Association of caffeine and related analytes with resistance to Parkinson disease among LRRK2 mutation carriers: A metabolomic study.

OBJECTIVE: To identify markers of resistance to developing Parkinson disease (PD) among LRRK2 mutation carriers (LRRK2+), we carried out metabolomic profiling in individuals with PD and unaffected controls (UC), with and without the LRRK2 mutation. METHODS: Plasma from 368 patients with PD and UC in the LRRK2 Cohort Consortium (LCC), comprising 118 LRRK2+/PD+, 115 LRRK2+/UC, 70 LRRK2-/PD+, and 65 LRRK2-/UC, and CSF available from 68 of them, were analyzed by liquid chromatography with mass spectrometry. For 282 analytes quantified in plasma and CSF, we assessed differences among the 4 groups and interactions between LRRK2 and PD status, using analysis of covariance models adjusted by age, study site cohort, and sex, with p value corrections for multiple comparisons. RESULTS: Plasma caffeine concentration was lower in patients with PD vs UC (p < 0.001), more so among LRRK2+ carriers (by 76%) than among LRRK2- participants (by 31%), with significant interaction between LRRK2 and PD status (p = 0.005). Similar results were found for caffeine metabolites (paraxanthine, theophylline, 1-methylxanthine) and a nonxanthine marker of coffee consumption (trigonelline) in plasma, and in the subset of corresponding CSF samples. Dietary caffeine was also lower in LRRK2+/PD+ compared to LRRK2+/UC with significant interaction effect with the LRRK2+ mutation (p < 0.001). CONCLUSIONS: Metabolomic analyses of the LCC samples identified caffeine, its demethylation metabolites, and trigonelline as prominent markers of resistance to PD linked to pathogenic LRRK2 mutations, more so than to idiopathic PD. Because these analytes are known both as correlates of coffee consumption and as neuroprotectants in animal PD models, the findings may reflect their avoidance by those predisposed to develop PD or their protective effects among LRRK2 mutation carriers.

Effect of Cerebrospinal Fluid Circulation on Nose-to-Brain Direct Delivery and Distribution of Caffeine in Rats.

Direct drug delivery from nose to brain has drawn much attention as an effective strategy for the treatment of central nervous system diseases. After intranasal administration, drug molecules can be directly delivered from the nose to the brain. However, the detailed mechanism for this direct delivery to the brain has not been elucidated. In the present study, the effect of the activation of the cerebral fluid circulation (the glymphatic system) on the efficacy of direct delivery from nose to brain was investigated. Because the glymphatic system is activated by some anesthetic regimens, the differences in brain delivery and the pharmacokinetics under anesthetic and conscious conditions were compared in rats. Under urethane anesthesia, direct delivery from the nose to the brain was facilitated, whereas the brain uptake from the systemic circulation via the blood-brain barrier was decreased. In addition, both the brain uptake of caffeine injected into the subarachnoid cerebrospinal fluid (CSF) and the extracerebral clearance of caffeine after intrastriatal injection were enhanced under anesthesia. For intranasal administration, caffeine was transported directly from the nose to the CSF and then delivered into the brain parenchyma by the CSF circulation. The results obtained in the present study clarified that the direct delivery from nose to brain could be facilitated by anesthesia. These findings suggest that fluid circulation in the brain can contribute to a wider cerebral distribution of the drug after direct delivery from nose to brain.

A LC-MS/MS method for the quantification of caffeine, betamethasone, clonidine and furosemide in cerebrospinal fluid of preterm infants.

BACKGROUND: Newborns, admitted to the Neonatal Intensive Care Unit (NICU), are exposed to a large number of medications, the majority of which are not labeled for use in infants, especially in preterm newborns, because clinical trials on their benefits and harms are lacking. There is a huge gap in knowledge on pharmacokinetic (PK) data in sick preterm infants, including that of drug penetration to cerebrospinal fluid (CSF). One of the issues is related to the lack of reliable analytical methods for the measurement of drugs in CSF. METHODS: In this paper we describe a specific and sensitive LC-MS/MS method for the simultaneous quantification in CSF of four commonly prescribed drugs in NICUs: caffeine, betamethasone, clonidine and furosemide. RESULTS: The method was validated following EMA guidelines and applied to several CSF samples of preterm infants with post-hemorrhagic ventricular dilatation in which a ventricular access device was applied. The range of the concentrations of the four drugs measured in the CSF was wide. CONCLUSIONS: Our method can be considered useful for further clinical studies to describe the PK aspects of these drugs in neonatal medicine.

Does Caffeine Consumption Modify Cerebrospinal Fluid Amyloid-ß Levels in Patients with Alzheimer's Disease?

