Uremic pruritus is one of the skin complications that perplex patients with end-stage renal disease undergoing hemodialysis or peritoneal dialysis. Because the specific pathogenesis is not clear, there is no unified treatment plan in the world. In August 2021, the US Food and Drug Administration approved the use of difelikefalin (under the trade name Korsuva) for the treatment of moderate to severe pruritus associated with chronic kidney disease in adult patients undergoing hemodialysis. Studies have shown that difelikefalin can remarkably reduce the intensity of pruritus and improve sleep and pruritus-related quality of life. The recommended dose of difelikefalin is 0.5 μg/kg, and difelikefalin is well tolerated and has high safety. This paper reviews the pharmacological effects, pharmacokinetics, clinical efficacy and safety of difelikefalin.

OBJECTIVETo investigate the expression of TMEMl6A in the colon of intractable functional constipation patients and its clinical implications.

METHODSA total of 30 patients with intractable chronic functional constipation were selected as trial group (full thickness tissue of sigmoid colon), 30 patients with colon cancer as control group (distant tissues at least 5 cm away from cancer). Tissues from two groups were collected in our hospital from February 2012 to June 2014 and confirmed by pathological diagnosis. Immunofluorescence staining, RT-PCR and Western blot were performed to detect the mRNA and protein expression of TMEM16A and c-kit in colon.

RESULTSTMEM16A and c-kit protein expressions were observed in similar sites of colon tissues in two groups. Expressions of TMEM16A and C-kit in colon tissues detected by immunofluorescence, RT-PCR, and Western blotting were significantly lower in trial group than those in control group (TMEM16A: mean A 1.84±0.25 vs. 3.65±0.32, P<0.05, gray intensity ratio 0.66±0.07 vs. 1.04±0.17, P<0.05, relative mRNA 0.41±0.05 vs. 1.00, P<0.05; c-kit: mean A 3.38±0.24 vs. 5.06±0.31, gray intensity ratio 0.64±0.06 vs. 0.98±0.09, relative mRNA 0.18±0.08 vs. 1.00, all P<0.05).

CONCLUSIONSTMEM16A expression in colon tissues of intractable functional constipation patients is significantly lower and may adjust the movement of colonic smooth muscle by regulating the c-kit expression. TMEMl6A may be used as a new candidate target for diagnosis and treatment of intractable functional constipation.

Anoctamin-1 ; Blotting, Western ; Chloride Channels ; Colon, Sigmoid ; Colonic Neoplasms ; Constipation ; Humans ; Muscle, Smooth ; Neoplasm Proteins ; Proteomics ; Proto-Oncogene Proteins c-kit ; RNA, Messenger

OBJECTIVETo establish an innovative rat model of slow transit constipation by selective chemical ablation of the colon enteric plexus.

METHODSSprague Dawley rats, 5-6 weeks old, were randomly divided into normal control group, sham operation group, treatment group I, II, III, IIII. The normal control group did not receive treatment. Rats in the sham operation group and the treatment groups received abdominal operation under anesthesia, and the gauze containing 0.9% normal saline, 0.05%, 0.1%, 0.25%, 0.5% benzalkonium chloride (BAC) was applied into colon for 30 minutes. Two weeks after operation, the number of feces, fecal dry weight in 24 h and gastrointestinal transit time were recorded, then hematoxylin-eosin (HE) staining, immunohistochemistry, ELISA were used for the evaluation of colonic pathology, enteric plexus, Interstitial cells of Cajal and neurotransmitters 5-hydroxytryptamine(5-HT).

RESULTSCompared to the normal control group and the sham operation group, the gastrointestinal transit time was significantly prolonged and fecal dry weight was lower in the treatment group II, III (all P<0.05). HE and immunohistochemical staining showed varying degrees of pathological changes in the treatment groups and in line with the pathological changes of slow transit constipation. 5-HT concentration reduced significantly in treatment group III compared to other groups (P<0.01).

CONCLUSIONThe animal model of STC is successfully established by applying 0.25% BAC selective chemical ablation of the colon enteric plexus. This model is simple, stable, and is more in line with pathological changes of slow transit constipation.

Animals ; Autonomic Pathways ; Constipation ; Disease Models, Animal ; Gastrointestinal Transit ; Immunohistochemistry ; Interstitial Cells of Cajal ; Rats ; Rats, Sprague-Dawley