Parkinson's Disease and Diabetes Mellitus: Synergistic Effects on Pathophysiology and GI Motility

Lactose malabsorption and intolerance in older adults

PURPOSE OF REVIEW

Lactose malabsorption and intolerance are very common conditions. However, their optimal approach, including the diagnostic assessment, remains a matter of debate, especially in advanced age. In this brief review, we focused on current knowledge, concerns, and impact in clinical practice of lactose malabsorption and intolerance in elderly.

RECENT FINDINGS

Older adults are at high risk of malnutrition, owing to frequent occurrence of cognitive impairment, loss of appetite, dysphagia, and poor oral health. A significant decrease in the consumption of dairy products may lead to inadequate intake of high-quality protein and minerals, with a consequent impact on muscle and bone health. Testing for lactose malabsorption may be challenging in older adults, if not useless. Instead, a detailed clinical evaluation should always be pursued to identify both lactose intolerance and all confounding factors mimicking the same clinical picture.

SUMMARY

The management of lactose malabsorption and intolerance in older adults deserves a personalized approach. Because of the importance of maintaining an adequate nutritional status in this age group, efforts should be put forth to avoid excessively restrictive diets.

The Contribution of Type 2 Diabetes to Parkinson's Disease Aetiology

Type 2 diabetes (T2D) and Parkinson's disease (PD) are chronic disorders that have a significant health impact on a global scale. Epidemiological, preclinical, and clinical research underpins the assumption that insulin resistance and chronic inflammation contribute to the overlapping aetiologies of T2D and PD. This narrative review summarises the recent evidence on the contribution of T2D to the initiation and progression of PD brain pathology. It also briefly discusses the rationale and potential of alternative pharmacological interventions for PD treatment.

Evaluation of bidirectional gut-brain axis and anorectal function in Parkinson's disease with constipation

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative movement disorder with prodromal and highly prevalent gastrointestinal (GI) symptoms, especially constipation. Although PD models suggest gut-brain axis dysfunction, the mechanistic underpinnings and their correlation with GI symptoms are poorly understood.

AIM

To examine the bidirectional gut-brain axis function in PD and correlate it with constipation severity, PD duration, and severity.

METHODS

Rectal sensory thresholds and afferent cortical evoked potentials (CEP) were assessed using a 4-ring EMG electrode probe. Efferent anal and rectal motor evoked potentials (MEPs) were obtained following transcranial and lumbosacral magnetic stimulation. Bowel symptoms were assessed by prospective stool diary. The CEP and MEP latencies, rectal sensory thresholds, and anorectal sensorimotor data were compared between PD subjects and age-adjusted healthy subjects.

KEY RESULTS

Twenty-five PD subjects with constipation (F/M = 6/19) and 20 healthy subjects (F/M = 14/6) were enrolled. The first and pain sensation thresholds were higher in PD subjects than healthy subjects (p < 0.002) but lost significance after adjustment for age. Age-adjusted rectal CEP and right-sided cortico-anal MEP latencies were prolonged in PD subjects compared to healthy subjects (p < 0.04). Also, half (4 of 8) age-adjusted spino-anal and rectal MEP latencies in PD subjects were significantly longer. In multivariate linear analysis, first rectal sensation and right-sided MEP latencies showed moderate correlation with constipation severity.

CONCLUSIONS & INFERENCES

Parkinson's disease is associated with significant bidirectional gut-brain axis dysfunction as evidenced by prolonged afferent and efferent neuronal signaling. Constipation severity in PD is correlated to abnormal rectal sensation and lateralized disturbance of efferent brain-gut signaling.

Step on the accelerator: modern treatment of constipation

PURPOSE OF REVIEW

This review aims to explore effective management of constipation, examine challenges in making a positive diagnosis, and highlights the significance of a positive patient-provider relationship and emerging treatments.

RECENT FINDINGS

Less than one-fifth of patients feel satisfied with treatment of their constipation. Sixty percent of patients with functional dyspepsia and gastroparesis have severe to very severe constipation that correlates with their upper gastrointestinal symptom severity. Two gold kiwifruits are noninferior to 10 g of psyllium in the treatment of constipation. More than 40% of patients undergoing lumbar fusion continue to fill opioid prescriptions 90 days after surgery, contributing to 80 000 chronic opioid users annually. Most patients are using over-the-counter (OTC) treatments for constipation with greater than 60% dissatisfied. Pharmacologic management involves the use of GCC agonists and emerging drug classes such as bile acid transport inhibitors and sodium hydrogen exchanger isoform 3 (NHE3) inhibitors. Nonpharmacologic treatments, including neuromodulation and FDA-approved vibrating capsule, show promise in improving symptoms and quality of life.

SUMMARY

Constipation significantly impacts patients' quality of life and well being and the majority of patients are refractory to conservative measures and OTC treatments. Both pharmacologic and nonpharmacologic treatments hold promise for improving constipation and quality of life.