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Keenan MJ, Zhou J, Hegsted M, Pelkman C, Durham HA, Coulon DB, Martin RJ. Role of resistant starch in improving gut health, adiposity, and insulin resistance. Adv Nutr 2015. [PMID: 25770258 DOI: 10.3945/an.114.007419.which] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
The realization that low-glycemic index diets were formulated using resistant starch led to more than a decade of research on the health effects of resistant starch. Determination of the metabolizable energy of the resistant starch product allowed for the performance of isocaloric studies. Fermentation of resistant starch in rodent studies results in what appears to be a healthier gut, demonstrated by increased amounts of short-chain fatty acids, an apparent positive change in the microbiota, and increased gene expression for gene products involved in normal healthy proliferation and apoptosis of potential cancer cells. Additionally, consumption of resistant starch was associated with reduced abdominal fat and improved insulin sensitivity. Increased serum glucagon-like peptide 1 (GLP-1) likely plays a role in promoting these health benefits. One rodent study that did not use isocaloric diets demonstrated that the use of resistant starch at 8% of the weight of the diet reduced body fat. This appears to be approximately equivalent to the human fiber requirement. In human subjects, insulin sensitivity is increased with the feeding of resistant starch. However, only 1 of several studies reports an increase in serum GLP-1 associated with resistant starch added to the diet. This means that other mechanisms, such as increased intestinal gluconeogenesis or increased adiponectin, may be involved in the promotion of improved insulin sensitivity. Future research may confirm that there will be improved health if human individuals consume the requirement for dietary fiber and a large amount of the fiber is fermentable.
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Vaziri ND, Liu SM, Lau WL, Khazaeli M, Nazertehrani S, Farzaneh SH, Kieffer DA, Adams SH, Martin RJ. High amylose resistant starch diet ameliorates oxidative stress, inflammation, and progression of chronic kidney disease. PLoS One 2014; 9:e114881. [PMID: 25490712 PMCID: PMC4260945 DOI: 10.1371/journal.pone.0114881] [Citation(s) in RCA: 204] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/14/2014] [Indexed: 12/30/2022] Open
Abstract
Inflammation is a major mediator of CKD progression and is partly driven by altered gut microbiome and intestinal barrier disruption, events which are caused by: urea influx in the intestine resulting in dominance of urease-possessing bacteria; disruption of epithelial barrier by urea-derived ammonia leading to endotoxemia and bacterial translocation; and restriction of potassium-rich fruits and vegetables which are common sources of fermentable fiber. Restriction of these foods leads to depletion of bacteria that convert indigestible carbohydrates to short chain fatty acids which are important nutrients for colonocytes and regulatory T lymphocytes. We hypothesized that a high resistant starch diet attenuates CKD progression. Male Sprague Dawley rats were fed a chow containing 0.7% adenine for 2 weeks to induce CKD. Rats were then fed diets supplemented with amylopectin (low-fiber control) or high fermentable fiber (amylose maize resistant starch, HAM-RS2) for 3 weeks. CKD rats consuming low fiber diet exhibited reduced creatinine clearance, interstitial fibrosis, inflammation, tubular damage, activation of NFkB, upregulation of pro-inflammatory, pro-oxidant, and pro-fibrotic molecules; impaired Nrf2 activity, down-regulation of antioxidant enzymes, and disruption of colonic epithelial tight junction. The high resistant starch diet significantly attenuated these abnormalities. Thus high resistant starch diet retards CKD progression and attenuates oxidative stress and inflammation in rats. Future studies are needed to explore the impact of HAM-RS2 in CKD patients.
