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The prevalence of erectile dysfunction (ED) has increased dramatically worldwide in parallel with the aging of the population. In 1995, ED was estimated to be present in more than 150 million men. Considering population aging in Western countries, estimates predict that more than 300 million men will be affected by ED by the year 2025. ED is a common and often distressing side effect of renal failure. It is present in 30% of patients with chronic renal failure and in 50% of patients undergoing dialysis treatment. Uremic men of different ages report a high variety of sexual problems including sexual hormonal pattern alterations, reduced or loss of libido, infertility, and impotence, thereby influencing their well-being. The pathogenetic mechanisms include physiologic, psychologic, and organic causes. Since the release of sildenafil citrate, the relationship between ED and the presence of cardiovascular disease (CVD) has been evaluated in several studies. Many of the risk factors for ED are the same as those for cardiac disease. CVD and ED are closely interrelated disease processes. Indeed, ED can be considered a symptom of vascular endothelial damage. Therefore, it can be expected that impotence will appear along with CVD, and the presence of ED suggests the existence of CVD. An accurate evaluation of the sexual histories of all men who present to internists, cardiologists, and also nephrologists for early detection of ED may allow for early diagnosis and management of CVD.

New knowledge on the physiologic role of L-carnitine and on the rationale of its use in patients on maintenance hemodialysis is provided. In particular, carnitine normalizes plasma and muscle carnitine levels and modifies both enzymatic pattern of muscle and morphology of single fibers, improving exercise tolerance. In addition, carnitine reduces erythropoietin requirements, the number of hypotensive episodes, improves ejection fraction, and decreases hospitalization.

A large body of evidence supports the validity of decreasing blood pressure to target levels in patients with essential hypertension to prevent cardiovascular disease. This issue becomes even more critical in chronic kidney disease because of the remarkably greater risk for cardiovascular fatal and nonfatal events. Indeed, renal patients should maintain blood pressure levels less than those suggested for the general population. Paradoxically, management of hypertension in this high-risk patient population is far from optimal and certainly worse with respect to essential hypertension. The Target Blood Pressure Levels in Chronic Kidney Disease (TABLE-CKD) study, performed in Italian patients with mild to advanced chronic kidney disease regularly followed-up by nephrologists, has shown that the prevalence of patients at target blood pressure is less than 20%. The assessment of antihypertensive strategy in these patients, however, suggests that there is room for improvement; in particular, a more aggressive treatment of volume expansion may ameliorate hypertension control in this population characterized by a high salt sensitivity of blood pressure.

Erectile dysfunction (ED) is a common and often distressing side effect of renal failure. Uremic men of different ages report a high variety of sexual problems, including sexual hormonal pattern alterations, reduced or loss of libido, infertility, and impotence, thereby influencing their well-being. The pathogenic mechanisms include physiologic, psychologic, and organic causes. To determine the contribution of morphologic factors to impotence we studied the ultrastructure of the corpora cavernosa in 20 patients with end-stage renal disease who were treated with chronic dialysis and compared the findings with 6 individuals with no clinical history of impotence. Our results indicated that in male uremic patients with sexual disturbances there were major changes in smooth muscle cells. This was characterized by reduction of dense bodies in the cytoplasm, thick basement membranes, and increased interstitial collagen fibers with resultant reduction of cell-to-cell contact. In addition, there was thickening and lamination of basement membranes of endothelial cells and increased accumulation of collagen between nerve fibers. These alterations were more evident in patients with longer time on dialysis and were independent of type of primary renal disease. We hypothesize that ED in dialysis patients is not related to the primary disease but to the uremic state.

