Tolvaptan-induced Liver Injury: Who is at Risk? A Case Report and Literature Review

Investigation of Basolateral Targeting Micelles for Drug Delivery Applications in Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is a complex disorder characterized by uncontrolled renal cyst growth, leading to kidney function decline. The multifaceted nature of ADPKD suggests that single-pathway interventions using individual small molecule drugs may not be optimally effective. As such, a strategy encompassing combination therapy that addresses multiple ADPKD-associated signaling pathways could offer synergistic therapeutic results. However, severe off-targeting side effects of small molecule drugs pose a major hurdle to their clinical transition. To address this, we identified four drug candidates from ADPKD clinical trials, bardoxolone methyl (Bar), octreotide (Oct), salsalate (Sal), and pravastatin (Pra), and incorporated them into peptide amphiphile micelles containing the RGD peptide (GRGDSP), which binds to the basolateral surface of renal tubules via integrin receptors on the extracellular matrix. We hypothesized that encapsulating drug combinations into RGD micelles would enable targeting to the basolateral side of renal tubules, which is the site of disease, via renal secretion, leading to superior therapeutic benefits compared to free drugs. To test this, we first evaluated the synergistic effect of drug combinations using the 20% inhibitory concentration for each drug (IC20) on renal proximal tubule cells derived from Pkd1flox/-:TSLargeT mice. Next, we synthesized and characterized the RGD micelles encapsulated with drug combinations and measured their in vitro therapeutic effects via a 3D PKD growth model. Upon both IV and IP injections in vivo, RGD micelles showed a significantly higher accumulation in the kidneys compared to NT micelles, and the renal access of RGD micelles was significantly reduced after the inhibition of renal secretion. Specifically, both Bar+Oct and Bar+Sal in the RGD micelle treatment showed enhanced therapeutic efficacy in ADPKD mice (Pkd1fl/fl;Pax8-rtTA;Tet-O-Cre) with a significantly lower KW/BW ratio and cyst index as compared to PBS and free drug-treated controls, while other combinations did not show a significant difference. Hence, we demonstrate that renal targeting through basolateral targeting micelles enhances the therapeutic potential of combination therapy in genetic kidney disease.

Dehydration Accelerates Cytogenesis and Cyst Growth in Pkd1-/- Mice by Regulating Macrophage M2 Polarization

Adult autosomal dominant polycystic kidney disease (ADPKD) has been shown to be related as a "third hit" to the occurrence of acute or chronic kidney injury. Here, we examined whether dehydration, as a common kidney risk factor, could cause cystogenesis in chronic-onset Pkd1-/- mice by regulating macrophage activation. First, we confirmed that dehydration accelerated cytogenesis in Pkd1-/- mice and that macrophages infiltrated the kidney tissues even earlier than macroscopic cyst formation. Then, microarray analysis suggested that glycolysis pathway may be involved in macrophage activation in Pkd1-/- kidneys under conditions of dehydration. Further, we confirmed glycolysis pathway was activated and lactic acid (L-LA) was overproduced in the Pkd1-/- kidney under conditions of dehydration. We have already proved that L-LA strongly stimulated M2 macrophage polarization and overproduction of polyamine in macrophage in vitro, and in the present study, we further discovered that M2 polarization-induced polyamine production shortened the primary cilia length by disrupting the PC1/PC2 complex. Finally, the activation of L-LA-arginase 1-polyamine pathway contributed to cystogenesis and progressive cyst growth in Pkd1-/- mice recurrently exposed to dehydration.

Efficacy of tolvaptan on the short and mid-term prognosis in elderly patients with acute heart failure coexisting with oliguria: A retrospective cohort study

Background

In patients with acute heart failure (AHF) coexisting with oliguria, high doses of loop diuretics are often ineffective in increasing urine output and may adversely affect the patient's prognosis, especially in elderly patients. We investigated the efficacy of adding tolvaptan (TLV) on improving the prognosis in elderly patients with AHF coexisting with oliguria.

Methods

All data for this retrospective cohort study were extracted from the electronic medical record system of the Second Medical Center of Chinese PLA General Hospital from January 2018 to December 2020. Patients diagnosed with AHF coexisting with oliguria were enrolled in this study and were divided into TLV and non-TLV groups based on the use of TLV. The primary outcome was all-cause mortality at 7 and 90-day. The secondary outcomes were the remission of AHF within 7 and 30 days or continued progression of AHF, and new-onset chronic kidney disease (CKD) after 90 days. Cox proportional hazards regression was used to assess the relationships between all-cause mortality and diuretic regimens, demographics, laboratory parameters, comorbidities, and medications.

Results

A total of 308 patients met the study criteria for the final statistical analysis, and they had a median age of 91 years (88, 95). The results showed that the addition of TLV was associated with a decreased risk of the 7 and 90-day all-cause mortality in patients with AHF with oliguria [adjusted HR, 95% CI: 0.60 (0.37, 0.98), p = 0.042; 0.56 (0.41, 0.75), p < 0.001, respectively]. Adding TLV significantly increased urine output and decreased N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in 7 days, and alleviated the progression of AHF within 30 days. There were no statistically significant differences between the patients with or without TLV in terms of the occurrence of hypernatremia, the development of hepatic impairment within 30 days, and new-onset CKD after 90 days.

Conclusions

This study demonstrated that the addition of TLV was clinically effective in increasing urine output, and had favorable effects on alleviating AHF progression and may reduce the risk of all-cause mortality at 7 and 90-day in elderly patients with AHF with oliguria, and TLV had a good safety profile.

