Nicotine inhibits LPS-induced cytokine production and leukocyte infiltration in rat placenta

Epigallocatechin gallate (EGCG) alleviates inflammation and endothelial dysfunction and improves pregnancy outcomes in preeclampsia (PE)-like rats via eNOS/Nrf2/HO-1 pathway

BACKGROUND AND PURPOSE

Epigallocatechin gallate (EGCG), a natural antioxidant, has shown protective effect in many diseases. We explore the effect and potential regulatory mechanisms of EGCG in preeclampsia (PE)-like rats.

METHODS AND MATERIALS

PE was mimicked in pregnant rats. EGCG was orally administered at a dosage of 25(Low, L) or 50 mg/kg (High, H) from gestational day (GD) 6-17. The blood pressure signatures, heart rates were monitored. The 24-h proteinuria and serum were analyzed. On GD 18, rats were sacrificed, and pups and placentas were weighed. Kidneys and placentas were analyzed using immunohistochemistry (IHC) and hematoxylin-eosin staining (H&E). Placentas were examined using western blot for sFlt1, eNOS, Nrf2, HO-1, SLC7A11. MDA, GSH, GPx and Fe2+ were measured.

RESULTS

EGCG inhibits systolic blood pressure, BUN, CREA, ALT, AST, UA and proteinuria levels in PE-like rats. EGCG enhances the pup weight and crown-rump length and reduces the rate of fetus growth restriction in PE group. Endothelial dysfunction and infiltration of inflammatory cells were found in kidney cortex and placenta tissues in PE group and were inhibited by EGCG treatment. sFlt1 was activated in placentas in PE group and inhibited by EGCG while eNOS/Nrf2/HO-1 were inhibited in PE group and restored by EGCG. MDA and Fe concentrations were elevated in PE group and reduced by EGCG while the GSH level, SLC7A11 and the GPx activity were inhibited in PE group and restored by EGCG.

CONCLUSION

EGCG alleviates inflammation, endothelial dysfunction and placental ferroptosis, improves pregnancy outcomes in PE-like rats via eNOS/Nrf2/HO-1.

BKCa channels are involved in spontaneous and lipopolysaccharide-stimulated uterine contraction in late gestation mice†

The large-conductance, voltage-gated, calcium (Ca2+)-activated potassium channel (BKCa) is one of the most abundant potassium channels in the myometrium. Previous work conducted by our group has identified a link between inflammation, BKCa channels and excitability of myometrial smooth muscle cells. Here, we investigate the role of BKCa channels in spontaneous and lipopolysaccharide (LPS)-stimulated uterine contraction to gain a better understanding of the relationship between the BKCa channel and uterine contraction in basal and inflammatory states. Uteri of C57BL/6 J mice on gestational day 18.5 (GD18.5) were obtained and either fixed in formalin or used immediately for tension recording or isolation of primary myocytes for patch-clamp. Paraffin sections were used for immunofluorescenctdetection of BKCa and Toll-like receptor (TLR4). For tension recordings, LPS was administered to determine its effect on uterine contractions. Paxilline, a BKCa inhibitor, was used to dissect the role of BKCa in uterine contraction in basal and inflammatory states. Finally, patch-clamp recordings were performed to investigate the relationship between LPS, the BKCa channel and membrane currents in mouse myometrial smooth muscle cells (mMSMCs). We confirmed the expression of BKCa and TLR4 in the myometrium of GD18.5 mice and found that inhibiting BKCa channels with paxilline suppressed both spontaneous and LPS-stimulated uterine contractions. Furthermore, application of BKCa inhibitors (paxilline or iberiotoxin) after LPS inhibited BKCa channel activity in mMSMCs. Moreover, pretreatment with BKCa inhibitor or the TLR4 inhibitor suppressed LPS-activated BKCa currents. Our study demonstrates that BKCa channels are involved in both basal and LPS-stimulated uterine contraction in pregnant mice.