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Keim NL, Martin RJ. Dietary whole grain–microbiota interactions: insights into mechanisms for human health. Adv Nutr 2014; 5:556-7. [PMID: 25469393 PMCID: PMC4188231 DOI: 10.3945/an.114.006536] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
This article summarizes the presentations from the “Dietary Whole Grain–Microbiota Interactions: Insights into Mechanisms for Human Health” symposium held at the ASN Scientific Sessions and Annual Meeting at Experimental Biology 2014 in San Diego, CA, on 28 April 2014. The symposium focused on the interactive effects of whole grains and nondigestible carbohydrates with the gut microbiota with the goal of identifying the benefits of whole grains that are mediated through their effects on the gut microbiome. This theme was addressed by 4 speakers, each with their own unique perspective. Dr. Michael Lefevre reviewed the impact of whole grains on markers of subclinical inflammation, drawing examples from epidemiologic literature, clinical trials, and animal experiments. Dr. Knud Erik Bach Knudsen discussed data from studies he conducted to identify specific carbohydrates that enhance colonic butyrate production. Dr. Michael Keenan presented a chronology of his research program devoted to understanding the mechanisms underlying the metabolic effects of resistant starch, particularly high-amylose maize. Dr. Jens Walter emphasized that whole grains can impact gut microbial ecology by increasing microbial diversity and inducing compositional alterations, some of which are considered to have beneficial effects on the host.
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Dragsted LO, Alexander J, Amdam G, Bryan N, Chen D, Haug A, Karlsson AH, de Kok T, Kulseng BE, Martin RJ, Milkowski A, Pajari AM, Pickowa J, Rudi K, Sødring MS, Oostindjer M, Egelandsdal B. Letter to the editor: Colorectal cancer risk and association with red meat--is it inconsistent? Answer to the letter by Corpet, De Smet and Demeyer. Meat Sci 2014; 98:792-4. [PMID: 25150631 DOI: 10.1016/j.meatsci.2014.07.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 07/27/2014] [Accepted: 07/28/2014] [Indexed: 11/16/2022]
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Oostindjer M, Alexander J, Amdam GV, Andersen G, Bryan NS, Chen D, Corpet DE, De Smet S, Dragsted LO, Haug A, Karlsson AH, Kleter G, de Kok TM, Kulseng B, Milkowski AL, Martin RJ, Pajari AM, Paulsen JE, Pickova J, Rudi K, Sødring M, Weed DL, Egelandsdal B. The role of red and processed meat in colorectal cancer development: a perspective. Meat Sci 2014; 97:583-96. [DOI: 10.1016/j.meatsci.2014.02.011] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/14/2014] [Accepted: 02/17/2014] [Indexed: 02/07/2023]
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Abu Jawdeh EG, O'Riordan M, Limrungsikul A, Bandyopadhyay A, Argus BM, Nakad PE, Supapannachart S, Yunis KA, Davis PG, Martin RJ. Methylxanthine use for apnea of prematurity among an international cohort of neonatologists. J Neonatal Perinatal Med 2014; 6:251-6. [PMID: 24246598 DOI: 10.3233/npm-1371013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND A recent multinational clinical trial in preterm infants has demonstrated pulmonary and neurodevelopmental benefits from caffeine therapy. Indications for caffeine use in that study were predominantly for treatment of apnea and facilitation of extubation rather than prophylaxis. There are no recent studies that describe current practice of neonatologists and regional differences in regards to indications for starting, monitoring and discontinuing methylxanthine therapy in premature infants. OBJECTIVE To characterize the spectrum of current practice and demonstrate the extent to which methylxanthine therapy varies by location. METHODS A cross-sectional survey of all neonatologists in Thailand, Lebanon, Australia, and a representative sample in the USA regarding management of apnea of prematurity. RESULTS The response rate was 50% (342/681). The methylxanthine of choice varied greatly across study locations. Prophylactic methylxanthine use is common (62%) among neonatologists in all four study locations. Significant variation exists in almost all aspects of apnea pharmacotherapy practice among neonatologists in different international locations. CONCLUSIONS Prophylactic use of methylxanthine therapy for apnea of prematurity is widespread. We speculate that this expanded use is possibly attributed to the beneficial effects of caffeine therapy in the Caffeine for Apnea of Prematurity (CAP) Trial.
