Pharmacodynamic characterization of rytvela, a novel allosteric anti-inflammatory therapeutic, to prevent preterm birth and improve fetal and neonatal outcomes.

BACKGROUND: Preterm birth is the leading cause of neonatal morbidity and mortality. Studies have shown that interleukin 1 plays a major role in the pathophysiology of preterm birth by inducing the production of proinflammatory mediators and uterine activation proteins leading to labor. More importantly, uteroplacental inflammation, associated with preterm birth parturition pathways, is detrimental to fetal tissues and leads to long-term sequelae. Our group has developed an allosteric antagonist of the interleukin 1 receptor, rytvela, found to be potent and safe in preventing preterm birth by suppressing inflammation via the inhibition of the mitogen-activated protein kinase pathway while preserving the Nuclear factor kappa B pathway (important in immune vigilance). Rytvela has been shown to inhibit inflammatory up-regulation and uterine activation while preserving fetal development. OBJECTIVE: This study aimed to further the preclinical development of rytvela by evaluating its optimal dose and minimal duration of treatment to inhibit the inflammatory cascade, prolong gestation, and promote neonatal outcomes. STUDY DESIGN: Pregnant CD-1 mice were administered with lipopolysaccharide (10 µg, intraperitoneal administration) or interleukin 1 (1 µg/kg, intrauterine administration) on gestational day 16 to induce preterm labor. Rytvela was administered at different doses (0.1, 0.5, 1.0, 2.0, 4.0 mg/kg/d subcutaneously) from gestational days 16 to 18.5. To evaluate the minimal duration of treatment, the mice were administered with rytvela (2 mg/kg/d subcutaneously) for 24, 36, or 48 hours. The rate of prematurity (gestational day <18.5) and neonate survival and weight were evaluated. Gestational tissues were collected at gestational day 17.5 to quantify cytokines, proinflammatory mediators, and uterine activating proteins by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. The neonatal lungs and intestines were collected from postnatal days 5 to 7 and analyzed by histology. RESULTS: Rytvela exhibited a dose-response profile and achieved maximum efficacy at a dose of 2 mg/kg/d by reducing 70% of lipopolysaccharide-induced preterm births and 60% of interleukin 1ß-induced preterm births. In addition, rytvela attained maximum efficacy at a dose of 1 mg/kg/d by increasing neonate survival by up to 65% in both models of preterm birth. Rytvela protected fetuses from inflammatory insult as of 24 hours, preserving lung and intestinal integrity, and prevented preterm birth and fetal mortality by 60% and 50%, respectively, as of 36 hours of treatment. CONCLUSION: The maximum efficacy of rytvela was achieved at 2 mg/kg/d with improved birth outcomes and prevented inflammatory up-regulation upon 36 hours (only) of treatment. Rytvela exhibited desirable properties for the safe prevention of preterm birth and fetal protection.

Preventing Preterm Birth: Exploring Innovative Solutions.

This review examines the complexities of preterm birth (PTB), emphasizes the pivotal role of inflammation in the pathogenesis of preterm labor, and assesses current available interventions. Antibiotics, progesterone analogs, mechanical approaches, nonsteroidal anti-inflammatory drugs, and nutritional supplementation demonstrate a limited efficacy. Tocolytic agents, targeting uterine activity and contractility, inadequately prevent PTB by neglecting to act on uteroplacental inflammation. Emerging therapies targeting toll-like receptors, chemokines, and interleukin receptors exhibit promise in mitigating inflammation and preventing PTB.

Inflammatory mechanisms of preterm labor and emerging anti-inflammatory interventions.

Preterm birth is a major public health concern, requiring a deeper understanding of its underlying inflammatory mechanisms and to develop effective therapeutic strategies. This review explores the complex interaction between inflammation and preterm labor, highlighting the pivotal role of the dysregulation of inflammation in triggering premature delivery. The immunological environment of pregnancy, characterized by a fragile balance of immune tolerance and resistance, is disrupted in preterm labor, leading to a pathological inflammatory response. Feto-maternal infections, among other pro-inflammatory stimuli, trigger the activation of toll-like receptors and the production of pro-inflammatory mediators, promoting uterine contractility and cervical ripening. Emerging anti-inflammatory therapeutics offer promising approaches for the prevention of preterm birth by targeting key inflammatory pathways. From TLR-4 antagonists to chemokine and interleukin receptor antagonists, these interventions aim to modulate the inflammatory environment and prevent adverse pregnancy outcomes. In conclusion, a comprehensive understanding of the inflammatory mechanisms leading to preterm labor is crucial for the development of targeted interventions in hope of reducing the incidence of preterm birth and improving neonatal health outcomes.

