Biphasic release of betamethasone from an injectable HA hydrogel implant for alleviating lumbar disc herniation induced sciatica.

Epidural steroid injection (ESI) is a common therapeutic approach for managing sciatica caused by lumbar disc herniation (LDH). However, the short duration of therapeutic efficacy and the need for repeated injections pose challenges in LDH treatment. The development of a controlled delivery system capable of prolonging the effectiveness of ESI and reducing the frequency of injections, is highly significant in LDH clinical practice. In this study, we utilized a thiol-ene click chemistry to create a series of injectable hyaluronic acid (HA) based release systems loaded with diphasic betamethasone, including betamethasone dipropionate (BD) and betamethasone 21-phosphate disodium (BP) (BD/BP@HA). BD/BP@HA hydrogel implants demonstrated biocompatibility and biodegradability to matched neuronal tissues, avoiding artificial compression following injection. The sustained release of betamethasone from BD/BP@HA hydrogels effectively inhibited both acute and chronic neuroinflammation by suppressing the nuclear factor kappa-B (NF-κB) pathway. In a mouse model of LDH, the epidural administration of BD/BP@HA efficiently alleviated LDH-induced sciatica for at least 10 days by inhibiting the activation of macrophages and microglia in dorsal root ganglion and spinal dorsal horn, respectively. The newly developed HA hydrogels represent a valuable platform for achieving sustained drug release. Additionally, we provide a simple paradigm for fabricating BD/BP@HA for epidural injection, demonstrating greater and sustained efficiency in alleviating LDH-induced sciatica compared to traditional ESI and displaying potentials for clinical translation. This system has the potential to revolutionize drug delivery for co-delivery of both soluble and insoluble drugs, thereby making a significant impact in the pharmaceutical industry. STATEMENT OF SIGNIFICANCE: Lumbar disc herniation (LDH) is a common degenerative disorder leading to sciatica and spine surgery. Although epidural steroid injection (ESI) is routinely used to alleviate sciatica, the efficacy is short and repeated injections are required. There remains challenging to prolong the efficacy of ESI. Herein, an injectable hyaluronic acid (HA) hydrogel implant by crosslinking acrylated-modified HA (HA-A) with thiol-modified HA (HA-SH) was designed to achieve a biphasic release of betamethasone. The hydrogel showed biocompatibility and biodegradability to match neuronal tissues. Notably, compared to traditional ESI, the hydrogel better alleviated sciatica in vivo by synergistically inhibiting the neuroinflammation in central and peripheral nervous systems. We anticipate the injectable HA hydrogel implant has the potential for clinical translation in treating LDH-induced sciatica.

Physicochemical Stability and Compatibility of Mixtures of Ropivacaine with Dexamethasone or Betamethasone for Epidural Steroid Injections: An In Vitro Study.

BACKGROUND: Epidural steroid injections are widely used to treat spinal and radiating pain. However, crystal formation has recently been reported in mixtures of ropivacaine and nonparticulate steroids, commonly used in epidural steroid injections. OBJECTIVES: Our study assessed the physicochemical stability of mixtures of different nonparticulate steroids and ropivacaine and aimed to propose a safe regimen for epidural steroid injections. STUDY DESIGN: An in vitro protocol was used to examine the physicochemical stability of epidural steroid injection mixtures most commonly used at our institution. SETTING: In vitro laboratory study. METHODS: Twelve solutions were prepared by mixing 0.75% or 0.2% ropivacaine with dexamethasone or betamethasone at volume ratios of 1:1, 2:1, and 3:1 in propylene syringes at 24°C. The physical properties of the mixtures were observed with the naked eye and under a microscope, and their pH was measured. The concentration of each drug in the mixture was evaluated using high-performance liquid chromatography. RESULTS: None of the ropivacaine and dexamethasone mixtures showed macroscopic or microscopic crystal formation after 2 hours, and there were no significant changes in pH. The concentrations of the 2 drugs remained stable for up to 2 hours. In contrast, at least 10 mu-m crystals were observed microscopically and macroscopically in all mixtures of ropivacaine and betamethasone; the ropivacaine concentration was reduced by > 10% after one hour. LIMITATIONS: Confirming the stability of drugs in vitro does not ensure that their pharmacokinetics and pharmacodynamics remain unaltered in vivo. CONCLUSION: The combination of ropivacaine and betamethasone should be avoided because of their physicochemical instability. Combinations of ropivacaine and dexamethasone should be administered cautiously because they are more physicochemically stable than combinations of ropivacaine and betamethasone.

Epileptic spasms in infancy: Transferring rat prenatal betamethasone-postnatal NMDA model to mice.