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Laeger T, Reed SD, Henagan TM, Fernandez DH, Taghavi M, Addington A, Münzberg H, Martin RJ, Hutson SM, Morrison CD. Leucine acts in the brain to suppress food intake but does not function as a physiological signal of low dietary protein. Am J Physiol Regul Integr Comp Physiol 2014; 307:R310-20. [PMID: 24898843 DOI: 10.1152/ajpregu.00116.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intracerebroventricular injections of leucine are sufficient to suppress food intake, but it remains unclear whether brain leucine signaling represents a physiological signal of protein balance. We tested whether variations in dietary and circulating levels of leucine, or all three branched-chain amino acids (BCAAs), contribute to the detection of reduced dietary protein. Of the essential amino acids (EAAs) tested, only intracerebroventricular injection of leucine (10 μg) was sufficient to suppress food intake. Isocaloric low- (9% protein energy; LP) or normal- (18% protein energy) protein diets induced a divergence in food intake, with an increased consumption of LP beginning on day 2 and persisting throughout the study (P < 0.05). Circulating BCAA levels were reduced the day after LP diet exposure, but levels subsequently increased and normalized by day 4, despite persistent hyperphagia. Brain BCAA levels as measured by microdialysis on day 2 of diet exposure were reduced in LP rats, but this effect was most prominent postprandially. Despite these diet-induced changes in BCAA levels, reducing dietary leucine or total BCAAs independently from total protein was neither necessary nor sufficient to induce hyperphagia, while chronic infusion of EAAs into the brain of LP rats failed to consistently block LP-induced hyperphagia. Collectively, these data suggest that circulating BCAAs are transiently reduced by dietary protein restriction, but variations in dietary or brain BCAAs alone do not explain the hyperphagia induced by a low-protein diet.
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Vidrine K, Ye J, Martin RJ, McCutcheon KL, Raggio AM, Pelkman C, Durham HA, Zhou J, Senevirathne RN, Williams C, Greenway F, Finley J, Gao Z, Goldsmith F, Keenan MJ. Resistant starch from high amylose maize (HAM-RS2) and dietary butyrate reduce abdominal fat by a different apparent mechanism. Obesity (Silver Spring) 2014; 22:344-8. [PMID: 23630079 DOI: 10.1002/oby.20501] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 04/14/2013] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Obesity is a health concern. Resistant starch (RS) type 2 from high-amylose maize (HAM-RS2) and dietary sodium butyrate (SB) reduce abdominal fat in rodents. RS treatment is associated with increased gut hormones peptide YY (PYY) and glucagon-like peptide 1 (GLP-1), but it is not known if SB increases these hormones. DESIGN AND METHODS This was investigated in a 2 × 2 rat study with HAM-RS2 (0 or 28% weight) and dietary sodium butyrate (0 and 3.2%) resulting in isocaloric treatments: energy control (EC), sodium butyrate (SB), HAM-RS2 (RS), and the combination (SBRS). RESULTS RS and SB reduced abdominal fat and the combination reduced abdominal fat compared to SB and RS. RS was associated with increased fermentation in the cecum. Serum PYY and GLP-1 total were increased with RS treatment. RS treatment was associated with increased cecal butyrate produced from fermentation of RS, but there was no cecal increase for dietary SB. CONCLUSIONS SB after its absorption into the blood appears to not affect production of PYY and GLP-1, while butyrate from fermentation in the cecum promotes increased PYY and GLP-1. Future studies with lower doses of RS and SB are warranted and the combination may be beneficial for human health.
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Winners-Mendizabal OG, Orge FH, Di Fiore JM, Martin RJ, Kc P. Hypoxia-hyperoxia paradigms in the development of oxygen-induced retinopathy in a rat pup model. J Neonatal Perinatal Med 2014; 7:113-117. [PMID: 25104123 DOI: 10.3233/npm-1475613] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
BACKGROUND Retinopathy of prematurity [ROP] continues to be a significant clinical problem in preterm infants. There is a need for animal models to better understand the roles of hypoxia/hyperoxia in the pathogenesis and management of ROP. OBJECTIVES To test the hypothesis that multiple daily cycles of intermittent hypoxia, followed by brief hyperoxia, would provide a clinically relevant protocol for generation of ROP in a rat pup. METHODS Rat pups were exposed for the first 14 days to one of three protocols: room air [RA], sustained cycles of hyperoxia/hypoxia [SHH] as previously employed to produce ROP in rat pups, and intermittent hypoxia/hyperoxia [IHH] in order to more closely simulate clinical conditions in preterm infants. Retinae were obtained at 18 days and imaged for both avascularization and neovascularization. RESULTS As expected, the SHH group demonstrated significantly increased avascularity [40.9 ± 7.9% of retina] which was minimal in both RA and IHH groups. All SHH exposed pups exhibited neovascularization which occurred in 5/7 IHH exposed retinae versus 0 in the RA group [p = 0.02]. However, mean number of clock hours of neovascularization after IHH was 1.9 ± 2.1 which did not differ from the RA group, and was less than in the SHH group [8.3 ± 1.9, p < 0.001]. CONCLUSION A more clinically relevant intermittent hypoxia/hyperoxia [IHH] protocol does not produce the same degree of ROP as the traditional sustained hypoxia/hyperoxia [SHH] paradigm. Nonetheless, further refinement of our model may provide a suitable model for understanding the lesser degrees of ROP which predominate in preterm infants.
