Development of a 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitor as a novel anticancer agent with minimal toxicity.

BACKGROUND: Both the type I insulin-like growth factor receptor (IGF1R) and Src pathways are associated with the development and progression of numerous types of human cancer, and Src activation confers resistance to anti-IGF1R therapies. Hence, targeting both IGF1R and Src concurrently is one of the main challenges in combating resistance to the currently available anti-IGF1R-based anticancer therapies. However, the enhanced toxicity from this combinatorial treatment could be one of the main hurdles for this strategy, suggesting the necessity of developing a novel strategy for co-targeting IGF1R and Src to meet an urgent clinical need. METHODS: We synthesized a series of 4-aminopyrazolo[3,4-d]pyrimidine-based dual IGF1R/Src inhibitors, selected LL28 as an active compound and evaluated its potential antitumor effects in vitro and in vivo using the MTT assay, colony formation assays, flow cytometric analysis, a tumor xenograft model, and the Kras G12D/+ -driven spontaneous lung tumorigenesis model. RESULTS: LL28 markedly suppressed the activation of IGF1R and Src and significantly inhibited the viability of several NSCLC cell lines in vitro by inducing apoptosis. Administration of mice with LL28 significantly suppressed the growth of H1299 NSCLC xenograft tumors without overt toxicity and substantially reduced the multiplicity, volume, and load of lung tumors in the Kras G12D/+ -driven lung tumorigenesis model. CONCLUSIONS: The present results suggest the potential of LL28 as a novel anticancer drug candidate targeting both IGF1R and Src, providing a new avenue to efficient anticancer therapies. Further investigation is warranted in advanced preclinical and clinical settings.

Correction of hyponatremia and osmotic demyelinating syndrome: have we neglected to think intracellularly?

BACKGROUND: Osmotic demyelination syndrome (ODS) is a complication generally associated with overly rapid correction of hyponatremia. Traditionally, nephrologists have been trained to focus solely on limiting the correction rate. However, there is accumulating evidence to suggest that the prevention of ODS is beyond achieving slow correction rates. METHODS: We (1) reviewed the literature for glial intracellular protective alterations during hyperosmolar stress, a state presumed equivalent to the rapid correction of hyponatremia, and (2) analyzed all available hyponatremia-associated ODS cases from PubMed for possible contributing factors including correction rates and concurrent metabolic disturbances involving hypokalemia, hypophosphatemia, hypomagnesemia, and/or hypoglycemia. RESULTS: In response to acute hyperosmolar stress, glial cells undergo immediate extracellular free water shift, followed by active intracellular Na(+), K(+) and amino acid uptake, and eventual idiogenic osmoles synthesis. At minimum, protective mechanisms require K(+), Mg(2+), phosphate, amino acids, and glucose. There were 158 cases of hyponatremia-associated ODS where both correction rates and other metabolic factors were documented. Compared with the rapid correction group (>0.5 mmol/L/h), the slow correction group (≤0.5 mmol/L/h) had a greater number of cases with concurrent hypokalemia (49.4 vs. 33.3 %, p = 0.04), and a greater number of cases with any concurrent metabolic derangements (55.8 vs. 38.3 %, p = 0.03). CONCLUSION: Glial cell minimizes volume changes and injury in response to hyperosmolar stress via mobilization and/or utilization of various electrolytes and metabolic factors. The prevention of ODS likely requires both minimization of correction rate and optimization of intracellular response during the correction phase when a sufficient supply of various factors is necessary.

BK virus infection following kidney transplantation: an overview of risk factors, screening strategies, and therapeutic interventions.