Epileptic spasms during infancy represent a devastating and refractory epilepsy syndrome. To advance studies on mechanisms and treatment using available mouse mutant models, we transferred our validated rat model of epileptic spasms to mice. Initially, we determined sensitivity of C57BL/6J mice to various doses (12-20 mg/kg) of NMDA on postnatal day 11 (P11) and P15. We primed mice with different doses of betamethasone (0.4-2.0 mg/kg) prenatally on gestational day (G)14 or G12 and tested spasms on P11. We also tested 2 different ACTH treatment paradigms (0.3 or 1.0 mg/kg) in prenatally primed as well as naïve mice. Data show that spasms in P11 mice, can be induced with the highest yield after 12 mg/kg dose of NMDA. Prenatal priming on G14 did not modify response to NMDA or sensitize spasms to ACTH. The betamethasone priming on G12 resulted in an increase in the number of NMDA-triggered spasms. Data indicate that the model transfer from rats to mice is non-linear and differences in prenatal brain development, metabolic rates, as well as sensitivity to convulsant drugs have to be considered.

LPCAT1 levels in the placenta, the maternal plasma and the fetal plasma do not predict fetal lung responses to glucocorticoids in a sheep model of pregnancy.

INTRODUCTION: Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is important for saturated phosphatidylcholine (Sat-PC) production in the lung. Sat-PC is a critical component of pulmonary surfactant, which maintains low alveolar surface tension, facilitating respiration. Previous studies have reported an association between maternal and fetal LPCAT1 levels and neonatal lung function. Using a sheep model of pregnancy, we investigated a potential correlation between glucocorticoid-induced lung maturation and LPCAT1 mRNA and/or protein levels in the fetal lung, the placenta, the fetal plasma, and the maternal plasma. METHODS: Eighty seven single pregnant ewes received maternal intramuscular injections of betamethasone. A sub-group of five animals had both maternal and fetal catheters installed to allow for sequential sampling from both plasma compartments. Lambs were surgically delivered under terminal anaesthesia between 2 and 8 days after initial ANS treatment, at a gestational age of 121-123 days. Lambs were ventilated for 30 min to determine functional lung maturation before being euthanized for necropsy and sample collection. Fetal lung, placenta, and fetal and maternal plasma samples were used to analyse LPCAT1 gene expression and protein levels. RESULTS: The expression of LPCAT1 mRNA in the fetal lung was significantly corelated to Sat-PC levels at 8 days (R2 = 0.23, p < 0.001) and lung maturation status overall (gas exchange efficiency as determined by measurements of lamb PaCO2 during ventilation, R2 = 0.20, p < 0.001). Similarly, fetal lung LPCAT1 mRNA was also significantly correlated with the individual durability of ANS effects on fetal lung maturation (R2 = 0.20, p < 0.001). Although ANS therapy altered LPCAT1 mRNA expression in the placenta, observed changes were independent of fetal lung maturation outcomes. Neither maternal nor fetal plasma LPCAT1 levels were changed by ANS therapy over the period, including in analysis of serial maternal and fetal samples from chronically catheterised animals. DISCUSSION: LPCAT1 expression in the fetal lung was associated with the durability of glucocorticoid effects on fetal lung maturation. However, LPCAT1 expression in the placenta, the fetal plasma, and the maternal plasma was neither associated with, nor predictive of fetal lung maturation after glucocorticoid treatment in a sheep model of pregnancy.

Reproductive endocrine disruption and gonadal intersex induction in male Japanese medaka chronically exposed to betamethasone at environmentally relevant levels.

The broad utilization of betamethasone in medical treatments may pose a significant ecotoxicological risk to aquatic organisms, yet its potential reproductive toxicity remains unclear. The present study examined the impacts of environmental exposure on male reproduction using Japanese medaka (Oryzias latipes). After 110 days of betamethasone exposure at environmentally relevant concentrations (0, 20 and 200 ng/L), LH/FSH synthesis and release in the pituitary was inhibited, and the production of sex hormones and their signaling pathways in the gonads of male medaka were greatly influenced. This synthetic glucocorticoid restrained testosterone (T) synthesis and gave rise to a significant increase in E2/T and E2/11-KT ratios. Furthermore, chronic betamethasone exposure (20 and 200 ng/L) led to the suppression of androgen receptor (AR) signaling and enhancement of estrogen receptors (ERs) signaling. An increase in hepatic vitellogenin contents was also detected, and testicular oocytes were observed in both 20 and 200 ng/L betamethasone-treated groups. It showed that 20 and 200 ng/L betamethasone could induce male feminization and even intersex, triggering abnormal spermatogenesis in medaka males. With its adverse effects on male fertility, betamethasone could potentially influence the fishery productivity and population dynamics in aquatic ecosystems.