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Mayer CA, Di Fiore JM, Martin RJ, Macfarlane PM. Vulnerability of neonatal respiratory neural control to sustained hypoxia during a uniquely sensitive window of development. J Appl Physiol (1985) 2013; 116:514-21. [PMID: 24371020 DOI: 10.1152/japplphysiol.00976.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The first postnatal weeks represent a period of development in the rat during which the respiratory neural control system may be vulnerable to aberrant environmental stressors. In the present study, we investigated whether sustained hypoxia (SH; 11% O2) exposure starting at different postnatal ages differentially modifies the acute hypoxic (HVR) and hypercapnic ventilatory response (HCVR). Three different groups of rat pups were exposed to 5 days of SH, starting at either postnatal age 1 (SH1-5), 11 (SH11-15), or 21 (SH21-25) days. Whole body plethysmography was used to assess the HVR and HCVR the day after SH exposure ended. The primary results indicated that 1) the HVR and HCVR of SH11-15 rats were absent or attenuated (respectively) compared with age-matched rats raised in normoxia; 2) there was a profoundly high (∼84% of pups) incidence of unexplained mortality in the SH11-15 rats; and 3) these phenomena were unique to the SH11-15 group with no comparable effect of the SH exposure on the HVR, HCVR, or mortality in the younger (SH1-5) or older (SH21-25) rats. These results share several commonalities with the risk factors thought to underlie the etiology of sudden infant death syndrome, including 1) a vulnerable neonate; 2) a critical period of development; and 3) an environmental stressor.
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Bogacka I, Roane DS, Xi X, Zhou J, Li B, Ryan DH, Martin RJ. Expression Levels of Genes Likely Involved in Glucose-sensing in the Obese Zucker Rat Brain. Nutr Neurosci 2013; 7:67-74. [PMID: 15279492 DOI: 10.1080/10284150410001710401] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
It has been suggested that certain cells in the brain, like pancreatic beta-cells, use glucose transporter-2 (GLUT-2), glucokinase and glucagon-like peptide-1 receptor (GLP-1R) to sense glucose in the service of multiple aspects of energy balance. The obese Zucker rat displays numerous disturbances in energy homeostasis and may provide a model of dysfunctional expression of genes related to nutrient control systems. Using real-time RT-PCR we measured gene expression for three of the pancreatic glucose-sensing markers and neuropeptide Y (NPY) in the medial, lateral hypothalamus and hindbrain of lean and obese Zucker rats of both genders. Additionally, we measured circulating levels of glucose, leptin, insulin, corticosterone and glucagon. The results indicate that GLUT-2 mRNA expression is decreased, whereas glucokinase is increased in the hindbrain of obese rats. NPY mRNA level is significantly higher, whereas GLP-1R is significantly lower in the medial hypothalamus in obese individuals. Gender-related differences were found in the hindbrain and medial hypothalamus for GLUT-2 and in the lateral hypothalamus for GLP-1R and they may be related to the fact that the female Zucker rats do not develop diabetes as readily as males. Furthermore, the hindbrain may be an important site for glucose-sensing where major phenotypic changes occur for glucose-sensing genes expression.
