After acute kidney injury, bone marrow cells contribute to renal repair by converting into renal cells, but the mechanism of this conversion is not well understood. To determine whether cell fusion between bone marrow cells and injured renal cells plays a role, we subjected female mice expressing Cre recombinase in tubular epithelial cells to unilateral renal ischemia-reperfusion injury, and subsequently transplanted male bone marrow cells containing a loxP-flanked reporter gene. After 28 days, cell fusion was detected by polysomy for the sex chromosomes and Cre-mediated activation of the reporter gene. After injury, 1.8% of tubular cells were bone marrow-derived, but Cre/loxP recombination demonstrated a frequency of fusion between tubular epithelial and bone marrow cells of only 0.066% (approximately 7 per 10,000 tubular cells). The second strategy, chromosome fluorescence in situ hybridization (FISH), detected cell fusion in 3.8% of bone marrow-derived tubular epithelial cells. No cell fusion was observed in nonischemic kidneys, suggesting that injury was required for cell fusion. This finding was substantiated in co-culture experiments, because cell fusion was only observed between bone marrow cells and renal tubular cells when the latter were depleted of ATP. In conclusion, bone marrow cells can fuse with renal epithelial cells after ischemic injury, but the low frequency of fusion does not account for the majority of the observed conversion of bone marrow cells into kidney cells.

Acute myeloid leukemia (AML) is the most common leukemia in adults. In rare cases, bone marrow necrosis (BMN) and osteolytic lesions are presenting features of AML. The following case describes a patient with known polycythemia vera (PV) that presented with signs of multiple myeloma, including hypercalcemia, anemia, and lytic lesions of the thoracic spine and skull. Laboratory workup was not indicative of myeloma. A bone marrow biopsy was performed, which revealed extensive BMN and initial pathology was consistent with metastatic carcinoma. However, no immunohistochemical stains could be performed due to the extent of BMN; a repeat biopsy was therefore performed. Flow cytometry and CD45 staining were consistent with PV that had transformed to AML. Due to the patient’s comorbidities, she was a poor candidate for stem cell transplant and did not wish to pursue chemotherapy. Ultimately, she pursued hospice care. Based on our literature review, both BMN and osteolytic lesions are rare manifestations of AML and have not been reported to occur simultaneously. These findings can lead to a diagnostic dilemma and suspicion of other malignancies. This case demonstrates that AML should remain in the differential diagnosis in those patients who present with BMN and osteolytic lesions.

Flow sensing by primary cilia of the epithelial cells is involved in cystogenesis in polycystic kidney disease. We investigate whether a similar mechanism applies to the pathogenesis of cyst-like tubular dilatation induced by ureteral obstruction in mice. Robust proliferation occurs in the obstructed tubules when urine flow is interrupted as well as in the repairing tubules when urine flow is reestablished after relief of the obstruction, suggesting a urine flow-independent mechanism of proliferation. In the urothelium, proliferation is only detected above the obstruction, although urine flow ceased both above and below the obstruction. Our results support mechanical strain- rather than flow-mediated proliferation in obstructive uropathy. To understand the mechanism of cell proliferation leading to increased tubular diameter in cyst-like tubular dilatation, we examine planar cell polarity (PCP), which is necessary for oriented cell division and maintenance of tubular diameter. In dilated tubules, the orientation of cell division is randomized, atypical PKC (aPKC) is mislocalized, and the pattern of the expression of a core PCP protein, Frizzled3 (Fz3), is altered. In addition, the level of Fz3 expression is increased. These results indicate that aberrant PCP may contribute to cyst-like tubular dilatation in obstructive uropathy. Interestingly, the orientation of cell division, localization of aPKC, and Fz3 expression return to normal when obstruction is relieved, which suggest a role of normal PCP signaling in tubular repair.

Hepatocellular carcinoma (HCC) is an aggressive liver tumor that occurs with chronic liver disease. Surgical resection is the mainstay of therapy for localized disease whereas therapeutic options for advanced disease are limited. The innovative blockade of immune checkpoints with targeted immunotherapies, such as monoclonal antibodies against programmed death receptor 1 (PD-1), have shown promise in the treatment of solid malignancies. The PD-1 inhibiting antibodies, nivolumab and pembrolizumab prolonged overall survival in randomized trials in metastatic melanoma and advanced non-small cell lung cancer. This is a report of a 75-year-old male patient with metastatic HCC who was initially treated with the standard of therapy sorafenib. After failure of sorafenib therapy, pembrolizumab was started. There was a dramatic response to pembrolizumab with decrease in tumor size and drop in alfa fetoprotein. To the best of our knowledge, this is the first case report of metastatic HCC responsive to pembrolizumab after failure of sorafenib.

Purpose: Interferon-a favors a Th1 shift in immunity, and combining with ipilimumab (ipi) at 3 or 10 mg/kg may downregulate CTLA4-mediated suppressive effects, leading to more durable antitumor immune responses. A study of tremelimumab and high-dose interferon-a (HDI) showed promising efficacy, supporting this hypothesis. Patients and Methods: E3611 followed a 2-by-2 factorial design (A: ipi10þHDI; B: ipi10; C: ipi3þHDI; D: ipi3) to evaluate (i) no HDI versus HDI (across ipilimumab doses) and (ii) ipi3 versus ipi10 (across HDI status). We hypothesized that median progression-free survival (PFS) would improve from 3 to 6 months with HDI versus no HDI and with ipi10 versus ipi3. Results: For eligible and treated patients (N ¼ 81) at a median follow-up time of 29.8 months, median PFS was 4.4 months [95% confidence interval (CI), 2.7-8.2] when ipilimumab was used alone and 7.5 months (95% CI, 5.1-11.0) when HDI was added. Median PFS was 3.8 months (95% CI, 2.6-7.5) with 3 mg/kg ipilimumab and 6.5 months (95% CI, 5.1-13.5) with 10 mg/kg. By study arm, median PFS was 8.0 months (95% CI, 2.8-20.2) in arm A, 6.2 months (95% CI, 2.7-25.7) in B, 5.7 months (95% CI, 1.5-11.1) in C, and 2.8 months (95% CI, 2.6-5.7) in D. The differences in PFS and overall survival (OS) did not reach statistical significance. Adverse events were consistent with the known profiles of ipilimumab and HDI and significantly higher with HDI and ipi10. Conclusions: Although PFS was increased, the differences resulting from adding interferon-a or a higher dose of ipilimumab did not reach statistical significance and do not outweigh the added toxicity risks.