Effects of dual therapy with betamethasone and tetracycline in a NC/Nga mouse model of atopic dermatitis.

Purpose: Our previous study has demonstrated that tetracycline exerts excellent bactericidal activity against Staphylococcus aureus strains isolated from patients with atopic dermatitis (AD) while simultaneously inhibiting the development of T helper (Th) type 2 (Th2) cells. The present study was designed to evaluate the effectiveness of dual therapy with betamethasone and tetracycline for AD. Methods: Betametasone (0.1%) and tetracycline (3%) were topically administered to NC/Nga mice with AD-like skin lesions. Skin severity scores, histological changes to the lesioned skin, and serum IgE levels were assessed as indicators of therapeutic effectiveness. Results: Topical treatment with both drugs reduced the skin severity score more significantly than was the case with betamethasone alone or tetracycline alone. This was associated with a reduction in the degree of epidermal thickening, the density of cellular infiltration into the dermis, the mast cell count in the dermis and the serum IgE concentration. Furthermore, the degree of Th1/Th2 cell development in auricular lymph nodes and the S. aureus count on the lesioned skin were synergistically suppressed by simultaneous application of both drugs. Conclusion: The present results show that simultaneous topical application of betamethasone and tetracycline synergistically ameliorates AD-like skin lesions in NC/Nga mice. This suggests that dual therapy with betamethasone and tetracycline for AD lesions colonized by S. aureus might be one of the best options for inhibiting the development of both Th1 and Th2 cells and acting on superficially located S. aureus .

Investigation of the potential of leukoreduction filters in the creation of anti-inflammatory compound.

BACKGROUND: Some viruses such as SARS, SARS-CoV-2, and MERS cause an imbalance in immune responses and leads to an acute inflammatory reaction named cytokine storm. In this situation, an anti-inflammatory component can modulate the immune system and decrease mortality. The aim of this study was investigate the potential of leukoreduction filters (LRFs) in creating an anti-inflammatory compound. MATERIALS AND METHODS: In this experimental study, firstly optimal dose of the anti-inflammatory drug was obtained through LRFs treatment with 0.1 mg, 0.4 mg, 0.6 mg of Betamethasone. Then inflammatory and anti-inflammatory cytokine in gene and protein level was evaluated. In the next step, LRFs were categorized into treatment 1, treatment 2, control assay, and control groups and treated with the optimal dose of the drug. Finally, the obtained compound was investigated for the concentration of IL1, IL6, and TNF-α as inflammatory and IL4, IL1Ra, and IL10 as anti-inflammatory cytokines. RESULTS: The results of the current study showed that the concentration of 0.4 mg of Betamethasone lead to a significant increase of anti-inflammatory cytokine in gene and protein levels. The results also showed that the Betamethasone treated groups (treatment1) causes a significant increase in the secretion of anti-inflammatory cytokine compares to the control while inflammatory cytokine remained at the control level. CONCLUSION: The results showed that under influence of anti-inflammatory drug treatments the production and secretion of anti-inflammatory cytokines can be induced in LRFs.

Effects of Premixing Betamethasone and Lidocaine on Chondrocyte Inflammation in an In Vitro Model.

BACKGROUND: It is common practice for hand surgeons to premix corticosteroids with a local anesthetic and store the mixture in pre-loaded syringes for rapid use during clinic. However, any possible loss of efficacy with this practice has never been studied. The purpose of this study, therefore, is to determine whether premixing betamethasone sodium phosphate/betamethasone acetate (BSP) and lidocaine (L) at different time intervals from injection has diminishing anti-inflammatory effects on chondrocytes in vitro. METHODS: Human articular chondrocytes were partitioned into six groups: two controls and four experimental conditions. The negative control had growth media only. The positive control had growth media and inflammatory cytokines (interleukin-1ß and oncostatin M). Experimental conditions were additionally treated with BSP alone or BSP mixed with lidocaine (BSP + L) at the time of treatment (0 hours), or at 4 or 24 hours prior. Relative expressions of inflammatory genes were measured. RESULTS: Relative to the positive control, chondrocytes in all experimental conditions decreased expression of TNF-α, MMP-3, and ADAMTS-4. Chondrocytes exposed to BSP only or BSP + L at 4 hours or 24 hours prior to treatment decreased expression of IL-8. Chondrocytes exposed to BSP only or BSP + L at 0 hours or 4 hours prior to treatment decreased expression of MMP-1. There were no significant differences in expression of IL-6 or MMP-13. CONCLUSIONS: Treatment with BSP + L prepared in pre-loaded syringes at varying time intervals up to 24 hours prior to injection does not significantly impact the ability of the mixture to reduce expression of certain key inflammatory mediators in vitro.