Upregulated TIMP1 facilitates and coordinates myometrial contraction by decreasing collagens and cell adhesive capacity during human labor

Myometrial contraction is one of the key events involved in parturition. Increasing evidence suggests the importance of the extracellular matrix (ECM) in this process, in addition to the functional role of myometrial smooth muscle cells, and our previous study identified an upregulated tissue inhibitor of metalloproteinase 1 (TIMP1) in human laboring myometrium compared to nonlabor samples. This study aimed to further explore the potential role of TIMP1 in myometrial contraction. First, we confirmed increased myometrial TIMP1 levels in labor and during labor with cervical dilation using transcriptomic and proteomic analyses, followed by real-time PCR, western blotting, and immunohistochemistry. Then, a cell contraction assay was performed to verify the decreased contractility after TIMP1 knockdown in vitro. To further understand the underlying mechanism, we used RNA-sequencing analysis to reveal the upregulated genes after TIMP1 knockdown; these genes were enriched in collagen fibril organization, cell adhesion, and ECM organization. Subsequently, a human matrix metalloproteinase (MMP) array and collagen staining were performed to determine the TIMPs, MMPs and collagens in laboring and nonlabor myometrium. A real-time cell adhesion assay was used to detect cell adhesive capacity. The results showed upregulated MMP8 and MMP9, downregulated collagens, and attenuated cell adhesive capacity in laboring myometrium, while lower MMP levels and higher collagen levels and cell adhesive capacity were observed in nonlabor. Moreover, TIMP1 knockdown led to restoration of cell adhesive capacity. Together, these results indicate that upregulated TIMP1 during labor facilitates and coordinates myometrial contraction by decreasing collagen and cell adhesive capacity, which may provide effective strategies for the regulation of myometrial contraction.

Placental ion channels: potential target of chemical exposure

The placenta is an important organ for the exchange of substances between the fetus and the mother, hormone secretion, and fetoplacental immunological defense. Placenta has an organ-specific distribution of ion channels and trophoblasts, and placental vessels express a large number of ion channels. Several placental housekeeping activities and pregnancy complications are at least partly controlled by ion channels, which are playing an important role in regulating hormone secretion, trophoblastic homeostasis, ion transport, and vasomotor activity. The function of several placental ion channels (Na, Ca, and Cl ion channels, cation channel, nicotinic acetylcholine receptors, and aquaporin-1) is known to be influenced by chemical exposure, i.e., their responses to different chemicals have been tested and confirmed in experimental models. Here, we review the possibility that placental ion channels are targets of toxicological concern in terms of placental function, fetal growth, and development.

Nicotine in Inflammatory Diseases: Anti-Inflammatory and Pro-Inflammatory Effects

As an anti-inflammatory alkaloid, nicotine plays dual roles in treating diseases. Here we reviewed the anti-inflammatory and pro-inflammatory effects of nicotine on inflammatory diseases, including inflammatory bowel disease, arthritis, multiple sclerosis, sepsis, endotoxemia, myocarditis, oral/skin/muscle inflammation, etc., mainly concerning the administration methods, different models, therapeutic concentration and duration, and relevant organs and tissues. According to the data analysis from recent studies in the past 20 years, nicotine exerts much more anti-inflammatory effects than pro-inflammatory ones, especially in ulcerative colitis, arthritis, sepsis, and endotoxemia. On the other hand, in oral inflammation, nicotine promotes and aggravates some diseases such as periodontitis and gingivitis, especially when there are harmful microorganisms in the oral cavity. We also carefully analyzed the nicotine dosage to determine its safe and effective range. Furthermore, we summarized the molecular mechanism of nicotine in these inflammatory diseases through regulating immune cells, immune factors, and the vagus and acetylcholinergic anti-inflammatory pathways. By balancing the “beneficial” and “harmful” effects of nicotine, it is meaningful to explore the effective medical value of nicotine and open up new horizons for remedying acute and chronic inflammation in humans.

