Environmental tobacco smoke exposure during pregnancy has limited effect on infant birthweight and umbilical vein endothelial nitric oxide synthase

Serum cotinine cut-points for secondhand smoke exposure assessment in children under 5 years: A systemic review

Background

Serum cotinine has become the most widely used biomarker of secondhand smoke exposure (SHS) over time in all ages. The aim of this study was to review the serum cotinine cut-points used to classify children under 5 years as exposed to SHS.

Methods

A systematic review performed in the Pubmed (MEDLINE) and EMBASE databases up to April 2021 was conducted using as key words "serum cotinine", “tobacco smoke pollution” (MeSH), "secondhand smoke", "environmental tobacco smoke" and “tobacco smoke exposure”. Papers which assessed SHS exposure among children younger than 5 years old were included. The PRISMA 2020 guidelines were followed. Analysis was pre-registered in PROSPERO (registration number: CRD42021251263).

Results

247 articles were identified and 51 fulfilled inclusion criteria. The selected studies were published between 1985–2020. Most of them included adolescents and adults. Only three assessed postnatal exposure exclusively among children under 5 years. None of the selected studies proposed age-specific cut-points for children < 5 years old. Cut-point values to assess SHS exposure ranged from 0.015 to 100 ng/ml. The most commonly used cut-point was 0.05 ng/ml, derived from the assay limit of detection used by the National Health and Nutrition Examination Survey (NHANES).

Conclusions

No studies have calculated serum cotinine age-specific cut-points to ascertained SHS exposure among children under 5 years old. Children’s age-specific cut-points are warranted for health research and public health purposes aimed at accurately estimating the prevalence of SHS exposure and attributable burden of disease to such exposure, and at reinforcing 100% smoke-free policies worldwide, both in homes, private vehicles and public places.

Fenofibrate Prevents nicotine-induced Acute Kidney Injury: Possible Involvement of Endothelial Nitric Oxide Synthase

Objective:

The present study investigated the possible effect of fenofibrate (peroxisome proliferator-activated receptors-α agonist) in nicotine-induced acute kidney injury (AKI) in rats.

Materials and Methods:

Nicotine (2 mg/kg/day, intraperitoneally) was administered for 4 weeks to induce AKI in rats. Lipid profile and renal oxidative stress were measured and expression of mRNA for eNOS was assessed using reverse transcription-polymerase chain reaction along with serum and renal tissue nitrite levels. Serum creatinine, blood urea nitrogen and microproteinuria were estimated along with the kidney histology, as markers of kidney function. Treatment with fenofibrate (30 mg/kg per oral, 4 weeks) was initiated 3 days before the administration of nicotine and continued for 4 weeks from the day of administration of nicotine.

Results:

Nicotine administered rats developed apparent AKI confirmed by elevated markers of kidney function and noticeable glomerulosclerosis and tubular cell degeneration. Nicotine decreases the expression of mRNA for eNOS, along with serum and renal tissue nitrite levels. In addition, nicotine showed significantly lipid alteration beside decrease oxidative stress, assessed in terms of increase in serum thiobarbituric acid reactive substance and a marked decrease in tissue reduced glutathione. However, fenofibrate significantly prevented the development of nicotine-AKI by reducing serum creatinine, BUN, and urinary protein, normalizing the lipid profile, reducing renal oxidative stress, increases the eNOS expression and concentration of serum and renal nitrate levels.

Conclusion:

Fenofibrate attenuates nicotine-induced AKI, via its antihyperlipidemic and antioxidant property. Moreover, fenofibrate induced upregulation of eNOS expression additionally play key roles in the improvement of nicotine-induced AKI could be the future alternative.

Plasma fibulin-1 levels during pregnancy and delivery: a longitudinal observational study

Background

Fibulin-1 is an extracellular matrix protein expressed at high levels in the placenta. Elevated circulating fibulin-1 have been observed in women with severe pre-eclampsia, whereas low levels have been found in the fetal membranes, prior to membrane rupture. The aim of the study was primarily to evaluate plasma fibulin-1 during expected normal pregnancy and delivery, and secondarily to explore fibulin-1 levels in women developing pre-eclampsia or preterm premature rupture of fetal membranes (PPROM).

