The burden of prenatal and early life maternal substance use among children at risk of maltreatment: A systematic review

ISSUES

Although maternal substance use is a known risk factor for child maltreatment, evidence on the scale of substance use is needed to inform prevention responses. This systematic review synthesised prevalence estimates of maternal substance use during pregnancy and early life among children at risk of maltreatment. Ovid, Pubmed, CINAHL, PsychInfo and ProQuest databases were searched. We included observational studies that sampled children at risk of maltreatment in high-income countries and reported information on maternal substance use during pregnancy and/or the child's first year of life. We extracted study characteristics and data to calculate prevalence, assessed risk of bias and conducted a narrative synthesis; there were insufficient comparable populations or outcomes to quantitatively synthesise results.

KEY FINDINGS

Thirty five of 14,084 titles were included. Fifteen studies had adequately sized and representative samples to estimate prevalence. Maternal substance use prevalence ranged from 2.4% to 40.6%. Maternal substance use was highest among infants referred to child protection at birth (40.6%) and children in out-of-home care (10.4% to 37.2%). Prevalence was higher when studies defined substance use more broadly and when maternal substance use was ascertained from both child and mother records.

IMPLICATIONS

Supportive, coordinated responses to maternal substance use are needed from health and child protection services, spanning alcohol and other drug treatment, antenatal and postnatal care.

CONCLUSIONS

Prenatal and early life maternal substance use is common among child maltreatment populations, particularly among younger children and those with more serious maltreatment.

Prevalence and Persistence of Prescription Opioid Use Following Hospital Discharge After Childbirth: An Australian Population-Based Cohort Study

BACKGROUND

Opioid analgesics are used for acute postpartum pain relief but carry risks, including persistent long-term opioid use. Our primary objective was to estimate the prevalence of persistent use following hospital discharge after childbirth.

METHODS

We conducted a population-based cohort study of women discharged from public or private hospitals in New South Wales, Australia, between 2012 and 2018 following vaginal birth (VB) or cesarean delivery (CD). We used linked hospitalization and medicine dispensing data to calculate the prevalence of opioid use within 14 days of hospital discharge for childbirth using an external estimate of the total number of hospital admissions for childbirth per year as the denominator. Among women dispensed an opioid postdischarge, we estimated the prevalence of persistent use defined as ≥3 dispensings between 30- and 365-days postdischarge. To calculate the odds of persistent opioid use, we performed a series of logistic regressions each including a single characteristic of interest. Included characteristics were maternal and birth characteristics, maternal medical conditions, prior use of certain medicines, and the initial opioid dispensed following discharge for childbirth.

RESULTS

The final cohort comprised of 38,832 women who were dispensed an opioid in the 14 days following discharge after childbirth. Between 2012 and 2018, the prevalence of opioid use was increased following CD (public hospital 16.6%-21.0%; private hospital 9.8%-19.5%) compared with VB (public hospital 1.5%-1.5%; private hospital 1.2%-1.4%) and was higher following discharge from public hospitals compared with private. The most commonly dispensed opioids following discharge for childbirth were oxycodone (44.8%; 95% confidence interval [CI], 44.3-45.3), codeine (42.1%; 95% CI, 41.6-42.6), and tramadol (12.9%; 95% CI, 12.6-13.2). Among women dispensed an opioid, the prevalence of persistent opioid use was 5.4% (95% CI, 5.1-5.6). This prevalence was 11.4% (95% CI, 10.5-12.3) following a VB as compared with 4.3% (95% CI, 4.1-4.6) among those who underwent a CD ( P < .001). Characteristics associated with persistent opioid use included smoking during pregnancy, age <25 years, living in remote areas, discharged from a public hospital, history of opioid use disorder, other substance use disorder, mental health diagnosis, or prior use of prescription opioids, nonopioid analgesics, or benzodiazepines.

CONCLUSIONS

The results of this cohort study indicate that Australian women have a higher prevalence of opioid use following CD compared to VB. One in 19 women dispensed an opioid postdischarge used opioids persistently. Careful monitoring of opioid therapy following childbirth is warranted, particularly among women with characteristics we identified as high risk for persistent opioid use.