Geniposide protects pulmonary arterial smooth muscle cells from lipopolysaccharide-induced injury via α7nAchR-mediated TLR-4/MyD88 signaling

Geniposide is a bioactive iridoid glucoside derived from Gardenia jasminoides that has proven anti-inflammatory effects against acute lung injury. The aim of this study was to determine whether geniposide could protect pulmonary arterial smooth muscle cells (PASMCs) from lipopolysaccharide (LPS)-induced injury and to explore the participation of α7 nicotinic acetylcholine receptor (α7nAChR), which was previously reported to suppress pro-inflammatory cytokine production in LPS-stimulated macrophages. In the present study, rat PASMCs were isolated and stimulated using LPS. The effect of geniposide on LPS-induced PASMC injury was then explored. Geniposide exerted anti-apoptotic and anti-inflammatory effects on LPS-treated PASMCs, as demonstrated by the downregulation of pro-apoptotic proteins and pro-inflammatory cytokines, respectively. Furthermore, the α7nAChR agonist PNU282987 accentuated the protective effect of geniposide against LPS-induced injury in PASMCs by inhibiting toll-like receptor-4/myeloid differentiation primary response 88 (TLR-4/MyD88) signaling and downregulating nuclear factor (NF)-κB expression. Conversely, methyllycaconitine, an inhibitor of α7nAChR, attenuated the effects of geniposide. These findings collectively suggested that in conjunction with geniposide, the activation of α7nAChR may contribute to further mitigating LPS-induced PASMC apoptosis and inflammation. In addition, the underlying mechanisms critically involve the NF-κB/MyD88 signaling axis. These results may provide novel insights into the treatment and management of lung diseases via geniposide administration.

The role of dorsal root ganglia alpha-7 nicotinic acetylcholine receptor in complete Freund's adjuvant-induced chronic inflammatory pain

BACKGROUND

Alpha-7 nicotinic acetylcholine receptor (α7 nAChR) was reported to have a critical role in the regulation of pain sensitivity and neuroinflammation. However, the expression level of α7 nAChR in dorsal root ganglion (DRG) and the underlying neuroinflammatory mechanisms associated with hyperalgesia are still unknown.

METHODS

In the present study, the expression and mechanism of α7 nAChR in chronic inflammatory pain was investigated using a complete Freund's adjuvant (CFA)-induced chronic inflammatory pain model. Subsequently, a series of assays including immunohistochemistry, western blotting, and quantitative real-time polymerase chain reaction (qRT-PCR) were performed.

RESULTS

α7 nAChR was mostly colocalized with NeuN in DRG and upregulated after CFA injection. Microinjection of α7 nAChR siRNA into ipsilateral L4/5 DRGs aggravated the CFA-induced pain hypersensitivity. Intrathecal α7 nAChR agonist GTS-21 attenuated the development of CFA-induced mechanical and temperature-related pain hypersensitivities. In neuronal the SH-SY5Y cell line, the knockdown of α7 nAChRs triggered the upregulation of TRAF6 and NF-κB under CFA-induced inflammatory conditions, while agitation of α7 nAChR suppressed the TRAF6/NF-κB activation. α7 nAChR siRNA also exacerbated the secretion of pro-inflammatory mediators from LPS-induced SH-SY5Y cells. Conversely, α7 nAChR-specific agonist GTS-21 diminished the release of interleukin-1beta (IL-1β), IL-6, IL-8, and tumor necrosis factor-α (TNFα) in SH-SY5Y cells under inflammatory conditions. Mechanistically, the modulation of pain sensitivity and neuroinflammatory action of α7 nAChR may be mediated by the TRAF6/NF-κB signaling pathway.

CONCLUSIONS

The findings of this study suggest that α7 nAChR may be potentially utilized as a therapeutic target for therapeutics of chronic inflammatory pain.

