Amphotericin B-induced nephrotoxicity: characterization of blood and urinary biochemistry and renal morphology in mice

Can Amphotericin B-mediated effects be limited using intranasal versus intravenous route?

Aim: CNS infections due to parasites often prove fatal. In part, this is due to inefficacy of drugs to cross the blood-brain barrier. Methods: Here, we tested intranasal and intravenous route and compared adverse effects of Amphotericin B administration, through blood biochemistry, liver, kidney and brain histopathological evidence of toxicities in vivo post-administration. Results: It was observed that intranasal route limits the adverse side effects of Amphotericin B, in contrast to intravenous route. Conclusion: As parasites such as Naegleria fowleri exhibit unequivocal affinity toward the olfactory bulb and frontal lobe in the central nervous system, intranasal administration would directly reach amoebae bypassing the blood-brain barrier selectivity and achieve the minimum inhibitory concentration at the target site.

Nephroprotective effect of magnesium isoglycyrrhizinate against arsenic trioxide‑induced acute kidney damage in mice

Magnesium isoglycyrrhizinate (MgIG) has anti-inflammatory, antioxidative, antiviral and anti-hepatotoxic effects. However, protective effects of MgIG against renal damage caused by arsenic trioxide (ATO) have not been reported. The present study aimed to clarify the protective function of MgIG on kidney damaged induced by ATO. Other than the control group and the group treated with MgIG alone, mice were injected intraperitoneally with ATO (5 mg/kg/day) for 7 days to establish a mouse model of kidney damage. On the 8th day, blood and kidney tissue were collected and the inflammatory factors and antioxidants levels in the kidney tissue and serum were measured. The expression of protein levels of caspase-3, Bcl-2, Bax, Toll-like receptor-4 (TLR4) and nuclear factor-κB (NF-κB) were determined via western blot analysis. In the renal tissue of mice, ATO exposure dramatically elevated markers of oxidative stress, apoptosis and inflammation. However, MgIG could also restore the activities of urea nitrogen and creatinine to normal levels, decrease the malondialdehyde level and reactive oxygen species formation and increase superoxide dismutase, catalase and glutathione activities. MgIG also ameliorated the morphological abnormalities generated by ATO, reduced inflammation and apoptosis and inhibited the TLR4/NF-κB signaling pathway. In conclusion, MgIG may mitigate ATO-induced kidney damage by decreasing apoptosis, oxidative stress and inflammation and its mechanism may be connected to the inhibition of TLR4/NF-κB signaling.

Vitamin D deficiency is a potential risk factor for lipid Amphotericin B nephrotoxicity

Invasive fungal infections (IFI) is a worldwide serious health problem and Amphotericin B (AmB) has been considered the drug of choice for IFI treatment. Despite its efficacy, clinical use of AmB has been associated with renal toxicity. Some lines of evidence have shown that an extemporaneous lipid emulsion preparation of AmB (AmB/LE) was able to attenuate nephrotoxicity, presenting similar benefits at a lower cost. Studies have been demonstrating that hypovitaminosis D may hasten the progression of kidney disease and reflect on a worse prognosis in cases of drug-induced nephrotoxicity. In view of the high worldwide incidence of hypovitaminosis D, the aim of this study was to investigate whether vitamin D deficiency may induce AmB/LE-related nephrotoxicity. Wistar rats were divided into four groups: control, received a standard diet for 34 days; AmB/LE, received a standard diet for 34 days and AmB/LE (5 mg/kg/day) intraperitoneally in the last 4 days; VDD, received a vitamin D-free diet for 34 days; and VDD+AmB/LE, received a vitamin D-free diet for 34 days and AmB/LE as described. At the end of the protocol, animals were euthanized and blood, urine and renal tissue samples were collected in order to evaluate AmB/LE effects on renal function and morphology. Association of AmB/LE and vitamin D deficiency led to diminished glomerular filtration rate and increased tubular injury, evidenced by reduced renal protein expression of NaPi-IIa and TRPM6 leading to hyperphosphaturia / hypermagnesuria. VDD+AmB/LE rats also presented alterations in the PTH-Klotho-FGF-23 signaling axis, urinary concentrating defect and hypertension, probably due to an inappropriate activation of the renin-angiotensin-aldosterone system. Hence, it is important to monitor vitamin D levels in AmB/LE treated patients, since vitamin D deficiency induces AmB/LE nephrotoxicity.

