Past, present and future of erythropoietin use in the elderly

Sexual Dysfunction in Women With Kidney Disease

Sexual health is inversely associated with estimated glomerular filtration rate and is associated with adverse cardiovascular outcomes, depression, poor self-image, and impaired quality of life. Many women with chronic kidney disease (CKD) and ESKD experience symptoms of sexual dysfunction which is underrecognized secondary to a variety of factors including physicians' discomfort in discussing sexual health, patients' reluctance to bring up sexual health, difficulty in the assessment of sexual health in comparison to men, and the overall lack of well-conducted clinical studies in women. The pathophysiology is not fully understood but likely involves changes in sex hormones throughout the hypothalamic-pituitary-ovarian axis. Proper evaluation of this axis is necessary as treatment is tailored to these findings and can improve outcomes. A comprehensive assessment of sexual dysfunction inclusive of women with varying gender identification and sexual orientation, partnered with recognition and treatment of contributing factors as well as identifying the underlying cause, is paramount. With the lack of studies, particularly in women with CKD, treatment options, in some cases, can be considered unchartered territory. In this article, we will review available evidence on the pathophysiology, clinical manifestations, and treatment for sexual dysfunction in women with CKD and ESKD.

Left ventricular hypertrophy and cognitive function: a systematic review

Cognitive impairment is common in patients with hypertension. Left ventricular hypertrophy (LVH) is recognised as a marker of hypertension-related organ damage and is a strong predictor of coronary artery disease, heart failure and stroke. There is evidence that LVH is independently associated with cognitive impairment, even after adjustment for the presence of hypertension. We conducted a systematic review that examined cognitive impairment in adults with LVH. Independent searches were performed in Ovid MEDLINE, Ovid psycInfo and PubMed with the terms left ventricular hypertrophy and cognition. Seventy-three studies were identified when both searches were combined. After limiting the search to studies that were: (1) reported in English; (2) conducted in humans; (3) in adults aged 50 years and older; and (4) investigated the relationship between LVH and cognitive performance, nine papers were included in this systematic review. The majority of studies found an association between LVH and cognitive performance. Inspection of results indicated that individuals with LVH exhibited a lower performance in cognitive tests, when compared to individuals without LVH. Memory and executive functions were the cognitive domains that showed a specific vulnerability to the presence of LVH. A possible mechanism for the relationship between LVH and cognition is the presence of cerebral white matter damage. White matter lesions occur frequently in patients with LVH and may contribute to cognitive dysfunction. Together, the results of this review suggest that memory impairment and executive dysfunction are the cognitive domains that showed a particular association with the presence of LVH.

Cognitive function in outbred house mice after 22 weeks of drinking oxygenated water

Oxygen-enriched drinking water, which is increasingly sold worldwide, is claimed to "keep both the body and the mind healthy." However, currently there is no scientific evidence for such a statement. Therefore, we assessed the effect of 22 weeks of drinking oxygenated water on cognitive performance in healthy mice, using a spatial learning task and behavioral observations. Thirty-six female mice (age 3 to 6 months) received either hyperoxic or normal tap water (approximately 6.6 vs. 1.8 microg O(2) g(-1) day(-1), respectively) throughout the study period. Mice were weighed one to two times per month, and a blood sample was taken from the tail to determine the hematocrit. In addition, red blood cells were counted microscopically one and two months after the start of the experiment. Four weeks after the last blood sample (21 weeks after the start of the experiment), exploration behavior and locomotor activity were observed on a holeboard, and learning ability tests were performed using an elevated open maze. No significant differences were seen between groups for any of the parameters investigated. Thus, the study does not support the hypothesis that drinking oxygenated water improves cognitive function or hematological parameters in mice.

Sexual function in chronic kidney disease

Endocrine abnormalities are common in patients with chronic kidney disease (CKD) and lead to sexual dysfunction, anemia, hyperparathyroidism, and altered mineral metabolism. Common clinical problems include disturbances in menstruation in women, erectile dysfunction in men, and decreased libido and infertility in both sexes. Organic factors tend to be prominent and are related to uremia and other comorbid illnesses. Psychological factors and depression may exacerbate the primary problem. Alterations in the hypothalamic-pituitary axis are seen early in CKD and tend to worsen after patients start dialysis. Hypogonadism plays a dominant role in male sexual function, whereas changes in hypothalamic-pituitary function predominate in female sexual dysfunction. In patients on dialysis, treatment strategies include optimizing dose of dialysis, correction of anemia with erythropoietin, and correction of hyperparathyroidism. Successful kidney transplantation may restore normal sexual function, especially in younger patients.

Recombinant human erythropoietin: effects on frataxin expression in vitro

BACKGROUND

Friedreich's ataxia (FRDA) is a neurodegenerative disorder caused by decreased expression of the protein frataxin, recently described to be an iron chaperone for the assembly of iron-sulphur clusters in the mitochondria, causing iron accumulation in mitochondria, oxidative stress and cell damage. Searching for compounds that could possibly influence frataxin expression, we found that the cytokine recombinant human erythropoietin (rhuEPO) significantly increases frataxin expression by a still unknown mechanism.

MATERIALS AND METHODS

Isolated lymphocytes from FRDA patients, isolated human cardiac cells (fibroblasts and myocytes) from patients undergoing heart transplantation and P19 mouse cells (neuronal typ), were incubated with different concentrations of rhuEPO, and immunoblot was carried out for the detection of frataxin.

RESULTS

We show for the first time that the cytokine recombinant human erythropoietin (rhuEPO) can, additionally to its reported neuro- and cardioprotective properties, increase frataxin expression in vitro. We show that rhuEPO significantly increases frataxin expression in primary lymphocytes from patients with Friedreich's ataxia. Further we show that rhuEPO can also increase frataxin expression in many other cell types; among them the most affected cell types in FRDA such as neurones and cardiac cells.

CONCLUSIONS

Our results provide a scientific basis for further studies examining the effectiveness of this agent for the treatment of FRDA patients.

Effect of erythropoietin on nitric oxide production in the rat hippocampus using in vivo brain microdialysis

In order to investigate the role of erythropoietin (EPO) in the hippocampus, we studied the effect of EPO on nitric oxide (NO) production in the rat hippocampus using brain microdialysis. The dialysis probe was stereotaxically inserted into the rat hippocampus 24 h before the dialysis experiment. The perfusion fluid (Krebs-HEPES buffer, pH 7.4) was collected at 15-min intervals under freely moving conditions and NO metabolites (NOx) in the perfusate were immediately measured using a NOx-analyzing high performance liquid chromatography (HPLC)system. Following the collection of four fractions, 1 microl of EPO (10(-10) M, 10(-8) M and 10(-6) M) or vehicle (saline) was gently injected into the hippocampal tissue. The perfusion fluid was collected for 3 h after the injection. The NOx levels were unchanged by the injection of vehicle alone. After the injection of EPO, NOx levels gradually increased. The EPO-induced increase in NOx levels was significant at 10(-6) M EPO. The EPO-induced increases in NOx levels were eliminated in the presence of anti-EPO antibody. The increase in NOx levels induced by EPO was blunted by nicardipine, a Ca2+ channel blocker, but not by MK-801, an antagonist of N-methyl-D-aspartate (NMDA) receptors. These findings, taken together, suggest that EPO increased NO production in the rat hippocampus by activating voltage-gated Ca2+ channels, but not through NMDA receptors.