Modulation of preeclampsia by the cholinergic anti-inflammatory pathway: Therapeutic perspectives

The cholinergic anti-inflammatory pathway (CAP) is vital for the orchestration of the immune and inflammatory responses under normal and challenged conditions. Over the past two decades, peripheral and central circuits of CAP have been shown to be critically involved in dampening the inflammatory reaction in a wide array of inflammatory disorders. Additionally, emerging evidence supports a key role for CAP in the regulation of the female reproductive system during gestation as well as in the advent of serious pregnancy-related inflammatory insults such as preeclampsia (PE). Within this framework, the modulatory action of CAP encompasses the perinatal maternal and fetal adverse consequences that surface due to antenatal PE programming. Albeit, a considerable gap still exists in our knowledge of the precise cellular and molecular underpinnings of PE/CAP interaction, which hampered global efforts in safeguarding effective preventive or therapeutic measures against PE complications. Here, we summarize reports in the literature regarding the roles of peripheral and reflex cholinergic neuroinflammatory pathways of nicotinic acetylcholine receptors (nAChRs) in reprogramming PE complications in mothers and their progenies. The possible contributions of α7-nAChRs, cholinesterases, immune cells, adhesion molecules, angiogenesis, and endothelial dysfunction to the interaction have also been reviewed.

Nicotine induces maternal and fetal inflammatory responses which predispose intrauterine infection risk in a rat model

Introduction

Both smoking and infection adversely impact pregnancy. Previously, our group identified in a rodent model that 6 mg/kg/d nicotine increased the risk of fetal infection at gestation day (GD) 18. Here, we investigate lower nicotine doses.

Methods

Pregnant Sprague-Dawley rats received nicotine infusion at 0, 1, or 3 mg/kg/d (no, low-, and mid-dose nicotine, respectively) from GD 6, with intravenous inoculation with Mycoplasma pulmonis (MP) at 10⁷ CFU (N = 20) or sterile broth (sham) (N = 11) on GD 14. Uterus and fetuses were retrieved on GD 18 for MP culture and histopathologic evaluation of maternal and fetal inflammatory responses (MIR and FIR).

Results

At 1 mg/kg/d nicotine, MP colonization rates were decreased, from 100% (9 of 9) to 40% (2 of 5) of MP-inoculated dams (p = .03), and 59% (66 of 111) to 39% (24 of 62) of fetuses (p = .01), versus no nicotine. Low-dose nicotine resulted in increased MIR and FIR in the sham-inoculated group; in the MP-inoculated group, this resulted in reduced relative risk (RR) for placental colonization (RR, 95% CI with high MIR = 0.14, 0.02 to 0.65; FIR = 0.38, 0.12 to 0.93). In contrast, 3 mg/kg/d nicotine treatment did not alter colonization rates; furthermore, FIR was completely suppressed, even in the face of placental or amniotic fluid colonization.

Conclusion

The 1 mg/kg/d nicotine dose decreased risk of intrauterine infection, with increased MIR and FIR. The 3 mg/kg/d nicotine dose inhibited FIR, and increased risk for intrauterine infection. Nicotine alterations of the intrauterine environment were markedly dose-dependent.

Implications

Nicotine exposure alters intrauterine infection and inflammation in a dose-dependent manner, potentially impacting fetal development and programming. Previous work in a rodent model showed that high-dose nicotine (6 mg/kg/d) exposure exacerbated intrauterine infection during pregnancy. The current study found that low-dose nicotine (1 mg/kg/d) exposure reduced colonization of placenta and amniotic fluid; this decrease was associated with increased intrauterine inflammation. Exposure to mid-dose nicotine (3 mg/kg/d) suppressed fetal inflammation. Elucidation of underlying mechanisms of these phenomena will inform public health and clinical care decisions, particularly in the context of risk assessment of nicotine replacement therapy during pregnancy for smoking cessation.