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Charrier JA, Martin RJ, McCutcheon KL, Raggio AM, Goldsmith F, Goita M, Senevirathne RN, Brown IL, Pelkman C, Zhou J, Finley J, Durham HA, Keenan MJ. High fat diet partially attenuates fermentation responses in rats fed resistant starch from high-amylose maize. Obesity (Silver Spring) 2013; 21:2350-5. [PMID: 23512798 PMCID: PMC5225625 DOI: 10.1002/oby.20362] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Accepted: 12/16/2012] [Indexed: 01/08/2023]
Abstract
OBJECTIVE The effects of type 2 resistant starch from high-amylose maize (HAM-RS2) in rodents fed with low-fat diets were demonstrated in previous studies. Fish oil is also reported to reduce body fat. In the current study, the effects of high fat and fish oil on HAM-RS2 feeding in rats were investigated. DESIGN AND METHODS Rats were fed 0 or 27% (weight) HAM-RS2 with low (15% energy) or high fat (42% energy) diets that included 0 or 10% (energy) tuna oil to test the effect of HAM-RS2 in diet-induced obesity and effects of tuna oil. Data were analyzed as 2 × 2 × 2 factorial. RESULTS Rats fed HAM-RS2 had decreased cecal contents pH, increased cecal and cecal contents weight, increased cecal contents acetate, propionate, and butyrate, increased GLP-1 and PYY, and decreased abdominal fat. However, high fat partially attenuated effects of HAM-RS2, but increased GLP-1 active. Dietary tuna oil had limited effects at concentration used. CONCLUSIONS Results demonstrated that a high fat diet partially attenuates the response to HAM-RS2. The mechanism may center on reduced levels of cecal contents propionate and butyrate and reduced serum PYY. This study demonstrated that with consumption of high fat, HAM-RS2 produces fermentation but results in partial attenuation of effects.
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Zhou J, Keenan MJ, Fernandez-Kim SO, Pistell PJ, Ingram DK, Li B, Raggio AM, Shen L, Zhang H, McCutcheon KL, Tulley RT, Blackman MR, Keller JN, Martin RJ. Dietary resistant starch improves selected brain and behavioral functions in adult and aged rodents. Mol Nutr Food Res 2013; 57:2071-4. [PMID: 23818307 DOI: 10.1002/mnfr.201300135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/09/2013] [Accepted: 04/10/2013] [Indexed: 11/12/2022]
Abstract
Resistant starch (RS) is a dietary fiber that exerts multiple beneficial effects. The current study explored the effects of dietary RS on selected brain and behavioral functions in adult and aged rodents. Because glucokinase (GK) expression in hypothalamic arcuate nucleus and area postrema of the brainstem is important for brain glucose sensing, GK mRNA was measured by brain nuclei microdissection and PCR. Adult RS-fed rats had a higher GK mRNA than controls in both brain nuclei, an indicator of improved brain glucose sensing. Next, we tested whether dietary RS improve selected behaviors in aged mice. RS-fed aged mice exhibited (i) an increased eating responses to fasting, a behavioral indicator of improvement in aged brain glucose sensing; (ii) a longer latency to fall from an accelerating rotarod, a behavioral indicator of improved motor coordination; and (iii) a higher serum active glucagon-like peptide-1 (GLP-1). Then, GLP-1 receptor null (GLP-1RKO) mice were used to test the role of GLP-1 in brain glucose sensing, and they exhibited impaired eating responses to fasting. We conclude that in rodents (i) dietary RS improves two important indicators of brain function: glucose sensing and motor coordination, and (ii) GLP-1 is important in the optimal feeding response to a fast.
