Discovery of Novel SPAK Inhibitors That Block WNK Kinase Signaling to Cation Chloride Transporters

Upon activation by with-no-lysine kinases, STE20/SPS1-related proline–alanine-rich protein kinase (SPAK) phosphorylates and activates SLC12A transporters such as the Na⁺-Cl⁻ cotransporter (NCC) and Na⁺-K⁺-2Cl⁻ cotransporter type 1 (NKCC1) and type 2 (NKCC2); these transporters have important roles in regulating BP through NaCl reabsorption and vasoconstriction. SPAK knockout mice are viable and display hypotension with decreased activity (phosphorylation) of NCC and NKCC1 in the kidneys and aorta, respectively. Therefore, agents that inhibit SPAK activity could be a new class of antihypertensive drugs with dual actions (i.e., NaCl diuresis and vasodilation). In this study, we developed a new ELISA-based screening system to find novel SPAK inhibitors and screened >20,000 small-molecule compounds. Furthermore, we used a drug repositioning strategy to identify existing drugs that inhibit SPAK activity. As a result, we discovered one small-molecule compound (Stock 1S-14279) and an antiparasitic agent (Closantel) that inhibited SPAK-regulated phosphorylation and activation of NCC and NKCC1 in vitro and in mice. Notably, these compounds had structural similarity and inhibited SPAK in an ATP-insensitive manner. We propose that the two compounds found in this study may have great potential as novel antihypertensive drugs.     

Granulocytic sarcoma of the colon in chronic myelomonocytic leukemia

A 59-year-old man with a six-month history of chronic myelomonocytic leukemia (CMML) was admitted to the Kitasato University Hospital because of melena in September 2000. Colonofiberscopy and barium enema demonstrated an ulcerated tumorous lesion in the transverse colon. The histopathologic findings of the ulcer bed revealed diffuse infiltration of granulocytes at each stage of differentiation. The diagnosis of granulocytic sarcoma (GS) was made. Surgical resection was not indicated, because thrombocytopenia was hardly improved enough to allow surgery despite repetitive transfusion of platelet concentrates. CMML developed to refractory anemia with excess of blast in transformation in February 2001. Two courses of low dose cytarabine plus aclarubicin were ineffective on the GS in spite of a decrease in the peripheral blood blasts. Progression to acute myeloid leukemia eventually broke out, in July 2001. The patient died of leukemia complicated with pneumonia and intestinal obstruction. At present, nine cases of GS in the colon have been reported. However, these cases did not include CMML. This is the first report describing GS in the colon associated with CMML.     

Cerebral Blood Flow in Patients With Peritoneal Dialysis by an Easy Z‐Score Imaging System for Brain Perfusion Single‐Photon Emission Tomography

Cognitive impairment has long been recognized as a complication of chronic kidney disease. However, there is little information available regarding regional cerebral blood flow (rCBF) in patients with peritoneal dialysis (PD). Therefore, we evaluated rCBF using brain single photon emission computed tomography (SPECT). We conducted a cross‐sectional study in our hospital. Eighteen consecutive PD patients who could visit the hospital by themselves without any history of stroke were examined by Technetium‐99 m‐labeled ethylcrysteinate dimer brain SPECT. An easy Z‐score imaging system (eZIS) was used to compare rCBF in PD patients with those in age‐matched healthy controls. We also evaluated cognitive dysfunction with the mini‐mental state examination (MMSE) questionnaire. Only one patient showed an MMSE score of 18 points, and the remaining 14 patients were considered as normal (MMSE ≥ 27), and three patients were considered to have mild cognitive impairment (24 ≤ MMSE ≤ 26). In all patients, rCBF in the posterior cingulated gyri, precunei, and parietal cortices was significantly decreased. The ratio of the reduction of rCBF in each region relative to that of rCBF across the whole brain correlated positively with the PD duration (r = 0.559; P < 0.05). The serum β2‐microglobulin level was significantly higher in patients who had a higher ratio of rCBF reduction compared with those with lower ratios. In conclusion, all PD patients in the present study had decreased rCBF irrespective of MMSE scores.     

Study protocol of a multicenter registry of patients with rheumatoid arthritis starting biologic therapy in Japan: Tsurumai Biologics Communication Registry (TBCR) Study

Biologic agents have proven to be effective against rheumatoid arthritis (RA) in clinical trials and post-marketing surveillance (PMS) studies. However, limited follow-up periods and strict criteria for recruitment might lead to an underestimation of adverse events. To document the long-term course of patients with RA treated with biologics in clinical settings, we established the Tsurumai Biologics Communication Registry (TBCR). First, we retrospectively collected data of patients registered for any biologic PMS study or clinical trial at participating institutes. Thus far, thirteen institutes have joined the registry and 860 patients have been identified. Comparing baseline characteristics by age and initiation year of biologics, young patients had significantly less joint damage and dysfunction and a higher dose of concomitant methotrexate (MTX) compared to older patients. Older age and functional class were significantly related to the incidence of adverse events that resulted in discontinuation of the 1st biologic treatment. The TBCR is in its initial stages, and information on all patients newly starting biologic therapy at participating institutes is being collected prospectively. Differences in baseline characteristics by age and initiation year of biologics need to be carefully evaluated in order to report on drug-related survival and long-term prognosis, using follow-up data in the near future.     

