Low magnesium levels and prognosis in newly diagnosed diffuse large B-cell lymphoma.

Magnesium (Mg) is an essential element involved in cellular metabolism. We demonstrated that in patients with diffuse large B-cell lymphoma (DLBCL) undergoing autologous stem cell transplant (SCT), those with a serum Mg < 2.0 mg/dL at the time of transplant had worse outcomes. In this study, we aimed to learn the prognostic value of low serum Mg in patients with untreated DLBCL. We analyzed serum from 408 patients and tested 2 Mg cutpoints-low (<1.7 mg/dL) and low normal (<2.0 mg/dL), a range we found associated with lower survival in the SCT group. We found 3% of patients with low levels and 23% with low normal levels. Low normal serum Mg levels were associated with a higher stage at diagnosis, more extranodal involvement, higher international prognostic index score, lower overall survival (OS), and event-free survival. These data warrant testing Mg replacement to a target of >2.0 mg/dL to learn if survival can be improved.

Atezolizumab plus bevacizumab as first-line systemic therapy for hepatocellular carcinoma: a multi-institutional cohort study.

BACKGROUND: Atezolizumab plus bevacizumab is the standard of care for advanced hepatocellular carcinoma (HCC) in the first-line setting, although was only evaluated in patients with Child-Pugh (CP) A liver function in the IMbrave150 trial. We sought to determine the outcomes of these patients based on CP score and ALBI grade in the US population. METHODS: This multicenter cohort study included patients with HCC who received atezolizumab with bevacizumab as first-line systemic therapy between March 2018 and November 2023. Overall survival (OS) was determined using the Kaplan-Meier method and multivariate analyses were performed using Cox proportional hazard regression method. RESULTS: Among 322 patients, 226, 86, and 10 patients had CP-A, CP-B, and CP-C liver function, respectively. Median age was 66.5 years, 78.6% were male, and 82.6% were White. Median OS (mOS) was 21.6 months for those with CP-A, 9.1 months for those with CP-B7, and 4.7 months for those with CP-B8-C12 (P < .0001). Among patients with CP-A, those with ALBI grade 1 had an mOS of 34.9 months versus 14.2 months in those with grade 2. In multivariate analyses, CP score, ALBI grade, hepatitis B, performance status, and macrovascular invasion were significantly associated with survival. CONCLUSIONS: CP score is an important prognostic tool for patients with HCC receiving atezolizumab plus bevacizumab, and this regimen remains a viable option for patients with CP-B7 with no additional safety concern, although the benefit is significantly less than those with CP-A. ALBI score has independent predictive value in patients with CP-A liver function.

The Period 2 Enhancer Nobiletin as Novel Therapy in Murine Models of Circadian Disruption Resembling Delirium.

OBJECTIVES: Delirium occurs in approximately 30% of critically ill patients, and the risk of dying during admission doubles in those patients. Molecular mechanisms causing delirium are largely unknown. However, critical illness and the ICU environment consistently disrupt circadian rhythms, and circadian disruptions are strongly associated with delirium. Exposure to benzodiazepines and constant light are suspected risk factors for the development of delirium. Thus, we tested the functional role of the circadian rhythm protein Period 2 (PER2) in different mouse models resembling delirium. DESIGN: Animal study. SETTING: University experimental laboratory. SUBJECTS: Wildtype, Per2 mice. INTERVENTIONS: Midazolam, lipopolysaccharide (lipopolysaccharide), constant light, nobiletin, or sham-treated animals. MEASUREMENTS AND MAIN RESULTS: Midazolam significantly reduced the expression of PER2 in the suprachiasmatic nucleus and the hippocampus of wild-type mice. Behavioral tests following midazolam exposure revealed a robust phenotype including executive dysfunction and memory impairment suggestive of delirium. These findings indicated a critical role of hippocampal expressed PER2. Similar results were obtained in mice exposed to lipopolysaccharide or constant light. Subsequent studies in Per2 mice confirmed a functional role of PER2 in a midazolam-induced delirium-like phenotype. Using the small molecule nobiletin to enhance PER2 function, the cognitive deficits induced by midazolam or constant light were attenuated in wild-type mice. CONCLUSIONS: These experiments identify a novel role for PER2 during a midazolam- or constant light-induced delirium-like state, highlight the importance of hippocampal PER2 expression for cognitive function, and suggest the PER2 enhancer nobiletin as potential therapy in delirium-like conditions associated with circadian disruption.