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Keenan MJ, Janes M, Robert J, Martin RJ, Raggio AM, McCutcheon KL, Pelkman C, Tulley R, Goita M, Durham HA, Zhou J, Senevirathne RN. Resistant starch from high amylose maize (HAM-RS2) reduces body fat and increases gut bacteria in ovariectomized (OVX) rats. Obesity (Silver Spring) 2013; 21:981-4. [PMID: 23784900 PMCID: PMC4826615 DOI: 10.1002/oby.20109] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 07/29/2012] [Accepted: 09/19/2012] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Obesity after menopause is a health concern for older females. Changes in the microbiota are likely to occur with this condition. Modifying the microbiota with a prebiotic is a plausible strategy for improving the health of menopausal females. DESIGN AND METHODS Resistant starch type 2 from high-amylose maize (HAM-RS2) was used as a prebiotic in rats in a 2 × 2 factorial study with two levels of HAM-RS2 (0 or 29.7% of weight of diet) referred to as energy control (EC) and HAM-RS2 diets, respectively; and two levels of surgery, ovariectomized (OVX) and sham. RESULTS In a 6-week, postsurgery recovery period, OVX rats gained more body weight with consumption of a similar amount of food. Subsequently, consumption of HAM-RS2 versus EC diets resulted in reduced abdominal fat in both OVX and sham rats; but when normalized for disemboweled body weight (body weight minus GI tract), there was no effect of surgery, only reduction with HAM-RS2. Targeted bacterial populations were estimated that are known to ferment HAM-RS2 or metabolize the products of that initial fermentation. OVX and sham rats demonstrated increased bacterial levels with dietary HAM-RS2 for all bacteria. Additionally, culture techniques and qPCR provided similar results. CONCLUSION This study shows that, as expected, OVX increases adiposity. However, contrary to previous effects seen in obese mice, this did not prevent fermentation of HAM-RS2 and consequently, the fat gain associated with OVX was attenuated.
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Mayer CA, Ao J, Di Fiore JM, Martin RJ, MacFarlane PM. Impaired hypoxic ventilatory response following neonatal sustained and subsequent chronic intermittent hypoxia in rats. Respir Physiol Neurobiol 2013; 187:167-75. [PMID: 23562917 DOI: 10.1016/j.resp.2013.03.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/20/2013] [Accepted: 03/21/2013] [Indexed: 11/15/2022]
Abstract
Neonatal chronic intermittent hypoxia (CIH) enhances the ventilatory sensitivity to acute hypoxia (acute hypoxic ventilatory response, HVR), whereas sustained hypoxia (SH) can have the opposite effect. Therefore, we investigated whether neonatal rats pre-treated with SH prior to CIH exhibit a modified HVR. Rat pups were exposed to CIH (5% O2/5min, 8h/day) between 6 and 15 days of postnatal age (P6-15) after pre-treatment with either normoxia or SH (11% O2; P1-5). Using whole-body plethysmography, the acute (5min, 10% O2) HVR at P16 (1 day post-CIH) was unchanged following CIH (67.9±6.7% above baseline) and also SH (58.8±10.5%) compared to age-matched normoxic rats (54.7±6.3%). In contrast, the HVR was attenuated (16.5±6.0%) in CIH exposed rats pre-treated with SH. These data suggest that while neonatal SH and CIH alone have little effect on the magnitude of the acute HVR, their combined effects impose a synergistic disturbance to postnatal development of the HVR. These data could provide important insight into the consequences of not maintaining adequate levels of oxygen saturation during the early neonatal period, especially in vulnerable preterm infants susceptible to frequent bouts of hypoxemic events (CIH) that are commonly associated with apnea of prematurity.
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Robertson AP, Buxton SK, Martin RJ. Whole-cell patch-clamp recording of nicotinic acetylcholine receptors in adult Brugia malayi muscle. Parasitol Int 2013; 62:616-8. [PMID: 23562945 DOI: 10.1016/j.parint.2013.03.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 03/06/2013] [Accepted: 03/15/2013] [Indexed: 11/19/2022]
Abstract
Lymphatic filariasis is a debilitating disease caused by clade III parasites like Brugia malayi and Wuchereria bancrofti. Current recommended treatment regimen for this disease relies on albendazole, ivermectin and diethylcarbamazine, none of which targets the nicotinic acetylcholine receptors in these parasitic nematodes. Our aim therefore has been to develop adult B. malayi for electrophysiological recordings to aid in characterizing the ion channels in this parasite as anthelmintic target sites. In that regard, we recently demonstrated the amenability of adult B. malayi to patch-clamp recordings and presented results on the single-channel properties of nAChR in this nematode. We have built on this by recording whole-cell nAChR currents from adult B. malayi muscle. Acetylcholine, levamisole, pyrantel, bephenium and tribendimidine activated the receptors on B. malayi muscle, producing robust currents ranging from >200 pA to ~1.5 nA. Levamisole completely inhibited motility of the adult B. malayi within 10 min and after 60 min, motility had recovered back to control values.