Potential Suppressive Effect of Nicotine on the Inflammatory Response in Oral Epithelial Cells: An In Vitro Study

Smoking is a well-recognized risk factor for oral mucosal and periodontal diseases. Nicotine is an important component of cigarette smoke. This study aims to investigate the impact of nicotine on the viability and inflammatory mediator production of an oral epithelial cell line in the presence of various inflammatory stimuli. Oral epithelial HSC-2 cells were challenged with nicotine (10⁻⁸–10⁻² M) for 24 h in the presence or absence of Porphyromonas gingivalis lipopolysaccharide (LPS, 1 µg/mL) or tumor necrosis factor (TNF)-α (10⁻⁷ M) for 24 h. The cell proliferation/viability was determined by MTT assay. Gene expression of interleukin (IL)-8, intercellular adhesion molecule (ICAM)-1, and β-defensin was assayed by qPCR. The production of IL-8 protein and cell surface expression of ICAM-1 was assessed by ELISA and flow cytometry, respectively. Proliferation/viability of HSC-2 cells was unaffected by nicotine at concentrations up to 10⁻³ M and inhibited at 10⁻² M. Nicotine had no significant effect on the basal expression of IL-8, ICAM-1, and β-defensin. At the same time, it significantly diminished P. gingivalis LPS or the TNF-α-induced expression levels of these factors. Within the limitations of this study, the first evidence was provided in vitro that nicotine probably exerts a suppressive effect on the production of inflammatory mediators and antimicrobial peptides in human oral epithelial cells.

Nicotine reverses the enhanced renal vasodilator capacity in endotoxic rats: Role of α7/α4β2 nAChRs and HSP70

BACKGROUND

Nicotine alleviates renal inflammation and injury induced by endotoxemia. This study investigated (i) the nicotine modulation of hemodynamic and renal vasodilatory responses to endotoxemia in rats, and (ii) roles of α7 or α4β2-nAChRs and related HSP70/TNFα/iNOS signaling in the interaction.

METHODS

Endotoxemia was induced by ip lipopolysaccharide (5 mg/kg/day, for 2 days) and changes in systolic blood pressure and vasodilator responsiveness of isolated perfused kidney to acetylcholine or 5'-N-ethylcarboxamidoadenosine (NECA, adenosine receptor agonist) were evaluated.

RESULTS

Lipopolysaccharide had no effect on serum creatinine, reduced blood pressure, and increased renal vasodilations induced by acetylcholine or NECA in male and female preparations. Immunohistochemical analyses showed that lipopolysaccharide reduced renal HSP70 expression, but increased α7-nAChRs, α4β2-nAChRs and iNOS expressions. The co-administration of aminoguanidine (iNOS inhibitor), pentoxifylline (TNFα inhibitor), or nicotine attenuated lipopolysaccharide mediation of renal vasodilations and elevations in α7/α4β2-nAChR and iNOS expressions. Nicotine also reversed the downregulating effect of lipopolysaccharide on HSP70 expression. α7-nAChRs (methyllycaconitine citrate, MLA) or α4β2-nAChRs (dihydro-β-erythroidine, DHβE) blockade potentiated the lipopolysaccharide enhancement of renal vasodilations, and abolished the depressant effect of nicotine on lipopolysaccharide responses. A similar abolition of nicotine effects was seen after HSP70 inhibition by quercetin. Alternatively, lipopolysaccharide hypotension was eliminated in rats treated with DHβE/nicotine or quercetin/nicotine regimen in contrast to no effect for nicotine alone or combined with MLA.

CONCLUSIONS

These findings establish that nicotine offsets lipopolysaccharide facilitation of renal vasodilations possibly through a crosstalk between HSP70 and nAChRs of the α7 and α4β2 types.