Carnitine is a small water-soluble molecule that is present in almost all animal species. It plays an indispensable role in fatty acid metabolism, where it is involved in the transport of activated fatty acids between different cellular compartments. Uremic patients, as well as patients with chronic renal failure, appear to have abnormal renal handling of carnitine leading to dyslipidemia, lethargy, muscular weakness, hypotension, cardiac dysfunction and arrhythmias, and recurrent cramps. It often is difficult to distinguish these symptoms from similar ones related to uremia and dialysis. Many investigators have advocated L-carnitine supplementation in an attempt to alleviate carnitine deficiencies, and good results from this therapy have been reported. Moreover, several studies have shown that L-carnitine supplementation improves the response to erythropoietin. Chronic inflammation is another particular aspect affecting these patients. Anti-inflammatory properties of L-carnitine in hemodialysis patients have been shown by our group. Treatment with L-carnitine (20 mg/kg, given intravenously at the end of each dialysis session for 6 mo), significantly decreased serum C-reactive protein (CRP) levels, a proinflammatory cytokine known to inhibit erythropoiesis. Moreover, data from published literature are indicative of L-carnitine modulation of the immune system by the activation of glucocorticoid receptors and the modulation of the transcription of glucocorticoid-responsive genes. Our study showed that in these patients, treatment with L-carnitine has been able to improve their body mass index, likely by promoting a positive protein balance. This aspect is strictly correlated with the status of insulin resistance, which is well described in patients with renal diseases. Many studies showed that carnitine allowed mitochondrial fatty acid usage to link to the rate of glucose usage, thus improving insulin resistance. In conclusion, clinical beneficial effects of L-carnitine treatment on patients suffering from renal diseases are supported by molecular evidence involving both inflammatory and metabolic aspects of the disease.

Carnitine, gamma-trimethyl-beta-hydroxybutyrobetaine, is a small molecule widely present in all cells from prokaryotic to eukaryotic. It is an important element in the beta-oxidation of fatty acids. A lack of carnitine in hemodialysis patients is caused by insufficient carnitine synthesis and particularly by the loss through dialytic membranes, leading in some patients to carnitine depletion with a relative increase of esterified forms. The authors found a decrease in plasma-triglyceride and increase of high-density lipoprotein cholesterol (HDL-Chol) in dialysis patients during carnitine treatment. Many studies have shown that L-carnitine supplementation leads to improvements in several complications seen in uremic patients, including cardiac complications, impaired exercise and functional capacities, muscle symptoms, increased symptomatic intradialytic hypotension, and erythropoietin-resistant anemia, normalizing the reduced carnitine palmitoyl transferase activity in red cells. In addition, carnitine supplementation may improve protein metabolism and insulin resistance. Recently, carnitine supplementation has been approved by the US Food and Drug Administration not only for the treatment, but also for the prevention of carnitine depletion in dialysis patients. Regular carnitine supplementation in hemodialysis patients can improve their lipid metabolism, protein nutrition, antioxidant status, and anemia requiring large doses of erythropoietin, It also may reduce the incidence of intradialytic muscle cramps, hypotension, asthenia, muscle weakness, and cardiomyopathy.

The two words that mean sexual dysfunction, impotence and erectile dysfunction (ED), express two different concepts. Impotence is a general male sexual dysfunction that includes libidinal, orgasmic, and ejaculatory dysfunction. ED is the inability to achieve or maintain an erection sufficient to allow satisfactory sexual intercourse and is part of the general male sexual dysfunction termed impotence that includes libidinal, orgasmic, and ejaculatory dysfunction. Uremic men of different ages report a variety of sexual problems, including sexual hormonal pattern alterations, reduction in or loss of libido, infertility, and impotence, conditioning their well-being status. In evaluating and treating sexual dysfunction, a nephrologist must consider factors involved in its pathogenesis, such as hypothalamic-pituitary-gonadal axis alterations, psychological problems related to chronic disease, secondary hyperparathyroidism, anemia, autonomic neuropathy, derangements in arterial supply or venous outflow, and the normal structure of cavernous body smooth muscle cells. The introduction of sildenafil to treat impotent patients has completely changed the approach to evaluating these subjects because this drug is considered an effective well-tolerated treatment for men with ED. In the past, we proposed an algorithm that gave the opportunity to explore the previously mentioned factors using such instrumental interventions as the nocturnal penile tumescence test, penile echo color Doppler, nervous conduction velocity, and cavernous body biopsy, addressed to prescribe needed surgical or medical interventions. The complexity of the proposed algorithm requires many diagnostic procedures and much time and economic resources to localize the pathological lesions responsible for ED. Because of the new oral drug sildenafil, we propose a new algorithm to test the possibility of obtaining an erection and classify patients as responders or nonresponders to the sildenafil test.

Autonomic nervous system dysfunction is a common feature in uremia and may have a number of clinical sequelae. Simple cardiovascular reflex screening can be performed in patients during conservative treatment, on periodic dialysis therapy, or after kidney transplantation to diagnose and follow up autonomic function impairment. Other approaches, such as heart-rate variability studies in the frequency domain by power spectral analysis, can provide a more accurate investigation of the disease.