Cyclosporine and Tacrolimus: Influence on Cardiovascular Risk Factors

Overcoming the Anatomical and Physiological Barriers in Topical Eye Surface Medication Using a Peptide-Decorated Polymeric Micelle

The sealed anatomical features of the eye and its physiological activity that rapidly removes drugs are called anatomical and physiological barriers, which are the cause of more than 90% of drug loss. This aspect remains a critical issue in eye surface medication. Thus, promoting tissue permeability of drugs as well as prolonging their retention on the eye surface can improve their bioavailability and enhance their therapeutic effects. Thanks to the existence of a negatively charged mucin layer on the eye surface, several peptide-decorated polymeric micelles were prepared to enhance the interaction between the micelle and eye surface, thus prolonging the drug retention on the eye surface and promoting its tissue permeability. Tacrolimus (also known as FK506) is a hydrophobic macrolide immunosuppressant used to treat dry eye syndrome and other eye diseases. However, its hydrophobic nature makes its delivery as a topical eye surface medication difficult, with the risk of side effects due to overdoses. Therefore, the aim of this work is to evaluate the ability of FK506 micelles in promoting their permeability on the eye surface. Our results showed that the positively charged nanomicelles could significantly prolong FK506 retention on the eye surface and enhance its corneal permeability in ex vivo and in vivo conditions. FK506 nanomicelles exhibited superior curing effects against dry eye diseases than the FK506 suspension and a commercial FK506 formula. It exerted better inhibitory effects on eye surface inflammation and corneal epithelium apoptosis when examined by a slip lamp and a transferase-mediated dUTP nick end labeling assay, respectively. Further assays revealed the higher suppressive effects on the expression of several inflammation-related factors at an mRNA and protein level. Hence, our results suggested that these positively charged nanomicelles might be a good drug delivery system for ocular surface medication.

Acute effects of fructose consumption on uric acid and plasma lipids in patients with impaired renal function

OBJECTIVE

Metabolic disturbances are common in patients with renal function impairment and are related to high rates of cardiovascular incidents and mortality. Kidney transplantation leads to improved survival but may lead to additional metabolic alterations caused by immunosuppressive drugs and improved nutrition.

MATERIALS AND METHODS

The short-term effect of oral fructose load on serum uric acid (UA), plasma lipids, and blood pressure (BP) was studied in 85 patients with chronic kidney disease (CKD) and impairment of renal function (glomerular filtration rate 50-65 ml/min per 1.73 m(2)), comprising 55 renal transplant recipients (RTR) treated with standard triple immunosuppressive therapy including a calcineurin inhibitor (CNI) cyclosporine A (CsA) or tacrolimus (Tac) and 30 non-transplanted patients with CKD. Both non-transplanted CKD patients and RTR had stable renal function and a comparable degree of kidney dysfunction. All subjects received orally 70 g of fructose dissolved in 200 ml of water. Serum UA, lipids, and blood pressure were measured at baseline and 60, 120, 180, and 240 minutes after fructose administration.

RESULTS

There was a significant increase of serum UA concentration (p<0.001) in both CKD patients and RTR--CsA- or Tac-treated patients comparable in the latter. Total cholesterol (TC), LDL, and HDL cholesterol significantly decreased and serum triglycerides (TG) markedly increased in RTR, whereas in CKD patients all serum lipid fractions increased. Blood pressure was unaffected by fructose intake.

CONCLUSION

Both non-transplanted and transplanted patients with mild renal function impairment show similar acute purine metabolic disturbances following oral administration of fructose but in the latter dietary fructose may induce a smaller hyperlipidemic response.

Changes in oxidative stress in renal graft patients receiving calcineurin inhibitors: cyclosporine versus tacrolimus

OBJECTIVES

The effects of calcineurin inhibitors on oxidative stress after renal transplant are obscure. This study sought to investigate the changes in plasma oxidative stress and lipid levels in patients receiving cyclosporine or tacrolimus before and after renal transplant for 6 months.

MATERIALS AND METHODS

Twenty-one patients and 15 healthy controls were involved in our study. Twelve of the patients were treated with cyclosporine and 9 were treated with tacrolimus. Plasma malondialdehyde, nitrite/nitrate, vitamin C, vitamin E, and plasma glutathione levels, as well as total cholesterol and triglyceride levels, were evaluated before and after transplant for 6 months.

RESULTS

Before the transplant, patients had higher malondialdehyde and plasma glutathione levels than did healthy controls (3.76 ± 0.79 nmol/mL vs 3.21 ± 0.57 nmol/mL; P < .05, and 66.6 ± 23.2 μmol/L vs 43.3 ± 26.9 μmol/L; P < .05). In the overall group of patients, a significant increase in malondialdehyde levels was detected 3 and 6 months after transplant (3.76 ± 0.79 nmol/mL vs 4.38 ± 0.87 nmol/mL in the third month; P = .02; and 3.76 ± 0.79 nmol/mL vs 4.28 ± 0.69 nmol/mL in the sixth month; P = .04). A significant reduction in plasma glutathione levels 1 month after transplant and nitrite/nitrate levels 6 months after transplant was found. No changes in vitamin C and vitamin E levels were detected before and after transplant. After 3 and 6 months of transplant, cyclosporine-treated patients had higher levels of total cholesterol and triglycerides when compared with tacrolimus-treated patients.

CONCLUSIONS

An enhancement in plasma malondialdehyde levels was found after transplant at 6-month follow-up. However, no significant change in vitamin C, vitamin E, nitrite/nitrate levels between patients and controls was recorded. Although both calcineurin inhibitors showed similar effects on oxidative stress, cyclosporine-treated patients had higher levels of total cholesterol and triglycerides.

Effect of oral fructose load on serum uric acid and lipids in kidney transplant recipients treated with cyclosporine or tacrolimus

Hyperuricemia, frequently observed following kidney transplantation, may adversely affect graft survival. Although hyperuricemia is a well-known adverse effect of cyclosporine (CsA), a similar effect of tacrolimus (Tac) remains debatable. Hyperuricemia is also seen after oral fructose intake in beverages and processed foods. This sugar is blamed for the epidemic of obesity and metabolic syndrome. The aim of our study was to compare the effects of CsA and Tac on an acute oral fructose load in terms of plasma uric acid, serum lipids, and blood pressure in kidney transplant patients. Thirty-two kidney transplant recipients treated with CsA- or Tac-based triple (calcineurin inhibitor + mycophenolate mofetil + prednisone) immunosuppressive therapy displaying stable allograft function (mean glomerular filtration rate = 53 mL/min/1.73m(2)) received an oral challenge with 70 g of fructose. Serum uric acid, lipids, and blood pressure were measured before as well as 60, 120, 180, and 240 minutes after fructose administration. A significant increase in serum uric acid was observed in both groups after oral fructose administration (P < .001). A peak increase in serum uric acid was recorded at 120 minutes after fructose intake. Serum total, LDL, and HDL cholesterol also significantly decreased and serum triglycerides increased to a similar extent in both CsA and Tac groups. No significant changes in blood pressure were observed after fructose consumption. Oral fructose intake induced an acute rise in serum uric acid and triglycerides and decrease in serum cholesterol among kidney transplant recipients. Those changes were similar among patients treated with CsA or Tac.