward the goal of selecting more focused and mechanistic-based treatment options for pediatric patients with OI.