Association between low ambient temperature during pregnancy and adverse birth outcomes: A systematic review and meta-analysis

G-CSF + plerixafor versus G-CSF alone mobilized hematopoietic stem cells in patients with multiple myeloma and lymphoma: a systematic review and meta-analysis

AIM

The combination of granulocyte-colony stimulating factor (G-CSF) and plerixafor is one of the approaches for hematopoietic stem cell mobilization in patients with multiple myeloma (MM), non-Hodgkin's lymphoma (NHL), and Hodgkin's lymphoma (HL). This systematic review and meta-analysis aimed to determine the ability of G-CSF + plerixafor to mobilize peripheral blood (PB) CD34+ cells and examine its safety profile.

METHODS

We performed a database search using the terms 'granulocyte colony stimulating factor', 'G-CSF', 'AMD3100', and 'plerixafor', published up to May 1, 2023. The methodology is described in further detail in the PROSPERO database (CRD42023425760).

RESULTS

Twenty-three studies were included in this systematic review and meta-analysis. G-CSF + plerixafor resulted in more patients achieving the predetermined apheresis yield of CD34+ cells than G-CSF alone (OR, 5.33; 95%, 4.34-6.55). It was further discovered that G-CSF + plerixafor could mobilize more CD34+ cells into PB, which was beneficial for the next transplantation in both randomized controlled (MD, 18.30; 95%, 8.74-27.85) and single-arm (MD, 20.67; 95%, 14.34-27.00) trials. Furthermore, G-CSF + plerixafor did not cause more treatment emergent adverse events than G-CSF alone (OR, 1.25; 95%, 0.87-1.80).

CONCLUSIONS

This study suggests that the combination of G-CSF and plerixafor, resulted in more patients with MM, NHL, and HL, achieving the predetermined apheresis yield of CD34+ cells, which is related to the more effective mobilization of CD34+ cells into PB.

Environmental copper exposure, placental cuproptosis, and miscarriage

Copper pollution has become global environmental concern. Widespread Cu pollution results in excessive Cu exposure in human. Epidemiological studies and animal experiments revealed that Cu exposure might have reproductive toxicity. Cuproptosis is a newly reported Cu-dependent and programmed cell death formTsvetkov et al., 2022. However, whether copper exposure at real environmental exposure dose might cause placental cuproptosis and induce miscarriage was completely unexplored. In this study, we found that Cu exposure during pregnancy induced miscarriage or complete pregnancy loss by inducing placenta cuproptosis in CuCl2-exposed pregnant mice. Notably, Cu exposure at 1.3 mg/kg/d (a real environmental exposure dose) was enough to cause placenta cuproptosis. CuCl2 exposure disrupts the TCA cycle, causes proteotoxic stress, increases Cu2+ ion import/decreases Cu2+ export, and results in the loss of Fe-S cluster proteins in mouse placenta, which induces placenta cuproptosis. Moreover, we also identified that Cu exposure down-regulates the expression levels of mmu-miR-3473b, which interacts with Dlst or Rtel1 mRNA and simultaneously positively regulates Dlst or Rtel1 expression, thereby disrupting the TCA cycle and resulting in the loss of Fe-S cluster proteins, and thus epigenetically regulates placental cuproptosis. Treatment with TTM (a cuproptosis inhibitor) suppressed placental cuproptosis and alleviated miscarriage in CuCl2-exposed mice. This work provides novel reproductive toxicity of Cu exposure in miscarriage or complete pregnancy loss by causing placental cuproptosis. This study also provides new ways for further studies on other toxicological effects of Cu and proposes a new approach for protection against Cu-induced reproductive diseases.

Ambient temperature and preterm birth: A case-crossover study

OBJECTIVE

To investigate the association between ambient temperature and preterm birth (PTB) and to estimate the population attributable fraction (PAF) of PTBs due to low and high temperatures.

DESIGN

Time-stratified case-crossover design.

SETTING

Japan (46 prefectures, excluding Okinawa), 2011-2020.

SAMPLE

214 050 PTBs registered in the Japan Perinatal Registry Network database among 1 908 168 singleton live births.

METHODS

A quasi-Poisson regression model with a distributed lag nonlinear model was employed to assess the associations between daily mean temperature and PTBs for a lag of 0-27 days in each prefecture. A random effects meta-analysis was conducted by combining effect estimates from the 46 prefectures to estimate pooled relative risks (RRs). The PAFs of the PTBs due to below or above the mean of the 46 median temperatures (16.0°C) were calculated.

MAIN OUTCOME MEASURES

Preterm singleton live births.

RESULTS

The association between daily mean temperature and PTB risk exhibited a U-shaped curve. The adjusted RRs were 1.15 (95% confidence interval [CI] 1.05-1.25) at the mean of the 1st percentiles (0.8°C) and 1.08 (95% CI 1.00-1.17) at the mean of the 99th percentiles (30.2°C) of 46 prefectures, with 16.0°C as the reference temperature. Approximately 2.3% (95% CI 0.6-4.0) of PTBs were attributable to low temperatures.

CONCLUSIONS

Both low and possibly high temperatures were associated with an increased risk of PTBs. These findings may help to inform preventive measures for pregnant women.

Maternal exposure to ambient air temperature and adverse birth outcomes: An umbrella review of systematic reviews and meta-analyses

BACKGROUND

Multiple systematic reviews on prenatal ambient temperature and adverse birth outcomes exist, but the overall epidemiological evidence and the appropriate metric for thermal stress remain unclear. An umbrella review was performed to summarise and appraise the evidence with recommendations.

METHODS

Systematic reviews and meta-analyses on the associations between ambient temperature and adverse birth outcomes (preterm birth, stillbirth, birth weight, low birth weight, and small for gestational age) up to December 20, 2023, were synthesised according to a published protocol. Databases PubMed, CINAHL, Scopus, MEDLINE/Ovid, EMBASE/Ovid, Web of Science Core Collection, systematic reviews repositories, electronic grey literature, and references were searched. Risk of bias was assessed using Joanna Briggs Institute's critical appraisal tool.

RESULTS

Eleven systematic reviews, including two meta-analyses, were included. This comprised 90 distinct observational studies that employed multiple temperature assessment metrics with a very high overlap of primary studies. Primary studies were mostly from the United States while both Africa and South Asia contributed only three studies. A majority (7 out of 11) of the systematic reviews were rated as moderate risk of bias. All systematic reviews indicated that maternal exposures to both extremely high and low temperatures, particularly during late gestation are associated with increased risks of preterm birth, stillbirth, and reduced fetal growth. However, due to great differences in the exposure assessments, high heterogeneity, imprecision, and methodological limitations of the included systematic reviews, the overall epidemiological evidence was classified as probable evidence of causation. No study assessed biothermal metrics for thermal stress.

CONCLUSIONS

Despite the notable methodological differences, prenatal exposure to extreme ambient temperatures, particularly during late pregnancy, was associated with adverse birth outcomes. Adhering to the appropriate systematic review guidelines for environmental health research, incorporating biothermal metrics into exposure assessment, evidence from broader geodemographic settings, and interventions are recommended in future studies.