PURPOSE OF REVIEW: In recipients of kidney transplants, the emergence of BK virus (BKV)-associated clinical syndromes, such as viruria, viremia, and BK nephropathy, coincided with the advent of potent immunosuppressive therapy. There is currently no standardized protocol for the management of BK viruria or viremia, or established BK nephropathy. Suggested risk factors for BKV replication and a literature overview on various treatment strategies for BKV-associated clinical syndromes are presented, followed by the authors' proposed approach for screening, monitoring, and treatment of post-transplant BKV infection. RECENT FINDINGS: BKV infection can occur under all combinations of immunosuppressive therapy. Although both humoral and cellular immunity may be essential, BKV-specific T-cell immunity appears to play a pivotal role in controlling BKV replication. Monitoring BKV-specific immune response might prove useful in guiding therapeutic intervention. The beneficial effects of antiviral agents remain unclear. Development of T-cell or antibody-based vaccines against BKV is a subject of future research. SUMMARY: In the absence of conclusive evidence that any particular immunosuppressive agent has a specific influence over another on BKV infection risk and the unclear benefit of antiviral agents, intensive monitoring of serum BKV using PCR and immunological containment of BKV replication should remain the mainstay of therapy. The routine recommendations of antiviral agents in the treatment of BKV-associated clinical syndromes await results of large prospective randomized trials.

Kidney transplantation in the obese transplant candidates: to transplant or not to transplant?

The prevalence of obesity (body mass index ≥30 kg/m(2)) at the time of transplantation among kidney transplant recipients in the United States has doubled between 1987 and 2001 and continues to increase inexorably. Single-center and large registry studies in kidney transplant recipients demonstrated that high body mass index (BMI) at transplant is associated with increased risk of wound and surgical site infections, delayed graft function (DGF), acute rejection episodes, and graft loss, among others. Hence, in many centers, obese transplant candidates are denied a transplant based on their body mass index (BMI) alone. The impact of obesity on short- and long-term graft and patient outcomes after kidney transplantation are herein revisited, followed by the authors' proposed approach to evaluate and select obese transplant candidates for a kidney transplant. Suggested interventions to optimize the health of such candidates are also discussed.

The impact of mycophenolate mofetil versus azathioprine as adjunctive therapy to cyclosporine on the rates of renal allograft loss due to glomerular disease recurrence.

BACKGROUND: Given the reported efficacy of mycophenolate mofetil (MMF) in the treatment of glomerular diseases, we question whether MMF can reduce the rate of renal allograft loss due to glomerular disease recurrence compared to azathioprine (AZA) as adjunctive therapy to cyclosporine (CSA)-based immunosuppression. METHODS: This is a retrospective study based on the Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) database designed to compare the Kaplan-Meier rates of graft loss due to disease recurrence stratified by primary renal diagnoses between recipients receiving CSA+AZA versus CSA+MMF. Recipients of primary kidney transplants (both deceased donor and living, related and unrelated) renal transplants performed between 1 January 1988 and 31 December 2007 with the primary renal diagnosis of IgA nephropathy (IgAN), membranous glomerulonephropathy (MGN), membranoproliferative glomerulonephropathy (MPGN), lupus nephritis (LN) or focal segmental glomerulosclerosis (FSGS) with a functioning allograft at discharge were included. RESULTS: Seven thousand eight hundred and twenty-six recipients of primary deceased donor kidney transplants (DDKT) [CSA + AZA: IgAN (890), MGN (380), MPGN (193), LN (1324), FSGS (1314) and CSA+MMF: IgAN (855), MGN (614), MPGN (116), LN (715), FSGS (1425)] and 5498 recipients of living donor kidney transplants (LDKT) [CSA+AZA: IgAN (694), MGN (229), MPGN (100), LN (592), FSGS (654) and CSA+MMF: IgAN (1066), MGN (435), MPGN (89), LN (530), FSGS (1109)] were included in the analysis. At 10-year follow-up (mean duration was 5.6 to 6.7±1.8 years in DDKT and 6.2 to 7.4±1.7 years in LDKT), mean times of transplantation (era of transplantation) were: 1992±1.6 years and 2002±1.9 years for the CSA+AZA and CSA+MMF groups, respectively. There was no statistically significant difference in the Kaplan-Meier rates of graft loss due to disease recurrence of any glomerular disease studied between the CSA+AZA and CSA+MMF groups in either DDKT or LDKT recipients. Chi-square analysis revealed no statistically significant difference between the two immunosuppressive regimen groups in terms of age, gender and ethnic background. CONCLUSION: The OPTN/UNOS database revealed no difference in the rates of renal allograft loss due to disease recurrence of IgAN, MGN, MPGN, LN and FSGS among recipients receiving either CSA+AZA or CSA+MMF maintenance immunosuppressive therapy at 10-year follow-up.

