Xerostomia, thirst, sodium gradient and inter-dialytic weight gain in hemodialysis diabetic vs. non-diabetic patients

A potential link between AQP3 and SLC14A1 gene expression level and clinical parameters of maintenance hemodialysis patients

Background

The transport of water and urea through the erythrocyte membrane is facilitated by aquaporins such as aquaglyceroporin (AQP3), and type B urea transporters (UT-B). As they may play an important role in osmotic balance of maintenance hemodialysis (HD) patients, the aim of the present study was to determine whether any relationship exists between the expression of their genes and the biochemical / clinical parameters in HD patients.

Methods

AQP3 and UT-B (SLC14A1) gene expression was evaluated using RT-qPCR analysis in 76 HD patients and 35 participants with no kidney failure.

Results

The HD group demonstrated significantly higher median expression of AQP3 and UT-B (Z = 2.16; P = 0.03 and Z = 8.82; p < 0.0001, respectively) than controls. AQP3 negatively correlated with pre-dialysis urea serum concentration (R = -0.22; P = 0.049) and sodium gradient (R = -0.31; P = 0.04); however, no significant UT-B correlations were observed. Regarding the cause of end-stage kidney disease, AQP3 expression positively correlated with erythropoietin dosages in the chronic glomerulonephritis (GN) subgroup (R = 0.6; P = 0.003), but negatively in the diabetic nephropathy subgroup (R = -0.59; P = 0.004). UT-B positively correlated with inter-dialytic weight gain% in the GN subgroup (R = 0.47; P = 0.03).

Conclusion

Maintenance hemodialysis seems significantly modify AQP3 and UT-B expression but their link to clinical and biochemical parameters needs further large-scale evaluation.

Effects of Electrical Stimulation of Acupoints on Xerostomia for Patients Who Undergo Hemodialysis

Xerostomia plays a major role in higher interdialytic weight gain (IDWG), which causes cardiovascular complications in patients who undergo hemodialysis. However, few studies have determined a method to manage xerostomia. This study determines the effect of transcutaneous electrical acupoint stimulation (TEAS) on hemodialysis patients with xerostomia and the percentage of IDWG. The study was a single-blind and quasi-experimental study. There are 75 participants: 37 in the TEAS group and 38 in the contrast group. The TEAS group used 250 µs and 50 Hz and the contrast group used 50 µs and 2 Hz three times a week for 3 weeks to stimulate ST 6 and TE17 acupoints. The salivary flow rates, dry mouth, and %IDWG were determined before, during and one week after the program. Compared with the contrast group, the TEAS group showed a significantly improved salivary flow rate (mL/min) (F (2, 123) = 15.28, p < 0.0001), and patients recovered their normal salivary flow rate. However, the results show that both groups showed significant improvement in dry mouth after treatment. The TEAS group demonstrated no effect in terms of %IDWG, as expected. The results show that a TEAS program is an effective means of symptom management for xerostomia patients who undergo hemodialysis. A TEAS program can be used to manage symptoms for xerostomia patients who undergo hemodialysis.

Thirst in patients on chronic hemodialysis: What do we know so far?

Thirst has been defined as "the sensation that leads animal's and human's actions toward the goal of finding and drinking water" or as "any drive that can motivate water intake, regardless of cause". Thirst, together with xerostomia, is the main cause of poor adherence to fluid restriction and of excessive intake of fluids in patients on chronic hemodialysis, and consequently of high interdialytic weight gain. Interdialytic weight gain (IDWG) should be lower than 4.0-4.5% of dry weight. Unfortunately, many patients have an IDWG greater than this value and some have IDWG of 10-20%. High IDWG is associated with a higher risk of all-cause and cardiovascular death and increased morbidity, such as ventricular hypertrophy and major adverse cardiac and cerebrovascular events. In addition, high IDWG leads to supplementary weekly dialysis sessions with consequent deterioration of quality of life and increased costs. Thus, the knowledge of thirst in patients on chronic hemodialysis is essential to prompt its adequate management to limit IDWG in the routine clinical practice. The present review aims to describe the physiology of thirst in patients on chronic hemodialysis, as well as the prevalence, its measures, the associated variables, the consequences, and the strategies for its reduction.