Amphotericin B (AmB) is the treatment of choice for systemic fungal infections. Despite its efficacy, clinical use of AmB has been associated with renal toxicity. In an attempt to improve the therapeutic effect and to reduce adverse reactions, lipid formulations of AmB were developed. Among these formulations, an in-house lipid emulsion preparation of AmB (AmB/LE) is a lower cost alternative with similar benefits. Furthermore, vitamin D is an essential nutrient for the regulation of several physiological activities. Hence, vitamin D deficiency or insufficiency can contribute to the progression of diseases and increase the risk of chronic illnesses as well. Nowadays, VDD is a health problem worldwide and its prevalence in general population is high, including the sunny and industrialized countries, where vitamin D supplementation has been successfully implemented. Thus, it is essential to monitor vitamin D levels in both patients treated with conventional or lipid formulations of AmB in order to ensure a better prognosis in the development of renal diseases.

Brief Overview: Assessment of Compound-induced Acute Kidney Injury Using Animal Models, Biomarkers, and In Vitro Platforms

The inability to unequivocally predict translatable drug-induced kidney injury in nonclinical studies during pharmacological development is evidenced by drug attrition in human clinical trials. Eight urinary proteins have been qualified as renal safety biomarkers for limited context of use in nonclinical drug development studies in rats. Formal qualification of human renal safety biomarkers is pending the submission of data from prospective clinical trials and analyses of biomarker performance to the Food and Drug Administration and European Medicines Agency by the Foundation for the National Institutes of Health and Predictive Safety Testing Consortium's Nephrotoxicity Working Group. In vitro kidney platforms may be leveraged to investigate the potential risk of compound-induced acute kidney injury and/or dysfunction. The early assessment of drug-related kidney safety profiles using biomarker-level changes in animal models and in vitro platforms could significantly reduce renal safety-related drug attrition; yet, there are no well-validated in vitro systems to enable comprehensive investigations of compound-induced nephrotoxicity. Thus, histopathology remains the gold standard for diagnosing nephron-specific damage. Traditional and emerging biomarker panels should be combined with histopathology and/or cytopathology to enable early identification of compound-induced kidney injury.

Oral administration of amphotericin B nanoparticles: antifungal activity, bioavailability and toxicity in rats

Amphotericin B (AMB) is used most commonly in severe systemic life-threatening fungal infections. There is currently an unmet need for an efficacious (AMB) formulation amenable to oral administration with better bioavailability and lower nephrotoxicity. Novel PEGylated polylactic-polyglycolic acid copolymer (PLGA-PEG) nanoparticles (NPs) formulations of AMB were therefore studied for their ability to kill Candida albicans (C. albicans). The antifungal activity of AMB formulations was assessed in C. albicans. Its bioavalability was investigated in nine groups of rats (n = 6). Toxicity was examined by an in vitro blood hemolysis assay, and in vivo nephrotoxicity after single and multiple dosing for a week by blood urea nitrogen (BUN) and plasma creatinine (PCr) measurements. The MIC of AMB loaded to PLGA-PEG NPs against C. albicans was reduced two to threefold compared with free AMB. Novel oral AMB delivery loaded to PLGA-PEG NPs was markedly systemically available compared to Fungizone® in rats. The addition of 2% of GA to the AMB formulation significantly (p < 0.05) improved the bioavailability from 1.5 to 10.5% and the relative bioavailability was > 790% that of Fungizone®. The novel AMB formulations showed minimal toxicity and better efficacy compared to Fungizone®. No nephrotoxicity in rats was detected after a week of multiple dosing of AMB NPs based on BUN and PCr, which remained at normal levels. An oral delivery system of AMB-loaded to PLGA-PEG NPs with better efficacy and minimal toxicity was formulated. The addition of glycyrrhizic acid (GA) to AMB NPs formulation resulted in a significant oral absorption and improved bioavailability in rats.