Sleep impairment and reduced interneuron excitability in a mouse model of Dravet Syndrome.

Dravet Syndrome (DS) is caused by heterozygous loss-of-function mutations in voltage-gated sodium channel NaV1.1. Our mouse genetic model of DS recapitulates its severe seizures and premature death. Sleep disturbance is common in DS, but its mechanism is unknown. Electroencephalographic studies revealed abnormal sleep in DS mice, including reduced delta wave power, reduced sleep spindles, increased brief wakes, and numerous interictal spikes in Non-Rapid-Eye-Movement sleep. Theta power was reduced in Rapid-Eye-Movement sleep. Mice with NaV1.1 deleted specifically in forebrain interneurons exhibited similar sleep pathology to DS mice, but without changes in circadian rhythm. Sleep architecture depends on oscillatory activity in the thalamocortical network generated by excitatory neurons in the ventrobasal nucleus (VBN) of the thalamus and inhibitory GABAergic neurons in the reticular nucleus of the thalamus (RNT). Whole-cell NaV current was reduced in GABAergic RNT neurons but not in VBN neurons. Rebound firing of action potentials following hyperpolarization, the signature firing pattern of RNT neurons during sleep, was also reduced. These results demonstrate imbalance of excitatory vs. inhibitory neurons in this circuit. As predicted from this functional impairment, we found substantial deficit in homeostatic rebound of slow wave activity following sleep deprivation. Although sleep disorders in epilepsies have been attributed to anti-epileptic drugs, our results show that sleep disorder in DS mice arises from loss of NaV1.1 channels in forebrain GABAergic interneurons without drug treatment. Impairment of NaV currents and excitability of GABAergic RNT neurons are correlated with impaired sleep quality and homeostasis in these mice.

Outcomes of Invasive Fungal Infections Treated with Isavuconazole: A Retrospective Review.

BACKGROUND: Isavuconazole (ISA) has a favorable side effect profile that makes it attractive for treatment of invasive fungal infections (IFI). It carries FDA approval for invasive aspergillosis and mucormycosis, but there are fewer data for other organisms and non-pulmonary infections. We conducted this review to investigate how ISA performed at treating IFI, with an especial interest in these non-approved indications. METHODS: We retrospectively identified and reviewed 131 patients who received ISA as treatment for IFI at our institution, some of whom received ISA as their first anti-fungal therapy and others who received ISA as either step-down therapy or salvage therapy. We identified the microbiologic cause of infection as well as the anatomic site involved for each patient. We then classified patients according to their response to ISA: namely cured, partially responded, or stabilized. RESULTS: The majority of patients were immunocompromised (n = 76, 58%). ISA was used primarily as a secondary therapy (n = 116, 89%); either as a step-down/switching from other agents, or as salvage therapy. The most common reasons for switching to ISA were toxicities with prior agents followed by QT prolongation. Although pulmonary aspergillosis and mucormycosis were represented in more than half of the cohort, ISA was also used off-label for treatment of other organisms such as endemic fungi (n = 19, 15%) as well as central nervous system (CNS) infections (n = 15, 11%). We have described the detailed clinical characteristics of these CNS infections cases. The overall clinical response rate varied by type of infection and site involved (57-73% response rate). CONCLUSIONS: We demonstrated encouraging clinical responses, particularly outside the FDA-approved indications, as well as good tolerability. This report highlights the critical need for expanded scope of prospective studies to delineate the efficacy of this better-tolerated agent, especially in central nervous system infections.

Outcomes of Patients with Advanced Hepatocellular Carcinoma Receiving Lenvatinib following Immunotherapy: A Real World Evidence Study.

