Caffeine for apnea of prematurity: Effects on the developing brain

Endocrine disrupting chemicals in children's and their parents' urine: Is the exposure related to the Chinese and Western lifestyle?

Children are known to be more vulnerable to exposure to endocrine-disrupting chemicals (EDCs) compared to adults, but evaluating the exposure pathways can be challenging. This research employed target and non-target analysis (NTA) to examine the exposure characteristics of EDCs in spot urine samples collected from 46 children's (aged 3-12 years) and their parents in Hong Kong (Chinese/Western lifestyle) and Guangzhou (mainly Chinese lifestyle). The results revealed that the geometric mean concentrations of phthalate esters metabolites (mPAEs) and bisphenols (BPs) in children's urine were 127.3 μg/gcrea and 2.5 μg/gcrea in Guangzhou, and 93.7 μg/gcrea and 2.9 μg/gcrea in Hong Kong, respectively, which were consistent with global levels. NTA identified a total of 1069 compounds, including 106 EDCs, commonly detected in food, cosmetics, and drugs. Notable regional differences were observed between Guangzhou and Hong Kong with potential sources of EDCs including dietary and cosmetic additives, toys, flooring and dust, as well as differences in lifestyles, diet, and living environment. However, age was found to significantly impact EDC exposure. The quantified EDCs (mPAEs and BPs) posed possible health risks to 60% of the children. Moreover, the presence of caffeine in children's urine, which exhibited higher detection rates in children from Hong Kong (95.6%) and Guangzhou (44.4%), warrants further attention. The sources of EDCs exposure in these regions need to be fully confirmed.

Cardiovascular and cerebrovascular effects of caffeine maintenance in preterm infants during the transitional period

BACKGROUND AND AIM

Caffeine is routinely used for the prophylaxis of prematurity-related apnoeas. We aimed to evaluate the effect of caffeine maintenance on cardiovascular and cerebrovascular haemodynamics using a non-invasive multimodal monitoring in preterm infants during the transitional period.

METHODS

Infants <32 weeks' gestational age (GA) were enrolled in this observational prospective study. The following parameters were recorded before and after the administration of caffeine citrate 5 mg/kg using near-infrared spectroscopy, pulse oximetry and electrical velocimetry: heart rate, cardiac output, stroke volume, cardiac contractility, systemic vascular resistance (SVR), perfusion index, peripheral and cerebral oxygenation, cerebral fractional oxygen extraction, correlation index between cerebral oxygenation and heart rate (TOHRx, marker of cerebrovascular reactivity). Multilevel mixed-effects linear models were used to assess the impact of caffeine and of relevant clinical covariates on each parameter.

RESULTS

Seventy-seven infants (mean GA 29.3 ± 2.5 weeks, mean birthweight 1148 ± 353 g) were included. Caffeine administration was associated with increased SVR (B = 0.623, p = 0.004) and more negative TOHRx values (B = -0.036, p = 0.022), which suggest improved cerebrovascular reactivity.

CONCLUSIONS

Caffeine administration at maintenance dosage during postnatal transition is associated with increased systemic vascular tone and improved cerebrovascular reactivity. A possible role for caffeine-mediated inhibition of adenosine receptors may be hypothesized.

IMPACT

This study provides a thorough and comprehensive overview of multiple cerebrovascular and cardiovascular parameters, monitored non-invasively by combining near-infrared spectroscopy, electrical velocimetry and pulse oximetry, before and after the administration of caffeine at maintenance dosage in preterm infants during postnatal transition. Caffeine was associated with an improvement in cerebrovascular reactivity and with a slight but significant increase in systemic vascular resistance, with no additional effects on other cardiovascular and cerebrovascular parameters. Our results support the safety of caffeine treatment even during a phase at risk for haemodynamic instability such as postnatal transition and suggest potential beneficial effects on cerebral haemodynamics.

Caffeine versus other methylxanthines for the prevention and treatment of apnea in preterm infants

BACKGROUND

Methylxanthines, including caffeine, theophylline, and aminophylline, work as stimulants of the respiratory drive, and decrease apnea of prematurity, a developmental disorder common in preterm infants. In particular, caffeine has been reported to improve important clinical outcomes, including bronchopulmonary dysplasia (BPD) and neurodevelopmental disability. However, there is uncertainty regarding the efficacy of caffeine compared to other methylxanthines.

OBJECTIVES

To assess the effects of caffeine compared to aminophylline or theophylline in preterm infants at risk of apnea, with apnea, or in the peri-extubation phase.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Epistemonikos, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), and clinicaltrials.gov in February 2023. We also checked the reference lists of relevant articles to identify additional studies.

SELECTION CRITERIA

Studies: randomized controlled trials (RCTs) and quasi-RCTs Participants: infants born before 34 weeks of gestation for prevention and extubation trials, and infants born before 37 weeks of gestation for treatment trials Intervention and comparison: caffeine versus theophylline or caffeine versus aminophylline. We included all doses and duration of treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We evaluated treatment effects using a fixed-effect model with risk ratio (RR), risk difference (RD), and 95% confidence intervals (CI) for categorical data, and mean, standard deviation, and mean difference for continuous data. We used the GRADE approach to evaluate the certainty of evidence.

MAIN RESULTS

We included 22 trials enrolling 1776 preterm infants. The indication for treatment was prevention of apnea in three studies, treatment of apnea in 13 studies, and extubation management in three studies. In three studies, there were multiple indications for treatment, and in one study, the indication for treatment was unclear. In 19 included studies, the infants had a mean gestational age between 28 and 32 weeks and a mean birth weight between 1000 g and 1500 g. One study's participants had a mean gestational age of more than 32 weeks, and two studies had participants with a mean birth weight of 1500 g or more. Caffeine administrated for any indication may result in little to no difference in all-cause mortality prior to hospital discharge compared to other methylxanthines (RR 1.12, 95% CI 0.68 to 1.84; RD 0.02, 95% CI -0.05 to 0.08; 2 studies, 396 infants; low-certainty evidence). Only one study enrolling 79 infants reported components of the outcome moderate to severe neurodevelopmental disability at 18 to 26 months. The evidence is very uncertain about the effect of caffeine on cognitive developmental delay compared to other methylxanthines (RR 0.17, 95% CI 0.02 to 1.37; RD -0.12, 95% CI -0.24 to 0.01; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on language developmental delay compared to other methylxanthines (RR 0.76, 95% CI 0.37 to 1.58; RD -0.07, 95% CI -0.27 to 0.12; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on motor developmental delay compared to other methylxanthines (RR 0.50, 95% CI 0.13 to 1.96; RD -0.07, 95% CI -0.21 to 0.07; 1 study, 79 infants; very low-certainty evidence). The evidence is very uncertain about the effect of caffeine on visual and hearing impairment compared to other methylxanthines. At 24 months of age, visual impairment was seen in 8 out of 11 infants and 10 out of 11 infants in the caffeine and other methylxanthines groups, respectively. Hearing impairment was seen in 2 out of 5 infants and 1 out of 1 infant in the caffeine and other methylxanthines groups, respectively. No studies reported the outcomes cerebral palsy, gross motor disability, and mental development. Compared to other methylxanthines, caffeine may result in little to no difference in BPD/chronic lung disease, defined as 28 days of oxygen exposure at 36 weeks' postmenstrual age (RR 1.40, 95% CI 0.92 to 2.11; RD 0.04, 95% CI -0.01 to 0.09; 3 studies, 481 infants; low-certainty evidence). The evidence is very uncertain about the effect of caffeine on side effects (tachycardia, agitation, or feed intolerance) leading to a reduction in dose or withholding of methylxanthines compared to other methylxanthines (RR 0.17, 95% CI 0.02 to 1.32; RD -0.29, 95% CI -0.57 to -0.02; 1 study, 30 infants; very low-certainty evidence). Caffeine may result in little to no difference in duration of hospital stay compared to other methylxanthines (median (interquartile range): caffeine 43 days (27.5 to 61.5); other methylxanthines 39 days (28 to 55)). No studies reported the outcome seizures.