Prostate cancer cell proliferation is influenced by LDL-cholesterol availability and cholesteryl ester turnover

BACKGROUND

Prostate cancer growth is driven by androgen receptor signaling, and advanced disease is initially treatable by depleting circulating androgens. However, prostate cancer cells inevitably adapt, resulting in disease relapse with incurable castrate-resistant prostate cancer. Androgen deprivation therapy has many side effects, including hypercholesterolemia, and more aggressive and castrate-resistant prostate cancers typically feature cellular accumulation of cholesterol stored in the form of cholesteryl esters. As cholesterol is a key substrate for de novo steroidogenesis in prostate cells, this study hypothesized that castrate-resistant/advanced prostate cancer cell growth is influenced by the availability of extracellular, low-density lipoprotein (LDL)-derived, cholesterol, which is coupled to intracellular cholesteryl ester homeostasis.

METHODS

C4-2B and PC3 prostate cancer cells were cultured in media supplemented with fetal calf serum (FCS), charcoal-stripped FCS (CS-FCS), lipoprotein-deficient FCS (LPDS), or charcoal-stripped LPDS (CS-LPDS) and analyzed by a variety of biochemical techniques. Cell viability and proliferation were measured by MTT assay and Incucyte, respectively.

RESULTS

Reducing lipoprotein availability led to a reduction in cholesteryl ester levels and cell growth in C4-2B and PC3 cells, with concomitant reductions in PI3K/mTOR and p38MAPK signaling. This reduced growth in LPDS-containing media was fully recovered by supplementation of exogenous low-density lipoprotein (LDL), but LDL only partially rescued growth of cells cultured with CS-LPDS. This growth pattern was not associated with changes in androgen receptor signaling but rather increased p38MAPK and MEK1/ERK/MSK1 activation. The ability of LDL supplementation to rescue cell growth required cholesterol esterification as well as cholesteryl ester hydrolysis activity. Further, growth of cells cultured in low androgen levels (CS-FCS) was suppressed when cholesteryl ester hydrolysis was inhibited.

CONCLUSIONS

Overall, these studies demonstrate that androgen-independent prostate cancer cell growth can be influenced by extracellular lipid levels and LDL-cholesterol availability and that uptake of extracellular cholesterol, through endocytosis of LDL-derived cholesterol and subsequent delivery and storage in the lipid droplet as cholesteryl esters, is required to support prostate cancer cell growth. This provides new insights into the relationship between extracellular cholesterol, intracellular cholesterol metabolism, and prostate cancer cell growth and the potential mechanisms linking hypercholesterolemia and more aggressive prostate cancer.

Prescription opioid use in Australian women of reproductive age: Implications for unplanned pregnancies

AIMS

To examine trends in the prevalence and incidence of prescription opioid analgesic use in Australian women of reproductive age and to estimate the number of calendar months each year that women were dispensed opioids.

METHODS

We conducted a retrospective cross-sectional study involving women aged 15-44 years using pharmaceutical dispensing claims for a 10% random sample of Australians. For the period 2013-2020, we calculated the annual prevalence and incidence of opioid analgesic dispensing per 100 (%) population by opioid type and age group. We also estimated the total number of calendar months that women were dispensed at least 1 opioid each year.

RESULTS

The prevalence of opioid use decreased from 12.8% in 2013 to 11.3% in 2020, representing a relative decrease of 11.6% (95% confidence interval 10.7, 12.6%). The incidence of opioid use decreased from 10.3% in 2014 to 8.3% in 2020, representing a relative decrease of 18.6% (95% confidence interval 17.6, 19.6%). Codeine in combination products, followed by oxycodone and tramadol, were the most prevalent opioids. Prevalence and incidence of opioid use were lowest in women aged 15-19 years and the highest in women 30 years and above. Among all women dispensed opioids, 72.7% were dispensed an opioid in only 1 month each year.

CONCLUSION

Prescription opioid use remains common, although decreasing, among women of reproductive age in Australia. However, it is reassuring that the majority of opioid use in this population is short term.

Insulin signaling requires glucose to promote lipid anabolism in adipocytes

Adipose tissue is essential for metabolic homeostasis, balancing lipid storage and mobilization based on nutritional status. This is coordinated by insulin, which triggers kinase signaling cascades to modulate numerous metabolic proteins, leading to increased glucose uptake and anabolic processes like lipogenesis. Given recent evidence that glucose is dispensable for adipocyte respiration, we sought to test whether glucose is necessary for insulin-stimulated anabolism. Examining lipogenesis in cultured adipocytes, glucose was essential for insulin to stimulate the synthesis of fatty acids and glyceride-glycerol. Importantly, glucose was dispensable for lipogenesis in the absence of insulin, suggesting that distinct carbon sources are used with or without insulin. Metabolic tracing studies revealed that glucose was required for insulin to stimulate pathways providing carbon substrate, NADPH, and glycerol 3-phosphate for lipid synthesis and storage. Glucose also displaced leucine as a lipogenic substrate and was necessary to suppress fatty acid oxidation. Together, glucose provided substrates and metabolic control for insulin to promote lipogenesis in adipocytes. This contrasted with the suppression of lipolysis by insulin signaling, which occurred independently of glucose. Given previous observations that signal transduction acts primarily before glucose uptake in adipocytes, these data are consistent with a model whereby insulin initially utilizes protein phosphorylation to stimulate lipid anabolism, which is sustained by subsequent glucose metabolism. Consequently, lipid abundance was sensitive to glucose availability, both during adipogenesis and in Drosophila flies in vivo Together, these data highlight the importance of glucose metabolism to support insulin action, providing a complementary regulatory mechanism to signal transduction to stimulate adipose anabolism.