Nicotine protects fetus against LPS-induced fetal growth restriction through ameliorating placental inflammation and vascular development in late pregnancy in rats

Our previous work has shown that nicotine suppressed lipopolysaccharide (LPS)-induced placental inflammation by inhibiting cytokine release as well as infiltration of leukocytes into the placenta through the cholinergic anti-inflammatory pathway. Nicotine also increased fetal survival and restored pup weight. In the present study, we aim to further investigate if fetal growth restriction (FGR) occurs with LPS treatment, and evaluate the protective effects of nicotine on fetuses in late gestation of rats. Pregnant Sprague–Dawley rats were divided into control group, nicotine group, LPS group and LPS + nicotine group. Rats were first pretreated with nicotine or vehicle by subcutaneous injection on gestation day (GD)14 and GD15, followed by LPS or vehicle intraperitoneal injection on GD16, and were killed on GD18. Loss of fetuses, number and weights of live fetuses and weights of placentas were recorded. Placentas were collected to evaluate placental pathology and determine inflammatory cytokines and vascular endothelial growth factor (VEGF) levels. We found that LPS treatment increased levels of placental inflammatory cytokines and placental pathological damage, decreased levels of VEGF, reduced number of live fetuses and induced FGR. Pretreatment with nicotine reversed LPS-induced high levels of placental inflammatory cytokines, low levels of placental VEGF and placental pathological damage, then rescued the number and weights of live fetuses. These data demonstrated that activation of the cholinergic anti-inflammatory pathway by nicotine protected fetus against LPS-induced FGR through ameliorating placental inflammation and vascular development in late pregnancy in rats. It may be an alternative therapeutic strategy for inflammation- induced FGR in late pregnancy.

Neuroinflammation and Cytokines in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Critical Review of Research Methods

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is the label given to a syndrome that can include long-term flu-like symptoms, profound fatigue, trouble concentrating, and autonomic problems, all of which worsen after exertion. It is unclear how many individuals with this diagnosis are suffering from the same condition or have the same underlying pathophysiology, and the discovery of biomarkers would be clarifying. The name "myalgic encephalomyelitis" essentially means "muscle pain related to central nervous system inflammation" and many efforts to find diagnostic biomarkers have focused on one or more aspects of neuroinflammation, from periphery to brain. As the field uncovers the relationship between the symptoms of this condition and neuroinflammation, attention must be paid to the biological mechanisms of neuroinflammation and issues with its potential measurement. The current review focuses on three methods used to study putative neuroinflammation in ME/CFS: (1) positron emission tomography (PET) neuroimaging using translocator protein (TSPO) binding radioligand (2) magnetic resonance spectroscopy (MRS) neuroimaging and (3) assays of cytokines circulating in blood and cerebrospinal fluid. PET scanning using TSPO-binding radioligand is a promising option for studies of neuroinflammation. However, methodological difficulties that exist both in this particular technique and across the ME/CFS neuroimaging literature must be addressed for any results to be interpretable. We argue that the vast majority of ME/CFS neuroimaging has failed to use optimal techniques for studying brainstem, despite its probable centrality to any neuroinflammatory causes or autonomic effects. MRS is discussed as a less informative but more widely available, less invasive, and less expensive option for imaging neuroinflammation, and existing studies using MRS neuroimaging are reviewed. Studies seeking to find a peripheral circulating cytokine "profile" for ME/CFS are reviewed, with attention paid to the biological and methodological reasons for lack of replication among these studies. We argue that both the biological mechanisms of cytokines and the innumerable sources of potential variance in their measurement make it unlikely that a consistent and replicable diagnostic cytokine profile will ever be discovered.

Nicotine and sleep deprivation: impact on pain sensitivity and immune modulation in rats

Repeated nicotine administration has been associated with increased paradoxical sleep in rats and antinociceptive properties, whereas paradoxical sleep deprivation (PSD) elicits pronociceptive and inflammatory responses. Thus, we aimed to evaluate the effect of repeated nicotine administration and its withdrawal combined with PSD on pain sensitivity and inflammatory markers. Sixty adult male Wistar rats were subjected to repeated injections of saline (SAL) or nicotine (NIC) for 12 days or 7 days of nicotine followed by acute mecamylamine administration on day 8 to precipitate nicotine abstinence (ABST). On day 9, the animals were submitted to PSD for 72 h or remained in control condition (CTRL); on day 12, thermal pain threshold was assessed by the hot plate test. PSD significantly decreased the latency to paw withdrawal in all groups compared to their respective controls. ABST-PSD animals presented higher levels of interleukin (IL)-6 compared to all groups, except ABST-CTRL. After adjustment for weight loss, IL-6, IL-4 and tumor necrosis factor alpha, ABST-PSD was associated with the lowest pain threshold. Nicotine and IL-4 levels were predictors of higher pain threshold. Hyperalgesia induced by PSD prevailed over the antinociceptive action of nicotine, while the association between PSD and ABST synergistically increased IL-6 concentrations and decreased pain threshold.