AUTHORS' CONCLUSIONS

Although caffeine has been shown to improve important clinical outcomes, in the few studies that compared caffeine to other methylxanthines, there might be little to no difference in mortality, bronchopulmonary dysplasia, and duration of hospital stay. The evidence is very uncertain about the effect of caffeine compared to other methylxanthines on long-term development and side effects. Although caffeine or other methylxanthines are widely used in preterm infants, there is little direct evidence to support the choice of which methylxanthine to use. More research is needed, especially on extremely preterm infants born before 28 weeks of gestation. Data from four ongoing studies might provide more evidence on the effects of caffeine or other methylxanthines.

Cardiorespiratory and Neuroprotective Effects of Caffeine in Neonate Animal Models

Caffeine is widely used to improve neonatal health in animals with low vitality. Due to its pharmacokinetics and pharmacodynamics, caffeine stimulates the cardiorespiratory system by antagonism of adenosine receptors and alteration in Ca+2 ion channel activity. Moreover, the availability of intracellular Ca+2 also has positive inotropic effects by increasing heart contractibility and by having a possible positive effect on neonate vitality. Nonetheless, since neonatal enzymatic and tissular systems are immature at birth, there is a controversy about whether caffeine is an effective therapy for newborns. This review aims to analyze the basic concepts of caffeine in neonatal animal models (rat and mouse pups, goat kids, lambs, and piglets), and it will discuss the neuroprotective effect and its physiological actions in reducing apnea in newborns.

Effects of caffeine on diaphragmatic activity in preterm infants

BACKGROUND

Caffeine is the first-choice drug for the treatment for apnea of prematurity (AOP) in preterm infants and it has been reported that it improves the diaphragm activity. The aim of this study was to evaluate by ultrasound possible changes in diaphragm contractility and motility induced by caffeine.

METHODS

We studied 26 preterm infants with gestational age ≤34 weeks treated with caffeine for the prevention or treatment of AOP. Diaphragmatic ultrasound was performed 15 min (T₀ ) before and 60 min (T₆₀ ) after the loading (20 mg/kg) or maintenance (5 mg/kg) dose of caffeine.

RESULTS

Diaphragmatic excursion (DE) and thickness at the end of inspiration (DT-in) and expiration (DT-ex), as well as peak velocity of the excursion at the end of inspiration (DT-in) and expiration (DT-ex) increased after administration of both loading and maintenance dose of caffeine.

CONCLUSIONS

Ultrasounds confirmed that caffeine improves the activity of diaphragm in preterm infants improving its thickness, amplitude of excursions, and contraction velocity. These results are consistent with the effectiveness of caffeine in treating AOP and decreasing the risk of failure of noninvasive respiratory support in preterm infants with respiratory distress syndrome (RDS).

Caffeine versus other methylxanthines for the prevention and treatment of apnea in preterm infants

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the effects of caffeine compared to aminophylline or theophylline in preterm infants at risk of apnea, with apnea, or in the peri‐extubation phase.

Protective Effects of Early Caffeine Administration in Hyperoxia-Induced Neurotoxicity in the Juvenile Rat

High-risk preterm infants are affected by a higher incidence of cognitive developmental deficits due to the unavoidable risk factor of oxygen toxicity. Caffeine is known to have a protective effect in preventing bronchopulmonary dysplasia associated with improved neurologic outcomes, although very early initiation of therapy is controversial. In this study, we used newborn rats in an oxygen injury model to test the hypothesis that near-birth caffeine administration modulates neuronal maturation and differentiation in the hippocampus of the developing brain. For this purpose, newborn Wistar rats were exposed to 21% or 80% oxygen on the day of birth for 3 or 5 days and treated with vehicle or caffeine (10 mg/kg/48 h). Postnatal exposure to 80% oxygen resulted in a drastic reduction of associated neuronal mediators for radial glia, mitotic/postmitotic neurons, and impaired cell-cycle regulation, predominantly persistent even after recovery to room air until postnatal day 15. Systemic caffeine administration significantly counteracted the effects of oxygen insult on neuronal maturation in the hippocampus. Interestingly, under normoxia, caffeine inhibited the transcription of neuronal mediators of maturing and mature neurons. The early administration of caffeine modulated hyperoxia-induced decreased neurogenesis in the hippocampus and showed neuroprotective properties in the neonatal rat oxygen toxicity model.

Precision caffeine therapy for apnea of prematurity and circadian rhythms: New possibilities open up

Caffeine is the globally consumed psychoactive substance and the drug of choice for the treatment of apnea of prematurity (AOP), but its therapeutic effects are highly variable among preterm infants. Many of the molecular underpinnings of the marked individual response have remained elusive yet. Interestingly, the significant association between Clock gene polymorphisms and the response to caffeine therapy offers an opportunity to advance our understanding of potential mechanistic pathways. In this review, we delineate the functions and mechanisms of human circadian rhythms. An up-to-date advance of the formation and ontogeny of human circadian rhythms during the perinatal period are concisely discussed. Specially, we summarize and discuss the characteristics of circadian rhythms in preterm infants. Second, we discuss the role of caffeine consumption on the circadian rhythms in animal models and human, especially in neonates and preterm infants. Finally, we postulate how circadian-based therapeutic initiatives could open new possibilities to promote precision caffeine therapy for the AOP management in preterm infants.

Recent developments of phosphodiesterase inhibitors: Clinical trials, emerging indications and novel molecules

The phosphodiesterase (PDE) enzymes, key regulator of the cyclic nucleotide signal transduction system, are long-established as attractive therapeutic targets. During investigation of trends within clinical trials, we have identified a particularly high number of clinical trials involving PDE inhibitors, prompting us to further evaluate the current status of this class of therapeutic agents. In total, we have identified 87 agents with PDE-inhibiting capacity, of which 85 interact with PDE enzymes as primary target. We provide an overview of the clinical drug development with focus on the current clinical uses, novel molecules and indications, highlighting relevant clinical studies. We found that the bulk of current clinical uses for this class of therapeutic agents are chronic obstructive pulmonary disease (COPD), vascular and cardiovascular disorders and inflammatory skin conditions. In COPD, particularly, PDE inhibitors are characterised by the compliance-limiting adverse reactions. We discuss efforts directed to appropriately adjusting the dose regimens and conducting structure-activity relationship studies to determine the effect of structural features on safety profile. The ongoing development predominantly concentrates on central nervous system diseases, such as schizophrenia, Alzheimer's disease, Parkinson's disease and fragile X syndrome; notable advancements are being also made in mycobacterial infections, HIV and Duchenne muscular dystrophy. Our analysis predicts the diversification of PDE inhibitors' will continue to grow thanks to the molecules in preclinical development and the ongoing research involving drugs in clinical development.

Therapeutic Interventions in Rat Models of Preterm Hypoxic Ischemic Injury: Effects of Hypothermia, Caffeine, and the Influence of Sex

Infants born prematurely have an increased risk of experiencing brain injury, specifically injury caused by Hypoxia Ischemia (HI). There is no approved treatment for preterm infants, in contrast to term infants that experience Hypoxic Ischemic Encephalopathy (HIE) and can be treated with hypothermia. Given this increased risk and lack of approved treatment, it is imperative to explore and model potential treatments in animal models of preterm injury. Hypothermia is one potential treatment, though cooling to current clinical standards has been found to be detrimental for preterm infants. However, mild hypothermia may prove useful. Caffeine is another treatment that is already used in preterm infants to treat apnea of prematurity, and has shown neuroprotective effects. Both of these treatments show sex differences in behavioral outcomes and neuroprotective effects, which are critical to explore when working to translate from animal to human. The effects and research history of hypothermia, caffeine and how sex affects these treatment outcomes will be explored further in this review article.