BACKGROUND: Lenvatinib, a multikinase inhibitor, is an FDA-approved treatment for advanced hepatocellular carcinoma (HCC) in the first-line setting. Recent trial data have established atezolizumab plus bevacizumab as well as tremelimumab plus durvalumab as preferred first-line treatment options for advanced HCC. The role of lenvatinib following progression on immunotherapy in patients with advanced HCC remains unclear. METHODS: We conducted a multicentric, retrospective analysis of patients with advanced HCC diagnosed between 2010 and 2021 at the Mayo Clinic in Minnesota, Arizona, and Florida who received immunotherapy followed by lenvatinib. Median overall survival and progression-free survival analyses were performed using the Kaplan-Meier method, and responses were determined using RECIST 1.1. Adverse events were determined using CTCAE v 4.0. RESULTS: We identified 53 patients with advanced HCC who received lenvatinib following progression on immunotherapy. Forty five (85%) patients had a Child Pugh class A at diagnosis, while 30 (58%) patients were still Child Pugh A at time of lenvatinib initiation. Lenvatinib was administered as a second-line treatment in 85% of the patients. The median PFS was 3.7 months (95% CI: 3.2-6.6), and the median OS from the time of lenvatinib initiation was 12.8 months (95% CI: 6.7-19.5). In patients with Child Pugh class A, the median OS and PFS was 14 and 5.2 months, respectively. Race, gender, and Child Pugh class was associated with OS on multivariate analysis. DISCUSSION: Our study, using real-world data, suggests that patients benefit from treatment with lenvatinib following progression on immunotherapy in advanced HCC. The optimal sequencing of therapy for patients with advanced HCC following progression on immunotherapy remains unknown, and these results need to be validated in a clinical trial.

Efficacy of first-line checkpoint inhibitors in combination with chemotherapy in high-grade extrapulmonary metastatic neuroendocrine carcinomas.

Poorly differentiated extrapulmonary neuroendocrine carcinomas (EP NECs) are aggressive cancers characterized by a high Ki-67 index, rapid tumor growth and poor survival, and are subdivided into small and large cell carcinoma. For small cell carcinoma of the lung, a pulmonary NEC, the combination of cytotoxic chemotherapy (CTX) and a checkpoint inhibitor (CPI) is considered standard therapy and superior to CTX alone. EP NECs are typically treated with platinum-based regimens, some clinicians have adopted the addition of a CPI to CTX based on data from trials in patients with small cell carcinoma of the lung. In this retrospective study of EP NECs, we report 38 patients treated with standard first-line CTX and 19 patients treated with CTX plus CPI. We did not observe any additional benefit of adding CPI to CTX in this cohort.

CAR-T Therapy in Lymphoma Patients With Coexisting Cardiomyopathy or Cardiac Lymphomatous Involvement.

Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the management of aggressive hematologic malignancies. However, its role in patients with lymphoma and cardiac metastasis or cardiomyopathy remains undefined due to potentially life-threatening complications such as ventricular rupture, cardiac tamponade, and circulatory failure. We present a case series of patients with lymphoma and cardiomyopathy or cardiac metastasis managed with chimeric antigen receptor T-cell therapy. (Level of Difficulty: Advanced.).

Evolving treatment patterns and improved outcomes in relapsed/refractory mantle cell lymphoma: a prospective cohort study.

Over the last two decades, the frontline therapy for mantle cell lymphoma (MCL) has evolved. However, the impact of subsequent lines of therapy on survival outcomes has not been well characterized. In this study, we investigated the treatment patterns and survival outcomes in patients with relapsed/refractory (R/R) MCL treated with second-line (2 L) therapy. Adult patients with newly diagnosed MCL from 2002 to 2015 were enrolled in a prospective cohort study. Clinical characteristics, 2 L treatment details, and outcomes were compared between patients who received 2 L treatment between 2003-2009 (Era 1), 2010-2014 (Era 2), and 2015-2021 (Era 3). 2 L treatment was heterogenous in all eras, and there was a substantial shift in the pattern of 2 L therapy over time. The estimated 2-year EFS rate was 21% (95% CI, 13-35), 40% (95% CI, 30-53), and 51% (95% CI, 37-68) in Era 1-3 respectively, and the 5-year OS rate was 31% (95% CI, 21-45), 37% (95% CI, 27-50), and 67% (95% CI, 54-83) in Era 1-3, respectively. These results provide real-world evidence on evolving treatment patterns of 2 L therapy based on the era of relapse. The changes in 2 L treatment correlated with improved EFS and OS, suggesting that treatment advances are associated with improved outcomes in patients with R/R MCL.

Outcomes following FGFR Inhibitor Therapy in Patients with Cholangiocarcinoma.