Caffeine may be protective against Alzheimer's disease (AD) by modulating amyloid-ß (Aß) metabolic pathways. The present work aimed to study a possible association of caffeine consumption with the cerebrospinal fluid (CSF) biomarkers, particularly Aß. The study included 88 patients with AD or mild cognitive impairment. The consumption of caffeine and theobromine was evaluated using a validated food questionnaire. Quantification of caffeine and main active metabolites was performed with liquid chromatography coupled to tandem mass spectrometry. The levels of A(1-42), total tau, and phosphorylated tau in the CSF were determined using sandwich ELISA methods and other Aß species, Aß(X-38), Aß(X-40), and Aß(X-42), with the MSD Aß Triplex assay. The concentration of caffeine was 0.79±1.15 µg/mL in the CSF and 1.20±1.88 µg/mL in the plasma. No correlation was found between caffeine consumption and Aß42 in the CSF. However, a significant positive correlation was found between the concentrations of theobromine, both in the CSF and in the plasma, with Aß42 in the CSF. Theobromine in the CSF was positively correlated with the levels of other xanthines in the CSF, but not in the plasma, suggesting that it may be formed by central metabolic pathways. In conclusion, caffeine consumption does not modify the levels of CSF biomarkers, and does not require to be controlled for when measuring CSF biomarkers in a clinical setting. Since theobromine is associated with a favorable Aß profile in the CSF, the possibility that it might have a protective role in AD should be further investigated.

Increases in cerebrospinal fluid caffeine concentration are associated with favorable outcome after severe traumatic brain injury in humans.

Caffeine, the most widely consumed psychoactive drug and a weak adenosine receptor antagonist, can be neuroprotective or neurotoxic depending on the experimental model or neurologic disorder. However, its contribution to pathophysiology and outcome in traumatic brain injury (TBI) in humans is undefined. We assessed serial cerebrospinal fluid (CSF) concentrations of caffeine and its metabolites (theobromine, paraxanthine, and theophylline) by high-pressure liquid chromatography/ultraviolet in 97 ventricular CSF samples from an established bank, from 30 adults with severe TBI. We prospectively selected a threshold caffeine level of > or = 1 micromol/L (194 ng/mL) as clinically significant. Demographics, Glasgow Coma Scale (GCS) score, admission blood alcohol level, and 6-month dichotomized Glasgow Outcome Scale (GOS) score were assessed. Mean time from injury to initial CSF sampling was 10.77+/-3.13 h. On initial sampling, caffeine was detected in 24 of 30 patients, and the threshold was achieved in 9 patients. Favorable GOS was seen more often in patients with CSF caffeine concentration > or = versus < the threshold (55.6 versus 11.8%, P=0.028). Gender, age, admission CGS score, admission blood alcohol level, and admission systolic arterial blood pressure did not differ between patients with CSF caffeine concentration > or = versus < the threshold. Increases in CSF concentrations of the caffeine metabolites theobromine and paraxanthine were also associated with favorable outcome (P=0.018 and 0.056, respectively). Caffeine and its metabolites are commonly detected in CSF in patients with severe TBI and in an exploratory assessment are associated with favorable outcome. We speculate that caffeine may be neuroprotective by long-term upregulation of adenosine A1 receptors or acute inhibition of A2a receptors.

Effect of caffeine on cerebral blood flow response to somatosensory stimulation.

Despite caffeine's wide consumption and well-documented psychoactive effects, little is known regarding the effects of caffeine on neurovascular coupling. In the present study, we evaluated the effects of caffeine, an adenosine receptor antagonist, on intracerebral arterioles in vitro and subsequently, on the pial circulation in vivo during cortical activation induced by contralateral sciatic nerve stimulation (SNS). In our in vitro studies, we utilized isolated intracerebral arterioles to determine the effects of caffeine (10 or 50 micromol/L) on adenosine-induced vasodilatation. At the lower concentration, caffeine was without effect, but at the higher concentration, caffeine produced significant attenuation. In our in vivo studies, we determined the cerebrospinal fluid (CSF) caffeine concentrations at 15, 30, and 60 mins after intravenous administration of 5, 10 and 40 mg/kg. At the latter two concentrations, CSF levels exceeded 10 micromol/L. We then evaluated the pial arteriolar response during cortical activation caused by contralateral SNS after administering caffeine intravenously (0, 5, 10, 20 30, and 40 mg/kg). The pial circulation was observed through a closed cranial window in chloralose-anesthetized Sprague-Dawley rats. The contralateral sciatic nerve was isolated, positioned on silver electrodes and stimulated for 20 secs (0.20 V, 0.5 ms, and 5 Hz). Arteriolar diameter was quantified using an automated video dimension analyzer. Contralateral SNS resulted in a 23.8% +/-3.9% increase in pial arteriolar diameter in the hindlimb sensory cortex under control conditions. Intravenous administration of caffeine at the lowest dose studied (5 mg/kg) had no effect on either resting arteriolar diameter or SNS-induced vasodilatation. However, at higher doses (10, 20, 30, and 40 mg/kg, intravenously), caffeine significantly (P < 0.05; n = 6) attenuated both resting diameter and cerebral blood flow (CBF) responses to somatosensory stimulation. Intravenous administration of theophylline (10, 20, and 40 mg/kg), another adenosine receptor antagonist, also significantly reduced SNS-induced vasodilatation in a dose-dependent manner. Hypercarbic vasodilatation was unaffected by either caffeine or theophylline. The results of the present study show that caffeine significantly reduces cerebrovascular responses to both adenosine and to somatosensory stimulation and supports a role of adenosine in the regulation of CBF during functional neuronal activity.

