Noninvasive 13C-octanoic acid breath test shows delayed gastric emptying in patients with amyotrophic lateral sclerosis

Abstract

ABC AbstractAmyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive loss of motor neurons. However, ALS has been recognized to also involve non-motor systems. Subclinical involvement of the autonomic system in ALS has been described. The recently developed 13 C-octanoic acid breath test allows the noninvasive measurement of gastric emptying. With this new technique we investigated 18 patients with ALS and 14 healthy volunteers. None of the patients had diabetes mellitus or other disorders known to cause autonomic dysfunction. The participants received a solid standard test meal labeled with 13 C-octanoic acid. Breath samples were taken at 15-min intervals for 5 h and were analyzed for 13 CO 2 by isotope selective nondispersive infrared spectrometry. Gastric emptying peak time (t peak ) and emptying half time (t½) were determined. All healthy volunteers displayed normal gastric emptying with a mean emptying t½ of 138 B 34 (range 68-172) min. Gastric emptying was delayed (t½ 1 160 min) in 15 of 18 patients with ALS. Emptying t½ in ALS patients was 218 B 48 (range 126-278) min (p ! 0.001). These results are compatible with autonomic involvement in patients with ALS, causing delayed gastric emptying of solids and encouraging the theory that ALS is a multisystem disease rather than a disease of the motor neurons only.

Increased peripheral lipid clearance in an animal model of amyotrophic lateral sclerosis

“…12/37/ dysfunction in ALS patients (24). Indeed, mutant SOD1 was highly expressed in intestinal mucosa with no age-dependent variations that could explain gastrointestinal dysfunction (figure 3A).…”

Impaired salivary gland function reveals autonomic dysfunction in amyotrophic lateral sclerosis

“…Previous reports on heart rate variability, cardiac innervation, gastric emptying, colonic transit time and skin response in ALS patients have revealed clinical or subclinical involvement of the autonomic nervous system. Both sympathetic and parasympathetic dysfunction were found [3,4,9,10,12,13]. Charchaflie et al [2] described a reduced parotid flow rate and bicarbonate concentration after indirect stimulation of the glands with intraoral citric acid in 10 ALS patients.…”

“…Sialorrhea is a disabling symptom in patients with bulbar ALS affecting up to 20 % of patients with ALS [11]. As reports of involvement of the autonomic nervous system in ALS grow [3,4,9,10,12,13], the question arises whether sialorrhea in bulbar ALS patients is a result of dysphagia or may be partially caused by dysfunction of the autonomic nervous system. In a preliminary study, we found a reduced radiotracer uptake in salivary gland scintigraphy in a small population of bulbar ALS patients (n = 5) suffering from extensive sialorrhea [5].As intraglandular injection of botulinum toxin A becomes a new choice of treatment in drooling, it may be helpful to characterize salivary gland function in ALS patients with sialorrhea before treatment begins.…”

Retention, Fixation, and Loss of the [13C] Label: A Review for the Understanding of Gastric Emptying Breath Tests

“…According to the conventional analytical method [3], GEC and t max are derived from the PER[t] curve, and t 1/ 2b from the CPR[t] curve. Currently, GEC seems to be going out of favor [26,27], whereas t max and t 1/2b are frequently used.…”