BACKGROUND: Sequencing efforts in patients with cholangiocarcinoma (CCA) have provided insights into molecular mechanisms including fibroblast growth factor receptor (FGFR) alterations. There is a lack of data on outcomes of patients following cessation of FGFR inhibitor (FGFRi) therapy. OBJECTIVE: We describe the clinical outcomes following initial FGFRi treatment in CCA harboring FGFR alterations. PATIENTS AND METHODS: We conducted a multicentric, retrospective analysis of patients with FGFR-altered CCA diagnosed between 2010 and 2021. Median overall survival (OS) and progression-free survival (PFS) analyses were performed using the Kaplan-Meier method. RESULTS: We identified 88 advanced or metastatic CCA patients, 28 males (31.8%) and 60 females (68.2%), harboring FGFR alterations who received FGFRi. Median PFS on initial FGFRi was 6.6 months (95% confidence interval (CI): 5.5-8.3). Following cessation of first FGFRi therapy, 55% patients received systemic therapy as next line: 67% received chemotherapy or targeted treatment and 33% received another FGFRi. Median PFS for patients who received chemotherapy or targeted agent was 2.1 months (95% CI 1.6-5.7) and for patients who received a second FGFRi was 3.7 months (95% CI 1.5-not evaluable). OS was 2.0 months for patients who did not receive any therapy compared to 8.7 months with chemotherapy and 8.6 months with another FGFRi. In addition, one patient treated with pemigatinib developed FGFR2 M540_I541insMM alteration at time of resistance, which has not been functionally characterized and its effect on protein function remains unknown. CONCLUSIONS: Understanding the mechanisms of resistance with FGFRi is essential to understand sequencing of treatments. In this study, patients received standard chemotherapy in the first line and were fit enough to be considered for subsequent therapy with an FGFRi. Almost half of the patients become ineligible to receive further systemic therapy following progression on FGFRi. As more agents are being introduced, detailed understanding of outcomes following treatment with an FGFRi, including subsequent FGFRi, is essential.

Cabozantinib Following Immunotherapy in Patients with Advanced Hepatocellular Carcinoma.

(1) Background: Cabozantinib, a multikinase inhibitor, is approved by the Food and Drug Administration (FDA) for the treatment of advanced hepatocellular carcinoma (HCC) following progression on sorafenib. Recently, atezolizumab plus bevacizumab has been approved in the first line setting for advanced HCC and has become the new standard of care. Whether cabozantinib improves outcomes following progression on immunotherapy remains unknown. We describe the clinical outcomes following treatment with immunotherapy in patients with advanced HCC who received cabozantinib. (2) Methods: We conducted a multicentric, retrospective analysis of patients with advanced HCC diagnosed between 2010-2021 at Mayo Clinic in Minnesota, Arizona, and Florida who received cabozantinib. Median overall survival and progression free survival analyses were performed using the Kaplan-Meier method. Adverse events were determined using Common Terminology Criteria for Adverse Events (CTCAE). (3). Results: We identified 26 patients with advanced HCC who received cabozantinib following progression on immunotherapy. Median progression free survival on cabozantinib therapy was 2.1 months (95% CI: 1.3-3.9) and median overall survival from time of cabozantinib initiation was 7.7 months (95% CI: 5.3-14.9). (4) Conclusion: The optimal sequencing of therapy for patients with advanced HCC following progression on immunotherapy remains unknown. Our study demonstrates that patients may benefit from treatment with cabozantinib following progression on immunotherapy.

Systemic lupus erythematosus multiorgan flare with quiescent serologic markers.

Systemic lupus erythematosus (SLE) can affect almost every organ with differing degrees of severity. Typically, SLE activity is associated with hypocomplimentaemia and elevated double-stranded DNA (dsDNA) levels. We describe a case of a severe multiorgan lupus flare including lupus cerebritis, autoimmune haemolytic anaemia, lupus nephritis and lupus myopericarditis with normal complement and dsDNA levels. This highlights the importance of understanding the heterogeneous nature of SLE flares.

Efficacy of Checkpoint Inhibitors in Neuroendocrine Neoplasms: Mayo Clinic Experience.

