Neuroimmunoendocrine Link Between Chronic Kidney Disease and Olfactory Deficits.

Ludivina Robles-Osorio,Benito Ordaz,Ernesto Sabath,Teresa Morales,Rebeca Corona

doi:10.3389/fnint.2022.763986

Abstract

Chronic kidney disease (CKD) is a multifactorial pathology that progressively leads to the deterioration of metabolic functions and results from deficient glomerular filtration and electrolyte imbalance. Its economic impact on public health is challenging. Mexico has a high prevalence of CKD that is strongly associated with some of the most common metabolic disorders like diabetes and hypertension. The gradual loss of kidney functions provokes an inflammatory state and endocrine alterations affecting several systems. High serum levels of prolactin have been associated with CKD progression, inflammation, and olfactory function. Also, the nutritional status is altered due to impaired renal function. The decrease in calorie and protein intake is often accompanied by malnutrition, which can be severe at advanced stages of the disease. Nutrition and olfactory functioning are closely interconnected, and CKD patients often complain of olfactory deficits, which ultimately can lead to deficient food intake. CKD patients present a wide range of deficits in olfaction like odor discrimination, identification, and detection threshold. The chronic inflammatory status in CKD damages the olfactory epithelium leading to deficiencies in the chemical detection of odor molecules. Additionally, the decline in cognitive functioning impairs the capacity of odor differentiation. It is not clear whether peritoneal dialysis and hemodialysis improve the olfactory deficits, but renal transplants have a strong positive effect. In the present review, we discuss whether the olfactory deficiencies caused by CKD are the result of the induced inflammatory state, the hyperprolactinemia, or a combination of both.

Highlights

The kidneys are in charge of filtering and eliminating the metabolic products and toxins from the blood, maintaining the control of the extracellular fluid, and the electrolyte and acid-base balance (Dhondup and Qian, 2017)
Chronic kidney disease (CKD) is characterized by a persistent deficiency in glomerular filtration rate (GFR) that leads to increased levels of uremic toxins, such as indoxyl sulfate and p-Cresol
The accumulation of uremic toxins promotes the activation of the immune system through the release of cytokines and the lack of clearance of PRL due to inadequate glomerular filtration

Summary

Introduction

The kidneys are in charge of filtering and eliminating the metabolic products and toxins from the blood, maintaining the control of the extracellular fluid, and the electrolyte and acid-base balance (Dhondup and Qian, 2017). This initiates an inflammatory cascade in the arcuate nucleus: increased cytokine and nitric oxide production lead to reduced TIDA neuron functioning, which culminates in lower dopamine synthesis and high levels of PRL that increase the risk for mammary and pituitary tumor development (Gilbreath et al, 2019).

Results

Conclusion