Cerebrospinal fluid concentrations of caffeine following oral drug administration: correlation with salivary and plasma concentrations.

Twelve hospitalized adult patients received 300 mg of oral caffeine 1 h before a diagnostic lumbar puncture. Caffeine concentrations were determined simultaneously in saliva, plasma, and cerebrospinal fluid (CSF). Mean caffeine concentrations in plasma, saliva, and CSF were 5.9 +/- 2.1, 4.4 +/- 1.5, and 2.9 +/- 1.1 micrograms/ml, respectively, with coefficients of correlation plasma-saliva, saliva-CSF, and plasma-CSF of 0.89, 0.79, and 0.77, respectively, all statistically significant (p < 0.001).

Application of microdialysis for study of caffeine distribution into brain and cerebrospinal fluid in rats.

The usefulness of microdialysis was examined for the chronological determination of caffeine concentration in the brain and cerebrospinal fluids (CSF) following intravenous administration of caffeine in rats. The recovery percent of caffeine by microdialysis, the concentration ratio of caffeine in the dialysate against that in the brain tissue or CSF was determined. The recovery percent was proved to be constant at 5 different steady-state plasma concentrations of caffeine (0.1-280 nmol/ml) and in different collecting periods of dialysate ranging from 30 s to 10 min. The mean recovery percent in the brain and CSF were 10.9 and 13.1%, respectively. Thus, microdialysis was proved useful for determination of drug concentration in the tissue and biological fluids with time resolution of more than 30 s. The microdialysis method was then applied for the chronological determination of caffeine concentration in the brain and CSF following intravenous bolus administration. The estimated caffeine concentration in the brain and CSF was the same as those obtained by direct determination in isolated brain and CSF, respectively. Transfer of caffeine from plasma to brain and CSF were further pharmacokinetically analyzed using a modified 2-compartment model. In this kinetic model, the transfer of caffeine between the CSF and brain was neglected, since the mutual transfer of caffeine was not detected in in vivo experiments. Calculated curves were well fitted on observed caffeine concentrations in the plasma, brain and CSF.

Caffeine as a potential risk factor for theophylline neurotoxicity.

Theophylline can cause life-threatening seizures when administered in excessive doses. The plasma concentrations associated with this neurotoxic effect vary widely among patients. To determine the reasons for the wide variation, an animal model of theophylline-induced seizures was developed and has now been used to determine the effect of pre-exposure to caffeine on theophylline-induced neurotoxicity. Male adult rats received an iv infusion of either caffeine citrate or sodium citrate solution for 15 min. Theophylline was then infused at a relatively rapid rate until onset of maximum seizures. A third group of rats received a rapid infusion of caffeine only until onset of seizures. Samples of blood, brain, and cerebrospinal fluid were obtained at that time for determination of caffeine and theophylline concentrations by HPLC. Prior exposure to caffeine was associated with a statistically significant reduction in the total amount of theophylline required to produce seizures and caused theophylline concentrations at all sampling sites to be significantly lower than in controls. Caffeine alone required a larger total dose and higher concentrations than theophylline alone to produce seizures. It is concluded that acute exposure to caffeine can increase the risk of theophylline-induced neurotoxicity.

Caffeine disposition in the pregnant rabbit. II. Fetal distribution of caffeine and paraxanthine during chronic maternal caffeine administration.

Twenty-three New Zealand White rabbits received a continuous intravenous infusion of caffeine during gestation. The amniotic fluid/maternal plasma concentration ratio was higher for caffeine than for its major metabolite, paraxanthine, throughout gestation, and increased near term for both compounds. Both compounds distributed nearly homogeneously to fluids and tissues of the 29-day fetus, with mean fetal/maternal concentration ratios of 0.7 for paraxanthine and 0.9 for caffeine. The free fraction of caffeine was constant during gestation (about 0.8), while that of paraxanthine increased from 0.25 to 0.4. Similar results were observed in 3 Dutch Belted rabbits given caffeine in their drinking water and sacrificed at 29 days of gestation.