OBJECTIVES: Checkpoint inhibitors (CPIs) for low- and intermediate-grade neuroendocrine tumors (NETs) have been associated with limited efficacy; recent studies suggest CPIs may represent promising treatment for high-grade neuroendocrine neoplasms (NENs). METHODS: We examined 57 patients with NENs who were treated with CPIs to determine if NETs and neuroendocrine carcinomas (NECs) respond to immunotherapy. RESULTS: Patients with poorly differentiated NECs on CPI monotherapy had an objective response rate (ORR) of 0% and median progression-free survival (PFS) of 2.1 months (95% confidence interval [CI], 0.5-4.6). Patients with poorly differentiated NECs on dual CPI therapy had an ORR of 13% and PFS of 3.5 months (95% CI, 1.4-not reached [NR]). Patients with poorly differentiated NECs on CPI and cytotoxic therapy had an ORR of 36% with PFS of 4.2 months (95% CI, 1.6-NR). Well-differentiated grade 1 and 2 NETs on CPI monotherapy had an ORR of 25% with PFS NR. Well-differentiated grade 3 NETs had 0% ORR with a PFS of 2.9 months (95% CI, 1.4-4.2) on CPI monotherapy. CONCLUSIONS: Checkpoint inhibitor therapy shows limited activity in patients with NENs. Future studies should identify biomarkers that can help identify patients who are likely responders to immunotherapy.

Hypomagnesemia at the time of autologous stem cell transplantation for patients with diffuse large B-cell lymphoma is associated with an increased risk of failure.

Magnesium is an essential element that is involved in critical metabolic pathways. A diet deficient in magnesium is associated with an increased risk of developing cancer. Few studies have reported whether a serum magnesium level below the reference range (RR) is associated with prognosis in patients with diffuse large B cell lymphoma (DLBCL). Using a retrospective approach in DLBCL patients undergoing autologous stem cell transplant (AHSCT), we evaluated the association of hypomagnesemia with survival. Totally, 581 patients eligible for AHSCT with a serum magnesium level during the immediate pre-transplant period were identified and 14.1% (82/581) had hypomagnesemia. Hypomagnesemia was associated with an inferior event-free (EFS) and overall survival (OS) compared to patients with a serum magnesium level within RR; median EFS: 3.9 years (95% CI: 1.63-8.98 years) versus 6.29 years (95% CI: 4.73-8.95 years) with HR 1.63 (95% CI: 1.09-2.43, p = 0.017) for EFS, and median OS: 7.3 years (95% CI: 2.91-upper limit not estimable) versus 9.7 years (95% CI: 6.92-12.3 years) with HR 1.90 (95% CI: 1.22-2.96, p = 0.005) for OS months 0-12, respectively. These findings suggest a potentially actionable prognostic factor for patients with DLBCL undergoing AHSCT.

FGFR Inhibitor Toxicity and Efficacy in Cholangiocarcinoma: Multicenter Single-Institution Cohort Experience.

Cholangiocarcinomas (CCA) are a group of heterogeneous tumors arising from the biliary epithelia. Significant sequencing efforts have provided further insights into the molecular mechanisms of this disease including fibroblast growth factor receptor (FGFR) alterations, which occurs in approximately 15%-20% of intrahepatic CCAs. Herein, we describe the FGFR inhibitor (FGFRi)-associated treatment toxicity and cancer-specific outcomes from a multicenter single-institution cohort. METHODS: This is a retrospective study of patients with CCA and known FGFR alterations treated with FGFRi. We describe the toxicity and efficacy in patients treated at Mayo Clinic between January 2010 and December 2020. RESULTS: Our group identified 61 patients with advanced or metastatic CCA, 19 males (31%) and 42 females (69%), harboring FGFR alterations who received FGFRi. The most common grade 1 or higher adverse events for all patients included fatigue (92%), AST elevations (78%), anemia (80%), decreased platelet count (63%), and hyperphosphatemia (74%). Median progression-free survival on FGFRi was 5.8 months for all patients (95% CI, 4.9 to 9.0). Females had significantly longer progression-free survival at 6.9 months (95% CI, 5.2 to 11.8) on FGFRi compared with males at 4.9 months (95% CI, 2.8 to not estimable; P = .038). CONCLUSION: FGFRi are well tolerated with clinical efficacy. With the recent approval of FGFRi by the US Food and Drug Administration and ongoing clinical trials for new FGFRi, understanding outcomes and toxicity associated with these medications is important for precision oncology.

A Role for the Adenosine ADORA2B Receptor in Midazolam Induced Cognitive Dysfunction.

