High Potassium Intake Blunts the Effects of High Sodium on Blood Pressure

Among 1285 adults providing overnight urine samples, potassium excretion and the sodium to potassium ratio were related to systolic and diastolic blood pressure (BP) only in individuals consuming more than 6 g/day of salt. According to the Journal of the American Society of Hypertension study, individuals in the highest sodium-to-potassium ratio quartile had 8 mm Hg and 7 mm Hg higher systolic and diastolic BP, respectively, compared with those in the first quartile. Individuals in the fourth quartile of urinary potassium excretion had 6 mm Hg and 4 mm Hg lower systolic and diastolic BP, respectively, than those in the first quartile.

Cyst Growth Important for ADPKD Pathogenesis

Research in mice indicates that growth of renal cysts likely plays a central role in early-stage ADPKD-associated hypertension, with activation of the intrarenal renin–angiotensin system as a key mechanism. Cyst growth may also be the main determinant in renal concentrating deficit, an early finding in ADPKD, because maximum urine osmolality and urine nitrite excretion were reduced in young cystic mice but not in noncystic controls. The findings, published in Kidney International, were discovered by researchers who bred a Pkd1 floxed allele with a nestin-Cre expressing line to generate cystic mice with preserved GFR.

Are Home Hemodialysis and High-Dose Hemodialysis Better for Patients? Many Nephrologists Say Yes

Among 324 nephrologists from Europe, Canada, and the US who managed more than 25 adult dialysis patients, in-center hemodialysis was the most common type of dialysis used by patients (90%), followed by peritoneal dialysis (8%), and home hemodialysis (2%). Most nephrologists in the study believed home hemodialysis provides better quality of life, increasing the frequency of dialysis beyond 3 times per week significantly improves clinical outcomes, and longer dialysis sessions performed nocturnally would lead to significantly better clinical outcomes than traditional in-center hemodialysis. The findings, based on survey results, are published in BMC Nephrology.

Study: Cigarettes increased nicotine content over last 15 years.

The Boston Globe (1/16, Kotz) reports a Massachusetts Department of Public Health and University of Massachusetts Medical School study published online in the journal Nicotine and Tobacco Research indicates that particular cigarette manufacturers have increased the nicotine in their product. Researchers found the average cigarette contained 1.65 milligrams of the substance in 1999, but increased 15% to 1.89 milligrams in 2011. Study leader Thomas Land believes the increase may have resulted from redesigning several brands with alterations on filters or product length.

        The Springfield (MA) Republican (1/16, Flynn) also quotes Land as saying, “Cigarettes are getting more efficient at delivering nicotine to smokers. This could make it more difficult for a current smoker who is trying to quit, and easier for a young smoker to become addicted.”

FDA advisory panel backs orthostatic hypotension medication.

Bloomberg News (1/14, Edney) reports that “Chelsea Therapeutics International Ltd. won the backing of” an FDA advisory panel “for its drug to prevent sudden drops in blood pressure, a boost for the company’s effort to bring its first product to market.” The piece notes that “many panel members who voted in favor of approval said Chelsea showed the drug works short-term, and that initially is enough for such a rare, devastating disease with no other treatment options.”

        Reuters (1/15, Clarke) reports that the drug, Nothera (droxidopa), is for patients with neurogenic orthostatic hypotension (NOH), a rare, chronic type of low blood pressure that is linked with certain neurological disorders such as Parkinson’s disease.

        The AP (1/14) and MedPage Today (1/15) also report this story.

Green Tea Compounds May Decrease Effectiveness of Blood Pressure Drug

A compound in green tea may prevent the body from absorbing nadolol, a β-blocker used to treat high blood pressure, researchers have found. The study followed 10 adults who drank 3 cups of green tea for 2 weeks before taking nadolol. Participants then switched to drinking water before taking nadolol. After drinking green tea, blood levels of nadolol were 76% lower than levels measured after drinking water. Urine levels were about 80% lower. Additional experiments suggest that EGCG, an antioxidant in green tea, inhibits proteins that transport nadolol into cells. The findings are published in Clinical Pharmacology & Therapeutics.

Research Findings Question the Use of Buttonhole Cannulation in Routine Clinical Practice

In a CJASN analysis of clinical outcomes in 90 home hemodialysis patients, buttonhole (blunt needle) cannulation of vascular arteriovenous fistulae was associated with higher rates of infectious events, increased staff support requirements, and no reduction in surgical fistula interventions compared with traditional rope ladder (sharp needle) cannulation. Initially, patients were trained in rope ladder; then from 2004, all incident patients were started on buttonhole, and prevalent patients were converted to this cannulation method. The investigators also performed a systematic review of the published literature, finding that buttonhole cannulation is associated with a higher risk of arteriovenous fistula–related infections.