Circadian renal rhythms influenced by implanted encapsulated hANP-producing cells in Goldblatt hypertensive rats

Abstract

Renal excretion in experimental hypertensive rats implanted with encapsulated human atrial natriuretic peptide (hANP)-producing cells is circadian periodic. Chinese hamster ovary (CHO) cells transfected with the plasmid hANP-cDNA were encapsulated in biocompatible polycaprolactone capsules for intraperitoneal implantation into two-kidney, one-clip (2K1C) hypertensive rats. During a 12:12 light-dark cycle, as compared to control CHO cells, the implantation of encapsulated hANPproducing CHO cells was associated with an increase in the net excretion of water, sodium and potassium, and with a reversal of the advanced circadian phases related to renovascular hypertension in 2K1C rats. The increase in blood pressure postimplantation was delayed, and increases in renal blood flow, glomerular filtration rate, sodium output, urinary excretion and urinary cyclic GMP concentrations were also found. Implantation of encapsulated hANP-producing cells affects circadian rhythms in kidney excretion functions of 2K1C rats, and may be useful for the treatment of cardiovascular disease.

Altered expression of circadian clock gene, mPer1, in mouse brain and kidney under morphine dependence and withdrawal

“…Chen et al . [ 27 ] reported that urinary water excretion, sodium excretion and potassium excretion exhibit circadian rhythms in the rats, with peak activity occurring at night. Our results showed that the expression of mPER1 in the kidneys was higher at night in the control mice, coinciding with the peak activity of potassium excretion [ 27 ].…”

Photosensitivity to different light intensities in blind and sighted rodents

“…To compare the sensitivity of the photoreception pathways of social voles and 'blind' mole rats we measured daily responses in urine production rate and urinary MEL concentration, as markers for biological rhythmicity, to increasing light intensity of the same irradiation wavelength. Daily urine production rate has been adopted as an index for rhythmicity because it is well established that its rhythm exhibits clear photoperiodmediated circadian oscillation in humans and rodent species, including social voles, with generally high levels during the active period and low levels during the inactive period (Mills, 1951;Ratte et al, 1974;Zisapel et al, 1999;Schibler et al, 2003;Chen et al, 2004;. Additionally, the procedure is non-invasive and easily conducted, making it particularly appealing for the investigation of daily rhythmicity in small rodent species.…”

Transplantation of microencapsulated genetically modified xenogeneic cells augments angiogenesis and improves heart function

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