Methods

From the historical longitudinal cohort originally consisting of 801 healthy Danish women with a singleton pregnancy, 128 women (632 samples) were selected. Of these, 107 women had normal pregnancies, nine experienced PPROM, and 12 pre-eclampsia. All samples were analyzed for fibulin-1, and levels were compared with blood donors. Differences in mean fibulin-1 between groups were estimated using a linear mixed model.

Results

The mean concentration of fibulin-1 in 120 blood donors was 15.7 µg/mL, (25th-75th-percentiles, 12.3–18.2), with no significant difference in groups stratified by gender or age. Compared to baseline levels in week 12–20, fibulin-1 levels increased significantly from week 29–34 (estimated difference, 5.6 µg/mL; standard error, 1.7; p < 0.001) and 35–42 (12.5 µg/mL; 1.6; p < 0.001) and normalized after birth. The decrease at delivery tended to be more pronounced after elective (-7.0 µg/mL; 2.3; p = 0.002) and emergency (-5.6 µg/mL; 2.9; p = 0.05) cesarean section than after vaginal delivery (reference group). Women who developed PPROM had lower fibulin-1 levels throughout their pregnancies (-11.6 µg/mL; 4.2; p = 0.006). We did not observe a correlate between late pre-eclampsia and fibulin-1 (-0.2 µg/mL; 3.0; p = 0.9).

Conclusions

Fibulin-1 was above non-pregnant levels at week 12 and increased significantly throughout pregnancy. We observed an association between low levels of fibulin-1 and PPROM. Further studies are needed to examine if fibulin-1 could serve as biomarker for the risk of PPROM. However, its role in late preeclampsia is doubtful.

Trial registration

The study was conducted in accordance with the Declaration of Helsinki. The participants provided written informed consent, including storage for future use. The study was approved on July 18, 2005 by The Danish National Committee on Bioethics (No. KA 05065 and S-20,090,061) and the Danish Data Protection Agency.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04110-y.

Newborn infant urinary cotinine and birth outcomes in the Jerusalem Environment Mother and Child Cohort Study

BACKGROUND

Environmental tobacco smoke (ETS) exposure during pregnancy can cause preterm delivery and childhood cancer. The aim of this study was to measure ETS exposure in pregnant women and in newborn infants in Israel using urinary cotinine measurements, to assess predictors of ETS exposure in these vulnerable groups, and to assess associations with birth effects (birth weight, birth length, head circumference) in newborn infants.

METHODS

We analyzed urinary cotinine and creatinine in 265 non-smoking pregnant women and 97 newborns, and analyzed associations with self-reported exposure to ETS, paternal smoking, sociodemographic variables and with birth outcomes (birth weight, birth length, head circumference).

RESULTS

37.7% of pregnant women and 29.0% of infants had urinary cotinine concentrations above the level of quantification (LOQ) of 1 μg/L, whereas 63.8% and 50.5%, respectively, had urinary cotinine concentrations above the level of detection (LOD) of 0.5 μg/L. Median unadjusted and creatinine adjusted urinary concentrations of cotinine in pregnant women were 0.7 μg/L, and 0.9 μg/g creatinine, respectively, and in newborn infants were 0.5 μg/L, and 1.3 μg/g creatinine, respectively. We did not find an association between maternal and infant urinary cotinine level. Maternal (but not infant) urinary cotinine was significantly associated with paternal smoking (p < 0.05). Infant (but not maternal) cotinine above the LOQ was negatively associated with birth weight (p < 0.05).

CONCLUSIONS

In this high socioeconomic cohort, almost a third of newborn infants born to non-smoking mothers had quantifiable levels of urinary cotinine. This is the first study showing that newborns with quantifiable urinary cotinine levels have lower birth weight.