Preventive effects of antenatal CDP-choline in a rat model of neonatal hyperoxia-induced lung injury.

Antenatal steroid administration to pregnant women at risk of prematurity provides pulmonary maturation in infants, while it has limited effects on incidence of bronchopulmonary dysplasia (BPD), the clinical expression of hyperoxia-induced lung injury (HILI). Cytidine-5'-diphosphate choline (CDP-choline) was shown to alleviate HILI when administered to newborn rats. Therefore, we investigated effects of maternal administration of CDP-choline, alone or in combination with betamethasone, on lung maturation in neonatal rats subjected to HILI immediately after birth. Pregnant rats were randomly assigned to one of the four treatments: saline (1 mL/kg), CDP-choline (300 mg/kg), betamethasone (0.4 mg/kg), or CDP-choline plus betamethasone (combination therapy). From postnatal day 1 to 11, pups born to mothers in the same treatment group were pooled and randomly assigned to either normoxia or hyperoxia group. Biochemical an d histopathological effects of CDP-choline on neonatal lung tissue were evaluated. Antenatal CDP-choline treatment increased levels of phosphatidylcholine and total lung phospholipids, decreased apoptosis, and improved alveolarization. The outcomes were further improved with combination therapy compared to the administration of CDP-choline or betamethasone alone. These results demonstrate that antenatal CDP-choline treatment provides benefit in experimental HILI either alone or more intensively when administered along with a steroid, suggesting a possible utility for CDP-choline against BPD.

Comparison Of Efficacy Of Steroids Alone And Combination Of Steroids With Hyaluronidase On Mouth Opening In Oral Submucous Fibrosis Patients.

BACKGROUND: Eventually Oral submucous fibrosis causes pronounced stiffness and failure to open the mouth. Objectives are to determine compare the efficacy of intralesional steroids alone and combination of steroids with hyaluronidase on mouth opening in oral submucous fibrosis. METHODS: It was a prospective comparative cohort study. Total of 74 patients both male and female having history of pan chewing and limited mouth opening and burning sensations were included in the study. Informed consent was taken and divided into two groups. Patients of group 1 were managed with mixture of betamethasone 1 ml and hyaluronidase 1500 IU and patients of group 2 were treated with only steroid injection of betamethasone 1 ml given intralesional, both injections were given intralesional, by multiple puncture technique and once a week and continued for twelve weeks (3 months). And data compiled and analyzed in SPSS-20. RESULTS: The mean age of group 1 was 40.027±6.97 years, and mean age of Group 2 was 37.351±5.48 years. In both groups, the greatest number of cases aged from 31-59 years. Compared to females in both groups, the majority of patients were males. In 32 (86.4)% patients of group 1 showed efficacy compared with 18[43.2] patients in group 2 [p-0.000]. Conclusion: In this study Intralesional steroids with hyaluronidase injections are more efficient for opening the mouth in patients with oral sub-mucus fibrosis.

Pharmacological basis of the putative therapeutic effect of Topical Vitamin D3 on the experimental model of atopic dermatitis in mice.

OBJECTIVE: The aim of the study was to explore the effect of topical vitamin D3 in atopic dermatitis (AD) induced by ovalbumin (OVA) in contrast with topical betamethasone in mice. MATERIALS AND METHODS: 35 BALB/c adult male mice, weighing between 25-30 gm were used to induce AD by topically sensitizing the dorsal surface of the skin with the OVA patch. Subsequently, treatments were performed in each group by application of vitamin D3 cream (0.0003%), betamethasone cream (0.1%), or vehicles (QV cream) on the skin. RESULTS: Remarkably, vitamin D3 had a marked improvement in the skin of OVA-induced AD mice. Additionally, vitamin D3 revealed a considerable diminution in the levels of IgE, IL-5, filaggrin, and epidermal thickness, whereas a significant augmentation in the levels of IL-4 and IL-13 was observed when compared with the control group, and histopathological studies had further confirmed these findings. CONCLUSIONS: This study essentially highlighted the anti-inflammatory effect of vitamin D3 by effective alteration in the immunological components responsible for AD. Moreover, this pioneer experimental work represents a new paradigm and sheds a light on the importance of vitamin D3 in the implications of AD. A comprehensive creative approach is crucial to concretely establish and further corroborate vitamin D3 for this therapeutic role.