Estimation of nicotine and tar yields from human-smoked cigarettes before and after the implementation of the cigarette ignition propensity regulations in Canada.

In 2005, Human-Smoked (HS) tar and nicotine yields from commercial Canadian cigarettes were determined using a part filter analysis method to obtain estimates representative of human smoking behavior. In 2006, new cigarette designs were introduced to ensure compliance with the Canadian Low Ignition Propensity (LIP) regulations. It was not known how the changes in product design would affect HS yields. To assess the impact of the cigarette design modifications on HS yields, a further group of Canadian smokers was recruited for smoking the modified version of 10 products previously assessed. No differences in estimated HS tar yields were found between products following product modification. The HS nicotine yield was different for one product. In general, HS yields were higher than ISO machine yields while Canadian intense machine yields were more representative of the maximum HS yields. The same product ranking order was obtained for HS yields and the two machine yields but differences between the mean HS yields and ISO yields were smaller as the product ISO yields increased. Higher HS yields were measured when products were smoked by male smokers. The methodology used in this study showed the wide range of HS yields obtained by smokers as well as a good degree of stability in average HS yields just before and after the introduction of LIP regulations.

The determinant role of IL-6 in the establishment of inflammation leading to spontaneous preterm birth.

Preterm birth (PTB) and its consequences are a major public health concern as preterm delivery is the main cause of mortality and morbidity at birth. There are many causes of PTB, but inflammation is undeniably associated with the process of premature childbirth and fetal injury. At present, treatments clinically available mostly involve attempt to arrest contractions (tocolytics) but do not directly address upstream maternal inflammation on development of the fetus. One of the possible solutions may lie in the modulation of inflammatory mediators. Of the many pro-inflammatory cytokines involved in the induction of PTB, IL-6 stands out for its pleiotropic effects and its involvement in both acute and chronic inflammation. Here, we provide a detailed review of the effects of IL-6 on the timing of childbirth, its occurrence during PTB and its indissociable roles with associated fetal tissue damage.

Interleukin-1 Receptor Modulation Using ß-Substituted α-Amino-γ-Lactam Peptides From Solid-Phase Synthesis and Diversification.

As a key cytokine mediator of inflammation, interleukin-1ß (IL-1ß) binds to the IL-1 receptor (IL-1R) and activates various downstream signaling mediators, including NF-κB, which is required for immune vigilance and cellular protection. Toward the development of IL-1-targeting therapeutics which exhibit functional selectivity, the all-D-amino acid peptide 1 (101.10, H-D-Arg-D-Tyr-D-Thr-D-Val-D-Glu-D-Leu-D-Ala-NH2) was conceived as an allosteric IL-1R modulator that conserves NF-κB signaling while inhibiting other IL-1-activated pathways. Employing ß-hydroxy-α-amino-γ-lactam (Hgl) stereoisomers to study the conformation about the Thr3 residue in 1, [(3R,4S)-Hgl3]-1 (2b), among all possible diastereomers, was found to exhibit identical in vitro and in vivo activity as the parent peptide and superior activity to the α-amino-γ-lactam (Agl) counterpart. Noting the relevance of the ß-hydroxyl substituent and configuration for the activity of (3R,4S)-2b, fifteen different ß-substituted-Agl3 analogs of 1 (e.g., 2c-q) have now been synthesized by a combination of solution- and solid-phase methods employing N-Fmoc-ß-substituted-Agl3-Val-OH dipeptide building blocks. Introduction of a ß-azido-Agl3 residue into the resin bound peptide and subsequent reduction and CuAAC chemistry gave access to a series of amine and triazole derivatives (e.g., 2h-q). ß-Substituted-[Agl3]-1 analogs 2c-q exhibited generally similar circular dichroism (CD) spectra as that of Hgl analog 2b in water, presenting curve shapes indicative of ß-turn structures. The relevance of the ß-substituent was indicated in rodent models of preterm labor and retinopathy of prematurity (ROP), in which certain analogs inhibited preterm birth and vaso-obliteration, respectively, with activity similar to 1 and 2b. The ß-substituted-[Agl3]-1 analogs exhibited functional selectivity on IL-1-induced signaling pathways. The described solid-phase method has provided discerning probes for exploring peptide structure-activity relationships and valuable leads for developing prototypes to treat inflammatory events leading to prematurity and retinopathy of prematurity, which are leading causes of infant morbidity and blindness respectively.