Comparative efficacy and safety of caffeine citrate and aminophylline in treating apnea of prematurity: A systematic review and meta-analysis

Background

Methylxanthine, including caffeine citrate and aminophylline, is the most common pharmacologic treatment for apnea of prematurity. However, due to the lack of high-quality evidence, there are no clear recommendations or guidelines on how to choose between caffeine and aminophylline.

Objective

This meta-analysis aimed to assess the comparative efficacy and safety of caffeine and aminophylline for apnea of prematurity, and provide reliable evidence for clinical medication in the treatment for apnea of prematurity.

Methods

PubMed, Scopus, Embase, EBSCO, Web of Science, and Cochrane databases were systematically searched from May 1975 to June 2022.

Results

Ten studies including a total of 923 preterm infants were evaluated. Our results showed that there was no significant difference in the effective rate of 1-3days between caffeine and aminophylline (OR 1.05, 95%CI: 0.40–2.74, P = 0.914). However, for side effects such as tachycardia (OR 0.22, 95%CI: 0.13–0.37, P<0.001) and feeding intolerance (OR 0.40, 95%CI: 0.23–0.70, P = 0.001), the incidence rate was lower in the caffeine group compared with the aminophylline group. No significant difference was found in hyperglycemia (OR 0.45, 95%CI: 0.19–1.05, P = 0.064).

Conclusion

This meta-analysis reveals that caffeine citrate and aminophylline have similar therapeutic effectiveness on respiratory function, but caffeine has fewer side effects and should be considered first for treatment.

Use of Antibiotics in Preterm Newborns

Due to complex maturational and physiological changes that characterize neonates and affect their response to pharmacological treatments, neonatal pharmacology is different from children and adults and deserves particular attention. Although preterms are usually considered part of the neonatal population, they have physiological and pharmacological hallmarks different from full-terms and, therefore, need specific considerations. Antibiotics are widely used among preterms. In fact, during their stay in neonatal intensive care units (NICUs), invasive procedures, including central catheters for parental nutrition and ventilators for respiratory support, are often sources of microbes and require antimicrobial treatments. Unfortunately, the majority of drugs administered to neonates are off-label due to the lack of clinical studies conducted on this special population. In fact, physiological and ethical concerns represent a huge limit in performing pharmacokinetic (PK) studies on these subjects, since they limit the number and volume of blood sampling. Therapeutic drug monitoring (TDM) is a useful tool that allows dose adjustments aiming to fit plasma concentrations within the therapeutic range and to reach specific drug target attainment. In this review of the last ten years’ literature, we performed Pubmed research aiming to summarize the PK aspects for the most used antibiotics in preterms.

The Conflicting Role of Caffeine Supplementation on Hyperoxia-Induced Injury on the Cerebellar Granular Cell Neurogenesis of Newborn Rats

Preterm birth disrupts cerebellar development, which may be mediated by systemic oxidative stress that damages neuronal developmental stages. Impaired cerebellar neurogenesis affects several downstream targets important for cognition, emotion, and speech. In this study, we demonstrate that oxidative stress induced with high oxygen (80%) for three or five postnatal days (P3/P5) could significantly damage neurogenesis and proliferative capacity of granular cell precursor and Purkinje cells in rat pups. Reversal of cellular neuronal damage after recovery to room air (P15) was augmented by treatment with caffeine. However, downstream transcripts important for migration and differentiation of postmitotic granular cells were irreversibly reduced by hyperoxia, without rescue by caffeine. Protective effects of caffeine in the cerebellum were limited to neuronal survival but failed to restore important transcript signatures.

The use of caffeine as a respiratory stimulant in a cat

OBJECTIVE

To report the use of caffeine as a respiratory stimulant in a cat with hypoventilation.

CASE SUMMARY

A cat was mechanically ventilated due to persistent hypercapnia (P_et co₂  > 75 mm Hg) following median sternotomy and thymectomy. After 3 days of mechanical ventilatory support, the cat would initiate breaths but failed weaning due to persistent hypercapnia. Following administration of intravenous caffeine (total 12 mg/kg over 24 h), respiratory and mental status rapidly improved. The cat was subsequently extubated and able to maintain Pvco₂  < 50 mm Hg. The cat was later diagnosed with myasthenia gravis. Quality of life 13 months after discharge was reported as excellent by her owner.

NEW OR UNIQUE INFORMATION PROVIDED

Caffeine may be considered as a respiratory stimulant in cats with hypoventilation.

Treating Apnea of Prematurity

Premature babies often suffer apnea of prematurity as a physiological consequence of an immature respiratory system. Hypercapnia may develop, and neonates with apnea of prematurity are at an increased risk of morbidity and mortality. The long-term effects of apnea of prematurity or their treatments are less clear. While a number of treatment options exist for apnea of prematurity, there is no clear-cut “first-line” approach or gold standard of care. Effective treatments, such as caffeine citrate, carbon dioxide inhalation, nasal continuous positive airway pressure, nasal intermittent positive pressure ventilation, and others, may be associated with safety concerns. More conservative treatments are available, such as kangaroo care, postural changes, and sensory stimulation, but they may not be effective. While apnea of prematurity resolves spontaneously as the respiratory system matures, it can complicate neonatal care and may have both short-term and long-term consequences. The role, if any, that apnea of prematurity may play in mortality of preterm neonates is not clear.

Molecular Mechanism of Caffeine in Preventing Bronchopulmonary Dysplasia in Premature Infants

Bronchopulmonary dysplasia (BPD) is a chronic respiratory complication commonly seen in premature infants. Following continuous advances in neonatal intensive care diagnosis and treatment technology, an increasing number of premature babies are being treated successfully. Despite these remarkable improvements, there has been no significant decline in the incidence of BPD; in fact, its incidence has increased as more extremely preterm infants survive. Therefore, in view of the impact of BPD on the physical and mental health of children and the increased familial and social burden on these children, early prevention of BPD is emphasized. In recent decades, the clinical application of caffeine in treating primary apnea in premature infants was shown not only to stimulate the respiratory center but also to confer obvious protection to the nervous and respiratory systems. Numerous clinical cross-sectional and longitudinal studies have shown that caffeine plays a significant role in the prevention and treatment of BPD, but there is a lack of overall understanding of its potential molecular mechanisms. In this review, we summarize the possible molecular mechanisms of caffeine in the prevention or treatment of BPD, aiming to better guide its clinical application.

Duration of Caffeine for Apnea of Prematurity-A Randomized Controlled Trial

OBJECTIVES

There is sufficient evidence to support use of caffeine therapy for apnea of prematurity, but practices vary widely when it comes to discontinuing therapy. This study was planned to compare 'recurrence of apnea of prematurity' (RAP); when 2 protocols were used to stop caffeine therapy.

METHODS

Neonates delivered at 26-32 wk gestation on caffeine therapy for apnea of prematurity were randomized into 2 groups: Group 1-caffeine stopped at 7 d apnea-free period, and Group 2-continued for a prefixed period till at least 34 wk postmenstrual age (PMA). Proportion of infants in each group with RAP were analyzed.

RESULTS

Each group consisted of 60 infants. Proportion of infants in each group with RAP, were not different (15% vs 13%); odds ratio (OR) 0.87; 95% confidence interval (CI) (0.31-2.43). Caffeine could be stopped earlier (33 vs 34 wk PMA); and cumulative duration of therapy was lesser (19.5 vs 33 d) when stopped at 7 d apnea-free period. Other studied outcomes were similar between the two groups.

CONCLUSIONS

Mandatorily continuing caffeine therapy up to 34 wk PMA in select preterm groups does not seem to decrease risk of recurrence of apnea. Larger trials that specifically study extremely preterm infants are required to make robust recommendations on when to stop therapy.

CLINICAL TRIALS REGISTRY OF INDIA NO

CTRI/2016/12/007559. http://ctri.nic.in/Clinicaltrials/pdf_generate.php?trialid=14195&EncHid=&modid=&compid=%27,%2714195det%27.

Premature birth: topics in physiology and pharmacological characteristics

OBJECTIVE

To review the main physiological and pharmacological changes related to prematurity, to promote the evidence-based clinical practice.