The Effect of the Long-Term Calcipotriol/Betamethasone Dipropionate Local Therapy on Tissue Resident Memory Cells Markers in Psoriatic Eruptions.

BACKGROUND: The natural course of psoriasis is characterized by the long-term persistence of lesions and a predilection for relapse in the same area. It is caused by the inherence of TRM (tissue resident memory T cells) in apparently healthy skin. These cells are able to initiate an inflammatory cascade and induce relapse of the disease. These cells are characterized by high resistance to damaging factors and apoptosis, which determines their longevity. AIM: The aim of our study was to evaluate the presence of TRM in psoriatic plaques before, during and after 12 weeks of therapy in patients treated with topical calcipotriol and betamethasone dipropionate (Cal/BD) foam. METHODS: TRM markers (CD4, CD8, CD103, CD69, CD49, CXCR6) and tissue expression of cytokines (IL-17A, IL-22) in the lesional psoriatic skin from 10 patients compared to 10 healthy skin samples were estimated by immunohistochemistry. Biopsy samples from the area of the same psoriatic plaque were collected three times: before the initiation of therapy, 4 and 12 weeks after its initiation. RESULTS: The presence of TRM markers in the epidermis and dermis of psoriatic lesions was significantly higher when compared to the skin of control group patients. A reduction in the expression of the characteristic TRM markers (CD8, CD4, CD103, CD69, CXCR6, IL-17A and IL-22) was observed in the epidermis on week 12 of therapy, while a depletion in the expression of TRM in the dermis was demonstrated only in CD4 and IL-22. CONCLUSIONS: Topical treatment with Cal/BD foam significantly decreased the expression of TRM markers mainly in the epidermis, and to a lesser extent in the dermis, during the 12-week observation period. It probably results from a worse penetration of the drug into the dermis and the effect of the preparation mainly on the epidermis. The persistence of a high expression of TRM markers in the dermis may result in the rapid recurrence of lesions after discontinuation of topical treatment.

The RelB-BLNK Axis Determines Cellular Response to a Novel Redox-Active Agent Betamethasone during Radiation Therapy in Prostate Cancer.

Aberrant levels of reactive oxygen species (ROS) are potential mechanisms that contribute to both cancer therapy efficacy and the side effects of cancer treatment. Upregulation of the non-canonical redox-sensitive NF-kB family member, RelB, confers radioresistance in prostate cancer (PCa). We screened FDA-approved compounds and identified betamethasone (BET) as a drug that increases hydrogen peroxide levels in vitro and protects non-PCa tissues/cells while also enhancing radiation killing of PCa tissues/cells, both in vitro and in vivo. Significantly, BET increases ROS levels and exerts different effects on RelB expression in normal cells and PCa cells. BET induces protein expression of RelB and RelB target genes, including the primary antioxidant enzyme, manganese superoxide dismutase (MnSOD), in normal cells, while it suppresses protein expression of RelB and MnSOD in LNCaP cells and PC3 cells. RNA sequencing analysis identifies B-cell linker protein (BLNK) as a novel RelB complementary partner that BET differentially regulates in normal cells and PCa cells. RelB and BLNK are upregulated and correlate with the aggressiveness of PCa in human samples. The RelB-BLNK axis translocates to the nuclear compartment to activate MnSOD protein expression. BET promotes the RelB-BLNK axis in normal cells but suppresses the RelB-BLNK axis in PCa cells. Targeted disruptions of RelB-BLNK expressions mitigate the radioprotective effect of BET on normal cells and the radiosensitizing effect of BET on PCa cells. Our study identified a novel RelB complementary partner and reveals a complex redox-mediated mechanism showing that the RelB-BLNK axis, at least in part, triggers differential responses to the redox-active agent BET by stimulating adaptive responses in normal cells but pushing PCa cells into oxidative stress overload.

The role of saffron in improvement of ocular surface disease in a mouse model of Lacrimal Gland Excision-induced dry eye disease.

