Modulation of individual components of gastric motor response to duodenal glucose

AIM:To evaluate individual components of the antro-pyloro-duodenal(APD)motor response to graded small intestinal glucose infusions in healthy humans.METHODS:APD manometry was performed in 15healthy subjects(12 male;40±5 years,body mass index 26.5±1.6 kg/m2)during four 20-min intraduodenal infusions of glucose at 0,0.5,1.0 and 1.5 kcal/min,in a randomised double-blinded fashion.Glucose solutions were infused at a rate of 1 mL/min and separated by 40-min"wash-out"period.Data are mean±SE.Inferential analyses are repeated measure analysis of variance with Bonferroni post-hoc testing.RESULTS:At 0 kcal/min frequency of pressure waves were:antrum(7.5±1.8 waves/20 min)and isolated pyloric pressure waves(IPPWs)(8.0±2.3 waves/20min)with pyloric tone(0.0±0.9 mmHg).Intraduodenal glucose infusion acutely increased IPPW frequency(P<0.001)and pyloric tone(P=0.015),and decreased antral wave frequency(P=0.007)in a dosedependent fashion.A threshold for stimulation was observed at 1.0 kcal/min for pyloric phasic pressure waves(P=0.002)and 1.5 kcal/min for pyloric tone and antral contractility.CONCLUSION:There is hierarchy for the activation of gastrointestinal motor responses to duodenal glucose infusion.An increase in IPPWs is the first response observed.

Lower esophageal sphincter relaxation is impaired in older patients with dysphagia

AIM: To characterize the effects of age on the mechanisms underlying the common condition of esophageal dysphagia in older patients, using detailed manometric analysis. METHODS: A retrospective case-control audit was performed on 19 patients aged ≥ 80 years (mean age 85 ± 0.7 year) who underwent a manometric study for dysphagia (2004-2009). Data were compared with 19 younger dysphagic patients (32 ± 1.7 years). Detailed manometric analysis performed prospectively included basal lower esophageal sphincter pressure (BLESP), pre-swallow and nadir LESP, esophageal body pressures and peristaltic duration, during water swallows (5 mL) in right lateral (RL) and upright (UR) postures and with solids. Data are mean ± SE; a P-value < 0.05 was considered significant. RESULTS: Elderly dysphagic patients had higher BLESP than younger patients (23.4 ± 3.8 vs 14.9 ± 1.2 mmHg; P < 0.05). Pre-swallow LESP was elevated in the elderly in both postures (RL: 1 and 4 s P = 0.019 and P = 0.05; UR: P < 0.05 and P = 0.05) and solids (P < 0.01). In older patients, LES nadir pressure was higher with liquids (RL: 2.3 ± 0.6 mmHg vs 0.7 ± 0.6 mmHg, P < 0.05; UR: 3.5 ± 0.9 mmHg vs 1.6 ± 0.5 mmHg, P = 0.01) with shorter relaxation after solids (7.9 ± 1.5 s vs 9.7 ± 0.4 s, P = 0.05). No age-related differences were seen in esophageal body pressures or peristalsis duration. CONCLUSION: Basal LES pressure is elevated and swallow-induced relaxation impaired in elderly dysphagic patients. Its contribution to dysphagia and the effects of healthy ageing require further investigation.

Age-related impairment of esophagogastric junction relaxation and bolus flow time

AIM To investigate the functional effects of abnormal esophagogastric(EGJ) measurements in asymptomatic healthy volunteers over eighty years of age. METHODS Data from 30 young controls(11 M, mean age 37 ± 11 years) and 15 aged subjects(9 M, 85 ± 4 years) were compared for novel metrics of EGJ-function: EGJcontractile integral(EGJ-CI), "total" EGJ-CI and bolus flow time(BFT). Data were acquired using a 3.2 mm, 25 pressure(1 cm spacing) and 12 impedance segment(2 cm) solid-state catheter(Unisensor and MMS SolarGI system) across the EGJ. Five swallows each of 5 m L liquid(L) and viscous(V) bolus were analyzed. Mean values were compared using Student's t test for normally distributed data or Mann Whitney U-test when non-normally distributed. A P value < 0.05 was considered significant.RESULTS EGJ-CI at rest was similar for older subjects compared to controls. "Total" EGJ-CI, measured during liquid swallowing, was increased in older individuals when compared to young controls(O 39 ± 7 mm Hg.cm vs C 18 ± 3 mm Hg.cm; P = 0.006). For both liquid and viscous bolus consistencies, IRP4 was increased(L: 11.9 ± 2.3 mm Hg vs 5.9 ± 1.0 mm Hg, P = 0.019 and V: 14.3 ± 2.4 mm Hg vs 7.3 ± 0.8 mm Hg; P = 0.02) and BFT was reduced(L: 1.7 ± 0.3 s vs 3.8 ± 0.2 s and V: 1.9 ± 0.3 s vs 3.8 ± 0.2 s; P < 0.001 for both) in older subjects, when compared to young. A matrix of bolus flow and presence above the EGJ indicated reductions in bolus flow at the EGJ occurred due to both impaired bolus transport through the esophageal body(i.e., the bolus never reached the EGJ) and increased flow resistance at the EGJ(i.e., the bolus retained just above the EGJ).CONCLUSION Bolus flow through the EGJ is reduced in asymptomatic older individuals. Both ineffective esophageal bolus transport and increased EGJ resistance contribute to impaired bolus flow.