METHODS

This is a narrative review whose research was carried out in the ScienceDirect and Medline databases via PubMed, searching for articles in any language from January 2000 to February 2020.

RESULTS

Premature newborns are born before completing the maturation process that prepares them for extrauterine life, which occurs especially in the last weeks of pregnancy. Therefore, they have their own characteristics in development. Several physiological peculiarities stand out, such as disturbances in glucose regulation, adrenal function, thermoregulation, immunity, in addition to changes in liver, renal and respiratory functions. Pharmacological aspects were also highlighted, involving pharmacokinetics and pharmacodynamics.

CONCLUSIONS

Despite the recent advances in prematurity, it is still an area with many uncertainties, since several changes occur quickly and there are ethical issues that make studies difficult. Thus, it is clear that the therapeutic management of premature infants is still very much based on clinical practice.

Pharmacodynamic Effects of Standard versus High Caffeine Doses in the Developing Brain of Neonatal Rats Exposed to Intermittent Hypoxia

(1) Background: Caffeine citrate, at standard doses, is effective for reducing the incidence of apnea of prematurity (AOP) and may confer neuroprotection and decrease neonatal morbidities in extremely low gestational age neonates (ELGANs) requiring oxygen therapy. We tested the hypothesis that high-dose caffeine (HiC) has no adverse effects on the neonatal brain. (2) Methods: Newborn rat pups were randomized to room air (RA), hyperoxia (Hx) or neonatal intermittent hypoxia (IH), from birth (P0) to P14 during which they received intraperitoneal injections of LoC (20 mg/kg on P0; 5 mg/kg/day on P1-P14), HiC (80 mg/kg; 20 mg/kg), or equivalent volume saline. Blood gases, histopathology, myelin and neuronal integrity, and adenosine receptor reactivity were assessed. (3) Results: Caffeine treatment in Hx influenced blood gases more than treatment in neonatal IH. Exposure to neonatal IH resulted in hemorrhage and higher brain width, particularly in layer 2 of the cerebral cortex. Both caffeine doses increased brain width in RA, but layer 2 was increased only with HiC. HiC decreased oxidative stress more effectively than LoC, and both doses reduced apoptosis biomarkers. In RA, both caffeine doses improved myelination, but the effect was abolished in Hx and neonatal IH. Similarly, both doses inhibited adenosine 1A receptor in all oxygen environments, but adenosine 2A receptor was inhibited only in RA and Hx. (4) Conclusions: Caffeine, even at high doses, when administered in normoxia, can confer neuroprotection, evidenced by reductions in oxidative stress, hypermyelination, and increased Golgi bodies. However, varying oxygen environments, such as Hx or neonatal IH, may alter and modify pharmacodynamic actions of caffeine and may even override the benefits caffeine.

Encephalopathy in Preterm Infants: Advances in Neuroprotection With Caffeine

With the improvement in neonatal rescue technology, the survival rate of critically ill preterm infants has substantially increased; however, the incidence of brain injury and sequelae in surviving preterm infants has concomitantly increased. Although the etiology and pathogenesis of preterm brain injury, and its prevention and treatment have been investigated in recent years, powerful and effective neuroprotective strategies are lacking. Caffeine is an emerging neuroprotective drug, and its benefits have been widely recognized; however, its effects depend on the dose of caffeine administered, the neurodevelopmental stage at the time of administration, and the duration of exposure. The main mechanisms of caffeine involve adenosine receptor antagonism, phosphodiesterase inhibition, calcium ion activation, and γ-aminobutyric acid receptor antagonism. Studies have shown that there are both direct and indirect beneficial effects of caffeine on the immature brain. Accordingly, this article briefly reviews the pharmacological characteristics of caffeine, its mechanism of action in the context of encephalopathy in premature infants, and its use in the neuroprotection of encephalopathy in this patient population.

National and international guidelines for neonatal caffeine use: Are they evidenced-based?

The Caffeine for Apnea of Prematurity (CAP) trial showed that caffeine was safe when used with standard dosing and provided both pulmonary and neurological benefits to preterm infants. Since its publication almost 15 years ago, the use of caffeine in extremely premature infants in Newborn Intensive Care Units worldwide has increased, with almost all receiving the drug during their hospital stay. Subsequent observational studies suggested that administration of caffeine before 3 days of age may have greater benefits, leading many neonatologists to start caffeine prophylactically in all very low birth weight infants. Several publicly available national and international guidelines on caffeine advocate prophylactic use, and some recommend higher doses than those used in the CAP trial. This article will review the evidence basis for neonatal caffeine therapy in light of these guidelines.

When to start and stop caffeine and why respiratory status matters

Caffeine as tested in the CAP trial is safe and effective for preterm infants with birthweights less than 1250 g. Evidence for its use beyond the indications and timing used in this trial is of low quality and conflicting. Some studies suggest that earlier use of caffeine increases the risk of mortality while others suggest it has important benefits. It appears that infants with apnea of prematurity and those receiving assisted ventilation are the most likely to benefit from caffeine. Based on currently available evidence, routine early prescription of caffeine does not appear to be indicated. Infants continue to have potentially damaging episodes of hypoxia secondary to apnea beyond 34 weeks' postmenstrual age. It is unclear whether prolonged use of caffeine improves outcomes in these infants. Randomized trials to resolve these uncertainties are required. They need to be large, at least the size of the CAP trial, and include neurodevelopmental outcomes.

Caffeine intake and cognitive functions in children

RATIONALE

There is a growing concern over excessive caffeine use and development of caffeine use disorder in children.

OBJECTIVES

This study aimed to identify the association between caffeine intake and cognitive functioning in children.

METHODS

This study included 11,718 youths aged 9-10 years with cognitive and caffeine intake information that were extracted from the Adolescent Brain Cognitive Development (ABCD) study. The ABCD study is a longitudinal cohort study started in 2017 that aims to understand the relationships between substance use and neurocognition in youths living in the USA. Cognitive measures were obtained through the 7 core cognitive instruments from the NIH toolbox (vocabulary comprehension, reading decoding, inhibitory control, working memory, cognitive flexibility, processing speed, and episodic memory). Associations between caffeine intake and the seven cognitive functions were examined using multiple regression models.

RESULTS

Our study revealed that caffeine intake negatively correlated with all the seven cognitive measures. After adjustment for age, gender, sleep, and socioeconomic status (SES), caffeine intake was still found to be negatively associated with most of the cognitive functions, such as vocabulary comprehension, working memory, cognitive flexibility, processing speed, and episodic memory, except reading decoding, and inhibitory control.

CONCLUSIONS

As beverages with caffeine are consumed frequently, controlling their intake may reduce a risk for nonoptimal cognitive development in children.

Increased Seizure Susceptibility for Rats Subject to Early Life Hypoxia Might Be Associated with Brain Dysfunction of NRG1-ErbB4 Signaling in Parvalbumin Interneurons

Neuregulin 1 (NRG1)-induced activation of ErbB4 in parvalbumin (PV) inhibitory interneurons is reported to serve as a critical endogenous negative-feedback mechanism to repress brain epileptogenesis. Here, we investigated the seizure susceptibility and the role of NRG1-ErbB4 signaling in PV interneurons in the suppression of epileptic seizures for rats subject to early life hypoxia. Neonatal postnatal day 5 (P5) rats were exposed to intermittent hypoxia (IH) or control (CON) room air for 10 days. In the prefrontal cortex (PFC) of P54 rats, we determined the impact of neonatal IH exposures on the expression of PV, NRG1, ErbB4, and phosphorylated ErbB4 (p-ErbB4) during the seizure induction. Seizure susceptibility tests with the common convulsant agent pentylenetetrazole (PEN) at P54 revealed that rats subject to neonatal hypoxia exposure developed faster and more serious epileptic seizures. Neonatal IH exposures (1) decreased the number of PV cells in the PFC of P54 rats; (2) interrupted the expression of NRG1 gene; and (3) altered the activity of NRG1 on PV interneurons in the PFC after the seizure induction. Intracerebroventricular delivery of exogenous NRG1 before seizure induction by PEN significantly reduced the seizure susceptibility for neonatal IH-exposed rats. The ErbB4 inhibitor AG1478 inhibited the exogenous NRG1's effects on seizure susceptibility. Environmental enrichment (EE) rescued the abovementioned pathophysiological alterations and significantly attenuated the epileptic seizures after the seizure induction for neonatal IH-exposed rats. Our study indicated early life hypoxia exposure might increase the seizure susceptibility for rats and contribute to pathophysiological dysfunction of NRG1-ErbB4 signaling in PV interneurons in the suppression of epileptic seizures. EE might attenuate the increased seizure susceptibility for neonatal IH-exposed rats through rescuing pathophysiological alterations of NRG1-ErbB4 signaling in PV interneurons.