One of the most prevalent eye disorders is dry eye disease (DED), described by ocular dryness due to the tear insufficiency. Prolonged dry eye causes damage and ulcer to the surface of the cornea. The core of the DED mechanism is inflammation which is a biological response of the body to pathogens. Several studies have indicated that saffron has many beneficial biological effects, such as anti-inflammatory and free radical scavenging. This research aims to examine possible positive impact of saffron in the mice model of DED. The animals were divided into 4 groups. Induction of DED was done by right Lacrimal Gland Excision (LGE). Treatment was done by intraperitoneal (i.p.) injection of saffron (1 mg/kg/day, for 28 days after induction of DED) in the SAF group, betamethasone (the BET group) (i.p., 1 mg/kg/day, for 28 days after induction of DED), the LGE group (received normal saline i.p. for 28 days after induction of DED) and the sham group (no induction of DED). Ophthalmological assay with fluorescein staining on the 0, 14 and, 28 days, histopathological analysis (H & E assay) on the last day and, pro-inflammatory cytokine assays of eyes were done. Saffron and betamethasone reduced the fluorescein score of the eyes (P < 0.0001) and improved the ocular surface disease in H & E assay as well as reduced the eye levels of TNF-α (P < 0.01), IL-1ß (P < 0.0001) and, IL-6 (P < 0.001) compared to those of the LGE group. The current study indicated that treatment with saffron has a beneficial effect on LGE (Lacrimal gland excision)-induced DED in mice via its anti-inflammatory properties.

One percent of the clinical dose used for antenatal steroid therapy is sufficient to induce lung maturation when administered directly to the preterm ovine fetus.

Antenatal steroids (ANSs) are routinely administered to women judged to be at imminent risk of preterm delivery. Their principal benefit is precocious functional maturation of the preterm fetal lung. Current dosing regimens expose the mother and fetus to high steroid levels that may be unnecessary, increasing the potential risks of disruption to the maternal and fetal hypothalamic-pituitary-adrenal (HPA) axis and glucose regulation, alterations in placental function, and reduced fetal growth. Using a sheep model of pregnancy, we tested the hypothesis that direct fetal administration of an ultra-low dose course of betamethasone phosphate (∼0.33 mg) would be sufficient to elicit functional maturation of the fetal lung. A jugular catheter was installed in singleton ovine fetuses at 122-day gestation under general anesthesia. Animals were randomized to receive either: 1) fetal intravenous betamethasone phosphate to target fetal plasma betamethasone mean levels of 2 ng/mL for 26 h (fetal treatment group; n = 16); 2) fetal intravenous saline for 26 h and two maternal intramuscular injections of 0.25 mg/kg betamethasone phosphate + betamethasone acetate, simulating a standard clinical treatment (maternal treatment group; n = 12); or 3) fetal intravenous saline only for 26 h (negative control group; n = 10). Fetuses were delivered 48 h after surgery, ventilated for 30 min to allow the collection of lung function and physiological data, and euthanized. Quantitative PCR and Western blots were used to assess markers of lung maturation. The average total betamethasone phosphate dose for the fetal treatment group was 1% (0.3 mg) of the maternal treatment group (31-mg betamethasone phosphate + betamethasone acetate). At 30 min of ventilation, arterial [Formula: see text], pH, heart rate, and ventilation efficacy index (VEI) were significantly (P < 0.05) and equivalently improved in both the fetal treatment group and maternal treatment group, relative to the negative control group. Similarly, SP-A, SP-C, and AQ-5 mRNA expression was significantly higher in both the fetal treatment group and maternal treatment group, relative to negative control. Maternal steroid administration was not required to generate preterm fetal lung maturation in sheep. Using a low dose and targeting steroid treatments directly to the fetus has the potential to significantly reduce maternal exposures, while simultaneously reducing the potential risk of adverse outcomes associated with current clinical dosing regimens.

Continuous but not pulsed low-dose fetal betamethasone exposures extend the durability of antenatal steroid therapy.

Antenatal steroid (ANS) therapy is the standard care for women at imminent risk of preterm labor. Despite extensive and long-standing use, 40%-50% of babies exposed antenatally to steroids do not derive benefit; remaining undelivered 7 days or more after ANS treatment is associated with a lack of treatment benefit and increased risk of harm. We used a pregnant sheep model to evaluate the impact of continuous versus pulsed ANS treatments on fetal lung maturation at an extended, 8-day treatment to delivery interval. Continuous low-dose ANS treatments for more than 72 h in duration improved fetal lung maturation at 8 days after treatment initiation. If fetal ANS exposure was interrupted, the beneficial ANS effect was lost. Truncated treatments, including that simulating the current clinical treatment regimen, did not improve lung function. Variable fetal lung maturation was correlated to the amount of saturated phosphatidylcholine present in the lung fluid. These data demonstrate that 1) the durability of ANS therapy may be enhanced by employing an extended, low-dose treatment regimen by reducing total dose and 2) interrupting the continuity of fetal exposure by allowing it to fall below a minimal threshold was associated with comparably poor functional maturation of the preterm ovine lung.

Fetal glucocorticoid exposure leads to sex-specific changes in drug-transporter function at the blood-brain barrier in juvenile guinea pigs.