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Guice J, Page R, Goldsmith FR, Martin RJ, Coulon DB, Raggio AM, Pelkman C, Stout R, Durham HA, Gaither A, Ye J, Elzer R, Keenan MJ. Synergistic impact of whole grain (WG) and resistant starch (RS) components from high‐amylose maize ‐ effects on fermentation in the Zucker Diabetic Fatty (ZDF) rat. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.861.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hausman GJ, Wright JT, Latimer A, Watson R, Martin RJ. The Influence of Human Growth Hormone (GH) and Thyroxine (T4) on the Differentiation of Adipose Tissue in the Fetus. ACTA ACUST UNITED AC 2012; 1:345-56. [PMID: 16350585 DOI: 10.1002/j.1550-8528.1993.tb00012.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Late term fetuses from genetically obese dams have slightly larger fat cells, greater adipose tissue lipoprotein lipase (LPL) activities, elevated levels of thyroid hormones, and depressed growth hormone (GH) levels when compared to fetuses from lean dams. We have investigated the influence of thyroid hormone and GH status per se on these and other adipose tissue traits by chronically treating hypophysectomized (hypox) fetuses (day 70) between day 90 and 105 of gestation with either thyroxine (T4) or human GH. Treatment with T4 decreased body weights (P<.05), increased serum T4 levels (P<.05), and enhanced skin and hair development (P<.05). Quantitative analysis of sections of perirenal and subcutaneous adipose tissue indicated that T4 increased LPL activity (P<.05), slightly increased fat cell size, and more than doubled (P<.05) lipid accretion. A hypox induced deficit in fat cell cluster number in the outer layer of subcutaneous tissue was normalized by T4 (P<.05). Conversely, human GH (hGH) treatment had no influence on body weight, increased serum hGH levels, decreased fat cell size (P<.05) and LPL activity (P<.05) but had no influence on lipid accretion. Quantitative analysis of adipose tissue sections provided direct and indirect evidence of a "critical" or "sensitive" period between 90 and 105 days, since fetal hypox at day 70 severely impeded preadipocyte recruitment/replication during this period. Furthermore, T4 but not GH effectively normalized this hypox-induced deficiency in preadipocyte development. Therefore, T4 may have a major role in preadipocyte recruitment/replication during late fetal life.
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Grossman BM, Akoh CC, Hobbs JK, Martin RJ. Effects of a Fat Substitute, Sucrose Polyester, on Food Intake, Body Composition, and Serum Factors in Lean and Obese Zucker Rats. ACTA ACUST UNITED AC 2012; 2:271-8. [PMID: 16353428 DOI: 10.1002/j.1550-8528.1994.tb00057.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sucrose polyester, a fat substitute, has shown promise in reducing blood cholesterol and body weight of obese individuals. Effects of this compound in the Zucker rat, a genetic model of obesity, are unknown. Thus, we examined food intake, body weight, body composition, and several metabolic parameters in sera of lean and obese female Zucker rats. Eight-week-old lean and obese animals were given a choice between a control diet (15% corn oil) and fat substitute diet (5% corn oil and 10% sucrose polyester) for 2 days. Next, one-half of the lean and obese groups received control diet; the remaining lean and obese rats received fat substitute diet for 18 days. Cumulative food intake was depressed in fat substitute groups relative to control-fed animals; however, this effect was more predominant in obese animals. Obese rats consuming fat substitute diet (O-FS) gained less weight as compared to obese control-fed animals (O-C). Lean rats given fat substitute (L-FS) did not have significantly different body weights as compared to the L-C group. Fat substitute groups, combined, had lower body fat and higher body water as compared to controls. The O-FS group had lower serum glucose and insulin and higher fatty acid levels compared to the O-C group. There were no differences in serum cholesterol, HDL, or triglyceride levels due to fat substitute diet. These data suggest that the obese Zucker rat is unable to defend its body weight when dietary fat is replaced with sucrose polyester.