Trial registration

http://www.chictr.org.cn/showprojen.aspx?proj=148046, identifier: ChiCTR2200055518.

A Case of Hepatitis E Virus Infection: One of Differential Diagnosis of Liver Injury in Patients Undergoing Peritoneal Dialysis

Background

There are numerous causes of liver function disorder in patients undergoing peritoneal dialysis (PD). Infection with the Hepatitis E virus (HEV) is a rare cause of liver injury, and the behavior of HEV in patients with PD is unclear. Since patients undergoing dialysis are frequently polypharmatic, liver injury caused by HEV infection may be misdiagnosed as drug-induced liver injury.

Case Presentation

A 61-year-old woman with PD developed abrupt elevation of blood transaminase levels on a routine outpatient session. Since the patient has been receiving tolvaptan as the only new medication, we suspected tolvaptan induced liver injury. In further investigating the cause of liver injury, the blood screening test was found to be positive for HEV-IgA. The patient was diagnosed with HEV infection, and had a self-limited course.

Conclusion

When encountered with patients developing liver injury during PD, HEV infection should be included in the differential diagnosis.

Improving kidney targeting: The influence of nanoparticle physicochemical properties on kidney interactions

Kidney-targeted nanoparticles have become of recent interest due to their potential to deliver drugs directly to diseased tissue, decrease off-target adverse effects, and increase overall tolerability to patients with chronic kidney disease that require lifelong drug exposure. Given the physicochemical properties of nanoparticles can drastically affect their ability to extravasate past cellular and biological barriers and access the kidneys, we surveyed the literature from the past decade and analyzed how nanoparticle size, charge, shape, and material density affects passage and interaction with the kidneys. Specifically, we found that nanoparticle size impacted the mechanism of nanoparticle entry into the kidneys such as glomerular filtration or tubular secretion. In addition, we found charge, aspect ratio, and material density influences nanoparticle renal retention and provide insights for designing nanoparticles for passive kidney targeting. Finally, we conclude by highlighting active targeting strategies that bolster kidney retention and discuss the clinical status of nanomedicine for kidney diseases.

Risk-efficacy balance of ulipristal acetate compared to surgical alternatives

Aims

Uterine fibroids are benign tumours that cause various complaints. These complaints may significantly compromise quality of life, necessitating a clinical intervention in 25–50% of the affected women. Hysterectomy, myomectomy or embolization may offer symptomatic relief, but are costly, include a recovery period, can cause serious side‐effects, sometimes fail to treat symptoms completely and are not always desired by patients. Ulipristal is a conservative long‐term treatment that has a fibroid‐volume decreasing effect, acceptable side‐effects while preserving fertility and may be an alternative to surgical alternatives. Currently, ulipristal is investigated by the European Medicine Agency and suspended from marketing authorization because it may cause drug‐induced liver injury (DILI). However, many drugs can cause severe DILI and prospective studies estimate 14–19 DILI cases/100 000 people.

Methods

This overview will discuss the risk–benefit balance between ulipristal and DILI, describe the safety–efficacy balance of ulipristal and its alternative treatments and the arguments that led to the suspension of its marketing authorization.

Results

Ulipristal may be associated with DILI resulting in a risk of severe liver injury in 1.5:100 000 patients and fatal liver injury in 0.1:100 000 patients. This risk needs to be weighed against the higher mortality risk of >1:1000 and higher incidence of severe complications after surgery.

Conclusion

The DILI risk of ulipristal is considerably lower than that of other medicines that are not suspended, nor need additional safety measures. When evaluating drugs and drug safety, risks that apply to the alternative nonpharmacological treatment options should be taken into consideration.

The effect of size, charge, and peptide ligand length on kidney targeting by small, organic nanoparticles

Chronic kidney disease (CKD) affects 15% of the US adult population. However, most clinically available drugs for CKD show low bioavailability to the kidneys and non-specific uptake by other organs which results in adverse side effects. Hence, a targeted, drug delivery strategy to enhance kidney drug delivery is highly desired. Recently, our group developed small, organic nanoparticles called peptide amphiphile micelles (PAM) functionalized with the zwitterionic peptide ligand, (KKEEE)3K, that passage through the glomerular filtration barrier for kidney accumulation. Despite high bioavailability to the kidneys, these micelles also accumulated in the liver to a similar extent. To further optimize the physicochemical properties and develop design rules for kidney-targeting micelles, we synthesized a library of PAMs of varying size, charge, and peptide repeats. Specifically, variations of the original (KKEEE)3K peptide including (KKEEE)2K, (KKEEE)K, (EEKKK)3E, (EEKKK)2E, (EEKKK)E, KKKKK, and EEEEE were functionalized onto nanoparticles, and peptide surface density and PEG linker molecular weight were altered. After characterization with transmission electron microscopy (TEM) and dynamic light scattering (DLS), nanoparticles were intravenously administered into wildtype mice, and biodistribution was assessed through ex vivo imaging. All micelles localized to the kidneys, but nanoparticles that are positively-charged, close to the renal filtration size cut-off, and consisted of additional zwitterionic peptide sequences generally showed higher renal accumulation. Upon immunohistochemistry, micelles were confirmed to bind to the multiligand receptor, megalin, and histological analyses showed no tissue damage. Our study provides insight into the design of micelle carriers for kidney targeting and their potential for future therapeutic application.