Extracellular Fatty Acids Are the Major Contributor to Lipid Synthesis in Prostate Cancer

Prostate cancer cells exhibit altered cellular metabolism but, notably, not the hallmarks of Warburg metabolism. Prostate cancer cells exhibit increased de novo synthesis of fatty acids (FA); however, little is known about how extracellular FAs, such as those in the circulation, may support prostate cancer progression. Here, we show that increasing FA availability increased intracellular triacylglycerol content in cultured patient-derived tumor explants, LNCaP and C4-2B spheroids, a range of prostate cancer cells (LNCaP, C4-2B, 22Rv1, PC-3), and prostate epithelial cells (PNT1). Extracellular FAs are the major source (∼83%) of carbons to the total lipid pool in all cell lines, compared with glucose (∼13%) and glutamine (∼4%), and FA oxidation rates are greater in prostate cancer cells compared with PNT1 cells, which preferentially partitioned extracellular FAs into triacylglycerols. Because of the higher rates of FA oxidation in C4-2B cells, cells remained viable when challenged by the addition of palmitate to culture media and inhibition of mitochondrial FA oxidation sensitized C4-2B cells to palmitate-induced apoptosis. Whereas in PC-3 cells, palmitate induced apoptosis, which was prevented by pretreatment of PC-3 cells with FAs, and this protective effect required DGAT-1-mediated triacylglycerol synthesis. These outcomes highlight for the first-time heterogeneity of lipid metabolism in prostate cancer cells and the potential influence that obesity-associated dyslipidemia or host circulating has on prostate cancer progression. IMPLICATIONS: Extracellular-derived FAs are primary building blocks for complex lipids and heterogeneity in FA metabolism exists in prostate cancer that can influence tumor cell behavior.

Heterogeneity of fatty acid metabolism in breast cancer cells underlies differential sensitivity to palmitate-induced apoptosis

Breast cancer (BrCa) metabolism is geared toward biomass synthesis and maintenance of reductive capacity. Changes in glucose and glutamine metabolism in BrCa have been widely reported, yet the contribution of fatty acids (FAs) in BrCa biology remains to be determined. We recently reported that adipocyte coculture alters MCF-7 and MDA-MB-231 cell metabolism and promotes proliferation and migration. Since adipocytes are FA-rich, and these FAs are transferred to BrCa cells, we sought to elucidate the FA metabolism of BrCa cells and their response to FA-rich environments. MCF-7 and MDA-MB-231 cells incubated in serum-containing media supplemented with FAs accumulate extracellular FAs as intracellular triacylglycerols (TAG) in a dose-dependent manner, with MDA-MB-231 cells accumulating more TAG. The differences in TAG levels were a consequence of distinct differences in intracellular partitioning of FAs, and not due to differences in the rate of FA uptake. Specifically, MCF-7 cells preferentially partition FAs into mitochondrial oxidation, whereas MDA-MB-231 cells partition FAs into TAG synthesis. These differences in intracellular FA handling underpin differences in the sensitivity to palmitate-induced lipotoxicity, with MDA-MB-231 cells being highly sensitive, whereas MCF-7 cells are partially protected. The attenuation of palmitate-induced lipotoxicity in MCF-7 cells was reversed by inhibition of FA oxidation. Pretreatment of MDA-MB-231 cells with FAs increased TAG synthesis and reduced palmitate-induced apoptosis. Our results provide novel insight into the potential influences of obesity on BrCa biology, highlighting distinct differences in FA metabolism in MCF-7 and MDA-MB-231 cells and how lipid-rich environments modulate these effects.

