Effect of Bifidobacterium infantis 35624 (Align) on the Lactulose Breath Test for Small Intestinal Bacterial Overgrowth.

BACKGROUND: Small intestinal bacterial overgrowth (SIBO) may cause symptoms in patients with abdominal bloating, distension, and gas. SIBO can be assessed using the lactulose breath test (LBT). A commonly used probiotic supplement is Align containing Bifidobacterium infantis 35624. The aim of this study was to determine the effect of B. infantis 35624 on hydrogen and methane excretion during LBT. METHODS: Healthy subjects underwent LBT before and after 2 weeks of daily Align administration. Hydrogen and methane concentrations were measured for each breath sample. Results are expressed as mean ± SE and analyzed using repeated measures ANCOVA. A breath test was considered positive if hydrogen and/or methane increased > 20 ppm above baseline by 90 min of the test or if a dual hydrogen peak was present. RESULTS: Nineteen healthy subjects were studied. Hydrogen levels were similar pre- and post-probiotic across the 3-h study (p = 0.768). In contrast, methane levels were significantly higher with probiotic administration (p = 0.012). A rise in methane > 20 ppm was seen in three subjects pre-probiotic but six post-probiotic. Of the 19 subjects, an "abnormal" LBT pre-probiotic was present in ten subjects and during the probiotic, 13 were abnormal. CONCLUSIONS: This study found that 2 weeks of B. infantis 35624 (Align) supplementation affects LBT assessment for SIBO by significantly increasing methane, but not hydrogen, excretion after lactulose administration. Methane levels reached values that would be considered positive for SIBO patients. This study suggests that patients undergoing LBT should discontinue probiotics prior to the test as these supplements may alter the test results.

Visual Priming Enhances the Effects of Nonspatial Cognitive Rehabilitation Training on Spatial Learning After Experimental Traumatic Brain Injury.

Previous work demonstrates that spatial (explicit) and nonspatial (implicit) elements of place learning in the Morris water maze (MWM) task can be dissociated and examined in the context of experimental traumatic brain injury (TBI). Providing nonspatial cognitive training (CT) after injury can improve place learning compared with untrained controls. In the present study, we hypothesized that brief exposure to extra-maze cues, in conjunction with CT, may further improve MWM performance and extra-maze cue utilization compared with CT alone. Adult male Sprague-Dawley rats (n = 66) received controlled cortical impact (CCI) injury or sham surgery. Beginning day 8 postsurgery, CCI and sham rats received 6 days of no training (NT) or CT with/without brief, noncontextualized exposure to extra-maze cues (BE and CT, respectively). Acquisition (days 14-18), visible platform (VP; day 19), carryover (CO; days 20-26), and periodic probe trials were performed. Platform latencies, peripheral and target zone time allocation, and search strategies were assessed. CCI/BE rats had shorter acquisition trial latencies than CCI/NT (P < .001) and tended to have shorter latencies than CCI/CT rats (P < .10). Both BE and CT reduced peripheral zone swimming for CCI rats versus CCI/NT. CCI/BE animals increased spatial swim strategies from day 14 to day 18 relative to CCI/CT and showed similar swim strategy selection to the Sham/NT group. These data suggest that visual priming improves initial place learning in the MWM. These results support the visual priming response as another clinically relevant experimental rehabilitation construct, to use when assessing injury and treatment effects of behavioral and pharmacological therapies on cognition after TBI.

Developing a clinically relevant model of cognitive training after experimental traumatic brain injury.

BACKGROUND: Following traumatic brain injury (TBI), clinical cognitive training paradigms harness implicit and explicit learning and memory systems to improve function; however, these systems are differentially affected by TBI, highlighting the need for an experimental TBI model that can test efficacy of cognitive training approaches. OBJECTIVES: To develop a clinically relevant experimental cognitive training model using the Morris water maze (MWM) wherein training on implicitly learned task components was provided to improve behavioral performance post-TBI. METHODS: Eighty-one adult male rats were divided by injury status (controlled cortical impact [CCI]/Sham), non-spatial cognitive training (CogTrained/No-CogTrained), and extra-maze cues (Cued/Non-Cued) during MWM testing. Platform latencies, thigmotaxis, and search strategies were assessed during MWM trials. RESULTS: Cognitive training was associated with improved platform latencies, reduced thigmotaxis, and more effective search strategy use for Sham and CCI rats. In the Cued and Non-Cued MWM paradigm, there were no differences between CCI/CogTrained and Sham/No-CogTrained groups. During novel testing conditions, CogTrained groups applied implicitly learned knowledge/skills; however, sham-cued CogTrained/rats better incorporated extramaze cues into their search strategy than the CCI-Cued group. Cognitive training had no effects on contusion size or hippocampal cell survival. CONCLUSIONS: The results provide evidence that CCI-CogTrained rats that learned the nonspatial components of the MWM task applied these skills during multiple conditions of the place-learning task, thereby mitigating cognitive deficits typically associated with this injury model. The results show that a systematic application of clinically relevant constructs associated with cognitive training paradigms can be used with experimental TBI to affect place learning.