Patients with diabetes mellitus type 2 and hypomagnesemia may have enhanced glomerular filtration via hypocalcemia.

INTRODUCTION: Hypomagnesemia and glomerular hyperfiltration are commonly observed in patients with diabetes mellitus Type 2 (DM2). In the current study, we examined the relationship between hypomagnesemia and glomerular filtration rates in DM2 patients. MATERIALS AND METHODS: Data were obtained for DM2 patients without documented kidney disease seen at UCLAOlive View Medical Center during January through March 2001. Data for hemoglobin, hemoglobin A1C (HbA1C), routine electrolytes, lipid profiles, urinalyses, history of hypertension, and pharmacy profiles were retrieved. Estimation of glomerular filtration rate (eGFR) was based on the CKD-epi formula. Multivariate analyses were performed to determine the correlations between eGFR and clinical factors including age, gender, history of hypertension, the use of diuretics, renin angiotensin system (RAS) inhibitors, acetylsalicylic acid, and statins, serum calcium, magnesium, hemoglobin, HbA1C lipid profile, and degree of proteinuria. RESULTS: 550 patients (54% females) with mean age 57.5 ± 11.0 years and eGFR 95.7 ± 14.8 ml/min/1.73 m2 were included. Multivariate analysis revealed negative correlations with eGFR for age (Pearson-correlationcoefficient: -0.7, p < 0.0001), hypertension (-0.32, p < 0.0001), magnesium (-0.21, p < 0.0001), calcium (-0.13, p = 0.009), proteinuria (-0.17, p < 0.0001), and the use of RAS inhibitors (-0.21, p < 0.0001), and diuretics (-0.24, p < 0.0001) and a positive correlation for HbA1C (0.28, p < 0.0001). Further analysis of the interaction between serum magnesium and calcium, defined as magnesium × calcium (Mg × Ca), revealed a more significant correlation with eGFR than either cation alone (-0.24, p < 0.0001). CONCLUSIONS: Serum magnesium, calcium, and (Mg × Ca) all had significant negative correlations with eGFR. In particular, (Mg × Ca) had the strongest correlation with eGFR.

Optimal use of SGLT2 inhibitors in diabetic kidney transplant recipients.

Sodium-glucose cotransporter 2 inhibitor (SGLT2i), a glucosuric agent initially approved for use as an antidiabetic agent, was unexpectedly found to confer cardio-and reno-protective effects in individuals with or without type 2 diabetes mellitus. Despite mounting evidence suggesting that SGLT2i provides cardio- and reno-protective benefits in both diabetic and non-diabetic and in chronic kidney disease (CKD) patients in the general population, reservations for its use in the transplant setting persist due to concerns for increased risk of genital mycotic and urinary tract infections. A comprehensive review of the literature on the efficacy and safety of SGLT2i use in diabetic kidney transplant recipients is herein presented followed by authors' opinion on its optimal use in this patient population.

Immunosuppressive management of dialysis patients with recently failed transplants.

Over the past decade, patients returning to dialysis after a failed transplant comprised of 5-10% of the annual number of dialysis initiations in the United States, whereas retransplant candidates account for 5.0-13% of the annual deceased donor wait-list additions. The United States Renal Data System (USRDS) database revealed a >3-fold increase in the annual adjusted death rates for patients returning to dialysis after graft loss compared with patients with a functioning allograft (9.4% vs. 2.8%, respectively). Continuation of low-dose immunosuppression to maintain residual allograft function has been suggested as a contributing factor, presumably via treatment-related infectious and cardiovascular complications among others. In contrast, a survival advantage in maintaining patients on long-term immunosuppression after returning to peritoneal dialysis has also been suggested. Despite the significant number of patients requiring reinitiation of some form of renal replacement therapy after a failed transplant and the increasing evidence suggesting their high mortality and morbidity rates, management of the failed allograft in these patients has received little attention. This article presents an overview of the literature on the management of immunosuppression after allograft failure, a brief review on the pros and cons of allograft nephrectomy, and the authors' opinions on the management of immunosuppression in patients with a failed kidney allograft.