Respiratory management of infants with chronic neonatal lung disease beyond the NICU: A position statement from the Thoracic Society of Australia and New Zealand

Chronic neonatal lung disease (CNLD) is defined as continued need for any form of respiratory support (supplemental oxygen and/or assisted ventilation) beyond 36 weeks PMA. Low-flow supplemental oxygen facilitates discharge from hospital of infants with CNLD who are hypoxic in air and is widely used despite lack of evidence on the most appropriate minimum mean target oxygen saturations. Furthermore, there are minimal data to guide the home monitoring, titration or weaning of supplemental oxygen in these infants. The purpose of this position statement is to provide a guide for the respiratory management of infants with CNLD, with special emphasis on role and logistics of supplemental oxygen therapy beyond the NICU stay. Reflecting a variety of clinical practices and infant comorbidities (presence of pulmonary hypertension, retinopathy of prematurity and adequacy of growth), it is recommended that the minimum mean target range for SpO2 during overnight oximetry to be 93-95% with less than 5% of total recording time to be below 90% SpO2 . Safety of short-term disconnection from supplemental oxygen should be assessed before discharge, with majority of infants with CNLD not ready for discharge until supplemental oxygen requirement is ≤0.5 L/min. Sleep-time assessment of oxygenation with continuous overnight oximetry is recommended when weaning supplemental oxygen. Palivizumab is considered safe and effective for the reduction of hospital admissions with RSV infection in this group. This statement would be useful for paediatricians, neonatologists, respiratory and sleep physicians and general practitioners managing children with CNLD.

Caffeine prevents prostaglandin E1-induced disturbances in respiratory control in neonatal rats: implications for infants with critical congenital heart disease

Continuous infusion of prostaglandin E1 (PGE₁) is used to maintain ductus arteriosus patency in infants with critical congenital heart disease, but it can also cause central apnea suggesting an effect on respiratory neural control. In this study, we investigated whether 1) PGE₁ inhibits the various phases of the acute hypoxic ventilatory response (HVR; an index of respiratory control dysfunction) and increases apnea incidence in neonatal rats; and 2) whether these changes would be reversible with caffeine pretreatment. Whole body plethysmography was used to assess the HVR and apnea incidence in neonatal rats 2 h following a single bolus intraperitoneal injection of PGE₁ with and without prior caffeine treatment. Untreated rats exhibited a biphasic HVR characterized by an initial increase in minute ventilation followed by a ventilatory decline of the late phase (~5th minute) of the HVR. PGE₁ had a dose-dependent effect on the HVR. Contrary to our hypothesis, the lowest dose (1 µg/kg) of PGE₁ prevented the ventilatory decline of the late phase of the HVR. However, PGE₁ tended to increase postsigh apnea incidence and the coefficient of variability (CV) of breathing frequency, suggesting increased respiratory instability. PGE₁ also decreased brainstem microglia mRNA and increased neuronal nitric oxide synthase (nNOS) and platelet-derived growth factor-β (PDGF-β) gene expression. Caffeine pretreatment prevented these effects of PGE₁, and the adenosine A_2A receptor inhibitor MSX-3 had similar preventative effects. Prostaglandin appears to have deleterious effects on brainstem respiratory control regions, possibly involving a microglial-dependent mechanism. The compensatory effects of caffeine or MSX-3 treatment raises the question of whether prostaglandin may also operate on an adenosine-dependent pathway.

Caffeine preserves quiet sleep in preterm neonates

Caffeine is widely used in preterm neonates suffering from apnea of prematurity (AOP), and it has become one of the most frequently prescribed medications in neonatal intensive care units. Goal of this study is to investigate how caffeine citrate treatment affects sleep-wake behavior in preterm neonates. The observational study consists of 64 preterm neonates during their first 5 days of life with gestational age (GA) <32 weeks or very low birthweight of < 1500 g. A total of 52 patients treated with caffeine citrate and 12 patients without caffeine citrate were included. Sleep-wake behavior was scored in three stages: active sleep, quiet sleep, and wakefulness. Individual caffeine concentration of every neonate was simulated with a pharmacokinetic model. In neonates with GA ≥ 28 weeks, wakefulness increased and active sleep decreased with increasing caffeine concentrations, whereas quiet sleep remained unchanged. In neonates with GA < 28 weeks, no clear caffeine effects on sleep-wake behavior could be demonstrated. Caffeine increases fraction of wakefulness, alertness, and most probably also arousability at cost of active but not quiet sleep in preterm neonates. As such, caffeine should therefore not affect time for physical and cerebral regeneration during sleep in preterm neonates.

Long-term neurological effects of neonatal caffeine treatment in a rabbit model of preterm birth

BACKGROUND

Neonatal caffeine treatment might affect brain development. Long-term studies show conflicting results on brain-related outcomes. Herein we aimed to investigate the long-term effects of neonatal caffeine administration in a rabbit model of preterm birth.

METHODS

Preterm (born day 29) and term (day 32) pups were raised by wet nurses and allocated to treatment with saline or caffeine for 7 or 17 days. At pre-puberty, neurobehavioral tests were performed and brains were harvested for immunostaining of neurons, synapses, myelin, and astrocytes.

RESULTS

Survival was lower in preterm saline pups than in controls, whereas caffeine-treated preterm pups did not differ from term control pups. Preterm saline pups covered less distance compared to controls and were more likely to stay in the peripheral zone of the open field. Corresponding differences were not seen in preterm caffeine pups. Preterm animals had lower neuron density compared to controls, which was not influenced by caffeine treatment. Synaptic density, astrocytes, and myelin were not different between groups.

CONCLUSION

Caffeine appeared to be safe. All preterm rabbits had lower neuron density but anxious behavior seen in preterm saline rabbits was not seen in caffeine-treated preterm pups.

Caffeine in preterm infants: where are we in 2020?

The incidence of preterm birth is increasing, leading to a growing population with potential long-term pulmonary complications. Apnoea of prematurity (AOP) is one of the major challenges when treating preterm infants; it can lead to respiratory failure and the need for mechanical ventilation. Ventilating preterm infants can be associated with severe negative pulmonary and extrapulmonary outcomes, such as bronchopulmonary dysplasia (BPD), severe neurological impairment and death. Therefore, international guidelines favour non-invasive respiratory support. Strategies to improve the success rate of non-invasive ventilation in preterm infants include pharmacological treatment of AOP. Among the different pharmacological options, caffeine citrate is the current drug of choice. Caffeine is effective in reducing AOP and mechanical ventilation and enhances extubation success; it decreases the risk of BPD; and is associated with improved cognitive outcome at 2 years of age, and pulmonary function up to 11 years of age. The commonly prescribed dose (20 mg·kg⁻¹ loading dose, 5–10 mg·kg⁻¹ per day maintenance dose) is considered safe and effective. However, to date there is no commonly agreed standardised protocol on the optimal dosing and timing of caffeine therapy. Furthermore, despite the wide pharmacological safety profile of caffeine, the role of therapeutic drug monitoring in caffeine-treated preterm infants is still debated. This state-of-the-art review summarises the current knowledge of caff­eine therapy in preterm infants and highlights some of the unresolved questions of AOP. We speculate that with increased understanding of caffeine and its metabolism, a more refined respiratory management of preterm infants is feasible, leading to an overall improvement in patient outcome.

