Effect of Clemastine on Neurophysiological Outcomes in an Ovine Model of Neonatal Hypoxic-Ischemic Encephalopathy

Abstract

Originally approved by the U.S. Food and Drug Administration (FDA) for its antihistamine properties, clemastine can also promote white matter integrity and has shown promise in the treatment of demyelinating diseases such as multiple sclerosis. Here, we conducted an in-depth analysis of the feasibility, safety, and neuroprotective efficacy of clemastine administration in near-term lambs (n = 25, 141-143 days) following a global ischemic insult induced via an umbilical cord occlusion (UCO) model. Lambs were randomly assigned to receive clemastine or placebo postnatally, and outcomes were assessed over a six-day period. Clemastine administration was well tolerated. While treated lambs demonstrated improvements in inflammatory scores, their neurodevelopmental outcomes were unchanged.

Keywords: asphyxia; brain hypoxia-ischemia; clemastine; neonates; ovine model.

Figure 1

Clemastine pharmacokinetics and resuscitation outcomes: (A) Concentration-time profiles of clemastine levels in lamb plasma. (B) Clemastine females achieved higher MAP compared to placebo females in the immediate post-resuscitative period. Clemastine-treated animals also achieved higher SBP and MAP briefly after the UCO, (C) ROSC, and time from UCO occlusion to asystole; as well as (D) the incidence of 2nd dose of epinephrine and dextrose administration were similar between the studied groups. (E) Mortality and proportion of male and female sex were similar between the studied groups. (F) There were no differences in selected anthropometric parameters between clemastine and placebo groups. CPR—cardiopulmonary resuscitation; UCO—umbilical cord occlusion; ROSC—return of spontaneous circulation; SBP—systolic blood pressure; MAP—mean arterial pressure; DBP—diastolic blood pressure; C—clemastine-treated group, green. P—placebo, black. Controls—yellow; P-F—placebo females, red; P-M—placebo males, blue; C-F—clemastine females, orange; C-M—clemastine males, green. * p < 0.05.

Figure 2

Biochemical changes in response to the UCO: (A) UCO leads to profound acidosis in both clemastine-treated group, as well as placebo, compared to controls. The clemastine and placebo groups did not differ in levels of hyperlactatemia, base deficit, oxygen, or carbon dioxide levels. Clemastine-treated lambs experienced higher glucose levels at the baseline, whereas placebo lambs had persistent hyperglycemia as a result stress response to the UCO. (B) End-organ function markers showed elevated BUN in the clemastine group on D1 after the UCO. Creatinine was elevated in the placebo group at the baseline and 1 h after the UCO. Data in the graphs are mean ± SEM. For (A): Clemastine: n = 7–8, Placebo: n = 7–8; for (B): Clemastine:6, Placebo:12. preUCO-baseline pre-UCO; CPR—cardiopulmonary resuscitation; glc—glucose; BE—base excess; lac—lactate; BUN—blood urea nitrogen; Cr—creatinine; AST—aspartate aminotransferase; ALT—alanine transaminase. Clemastine-treated group, green, placebo, black. P-F—placebo females, red; P-M—placebo males, blue; C-F—clemastine females, orange; C-M—clemastine males, green. * p < 0.05.

Figure 3

Peripheral markers of inflammation: In the clemastine-treated groups, ALC differed at baseline and ANC on day 5 after the UCO. The inflammatory indices, SIRI and SII, were decreased in the clemastine-treated lambs compared to the placebo group on day 5. The summary column graphs are showing means ± SEM. WBC—white blood cells; ALC—absolute lymphocyte count; ANC—absolute neutrophil count; Mono—monocyte; Eos—eosinophils; PLT—platelets; SIRI—system inflammation response index; SII—systemic immune inflammation index. P-F—placebo females, red; P-M—placebo males, blue; C-F—clemastine females, orange; C-M—clemastine males, green. Clemastine-treated group, green. Placebo, black. * p < 0.05.

Figure 4

Neurological outcomes: (A), we assessed total outcomes score, as a composite score consisting of motor function and feeds + activity. Clemastine- treated group, green. Placebo- black. (B), The correlation matrix pictures Spearman’s correlation coefficients of selected study parameters with combined neurological outcomes scores on day 6 after the UCO that reached statistical significance (p < 0.05). We report also markers that did not reach statistical significance, BUN day1 (p < 0.07), glc at 60 min (p = 0.06) and Mono on day 6 (p = 0.06). UCO—umbilical cord occlusion, WBC—white blood cells, ROSC—return of spontaneous circulation, BUN—blood urea nitrogen, glc—glucose, Mono—monocytes.