Metabolomics as a tool to evaluate the toxicity of formulations containing amphotericin B, an antileishmanial drug

Amphotericin B (AmB) is a drug of choice against life-threatening systemic fungal infections and an alternative therapy for the treatment of all forms of leishmaniasis. It is known that AmB and its conventional formulation cause renal damage; however, the lipid formulations can reduce these effects. The aim of the present study was to identify metabolic changes in mice treated with two different AmB formulations, a nanoemulsion (NE) (lipid system carrier) loaded with AmB and the conventional formulation (C-AmB). For this purpose, metabolic fingerprinting represents a valuable strategy to monitor, in a non-targeted manner, the changes that are at the base of the toxicity mechanism of AmB. Plasma samples of BALB-c mice were collected after treatment with 3 alternate doses of AmB at 1 mg kg-1 administered intravenously and analysed with CE, LC and GC coupled to MS. Blood urea nitrogen (BUN) and plasma creatinine levels were also analysed. Kidney tissue specimens were collected and evaluated. It was not observed that there were any alterations in BUN and creatinine levels as well as in histopathological analysis. Approximately 30 metabolites were identified as potentially related to early C-AmB-induced nephrotoxicity. Disturbances in the arachidonic acid, glycerophospholipid, acylcarnitine and polyunsaturated fatty acid (PUFA) pathways were observed in C-AmB-treated mice. In the AmB-loaded NE group, it was observed that there were fewer metabolic changes, including changes in the plasma levels of cortisol and pyranose. The candidate biomarkers revealed in this study could be useful in the detection of the onset and severity of kidney injury induced by AmB formulations.

Prevenção da nefrotoxicidade da anfotericina B por meio do uso de fitomedicamentos

RESUMO Objetivo Avaliar ação renoprotetora dos flavonoides diosmina e hesperidina na prevenção da nefrotoxicidade da anfotericina B em modelo experimental com ratos. Método Ratos Wistar, adultos, machos foram distribuídos nos seguintes grupos: Salina; diosmina hesperidina (animais receberam 50 mg/kg de diosmina hesperidina em água de bebedouro por dez dias); Anfotericina B (animais receberam 15 mg/kg/dia de anfotericina B intraperitoneal por cinco dias); Anfotericina B+diosmina hesperidina. Foram avaliados função renal, fração de excreção de sódio, potássio e magnésio e os metabólitos oxidativos. Resultados O tratamento com anfotericina B reduziu a função renal, vista peloclearance de creatinina, elevou os marcadores de função tubular como a fração de excreção de sódio, potássio, magnésio e dos metabólitos oxidativos. O pré-condicionamento com diosmina hesperidina elevou o clearance de creatinina e atenuou da lesão tubular e oxidativa. Conclusão A administração de anfotericina B resultou no declínio da função renal com lesão tubular e a diosmina hesperidina demonstrou efeito renoprotetor antioxidante.

The extent of irradiation-induced long-term visceral organ damage depends on cranial/brain exposure

In case of high-dose radiation exposure, mechanisms controlling late visceral organ damage are still not completely understood and may involve the central nervous system. To investigate the influence of cranial/brain irradiation on late visceral organ damage in case of high-dose exposure, Wistar rats were irradiated at 12 Gy, with either the head and fore limbs or the two hind limbs protected behind a lead wall (head- and hind limbs-protected respectively), which allows long-term survival thanks to bone marrow protection. Although hind limbs- and head-protected irradiated rats exhibited similar hematopoietic and spleen reconstitution, a late body weight loss was observed in hind limbs-protected rats only. Histological analysis performed at this time revealed that late damages to liver, kidney and ileum were attenuated in rats with head exposed when compared to animals whose head was protected. Plasma measurements of inflammation biomarkers (haptoglobin and the chemokine CXCL1) suggest that the attenuated organ damage in hind limbs-protected rats may be in part related to reduced acute and chronic inflammation. Altogether our results demonstrate the influence of cranial/brain exposure in the onset of organ damage.