Caffeine is the current drug of choice to prevent and treat apnoea of prematurity. There is no agreed protocol on the optimal timing and dosage of caffeine therapy for preterm babies. Data on caffeine metabolism may optimise individualised therapy.http://bit.ly/2LMuJPY

[Safety and efficacy of caffeine use started at different time in preterm infants: a multicenter study in Jiangsu Province, China]

OBJECTIVE

To study the efficacy and safety of caffeine used in the early (≤72 hours after birth) and late (>72 hours after birth) stage in preterm infants with a gestational age of ≤31 weeks.

METHODS

A retrospective analysis was performed for 640 preterm infants (with a gestational age of ≤31 weeks) who were admitted to the neonatal intensive care unit of eight hospitals in Jiangsu Province, China. Of the 640 preterm infants, 510 were given caffeine in the early stage (≤72 hours after birth; early use group) and 130 were given caffeine in the late stage (>72 hours after birth; late use group). The clinical data were compared between the two groups.

RESULTS

There were no significant differences in birth weight, Apgar score, sex, gestational age, and age on admission between the two groups (P>0.05). Compared with the late use group, the early use group had a significantly younger age at the beginning and withdrawal of caffeine treatment (P<0.05) and a significantly shorter duration of caffeine treatment (P<0.05). There was no significant difference in respiratory support on admission between the two groups (P>0.05). Compared with the late use group, the early use group had significantly lower incidence rate of apnea (P<0.05) and significantly shorter oxygen supply time and length of hospital stay (P<0.05). There were no significant differences between the two groups in the incidence rates of neonatal intracranial hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, retinopathy of prematurity, and patent ductus arteriosus at discharge and NBNA score at the corrected gestational age of 40 weeks (P>0.05). However, significant differences were found in the incidence of bronchopulmonary dysplasia and the rate of home oxygen therapy, but there was no significant difference in the mortality rate between the two groups (P>0.05).

CONCLUSIONS

Early use of caffeine can shorten the duration of caffeine treatment, oxygen supply time, and length of hospital stay, with little adverse effect, in preterm infants with a gestational age of ≤31 weeks.

Subchondral bone dysplasia mediates susceptibility to osteoarthritis in female adult offspring rats induced by prenatal caffeine exposure

Our previous studies confirmed that prenatal caffeine exposure (PCE) could induce susceptibility to osteoarthritis in adult offspring rats due to poor chondrocyte differentiation, but its mechanism remains to be further investigated. This study aimed to explore whether subchondral bone dysplasia mediates susceptibility to osteoarthritis in adult offspring rats induced by PCE. Pregnant Wistar rats were treated with caffeine (120 mg/kg.d) or saline from gestational day (GD) 9 to 20. The female offspring were euthanized to collect femurs at GD20, postnatal week (PW) 6, and PW28 (non-ovariectomy and ovariectomy groups) to detect osteoarthritis-like phenotype, subchondral bone mass, ossification center development, and other evidence. The results showed that PCE increased the Mankin score of pathological articular cartilage, but decreased articular cartilage thickness and subchondral bone mass, which were more obvious after ovariectomy. Meanwhile, the correlation analysis results demonstrated that the Mankin score of articular cartilage was significantly negatively correlated with subchondral bone mass, and the thickness of articular cartilage was significantly positively correlated with subchondral bone mass. Further, the length and area of the primary and secondary ossification centers, the number of osteoblasts, and the related genes' expression of osteogenic differentiation (e.g., Runx2, BSP, ALP, and OCN) were all significantly decreased in the PCE group before and after birth. Taken together, PCE induced susceptibility to osteoarthritis in adult female offspring, which was likely related to the subchondral bone dysplasia and reduction of subchondral bone mass production due to developmental disorder of primary and secondary ossification centers caused by osteoblast differentiation disability before and after birth.

Programming changes in GLUT1 mediated the accumulation of AGEs and matrix degradation in the articular cartilage of female adult rats after prenatal caffeine exposure

Osteoarthritis is associated with intrauterine growth retardation (IUGR) and abnormal glucose metabolism. Our laboratory previously reported that prenatal caffeine exposure (PCE) can induce intrauterine maternal glucocorticoid (GC) overexposure in IUGR offspring and increase susceptibility to osteoarthritis after birth. In the present study, we demonstrated the essential role of glucose transporter 1 (GLUT1) programming changes in the increased matrix degradation of articular cartilage and susceptibility to osteoarthritis in female PCE adult offspring. In vivo, we found that PCE decreased the matrix content but did not significantly change the expression of matrix degradation-related genes in the articular cartilage of female fetal rats. The decreased expression of IGF1 and GLUT1 and the content of advanced-glycation-end-products (AGEs) were also detected. At different postnatal stages (2, 6, and 12 weeks), the cartilage matrix content decreased while the degradation-related genes expression increased in the PCE group. Meanwhile, the expression of IGF1 and GLUT1 and AGEs content in the local cartilage increased. In vitro, the expression levels of IGF1 and GLUT1 were inhibited by corticosterone but remained unchanged under caffeine treatment. Exogenous IGF1 can reverse the corticosterone-induced decrease in GLUT1 expression and promote AGEs production, while mifepristone (a glucocorticoid receptor inhibitor) reversed the corticosterone-induced low expression of IGF1 and GLUT1. Exogenous AGEs can increase the expression of inflammatory factors (IL-6 and TNF-α) and degradation-related genes, and decrease the matrix synthesis-related genes expression in chondrocyte. In conclusion, the GC-IGF1-GLUT1 axis mediated intrauterine dysplasia of articular cartilage, increased accumulation of AGEs and matrix degradation after birth in PCE female offspring, thereby increasing their susceptibility to osteoarthritis in adulthood.

Mechanistic actions of oxygen and methylxanthines on respiratory neural control and for the treatment of neonatal apnea

Apnea remains one of the most concerning and prevalent respiratory disorders spanning all ages from infants (particularly those born preterm) to adults. Although the pathophysiological consequences of apnea are fairly well described, the neural mechanisms underlying the etiology of the different types of apnea (central, obstructive, and mixed) still remain incompletely understood. From a developmental perspective, however, research into the respiratory neural control system of immature animals has shed light on both central and peripheral neural pathways underlying apnea of prematurity (AOP), a highly prevalent respiratory disorder of preterm infants. Animal studies have also been fundamental in furthering our understanding of how clinical interventions (e.g. pharmacological and mechanical) exert their beneficial effects in the clinical treatment of apnea. Although current clinical interventions such as supplemental O₂ and positive pressure respiratory support are critically important for the infant in respiratory distress, they are not fully effective and can also come with unfortunate, unintended (and long-term) side-effects. In this review, we have chosen AOP as one of the most common clinical scenarios involving apnea to highlight the mechanistic basis behind how some of the interventions could be both beneficial and also deleterious to the respiratory neural control system. We have included a section on infants with critical congenital heart diseases (CCHD), in whom apnea can be a clinical concern due to treatment with prostaglandin, and who may benefit from some of the treatments used for AOP.

Caffeine not associated with irritable behaviour in very low-birth-weight infants

This paper is an examination of irritable behaviour in very low-birth-weight infants in relation to caffeine or aminophylline. We assessed tremulous movement (a sub-score of General Movements Optimality Score) in 18 caffeine-treated subjects and 18 aminophylline-treated subjects. Caffeine, unlike aminophylline, was not associated with irritable behaviour at standard dose.