Severe Hyperphosphatemia in a Patient with Mild Acute Kidney Injury.

Hyperphosphatemia may arise from various conditions including exogenous ingestion, extracellular shifts due to cell death or alterations in acid-base status, increased bone resorption, hormonal dysregulations leading to reduced renal excretion, reduced kidney function, or faulty measurement techniques. We herein present a case of a young pregnant woman who presented with mild acute kidney injury (AKI), invasive mucormycosis receiving liposomal amphotericin, and hyperphosphatemia out of proportion to the degree of kidney injury. While the patient was given routine phosphate-binding agent by her primary care team for presumed AKI-associated hyperphosphatemia, a full investigation by the renal consulting team for contributing factors other than kidney injury revealed that she actually had pseudohyperphosphatemia associated with the use of liposomal amphotericin. Erroneous treatment of pseudohyperphosphatemia may have been detrimental to this pregnant patient. A literature review for conditions associated with pseudohyperphosphatemia other than the use of liposomal amphotericin will be discussed.

Development of the phenylpyrazolo[3,4-d]pyrimidine-based, insulin-like growth factor receptor/Src/AXL-targeting small molecule kinase inhibitor.

Rationale: The type I insulin-like growth factor receptor (IGF-1R) signaling pathway plays key roles in the development and progression of numerous types of human cancers, and Src and AXL have been found to confer resistance to anti-IGF-1R therapies. Hence, co-targeting Src and AXL may be an effective strategy to overcome resistance to anti-IGF-1R therapies. However, pharmacologic targeting of these three kinases may result in enhanced toxicity. Therefore, the development of novel multitarget anticancer drugs that block IGF-1R, Src, and AXL is urgently needed. Methods: We synthesized a series of phenylpyrazolo[3,4-d]pyrimidine (PP)-based compounds, wherein the PP module was conjugated with 2,4-bis-arylamino-1,3-pyrimidines (I2) via a copper(I)-catalyzed alkyne-azide cycloaddition reaction. To develop IGF-1R/Src/AXL-targeting small molecule kinase inhibitors, we selected LL6 as an active compound and evaluated its antitumor and antimetastatic effects in vitro and in vivo using the MTT assay, colony formation assays, migration assay, flow cytometric analysis, a tumor xenograft model, the KrasG12D/+ -driven spontaneous lung tumorigenesis model, and a spontaneous metastasis model using Lewis lung carcinoma (LLC) allografts. We also determined the toxicity of LL6 in vitro and in vivo. Results: LL6 induced apoptosis and suppressed viability and colony-forming capacities of various non-small cell lung cancer (NSCLC) cell lines and their sublines with drug resistance. LL6 also suppressed the migration of NSCLC cells at nontoxic doses. Administration of LL6 in mice significantly suppressed the growth of NSCLC xenograft tumors and metastasis of LLC allograft tumors with outstanding toxicity profiles. Furthermore, the multiplicity, volume, and load of lung tumors in KrasG12D/+ transgenic mice were substantially reduced by the LL6 treatment. Conclusions: Our results show the potential of LL6 as a novel IGF-1R/Src/AXL-targeting small molecule kinase inhibitor, providing a new avenue for anticancer therapies.

Evaluation of adult kidney transplant candidates.