Antenatal synthetic glucocorticoids (sGCs) are a life-saving treatment in managing pre-term birth. However, off-target effects of sGCs can impact blood-brain barrier (BBB) drug transporters essential for fetal brain protection, including P-glycoprotein (P-gp/Abcb1) and breast cancer resistance protein (BCRP/Abcg2). We hypothesized that maternal antenatal sGC treatment modifies BBB function in juvenile offspring in a sex-dependent manner. Thus, the objective of this study was to determine the long-term impact of a single or multiple courses of betamethasone on P-gp/Abcb1 and BCRP/Abcg2 expression and function at the BBB. Pregnant guinea pigs (N = 42) received 3 courses (gestation days (GDs) 40, 50, and 60) or a single course (GD50) of betamethasone (1 mg/kg) or vehicle (saline). Cerebral microvessels and brain endothelial cells (BEC) were collected from the post-natal day (PND) 14 offspring to measure protein, gene expression, and function of the drug transporters P-gp/Abcb1 and BCRP/Abcg2. P-gp protein expression was decreased (p < .05) in microvessels from male offspring that had been exposed to multiple courses and a single course of sGC, in utero. Multiple courses of sGC resulted in a significant decrease in P-gp function in BECs from males (p < .05), but not females. There was a very strong trend for increased P-gp function in males compared to females (p = .055). Reduced P-gp expression and function at the BBB of young male offspring following multiple prenatal sGC exposures, is clinically relevant as many drugs administered postnatally are P-gp substrates. These novel sex differences in drug transporter function may underlie potential sexual dimorphism in drug sensitivity and toxicity in the newborn and juvenile brain.

Neurocognitive sequelae of antenatal corticosteroids in a late preterm rabbit model.

BACKGROUND: Late preterm birth is associated with short-term respiratory and adaptive problems. Although antenatal corticosteroids seem to reduce the respiratory burden, this may come at the cost of adverse neuropsychological outcomes later in life. This impact has not been investigated. OBJECTIVE: Herein, we investigate what the short- and long-term neurodevelopmental effects of a single course of betamethasone in simulated late preterm birth. STUDY DESIGN: Time-mated pregnant does received 0.1 mg/kg betamethasone (n=8) or 1 mL saline intramuscular (n=6) at the postconceptional ages of 28 and 29 days. The antenatal corticosteroid dose and scheme were based on previous studies and were comparable with routine clinical use. Cesarean delivery was done on postconceptional age 30 days (term=31 days), and new-born rabbits were foster-cared for 28 days and were thereafter cared for in group housing. Neonatal lung function testing and short-term neurobehavioral testing was done. Open field, spontaneous alternation, and novel object recognition tests were subsequently performed at 4 and 8 weeks of age. On postnatal day 1 and at 8 weeks, a subgroup was euthanized and transcardially perfuse fixated. Ex vivo high-resolution Magnetic Resonance Imaging was used to calculate the Diffusion Tensor Imaging-derived fractional anisotropy and mean diffusivity. Fixated brains underwent processing and were serial sectioned, and a set of 3 coronal sections underwent anti-NeuN, Ki67, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. RESULTS: Antenatal corticosteroid exposure was associated with improved neonatal lung function, yet resulted in a long-term growth deficit that coincided with a persistent neurobehavioral deficit. We demonstrated lower neonatal motor scores; a persistent anxious behavior in the open field test with more displacements, running, and self-grooming episodes; persistent lower alternation scores in the T-Maze test; and lower discriminatory indexes in the novel object recognition. On neuropathological assessment, antenatal corticosteroid exposure was observed to result in a persistent lower neuron density and fewer Ki67+ cells, particularly in the hippocampus and the corpus callosum. This coincided with lower diffusion tensor imaging-derived fractional anisotropy scores in the same key regions. CONCLUSION: Clinical equivalent antenatal corticosteroid exposure in this late preterm rabbit model resulted in improved neonatal lung function. However, it compromised neonatal and long-term neurocognition.

Oxygen and steroids affect the regulatory role of natriuretic peptide receptor-C on surfactant secretion by type II cells.

