The solute carrier family 12(SLC12)of cation-chloride cotransporters(CCCs)comprises potassium chlo-ride cotransporters(KCCs,e.g.KCC1,KCC2,KCC3,and KCC4)-mediated Cl-extrusion,and sodium po-tassium chloride cotransporters(N[K]CCs,NKCC1,NKCC2,and NCC)-mediated Cl-loading.The CCCs play vital roles in cell volume regulation and ion homeostasis.Gain-of-function or loss-of-function of these ion transporters can cause diseases in many tissues.In recent years,there have been considerable ad-vances in our understanding of CCCs'control mechanisms in cell volume regulations,with many tech-niques developed in studying the functions and activities of CCCs.Classic approaches to directly measure CCC activity involve assays that measure the transport of potassium substitutes through the CCCs.These techniques include the ammonium pulse technique,radioactive or nonradioactive rubidium ion uptake-assay,and thallium ion-uptake assay.CCCs'activity can also be indirectly observed by measuring y-aminobutyric acid(GABA)activity with patch-clamp electrophysiology and intracellular chloride con-centration with sensitive microelectrodes,radiotracer 36Cl-,and fluorescent dyes.Other techniques include directly looking at kinase regulatory sites phosphorylation,flame photometry,22Na+uptake assay,structural biology,molecular modeling,and high-throughput drug screening.This review sum-marizes the role of CCCs in genetic disorders and cell volume regulation,current methods applied in studying CCCs biology,and compounds developed that directly or indirectly target the CCCs for disease treatments.

BACKGROUNDTraditional Chinese medical treatment of primary Sjögren's syndrome has advantages over Western medicine in terms of fewer side effects and improved patient conditions. This study was a multicenter, randomized, double-blind, placebo-controlled clinical trial of the efficacy and safety of ShengJinRunZaoYangXue granules for the treatment of primary Sjögren's syndrome, including the symptoms of dry mouth and dry eye.

METHODSWe undertook a 6-week, double-blind, randomized trial involving 240 patients with primary Sjögren's syndrome at five centers in East China. A computer-generated randomization schedule assigned patients at a 2:1 ratio to receive either ShengJinRunZaoYangXue granules or placebo once daily. Patients and investigators were blinded to treatment allocation. The primary endpoints were the salivary flow rate, Schirmer test results, and sugar test results. Intention-to-treat and per-protocol analyses were performed.

RESULTSAll 240 patients were randomly allocated to either the treatment group (n = 160, ShengJinRunZaoYangXue granules) or placebo group (n = 80) and were included in the intention-to-treat analysis. After program violation and loss to follow-up, a total of 199 patients were included in the per-protocol analysis. At six week, intention-to-treat and per-protocol analyses of the left-eye Schirmer I test results showed an improved difference of 1.36 mm/5 min (95% CI: 0.03 to 2.69 mm/5 min) and 1.35 mm/5 min (95% CI: 0.04 to 2.73 mm/5 min), respectively, and those of the right-eye Schirmer I test results showed an improved difference of 1.12 mm/5 min (95% CI: 0.02 to 2.22 mm/5 min) and 1.12 mm/5 min (95% CI: -0.02 to 2.27 mm/5 min), respectively. There was no significant difference between the two groups before treatment. After treatment, the between-group and within-group before-and-after paired comparison results were statistically significant (P < 0.05). Intention-to-treat and per-protocol analyses showed an improved salivary flow rate by 0.04 ml/15 min (95% CI: -0.49 to 0.58 ml/15 min) and 0.04 ml/15 min (95% CI: -0.52 to 0.60 ml/15 min), respectively, but the differences were not significant. Intention-to-treat and per-protocol analyses showed that the sugar test results were improved by 1.77 minutes (95% CI: 0.11 to 3.44 minutes) and 1.84 minutes (95% CI: 0.12 to 3.55 minutes), respectively, but the differences were not significant. For the secondary endpoint, intention-to-treat and per-protocol analyses showed significant improvement in the integrated evaluation of treated patients with dry eye and dry mouth after six weeks of treatment. The incidence of adverse events was 15.6% in the treatment group and 10.0% in the placebo group. Most (94%) adverse events were mild to moderate in the two groups, and only two cases of serious adverse events occurred in the treatment group; both were caused by autoimmune liver disease.

CONCLUSIONSSix-week treatment with ShengJinRun ZaoYangXue granules for primary Sjögren's syndrome in this large-scale study improved the symptoms of dry mouth, dry eyes, and low tear flow rate with minimal adverse events.

China ; Double-Blind Method ; Drugs, Chinese Herbal ; adverse effects ; therapeutic use ; Female ; Humans ; Male ; Medicine, Chinese Traditional ; Middle Aged ; Models, Theoretical ; Sjogren's Syndrome ; drug therapy