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Hausman DB, Hausman GJ, Martin RJ. Endocrine Regulation of Fetal Adipose Tissue Metabolism in the Pig: Role of Hydrocortisone. ACTA ACUST UNITED AC 2012; 2:314-20. [PMID: 16353579 DOI: 10.1002/j.1550-8528.1994.tb00070.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Glucocorticoids have been shown to be essential for the excessive fat deposition and development of obesity in several animal models. This study was performed to characterize the role of glucocorticoids in the developmental regulation of adipose tissue metabolism. On day 70 of gestation, pig fetuses were hypophysectomized by micro-cauterization. Hypophysectomized fetuses were implanted subcutaneously with hydrocortisone pellets or received no hormone replacement. Fetuses were removed by laparotomy on day 90 of gestation. Additional fetuses were hypophysectomized on day 70, implanted with hydrocortisone pellets on day 90 and removed on day 105 of gestation. Several intact fetuses were also implanted subcutaneously with hydrocortisone pellets during this later gestational period. Serum cortisol concentrations were reduced in hypophysectomized pigs at both fetal ages and were restored to intact levels by hydrocortisone treatment. Hydrocortisone supplementation enhanced lipolytic response to isoproterenol in intact fetuses but failed to restore lipolytic response to isoproterenol in hypophysectomized animals at either fetal age. Hydrocortisone induced a slight increase in lipogenesis in hypophysectomized fetuses when administered from 70 to 90 days of gestation and a more dramatic increase when administered from days 90 to 105 of gestation. However, hydrocortisone had no effect on basal or insulin stimulated lipogenesis in intact fetuses when administered from days 90 to 105 of gestation. These results indicate that hydrocortisone may have a primary influence on adipose tissue metabolism during late fetal development only in the absence of inhibition from counterregulatory hormones of pituitary origin.
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Keenan MJ, Martin RJ, Raggio AM, McCutcheon KL, Brown IL, Birkett A, Newman SS, Skaf J, Hegsted M, Tulley RT, Blair E, Zhou J. High-amylose resistant starch increases hormones and improves structure and function of the gastrointestinal tract: a microarray study. JOURNAL OF NUTRIGENETICS AND NUTRIGENOMICS 2012; 5:26-44. [PMID: 22516953 PMCID: PMC4030412 DOI: 10.1159/000335319] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 11/18/2011] [Indexed: 12/25/2022]
Abstract
BACKGROUND/AIMS Type 2 resistant starch from high-amylose maize (HAM-RS2) is associated with increased fermentation, increased expression of proglucagon (gene for GLP-1) and peptide YY (PYY) genes in the large intestine, and improved health. To determine what other genes are up- or downregulated with feeding of HAM-RS2, a microarray was performed. METHODS Adult, male Sprague Dawley rats were fed one of the following three diets for a 4-week study period: cornstarch control (CC, 3.74 kcal/g), dietary energy density control (EC, 3.27 kcal/g), and 30% HAM-RS2 (RS, 3.27 kcal/g). Rat microarray with ∼27,000 genes and validation of 94 representative genes with multiple qPCR were used to determine gene expression in total RNA extracts of cecal cells from rats. The RS versus EC comparison tested effects of fermentation as energy density of the diet was controlled. RESULTS For the RS versus EC comparison, 86% of the genes were validated from the microarray and the expression indicates promotion of cell growth, proliferation, differentiation, and apoptosis. Gut hormones GLP-1 and PYY were increased. CONCLUSIONS Gene expression results predict improved structure and function of the GI tract. Production of gut hormones may promote healthy functions beyond the GI tract.
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McCutcheon KL, LaBonte DR, Picha DH, Williams CC, Keenan MJ, Martin RJ. Gut fermentation and health effects of Louisiana sweet potato varieties. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.638.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Goldsmith F, Martin RJ, Raggio AM, McCutcheon KL, Goita M, Williams CC, Pelkman C, Finley J, Keenan MJ. Two prebiotics are effective in promoting fermentation in rats fed a high fat diet. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.830.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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McCutcheon KL, Martin RJ, Keenan MJ. Development of a proof of concept bioassay core laboratory for in vivo testing of functional food products in animal models. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.375.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tang T, Zhang J, Yin J, Staszkiewicz J, Gawronska-Kozak B, Jung DY, Ko HJ, Ong H, Kim JK, Mynatt R, Martin RJ, Keenan M, Gao Z, Ye J. Uncoupling of inflammation and insulin resistance by NF-κB in transgenic mice through elevated energy expenditure. J Biol Chem 2012. [DOI: 10.1074/jbc.a109.068007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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