Novel Anti-Interleukin-1ß Therapy Preserves Retinal Integrity: A Longitudinal Investigation Using OCT Imaging and Automated Retinal Segmentation in Small Rodents.

Retinopathy of prematurity (ROP) is the leading cause of blindness in neonates. Inflammation, in particular interleukin-1ß (IL-1ß), is increased in early stages of the disorder, and contributes to inner and outer retinal vasoobliteration in the oxygen-induced retinopathy (OIR) model of ROP. A small peptide antagonist of IL-1 receptor, composed of the amino acid sequence, rytvela, has been shown to exert beneficial anti-inflammatory effects without compromising immunovigilance-related NF-κB in reproductive tissues. We conducted a longitudinal study to determine the efficacy of "rytvela" in preserving the integrity of the retina in OIR model, using optical coherence tomography (OCT) which provides high-resolution cross-sectional imaging of ocular structures in vivo. Sprague-Dawley rats subjected to OIR and treated or not with "rytvela" were compared to IL-1 receptor antagonist (Kineret). OCT imaging and custom automated segmentation algorithm used to measure retinal thickness (RT) were obtained at P14 and P30; gold-standard immunohistochemistry (IHC) was used to confirm retinal anatomical changes. OCT revealed significant retinal thinning in untreated animals by P30, confirmed by IHC; these changes were coherently associated with increased apoptosis. Both rytvela and Kineret subsided apoptosis and preserved RT. As anticipated, Kineret diminished both SAPK/JNK and NF-κB axes, whereas rytvela selectively abated the former which resulted in preserved monocyte phagocytic function. Altogether, OCT imaging with automated segmentation is a reliable non-invasive approach to study longitudinally retinal pathology in small animal models of retinopathy.

An ex vivo approach to the differential parenchymal responses induced by cigarette whole smoke and its vapor phase.

Using a rat lung slice model, this study compared the stress responses induced by cigarette whole smoke (WS) to that induced by the vapor phase (VP) of the smoke. Following a 3-day exposure, lung slices exposed to 4, 10 and 20% WS retained 85, 42 and 16% relative survival respectively in comparison to the air-exposed ones. Consistently, histological observations revealed concentration-related alveolar damages in the lung slices. Expression of 5 stress-response genes was examined following a single 30 min exposure to 4% WS or VP. WS exposure resulted in 4, 11 and 50-fold induction of IL-1ß, kinin type I receptor (B1R) and CYP1A1 genes, respectively, while CYP1B1 and TNF-α genes expression was found only two times higher in comparison to VP group. Since cigarette WS consists of particulate and vapor phases, these results highlight the preferential or synergistic role of the particulate phase in the induction of IL-1ß, B1R and CYP1A1 genes and that VP did not have comparable effects on expression of these genes. However, both phases fairly contributed to the induction of CYP1B1 and TNF-α genes. VP was the fraction responsible for the toxic effect since WS did not produce further toxicity. The 4% whole smoke deposited about 7.1 µg/cm² of total particulate matter (TPM) to the exposure chamber which may account for observed differential stress responses in the lung slices.

The use of a novel tobacco treatment process to reduce toxicant yields in cigarette smoke.

The US Institute of Medicine has encouraged the pursuit and development of potential reduced-exposure products (PREPs) - tobacco products that substantially reduce exposure to one or more tobacco toxicants and can reasonably be expected to reduce the risk of one or more specific diseases or other adverse health effects. One potential approach is to reduce levels of some smoke toxicant precursors, such as proteins and polyphenols, in tobacco. We describe a treatment process involving aqueous tobacco extraction and treatment with protease; filtration of the extract to remove peptides, amino acids and polyphenols, and recombination of extract and treated tobacco. The process reduced levels of protein nitrogen (59%), polyphenols (33-78%) and nicotine (12%) while sugars increased 16%. ISO mainstream smoke yields of 43 toxicants were measured from cigarettes containing treated tobaccos; lower yields of tar, nicotine, carbon monoxide (16-20%), acrylonitrile, ammonia, aromatic amines, pyridine, quinolene and hydrogen cyanide (33-51%), tobacco specific nitrosamines (25-32%); phenolics (24-56%), benzene (16%), toluene (25%) and cadmium (34%) were obtained. There were significantly increased yields of formaldehyde (49%) and isoprene (17%). Reductions in sidestream yields of nitrogenous smoke toxicants and increases in sidestream yields of several carbonyls, benzo(a)pyrene and isoprene were also observed.