Important advances in immunosuppressive therapy and refinement in surgical techniques have allowed renal transplantation to become the treatment of choice for virtually all suitable candidates with end-stage renal disease. Compared to dialysis, kidney transplantation improves both patient survival and quality of life and, over time, can reduce the total cost of medical care. It must be noted, however, that although the risk of death in the first year after transplantation is <5%, not all patients qualify for the surgery because of their unacceptable risks for complications. The transplant evaluation process requires a comprehensive assessment of each patient's medical, surgical, and psychosocial histories. Selection of the suitable transplant candidate remains a challenge for transplant physicians owing, predominantly, to the presence of complex medical issues in the potential candidates and nonstandardized criteria for acceptance or rejection among transplant centers. Furthermore, with the ever-increasing disparity between donor organ supply and demand and resultant increased wait-list times, the transplant physicians must further consider the optimal management and re-evaluation of wait-list patients during the waiting period. This article describes a systematic approach for the evaluation of a potential renal transplant candidate. Various medical issues that arise during the evaluation process are discussed.

Management of renal dysfunction in the liver transplant recipient.

PURPOSE OF REVIEW: Acute and chronic kidney injury following orthotopic liver transplantation (OLT) is associated with increased morbidity and mortality. With the increasing longevity of liver transplant recipients, chronic kidney disease (CKD) has become an increasingly prevalent complication among long-term survivors. This article provides an overview of the literature on suggested risk factors for acute and CKD following OLT and a discussion of an approach to their medical management. RECENT FINDINGS: In OLT candidates with pretransplant renal dysfunction, the use of interleukin-2 receptor blockers or antithymocyte globulin induction therapy in conjunction with delayed introduction of calcineurin inhibitors may preserve early renal function. In long-term stable OLT recipients with established calcineurin inhibitor nephrotoxicity, calcineurin inhibitor minimization or withdrawal protocols may halt or ameliorate renal dysfunction without compromising patient and graft survival. However, large-scale, multicenter, randomized controlled trials are still needed. SUMMARY: The occurrence of acute kidney injury is common immediately after OLT, whereas the incidence of CKD and end-stage renal disease increases with time. Identifying patients at risk for acute kidney injury and CKD following OLT and early implementation of measures to preserve, halt, or ameliorate the progression of renal dysfunction should be an integral part in the management of OLT recipients.

Acute Kidney Failure in a Young African American Male.

Retroperitoneal fibrosis (RPF) is a condition characterized by chronic inflammatory and fibrotic changes in the retroperitoneum that can lead to serious complications including kidney failure, mesenteric and limb ischemia, and deep venous thrombosis among others. Affected individuals may present with nonspecific symptomology that would require a high clinical index of suspicion for prompt diagnosis. We herein discuss a case of a young African-American man with recurrent deep venous thrombosis who presents with a 4-week history of constant aching pain of abdomen and back and kidney failure. Initial noncontrast computed tomogram (CT) only revealed mild bilateral hydroureteronephrosis with inflammatory changes but without obvious mass or lymphadenopathy. At the insistence of the renal consulting team to rule out RPF, a CT-urogram was performed which revealed an infiltrative mass encasing the aorta, inferior vena cava, and common iliac vessels. Laparoscopic biopsy revealed dense fibroadipose tissue, lymphocytic aggregates, focal scattered IgG4-positive plasma cells, and fibrin deposition. Patient underwent bilateral nephrostomy placement and empirical corticosteroid therapy with resolution of kidney failure. Our case illustrates a classic presentation of RPF with relatively benign findings on noncontrast CT that could have been missed if clinicians did not keep a high index of suspicion for the condition.

Thrombotic microangiopathy following pancreas after kidney transplants.

Advances in immunosuppressive therapy and refinement in surgical techniques have allowed pancreas after kidney (PAK) transplantation to become a viable therapeutic option for patients with brittle type I diabetic recipients of a living donor or previous deceased kidney alone transplant. Although maintenance immunosuppressive therapy is not significantly changed after the addition of a pancreas, a temporary booster in immunosuppressive therapy and an increase in the dose of calcineurin inhibitor (CNI) are required after PAK transplantation. The latter has been implicated in the observed variable decline in kidney allograft function. We herein report two cases of kidney allograft dysfunction following PAK transplant due to biopsy-proven transplant, thrombotic microangiopathy (TMA). Whether PAK transplantation pre-disposes a subset of patients to the development of post-transplant TMA is not known. Diagnostic kidney biopsies should be considered in PAK transplant recipients with worsening kidney allograft function.