Antifungal activity of topical microemulsion containing a thiophene derivative

Fungal infections have become a major problem of worldwide concern. Yeasts belonging to the Candida genus and the pathogenic fungus Cryptococcus neoformans are responsible for different clinical manifestations, especially in immunocompromised patients. Antifungal therapies are currently based on a few chemotherapeutic agents that have problems related to effectiveness and resistance profiles. Microemulsions are isotropic, thermodynamically stable transparent systems of oil, water and surfactant that can improve the solubilization of lipophilic drugs. Taking into account the need for more effective and less toxic drugs along with the potential of thiophene derivatives as inhibitors of pathogenic fungi growth, this study aimed to evaluate the antifungal activity of a thiophene derivative (5CN05) embedded in a microemulsion (ME). The minimum inhibitory concentration (MIC) was determined using the microdilution method using amphotericin B as a control. The formulations tested (ME- blank and ME-5CN05) showed physico-chemical properties that would allow their use by the topical route. 5CN05 as such exhibited moderate or weak antifungal activity against Candida species (MIC = 270–540 μg.mL⁻¹) and good activity against C. neoformans (MIC = 17 μg.mL⁻¹). Candida species were susceptible to ME-5CN05 (70–140 μg.mL⁻¹), but C. neoformans was much more, presenting a MIC value of 2.2 μg.mL⁻¹. The results of this work proved promising for the pharmaceutical industry, because they suggest an alternative therapy against C. neoformans.

Caffeic acid phenethyl ester protects against amphotericin B induced nephrotoxicity in rat model

The present study was conducted to investigate whether caffeic acid phenethyl ester (CAPE), an active component of propolis extract, has a protective effect on amphotericin B induced nephrotoxicity in rat models. Male Wistar-Albino rats were randomly divided into four groups: (I) control group (n = 10), (II) CAPE group (n = 9) which received 10 μmol/kg CAPE intraperitoneally (i.p.), (III) amphotericin B group (n = 7) which received one dose of 50 mg/kg amphotericin B, and (IV) amphotericin B plus CAPE group (n = 7) which received 10 μmol/kg CAPE i.p. and one dose of 50 mg/kg amphotericin B. The left kidney was evaluated histopathologically for nephrotoxicity. Levels of malondialdehyde (MDA), nitric oxide (NO), enzyme activities including catalase (CAT), and superoxide dismutase (SOD) were measured in the right kidney. Histopathological damage was prominent in the amphotericin B group compared to controls, and the severity of damage was lowered by CAPE administration. The activity of SOD, MDA, and NO levels increased and catalase activity decreased in the amphotericin B group compared to the control group (P = 0.0001, P = 0.003, P = 0.0001, and P = 0.0001, resp.). Amphotericin B plus CAPE treatment caused a significant decrease in MDA, NO levels, and SOD activity (P = 0.04, P = 0.02, and P = 0.0001, resp.) and caused an increase in CAT activity compared with amphotericin B treatment alone (P = 0.005). CAPE treatment seems to be an effective adjuvant agent for the prevention of amphotericin B nephrotoxicity in rat models.

Experimental central nervous system aspergillosis therapy: efficacy, drug levels and localization, immunohistopathology, and toxicity

We have shown previously that high-dose lipid amphotericin preparations are not more efficacious than lower doses in aspergillosis. We studied toxicity, drug concentrations and localization, and quantitative infection concurrently, using a 4-day model of central nervous system (CNS) aspergillosis to assess early events. Mice given Aspergillus fumigatus conidia intracerebrally, under a cyclophosphamide immunosuppressive regimen, were treated for 3 days (AmBisome at 3 or 10 mg/kg of body weight, Abelcet at 10 mg/kg, amphotericin B deoxycholate at 1 mg/kg, caspofungin at 5 mg/kg, or voriconazole at 40 mg/kg). Sampling 24 h after the last treatment showed that AmBisome at 3 but not at 10 mg/kg, as well as Abelcet, caspofungin, and voriconazole, reduced brain CFU. All regimens reduced renal infection. Minor renal tubular changes occurred with AmBisome or Abelcet therapy, whereas heart, lung, and brain showed no drug toxicity. Amphotericin B tissue and serum concentrations did not correlate with efficacy. Endothelial cell activation (ICAM-1 and P-selectin in cerebral capillaries) occurred during infection. Amphotericin B derived from AmBisome and Abelcet localized in activated endothelium and from Abelcet in intravascular monocytes. In 10-day studies dosing uninfected mice, minor renal tubular changes occurred after AmBisome or Abelcet at 1, 5, or 10 mg/kg with or without cyclophosphamide treatment; nephrosis occurred only with Abelcet in cyclophosphamide-treated mice. Hepatotoxicity occurred with AmBisome and Abelcet but was reduced in cyclophosphamide-treated mice. Marked CFU reduction by AmBisome at 3 mg/kg occurred in association with relatively more intense inflammation. Abelcet renal localization appears to be a precursor to late nephrotoxicity. Hepatotoxicity may contribute to high-dose Abelcet and AmBisome failures. Our novel observation of endothelial amphotericin localization during infection may contribute to amphotericin mechanism of efficacy.