The effect of venous caffeine on the prevention of apnea of prematurity in the very preterm infants in the neonatal intensive care unit of Shahid Motahhari Hospital, Urmia, during a year

Due to the importance of prevention of apnea of prematurity in the very preterm infants and the side effects of using methylxanthines in preterm infants, the present study was conducted and aimed at investigating the effects of prophylactic caffeine on the incident of apnea (short-term consequence). This is a clinical–experimental trial, in which the infants were included after receiving written consent from their parents. The infants were randomly divided into two groups, namely, Group A (receive caffeine) and Group B (did not receive caffeine). After sampling of the collected data, the two groups were analyzed using statistical tests using SPSS software 23. Among the 50 infants in the caffeine group and 50 infants in the control group, 1 (2%) and 2 (4%) infants required long-term oxygen, respectively. Three (6%) infants from the caffeine group and 2 (4%) infants from the control group had an intraventricular hemorrhage. Two (4%) infants from the caffeine group and 1 (2%) infant from the control group had a positive patent ductus arteriosus and needed treatment. Among the 50 infants in the caffeine group and 50 infants in the control group, 7 (14%) and 9 (18%) infants had apnea, respectively. According to the Fisher's exact test, there was no significant difference between the incident of apnea in the two groups (P = 0.58). Ten (20%) infants from the caffeine group and 7 (14%) infants from the control group died. The prescription of prophylactic caffeine had no effect on the incident of apnea in the infants. Hence, the use of that should be limited to the preterm infants lower than 1250 g in the prophylactic form.

Early Caffeine Administration and Neurodevelopmental Outcomes in Preterm Infants

BACKGROUND

Although caffeine use for apnea of prematurity is well studied, the long-term safety and benefit of routine early caffeine administration has not been explored. Our objective was to determine the association between early (within 2 days of birth) versus late caffeine exposure and neurodevelopmental outcomes in preterm infants.

METHODS

Infants of <29 weeks' gestation born between April 2009 and September 2011 and admitted to Canadian Neonatal Network units and then assessed at Canadian Neonatal Follow-up Network centers were studied. Neonates who received caffeine were divided into early- (received within 2 days of birth) and late-caffeine (received after 2 days of birth) groups. The primary outcome was significant neurodevelopmental impairment, defined as cerebral palsy, or a Bayley Scales of Infant and Toddler Development, Third Edition composite score of <70 on any component, hearing aid or cochlear implant, or bilateral visual impairment at 18 to 24 months' corrected age.

RESULTS

Of 2108 neonates who were eligible, 1545 were in the early-caffeine group and 563 were in the late-caffeine group. Rates of bronchopulmonary dysplasia, patent ductus arteriosus, and severe neurologic injury were lower in the early-caffeine group than in the late-caffeine group. Significant neurodevelopmental impairment (adjusted odds ratio 0.68 [95% confidence interval 0.50-0.94]) and odds of Bayley Scales of Infant and Toddler Development, Third Edition cognitive scores of <85 (adjusted odds ratio 0.67 [95% confidence interval 0.47-0.95]) were lower in the early-caffeine group than in the late-caffeine group. Propensity score-based matched-pair analyses revealed lower odds of cerebral palsy and hearing impairment only.

CONCLUSIONS

Early caffeine therapy is associated with better neurodevelopmental outcomes compared with late caffeine therapy in preterm infants born at <29 weeks' gestation.

Caffeine for apnea of prematurity and brain development at 11 years of age

Objective

Caffeine therapy for apnea of prematurity has been reported to improve brain white matter microstructure at term‐equivalent age, but its long‐term effects are unknown. This study aimed to investigate whether caffeine affects (1) brain structure at 11 years of age, and (2) brain development from term‐equivalent age to 11 years of age, compared with placebo.

Methods

Preterm infants born ≤1250 g were randomly allocated to caffeine or placebo. Magnetic resonance imaging (MRI) was performed on 70 participants (33 caffeine, 37 placebo) at term‐equivalent age and 117 participants (63 caffeine, 54 placebo) at 11 years of age. Global and regional brain volumes and white matter microstructure were measured at both time points.

Results

In general, there was little evidence for differences between treatment groups in brain volumes or white matter microstructure at age 11 years. There was, however, evidence that the caffeine group had a smaller corpus callosum than the placebo group. Volumetric brain development from term‐equivalent to 11 years of age was generally similar between treatment groups. However, there was evidence that caffeine was associated with slower growth of the corpus callosum, and slower decreases in axial, radial, and mean diffusivities in the white matter, particularly at the level of the centrum semiovale, over time than placebo.

Interpretation

This study suggests any benefits of neonatal caffeine therapy on brain structure in preterm infants weaken over time and are not clearly detectable by MRI at age 11 years, although caffeine may have long‐term effects on corpus callosum development.

Modulation of Microglial Activation by Adenosine A2a Receptor in Animal Models of Perinatal Brain Injury

Neuroinflammation has a key role in the pathogenesis of perinatal brain injury. Caffeine, a nonspecific antagonist of adenosine receptors (ARs), is widely used to treat apnea of prematurity and has been linked to a decrease in the incidence of cerebral palsy in premature infants. The mechanisms explaining its neuroprotective effect have not yet been elucidated. The objective of this study was to characterize the expression of adenosine and ARs in two neonatal rat models of neuroinflammation and to determine the effect of A2aR blockade on microglial activation assessed through inflammatory cytokine gene expression. We have used two rat models of microglial activation: the gestational low protein diet (LPD) model, associated with chronic brain injury, and postnatal ibotenate intracerebral injections, responsible for acute excitotoxicity injury. Adenosine blood levels have been measured by Tandem Mass Spectrometry. The expression of ARs in vivo was assessed using qPCR and immunohistochemistry. In vivo models have been replicated in vitro on primary microglial cell cultures exposed to A2aR agonist CGS-21680 or antagonist SCH-58261. The effects of these treatments have been assessed on the M1/M2 cytokine expressions measured by RT-qPCR. LPD during pregnancy was associated with higher adenosine levels in pups at postnatal day 1 and 4. A2aR mRNA expression was significantly increased in both cortex and magnetically sorted microglial cells from LPD animals compared to controls. CD73 expression, responsible for extracellular production of brain adenosine, was significantly increased in LPD cortex and sorted microglia cells. Moreover, CD73 protein level was increased in ibotenate treated animals. In vitro experiments confirmed that LPD or control microglial cells exposed to ibotenate display an increased expression, at both protein and molecular levels, of A2aR and M1 markers (IL-1β, IL-6, iNOS, TNFα). This pro-inflammatory profile was significantly reduced by SCH-58261, which reduces M1 markers in both LPD and ibotenate-exposed cells, with no effect on control cells. In the same experimental conditions, a partial increased of M1 cytokines was observed in response to A2aR agonist CGS-21680. These results support the involvement of adenosine and particularly of its receptor A2aR in the regulation of microglia in two different animal models of neuroinflammation.

Caffeine: an evidence-based success story in VLBW pharmacotherapy

Apnea of prematurity (AOP) is a common and pervasive problem in very low birth weight infants. Methylxanthines were reported >40 years ago to be an effective therapy and, by the early 2000s, caffeine had become the preferred methylxanthine because of its wide therapeutic index, excellent bioavailability, and longer half-life. A clinical trial to address unresolved questions and toxicity concerns, completed in 2004, confirmed significant benefits of caffeine therapy, including shorter duration of intubation and respiratory support, reduced incidence of chronic lung disease, decreased need for treatment of patent ductus arteriosus, reduced severity of retinopathy of prematurity, and improved motor and visual function. Cohort studies have now further delineated the benefits of initiation of therapy before 3 days postnatal age, and of higher maintenance doses to achieve incremental beneficial effects. This review summarizes the pivotal and in particular the most recent studies that have established the safety and efficacy of caffeine therapy for AOP and other respiratory and neurodevelopmental outcomes. Caffeine has a very favorable benefit-to-risk ratio, and has become one of the most prescribed and cost-effective pharmacotherapies in the NICU.

Caffeine Treatment for Apnea of Prematurity and the Influence on Dose-Dependent Postnatal Weight Gain Observed Over 15 Years

Background and Aim: To analyze the influence on weight gain of infants exposed to two dosage regimens of oral caffeine citrate (CC) for apnea of prematurity.