New onset diabetes mellitus after solid organ transplantation.

This article presents an overview of the literature on the current diagnostic criteria for new onset diabetes mellitus after transplantation (NODAT) and discusses suggested risk factors for the development of NODAT, its potential pathogenic mechanisms, and its impact on post-transplant outcomes after solid organ transplantation. Suggested guidelines for early identification and management of NODAT are also discussed.

Cardiovascular disease posttransplant.

Renal transplantation is currently the preferred treatment modality for virtually all suitable candidates with end-stage renal disease. Compared with dialysis, kidney transplantation improves both patient survival and quality of life. Nonetheless, posttransplant cardiac complications are associated with increased morbidity and mortality after renal transplantation. When compared with the general population, cardiovascular mortality in transplant recipients is increased by nearly 10-fold among patients within the age range of 35 and 44 and at least doubled among those between the ages of 55 and 64. Although renal transplantation ameliorates cardiovascular disease risk factors by restoring renal function, it introduces new cardiovascular risks derived, in part, from immunosuppressive medications. We provide an overview of the literature on conventional and unconventional cardiovascular disease risk factors after renal transplantation, and discuss an approach to their medical management.

Renal function outcomes following liver transplantation and combined liver-kidney transplantation.

Acute renal failure (ARF) is common immediately after orthotopic liver transplantation (OLT), whereas the incidences of chronic kidney disease (CKD) and end-stage renal disease increase with time. Introduction of the Model for End-stage Liver Disease (MELD) score-intended to prioritize patients with more-severe pretransplantation liver disease in general, and worse pretransplantation renal function in particular-for the allocation of liver grafts led to concerns about compromised patient and allograft survival and increased incidence of postoperative ARF and CKD. Nonetheless, it has been suggested that early OLT of candidates with baseline renal dysfunction improves post-transplantation renal outcomes. For OLT candidates with mild to moderate chronic renal impairment or recent-onset ARF, the decision of whether to perform OLT alone or combined liver-kidney transplantation (CLKT) can be challenging because no single factor has been shown to be predictive of the degree of renal function recovery or CKD progression following successful OLT. In this article, we provide an overview of the literature on renal function outcomes following OLT and CLKT, share our perspectives on the potential predictors of renal dysfunction or nonrecovery of renal function after OLT, and present United Network for Organ Sharing data on patient and allograft outcomes in CLKT recipients in the pre-MELD and post-MELD eras. Mechanisms that might underlie immunological protection of kidney grafts by liver allografts are also discussed.

Multiple Electrolyte and Metabolic Emergencies in a Single Patient.

While some electrolyte disturbances are immediately life-threatening and must be emergently treated, others may be delayed without immediate adverse consequences. We discuss a patient with alcoholism and diabetes mellitus type 2 who presented with volume depletion and multiple life-threatening electrolyte and metabolic derangements including severe hyponatremia (serum sodium concentration [SNa] 107 mEq/L), hypophosphatemia ("undetectable," <1.0 mg/dL), and hypokalemia (2.2 mEq/L), moderate diabetic ketoacidosis ([DKA], pH 7.21, serum anion gap [SAG] 37) and hypocalcemia (ionized calcium 4.0 mg/dL), mild hypomagnesemia (1.6 mg/dL), and electrocardiogram with prolonged QTc. Following two liters of normal saline and associated increase in SNa by 4 mEq/L and serum osmolality by 2.4 mosm/Kg, renal service was consulted. We were challenged with minimizing the correction of SNa (or effective serum osmolality) to avoid the osmotic demyelinating syndrome while replacing volume, potassium, phosphorus, calcium, and magnesium and concurrently treating DKA. Our management plan was further complicated by an episode of significant aquaresis. A stepwise approach was strategized to prioritize and correct all disturbances with considerations that the treatment of one condition could affect or directly worsen another. The current case demonstrates that a thorough understanding of electrolyte physiology is required in managing complex electrolyte disturbances to avoid disastrous outcomes.