Detection of the Cyanotoxins L-BMAA Uptake and Accumulation in Primary Neurons and Astrocytes

We show for the first time that a newly developed polyclonal antibody (pAb) can specifically target the cyanotoxin β-methylamino-L-alanine (BMAA) and can be used to enable direct visualization of BMAA entry and accumulation in primary brain cells. We used this pAb to investigate the effect of acute and chronic accumulation, and toxicity of both BMAA and its natural isomer 2,4-diaminobutyric acid (DAB), separately or in combination, on primary cultures of rat neurons. We further present evidence that co-treatment with BMAA and DAB increased neuronal death, as measured by MAP2 fluorescence level, and appeared to reduce BMAA accumulation. DAB is likely to be acting synergistically with BMAA resulting in higher level of cellular toxicity. We also found that glial cells such as microglia and astrocytes are also able to directly uptake BMAA indicating that additional brain cell types are affected by BMAA-induced toxicity. Therefore, BMAA clearly acts at multiple cellular levels to possibly increase the risk of developing neurodegenerative diseases, including neuro- and gliotoxicity and synergetic exacerbation with other cyanotoxins.

Current Evidence for a Role of the Kynurenine Pathway of Tryptophan Metabolism in Multiple Sclerosis

The kynurenine pathway (KP) is the major metabolic pathway of the essential amino acid tryptophan (TRP). Stimulation by inflammatory molecules, such as interferon-γ (IFN-γ), is the trigger for induction of the KP, driving a complex cascade of production of both neuroprotective and neurotoxic metabolites, and in turn, regulation of the immune response and responses of brain cells to the KP metabolites. Consequently, substantial evidence has accumulated over the past couple of decades that dysregulation of the KP and the production of neurotoxic metabolites are associated with many neuroinflammatory and neurodegenerative diseases, including Parkinson’s disease, AIDS-related dementia, motor neurone disease, schizophrenia, Huntington’s disease, and brain cancers. In the past decade, evidence of the link between the KP and multiple sclerosis (MS) has rapidly grown and has implicated the KP in MS pathogenesis. KP enzymes, indoleamine 2,3-dioxygenase (IDO-1) and tryptophan dioxygenase (highest expression in hepatic cells), are the principal enzymes triggering activation of the KP to produce kynurenine from TRP. This is in preference to other routes such as serotonin and melatonin production. In neurological disease, degradation of the blood–brain barrier, even if transient, allows the entry of blood monocytes into the brain parenchyma. Similar to microglia and macrophages, these cells are highly responsive to IFN-γ, which upregulates the expression of enzymes, including IDO-1, producing neurotoxic KP metabolites such as quinolinic acid. These metabolites circulate systemically or are released locally in the brain and can contribute to the excitotoxic death of oligodendrocytes and neurons in neurological disease principally by virtue of their agonist activity at N-methyl-d-aspartic acid receptors. The latest evidence is presented and discussed. The enzymes that control the checkpoints in the KP represent an attractive therapeutic target, and consequently several KP inhibitors are currently in clinical trials for other neurological diseases, and hence may make suitable candidates for MS patients. Underpinning these drug discovery endeavors, in recent years, several advances have been made in how KP metabolites are assayed in various biological fluids, and tremendous advancements have been made in how specimens are imaged to determine disease progression and involvement of various cell types and molecules in MS.

Expression of the Kynurenine Pathway in Human Peripheral Blood Mononuclear Cells: Implications for Inflammatory and Neurodegenerative Disease

The kynurenine pathway is a fundamental mechanism of immunosuppression and peripheral tolerance. It is increasingly recognized as playing a major role in the pathogenesis of a wide variety of inflammatory, neurodegenerative and malignant disorders. However, the temporal dynamics of kynurenine pathway activation and metabolite production in human immune cells is currently unknown. Here we report the novel use of flow cytometry, combined with ultra high-performance liquid chromatography and gas chromatography-mass spectrometry, to sensitively quantify the intracellular expression of three key kynurenine pathway enzymes and the main kynurenine pathway metabolites in a time-course study. This is the first study to show that up-regulation of indoleamine 2,3-dioxygenase (IDO-1), kynurenine 3-monoxygenase (KMO) and quinolinate phosphoribosyltransferase (QPRT) is lacking in lymphocytes treated with interferon gamma. In contrast, peripheral monocytes showed a significant elevation of kynurenine pathway enzymes and metabolites when treated with interferon gamma. Expression of IDO-1, KMO and QPRT correlated significantly with activation of the kynurenine pathway (kynurenine:tryptophan ratio), quinolinic acid concentration and production of the monocyte derived, pro-inflammatory immune response marker: neopterin. Our results also describe an original and sensitive methodological approach to quantify kynurenine pathway enzyme expression in cells. This has revealed further insights into the potential role of these enzymes in disease processes.