Methods: Retrospective descriptive observational study of an eligible very low birth weight cohort over a 15-year period in an Irish University hospital. Data were analyzed between two distinct postnatal ages: 14–28 and 29–56 days.

Results: During the 15-year study, 457 infants were prescribed caffeine. Among the 14–28-day group, after applying exclusion criteria, 418 infants qualified. Two hundred forty-eight infants received 5 mg/(kg·day) and 170 received 10 mg/(kg·day) of CC. Among the 29–56-day group, 362 infants were identified and after applying exclusions, 332 fulfilled entry criteria [214 on 5 mg/(kg·day) and 118 on 10 mg/(kg·day) regimen]. Baseline characteristics of infants were comparable between groups without statistically significant differences. Mean daily weight gain (MDWG) in grams from day 14 to 28 showed a higher rate of increase for the 5 mg/(kg·day) group compared with the 10 mg/(kg·day) group (17.2 ± 12 g vs. 13.0 ± 10.2 g [p = 0.04]). From day 29 to 56, also MDWG was higher among infants on 5 mg/(kg·day) of CC compared with 10 mg/(kg·day) group (15.6 ± 10.8 g vs. 10.2 ± 9.8 g [p = 0.011]).

Conclusion: While a variety of measures are optimized to promote postnatal weight gain of premature infants close to an ideal intrauterine growth curve, not paying sufficient attention to one of the most widely used catabolic agents in neonatology is questionable and warrants vigilance. Additional nutritional measures could be offered to those with prolonged caffeine exposure.

Bare carbon electrodes as simple and efficient sensors for the quantification of caffeine in commercial beverages

Food quality control is a mandatory task in the food industry and relies on the availability of simple, cost-effective and stable sensing platforms. In the present work, the applicability of bare glassy carbon electrodes for routine analysis of food samples was evaluated as a valid alternative to chromatographic techniques, using caffeine as test analyte. A number of experimental parameters were optimized and a differential pulse voltammetry was applied for quantification experiments. The detection limit was found to be 2 × 10^-5 M (3σ criterion) and repeatability was evaluated by the relative standard deviation of 4.5%. The influence of sugars, and compounds structurally related to caffeine on the current response of caffeine was evaluated and found to have no significant influence on the electrode performance. The suitability of bare carbon electrodes for routine analysis was successfully demonstrated by quantifying caffeine content in seven commercially available drinks and the results were validated using a standard ultra-high performance liquid chromatography method. This work demonstrates that bare glassy carbon electrodes are a simple, reliable and cost-effective platform for rapid analysis of targets such as caffeine in commercial products and they represent therefore a competitive alternative to the existing analytical methodologies for routine food analysis.

Neurobehavioral Outcomes 11 Years After Neonatal Caffeine Therapy for Apnea of Prematurity

BACKGROUND AND OBJECTIVES

Caffeine is effective in the treatment of apnea of prematurity. Although caffeine therapy has a benefit on gross motor skills in school-aged children, effects on neurobehavioral outcomes are not fully understood. We aimed to investigate effects of neonatal caffeine therapy in very low birth weight (500-1250 g) infants on neurobehavioral outcomes in 11-year-old participants of the Caffeine for Apnea of Prematurity trial.

METHODS

Thirteen academic hospitals in Canada, Australia, Great Britain, and Sweden participated in this part of the 11-year follow-up of the double-blind, randomized, placebo-controlled trial. Measures of general intelligence, attention, executive function, visuomotor integration and perception, and behavior were obtained in up to 870 children. The effects of caffeine therapy were assessed by using regression models.

RESULTS

Neurobehavioral outcomes were generally similar for both the caffeine and placebo group. The caffeine group performed better than the placebo group in fine motor coordination (mean difference [MD] = 2.9; 95% confidence interval [CI]: 0.7 to 5.1; P = .01), visuomotor integration (MD = 1.8; 95% CI: 0.0 to 3.7; P < .05), visual perception (MD = 2.0; 95% CI: 0.3 to 3.8; P = .02), and visuospatial organization (MD = 1.2; 95% CI: 0.4 to 2.0; P = .003).

CONCLUSIONS

Neonatal caffeine therapy for apnea of prematurity improved visuomotor, visuoperceptual, and visuospatial abilities at age 11 years. General intelligence, attention, and behavior were not adversely affected by caffeine, which highlights the long-term safety of caffeine therapy for apnea of prematurity in very low birth weight neonates.

Epidemiological trends among preterm infants with apnea. A twelve-year database review

OBJECTIVES

This study sought to characterize trends in the diagnosis of apnea, associated comorbidities and complications, and 30-day readmission rates in preterm singleton infants.

SUBJECTS AND METHODS

The study design was a retrospective, longitudinal, observational study. 2003-2014 New York State Statewide Planning and Research Cooperative System and New York City Vital Statistics databases were merged identifying preterm live singleton births. Hospitalizations of preterm newborns with and without apnea were compared; multivariable logistic regression and log-linear Poisson regression models applied.

RESULTS

Of 1,384,013 singleton births, 7.5% were identified as preterm. While relative risk of preterm birth rates declined (RR = 0.987, 95% CI = 0.982-0.991), the diagnosis of apnea increased significantly (RR = 1.069, 95% CI = 1.049-1.089). Multivariable analysis identified two apnea predictors, gastric reflux (OR = 3.19, 95% CI = 2.80-3.63) and early gestational age (OR = 0.83 for 1 week GA increase, 95% CI = 0.82-0.84). Preterm newborns with apnea were more likely to be readmitted within the first 30 days and total charges were 5.4 times higher.

CONCLUSIONS

While the preterm birth rate has declined the rate of diagnosis of apnea with associated comorbidities and complications has increased. Given the additional findings of higher 30-day readmission rates and charges, more multidisciplinary research appears warranted to identify ways to optimize the quality of high risk newborn care.

Caffeine controversies

PURPOSE OF REVIEW

Caffeine use in preterm infants has endured several paradigms: from standard of care to possible neurotoxin to one of the few medications for which there is evidence of bronchopulmonary dysplasia (BPD) risk reduction. The purpose of the review is to analyze this dynamic trajectory and discuss controversies that still remain after decades of caffeine use.

RECENT FINDINGS

Following concerns for caffeine safety in preterm infants, a large randomized controlled trial demonstrated a reduction in BPD and treatment for patent ductus arteriosus. The lower rate of death or neurodevelopmental impairment noted at 18-21 months was not statistically different at later timepoints; however, infants in the caffeine group had lower rates of motor impairment at 11-year follow-up. The time of caffeine therapy initiation is now substantially earlier, and doses used are sometimes higher that previously used, but there are limited data to support these practices.

SUMMARY

Caffeine therapy for apnea of prematurity (AOP) remains one of the pillars of neonatal care, although more evidence to support dosing and timing of initiation and discontinuation are needed.

Taurine, caffeine, and energy drinks: Reviewing the risks to the adolescent brain

Energy drinks are emerging as a major component of the beverage market with sales projected to top $60 billion globally in the next five years. Energy drinks contain a variety of ingredients, but many of the top-selling brands include high doses of caffeine and the amino acid taurine. Energy drink consumption by children has raised concerns, due to potential caffeine toxicity. An additional risk has been noted among college-aged consumers of energy drinks who appear at higher risk of over-consumption of alcohol when the two drinks are consumed together. The differential and combinatorial effects of caffeine and taurine on the developing brain are reviewed here with an emphasis on the adolescent brain, which is still maturing. Key data from animal studies are summarized to highlight both reported benefits and adverse effects reported following acute and chronic exposures. The data suggest that age is an important factor in both caffeine and taurine toxicity. Although the aged or diseased brain might benefit from taurine or caffeine supplementation, it appears that adolescents are not likely to benefit from supplementation and may, in fact, suffer ill effects from chronic ingestion of high doses. Additional work is needed though to address gaps in our understanding of how taurine affects females, since the majority of animal studies focused exclusively on male subjects.