Trigonelline Inhibits Inflammation and Protects β Cells to Prevent Fetal Growth Restriction during Pregnancy in a Mouse Model of Diabetes

Background: As an active component from traditional Chinese medicine, trigonelline has a protective effect on diabetes. This study evaluated the protective effects of trigonelline on diabetic mice during pregnancy. Methods: Diabetes was induced in female mice by intraperitoneal injection for continuous 5-day of 40 mg/kg/day streptozotocin. Female mice were divided into 4 groups after they were allowed to mate with normal male mice: nondiabetic, nondiabetic treated with trigonelline (70 mg/kg) for 18 days, diabetic, and diabetic treated with trigonelline (70 mg/kg). Results: Diabetic pregnant mice had significantly higher levels of blood glucose, serum total cholesterol, triglyceride, insulin, and leptin but lower serum omentin-1 level and insulin sensitivity index than the nondiabetic ones. Trigonelline improved the hyperglycemia, dyslipidemia, insulin resistance, and adipocytokine of diabetic pregnant mice. Diabetic pregnant mice had significantly reduced fetus numbers, fetal weight, and fetal/placental ratio, which were reversed by trigonelline. Trigonelline prevented the increase in proinflammatory cytokines and reduced interleukin-10 level in placenta of diabetic pregnant mice. Trigonelline increased β-cell replication and the decreased β-cell mass, and decreased the β-cell apoptosis of diabetic pregnant mice. Conclusion: These findings suggest that trigonelline protects diabetic pregnancy partly by suppressing inflammation, regulating the secretion of adipocytokines, increasing β-cell mass, replication, and decreasing β-cell apoptosis.

Choline Supplementation During Pregnancy Protects Against Gestational Lipopolysaccharide-Induced Inflammatory Responses

OBJECTIVES

To estimate the effects and mechanisms of choline, an essential nutrient and a selective α7 nicotinic acetylcholine receptor (α7nAChR) agonist, on the prevention of symptoms and the effects on the cholinergic anti-inflammatory pathways (CAP) in a lipopolysaccharide (LPS)-induced inflammatory response in a rat model.

METHODS

Inflammation was induced by LPS treatment (1.0 μg LPS/kg body weight) on gestational day (GD) 14. Nonpregnant and pregnant Sprague Dawley rats were placed on a normal choline diet (1.1 g/kg) or supplemented choline diet (5.0 g/kg) from GDs 1 to 20. Systolic blood pressure (SBP), urinary albumin, and pregnancy outcomes were recorded. On GD 20, serum and placentas were assayed for cytokines. Western blots were used to determine the expression of placenta α7nAChR and components of the α7nAChR-CAP, including nuclear factor-κB (NF-κB) and protein kinase B (AKT). Immunohistochemistry was used to localize placental sites for the p65 subunit of NF-κB.

RESULTS

Lipopolysaccharide significantly increased SBP and urinary albumin and decreased pregnancy outcomes, and these effects were partially reversed by higher choline treatment. Choline supplementation also significantly attenuated the LPS-induced increase in serum and placental inflammatory cytokines, decreased the expression of placental α7nAChR, lowered the activation of NF-κB signaling in placenta mononuclear cells, and inhibited placental AKT phosphorylation.

CONCLUSION

This study confirms that LPS induces inflammatory conditions in pregnant rats and shows that choline supplementation protects against the inflammatory symptoms through its action on α7nAChR and CAP. These observations have important implications for the prevention and treatment of inflammatory responses associated with pregnancy.