Efficacy of intravenous amphotericin B-polybutylcyanoacrylate nanoparticles against cryptococcal meningitis in mice

Amphotericin B deoxycholate (AmB), a classic antifungal drug, remains the initial treatment of choice for deep fungal infections, but it is not appropriate for treatment of cryptococcal meningitis due to its inability to pass through the blood–brain barrier (BBB). We examined the efficacy of amphotericin B-polybutylcyanoacrylate nanoparticles (AmB-PBCA-NPs) modified with polysorbate 80 that had a mean particle diameter less than 100 nanometers (69.0 ± 28.6 nm). AmB-PBCA-NPs were detected in the brain 30 minutes after systemic administration into BALB/c mice and had a higher concentration than systemically administered AmB liposome (AmB-L, P < 0.05); AmB was not detected in the brain. Following infection for 24 hours and then 7 days of treatment, the survival rate of mice in the AmB-PBCA-NP group (80%) was significantly higher than that of the AmB (0%) or AmB-L (60%) treatment groups. Fungal load was also lower when assessed by colony-forming unit counts obtained after plating infected brain tissue (P < 0.05). Our study indicates that AmB-PBCA-NPs with polysorbate 80 coating have the capacity to transport AmB across the BBB and is an efficient treatment against cryptococcal meningitis in a mouse model.

Pharmacokinetics and nephrotoxicity of amphotericin B-incorporated poly(ethylene glycol)-block-poly(N-hexyl stearate l-aspartamide) micelles

The purpose of this investigation was to study the pharmacokinetics and nephrotoxicity of amphotericin B (AmB), incorporated in poly(ethylene glycol)-block-poly(N-hexyl stearate l-aspartamide) (PEG-b-PHSA) micelles (AmB/PEG-b-PHSA). After AmB/PEG-b-PHSA or AmB for injection, United States Pharmacopeia (USP), was dosed intravenously in rats (0.8 mg/kg), serum was collected over 72 h, and organs collected at 72 h for AmB analysis. To test for the nephrotoxicity caused by AmB, renal markers of damage were assessed 24 h after a single injection of AmB/PEG-b-PHSA or AmB for injection, USP, focusing on detection of urinary enzymes. PEG-b-PHSA micelles caused a significantly lower area under serum concentration curve and higher clearance relative to AmB for injection, USP. PEG-b-PHSA micelles lowered the distribution of AmB in liver and lung tissues, but did not significantly lower the level of AmB in the kidneys relative to AmB for injection, USP. However, urine levels of N-acetyl-β-glucosaminidase and γ-glutamyltransferase were significantly lower for AmB/PEG-b-PHSA relative to AmB for injection, USP. In summary, PEG-b-PHSA micelles reduced the nephrotoxicity of AmB, the dose-limiting toxicity of this important antifungal agent.

Persistent hypokalemia in an acute lymphoblastic leukemia patient

Nephrotoxicity is an important adverse effect of Amphotericin B, and although risk factors for nephrotoxicity in adults have been investigated, studies examining nephrotoxicity in the pediatric population are scarce. We describe case of 10 year old boy (CALLA – VE B cell ALL) who received conventional Amphotericin-B, but he persisted with hypokalemia.