Atrial natriuretic peptide (ANP) and its receptors natriuretic peptide receptor (NPR)-A and NPR-C are all highly expressed in alveolar epithelial type II cells (AEC2s) in the late-gestation ovine fetal lung and are dramatically decreased postnatally. However, of all the components, NPR-C stimulation inhibits ANP-mediated surfactant secretion. Since alveolar oxygen increases dramatically after birth, and steroids are administered to mothers antenatally to enhance surfactant lung maturity, we investigated the effects of O2 concentration and steroids on NPR-C-mediated surfactant secretion in AEC2s. NPR-C expression was highest at 5% O2 while being suppressed by 21% O2, in cultured mouse lung epithelial cells (MLE-15s) and/or human primary AEC2s. Surfactant protein-B (SP-B) was significantly elevated in media from both in vitro and ex vivo culture at 13% O2 versus 21% O2 in the presence of ANP or terbutaline (TER). Both ANP and C-ANP (an NPR-C agonist) attenuated TER-induced SP-B secretion; this effect was reversed by dexamethasone (DEX) pretreatment in AEC2s and by transfection with NPR-C siRNA in MLE-15 cells. DEX markedly reduced AEC2 NPR-C expression, and pregnant ewes treated with betamethasone showed reduced ANP in fetal sheep lung fluid. These data suggest that elevated O2 downregulates AEC2 NPR-C and that steroid-mediated NPR-C downregulation in neonatal lungs may provide a novel mechanism for their effect on perinatal surfactant production.

Betamethasone phosphate reduces the efficacy of antenatal steroid therapy and is associated with lower birthweights when administered to pregnant sheep in combination with betamethasone acetate.

BACKGROUND: Antenatal corticosteroid therapy is a standard of care for women at imminent risk of preterm labor. However, the optimal (maximum benefit and minimal risk of side effects) antenatal corticosteroid dosing strategy remains unclear. Although conveying overall benefit when given to the right patient at the right time, antenatal corticosteroid treatment efficacy is highly variable and is not risk-free. Building on earlier findings, we hypothesized that when administered in combination with slow-release betamethasone acetate, betamethasone phosphate and the high maternal-fetal betamethasone concentrations it generates are redundant for fetal lung maturation. OBJECTIVE: Using an established sheep model of prematurity and postnatal ventilation of the preterm lamb, we aimed to compare the pharmacodynamic effects of low-dosage treatment with betamethasone acetate only against a standard dosage of betamethasone phosphate and betamethasone acetate as recommended by the American College of Obstetricians and Gynecologists for women at risk of imminent preterm delivery between 24 0/7 and 35 6/7 weeks' gestation. STUDY DESIGN: Ewes carrying a single fetus at 122±1 days' gestation (term=150 days) were randomized to receive either (1) maternal intramuscular injections of sterile saline (the saline negative control group, n=12), (2) 2 maternal intramuscular injections of 0.25 mg/kg betamethasone phosphate+betamethasone acetate administered at 24-hour dosing intervals (the betamethasone phosphate+betamethasone acetate group, n=12); or (3) 2 maternal intramuscular injections of 0.125 mg/kg betamethasone acetate administered at 24-hour dosing intervals (the betamethasone acetate group, n=11). The fetuses were surgically delivered 48 hours after treatment initiation and ventilated for 30 minutes to determine functional lung maturation. The fetuses were euthanized after ventilation, and the lungs were collected for analysis using quantitative polymerase chain reaction and Western blot assays. Fetal plasma adrenocorticotropic hormone levels were measured in the cord blood samples taken at delivery. RESULTS: Preterm lambs were defined as either antenatal corticosteroid treatment responders or nonresponders using an arbitrary cutoff, being a PaCO2 level at 30 minutes of ventilation being more extreme than 2 standard deviations from the mean value of the normally distributed saline control group values. Compared with the animals in the saline control group, the animals in the antenatal corticosteroid treatment groups showed significantly improved lung physiological responses (blood gas and ventilation data) and had a biochemical signature (messenger RNA and surfactant protein assays) consistent with functional maturation. However, the betamethasone acetate group had a significantly higher treatment response rate than the betamethasone phosphate+betamethasone acetate group. These physiological results were strongly correlated to the amount of surfactant protein A. Birthweight was lower in the betamethasone phosphate+betamethasone acetate group and the fetal hypothalamic-pituitary-adrenal axis was suppressed to a greater extent in the betamethasone phosphate+betamethasone acetate group. CONCLUSION: Low-dosage antenatal corticosteroid therapy solely employing betamethasone acetate was sufficient for fetal lung maturation. The elevated maternal-fetal betamethasone concentrations associated with the coadministration of betamethasone phosphate did not in addition improve lung maturation but were associated with greater fetal hypothalamic-pituitary-adrenal axis suppression, a lower antenatal corticosteroid treatment response rate, and lower birthweight-outcomes not desirable in a clinical setting. These data warranted a clinical investigation of sustained low-dosage antenatal corticosteroid treatments that avoid high maternal-fetal betamethasone exposures.