Laparoscopic pancreaticoduodenectomy after endovascular repair for abdominal aortic aneurysm

INTRODUCTIONMost gastroenterological surgeries, even pancreatic surgery, can now be performed laparoscopically. However, the management of concomitant abdominal aortic aneurysm (AAA) and intra-abdominal malignancy is controversial. The performance of endovascular repair (EVAR) for AAA has been increasing; however, there is no report of laparoscopic pancreaticoduodenectomy after EVAR.PRESENTATION OF CASEA pancreatic tumor was detected during follow-up after EVAR for AAA. The enlarging tumor was diagnosed as an intraductal papillary mucinous tumor with a nodule. Laparoscopic pancreaticoduodenectomy was safely performed. After laparoscopic dissection around the pancreas head, an additional incision was made in the upper abdomen, and pancreatic reconstruction was performed through the incision. In spite of grade B pancreatic fistulae, the patient recovered with medical therapy. The pathological diagnosis was intraductal papillary mucinous adenoma with small foci of carcinoma in situ. The patient has been well with neither recurrence of the tumor nor any cardiovascular events for 18 months.DISCUSSIONThe management of concomitant malignancy and AAA is challenging, especially in patients with a pancreatic tumor. The reasons for the rarity of treatment include prognosis, anatomical vicinity, and postoperative complications. EVAR reduces retroperitoneal adhesions. A laparoscopic approach provides a small operative field and decreases mutual interference with AAA. Moreover, reconstruction is performed through an upper abdominal incision apart from the AAA. Hand-sewing provides more reliable stability of the anastomosis.CONCLUSIONThe increasing frequency of performance of EVAR for AAA and subsequent computed tomography may help to detect malignancy. Laparoscopic surgery appears to be a valid approach to malignancy after EVAR.     

Mitochondrial respiratory chain complex IV deficiency complicated with chronic intestinal pseudo‐obstruction in a neonate

A female infant born at 36 weeks gestational age with birthweight 2135 g, and who developed respiratory disorder, hyperlactacidemia and hypertrophic cardiomyopathy after birth, was admitted to hospital at 3 days of age. After admission, bilious emesis, abdominal distention, and passage disorder of the gastrointestinal tract were resistant to various drugs. Exploratory laparotomy was performed at 93 days of age, but no organic lesions were identified and normal Meissner/Auerbach nerve plexus was confirmed, which led to a clinical diagnosis of chronic intestinal pseudo‐obstruction (CIPO). She was diagnosed with mitochondrial respiratory chain complex IV deficiency on histopathology of the abdominal rectus muscle and enzyme activity measurement. This is the first report of a neonate with mitochondrial respiratory chain complex deficiency with intractable CIPO. CIPO can occur in neonates with mitochondrial respiratory chain disorder, necessitating differential diagnosis from Hirschsprung disease.     

Phosphorylation of neuronal nitric oxide synthase at Ser847 in the nucleus intermediolateralis after spinal cord injury in mice

We previously demonstrated that Ca2+/calmodulin (CaM)-dependent protein kinase IIalpha (CaM-KIIalpha) can phosphorylate neuronal nitric oxide synthase (nNOS) at Ser847 and attenuate NOS activity in neuronal cells. In the present study we focused on chronological alteration in levels and cellular location of nNOS, phosphorylated (p)-Ser847-nNOS (NP847), CaM-KII and p-Thr286-CaM-KIIalpha following spinal cord injury (SCI) in mice. Western blot analysis showed nNOS to be significantly phosphorylated at Ser847 from 3 h after SCI, peaking at 24 h and gradually decreasing thereafter, and CaM-KII to be colocalized with nNOS after SCI. Immunohistochemical analysis revealed that SCI causes an increase in both NP847 and p-Thr286-CaM-KIIalpha in the nucleus intermediolateralis. These findings suggest that SCI induces p-Thr286-CaM-KIIalpha, which phosphorylates the nNOS at Ser847 in the nucleus intermediolateralis where NO is thought to play a role as a neurotransmitter in autonomic preganglionic neurons. Thus, the NP847 signaling pathway might be involved in the autonomic failure which occurs immediately after SCI.