BACKGROUND: We recently reported a role for the circadian rhythm protein Period 2 (PER2) in midazolam induced cognitive dysfunction. Based on previous studies showing a critical role for the adenosine A2B receptor (ADORA2B) in PER2 regulation, we hypothesized that hippocampal ADORA2B is crucial for cognitive function. METHODS: Midazolam treated C57BL/6J mice were analyzed for Adora2b hippocampal mRNA expression levels, and spontaneous T-maze alternation was determined in Adora2b-/- mice. Using the specific ADORA2B agonist BAY-60-6583 in midazolam treated C57BL/6J mice, we analyzed hippocampal Per2 mRNA expression levels and spontaneous T-maze alternation. Finally, Adora2b-/- mice were assessed for mRNA expression of markers for inflammation or cognitive function in the hippocampus. RESULTS: Midazolam treatment significantly downregulated Adora2b or Per2 mRNA in the hippocampus of C57BL/6J mice, and hippocampal PER2 protein expression or T-maze alternation was significantly reduced in Adora2b-/- mice. ADORA2B agonist BAY-60-6583 restored midazolam mediated reduction in spontaneous alternation in C57BL/6J mice. Analysis of hippocampal Tnf-α or Il-6 mRNA levels in Adora2b-/- mice did not reveal an inflammatory phenotype. However, C-fos, a critical component of hippocampus-dependent learning and memory, was significantly downregulated in the hippocampus of Adora2b-/- mice. CONCLUSION: These results suggest a role of ADORA2B in midazolam induced cognitive dysfunction. Further, our data demonstrate that BAY-60-6583 treatment restores midazolam induced cognitive dysfunction, possibly via increases of Per2. Additional mechanistic studies hint towards C-FOS as another potential underlying mechanism of memory impairment in Adora2b-/- mice. These findings suggest the ADORA2B agonist as a potential therapy in patients with midazolam induced cognitive dysfunction.

Magnesium: The overlooked electrolyte in blood cancers?

Magnesium is an important element that has essential roles in the regulation of cell growth, division, and differentiation. Mounting evidence in the literature suggests an association between hypomagnesemia and all-cause mortality. In addition, epidemiologic studies have demonstrated that a diet poor in magnesium increases the risk of developing cancer, highlighting its importance in the field of hematology and oncology. In solid malignancies, hypomagnesemia at diagnosis portends a worse prognosis. However, little is known about prognosis in patients with hypomagnesemia and blood cancers in general; lymphoma more specifically. Hypomagnesemia has been associated with a higher viral load of the Epstein Barr virus, a virus associated with a multitude of hematologic malignancies. The role of magnesium in the immune system has been further elucidated in studies of patients with a rare primary immunodeficiency known as XMEN disease (X-linked immunodeficiency with Magnesium defect, Epstein-Barr virus (EBV) infection, and Neoplasia disease). These patients have a mutation in the MAGT1 gene, which codes for a magnesium transporter. The mutation leads to impaired T cell activation and an increased risk of developing hematologic malignancies. In this review we discuss the relevance of magnesium as an electrolyte, current measurement techniques, and the known data related to cause and prognosis of blood cancers. The goal is to use these data to stimulate additional high-quality and well powered studies to further investigate the role of magnesium in preventing cancer and improving outcomes of patients with malignancy and concomitant magnesium deficiency.

The Circadian PER2 Enhancer Nobiletin Reverses the Deleterious Effects of Midazolam in Myocardial Ischemia and Reperfusion Injury.

BACKGROUND: Recently, we identified the circadian rhythm protein Period 2 (PER2) in robust cardioprotection from myocardial ischemia (MI). Based on findings that perioperative MI is the most common major cardiovascular complication and that anesthetics can alter the expression of PER2, we hypothesized that an anesthesia mediated downregulation of PER2 could be detrimental if myocardial ischemia and reperfusion (IR) would occur. METHODS AND RESULTS: We exposed mice to pentobarbital, fentanyl, ketamine, propofol, midazolam or isoflurane and determined cardiac Per2 mRNA levels. Unexpectedly, only midazolam treatment resulted in an immediate and significant downregulation of Per2 transcript levels. Subsequent studies in mice pretreated with midazolam using an in-situ mouse model for myocardial (IR)-injury revealed a significant and dramatic increase in infarct sizes or Troponin-I serum levels in the midazolam treated group when compared to controls. Using the recently identified flavonoid, nobiletin, as a PER2 enhancer completely abolished the deleterious effects of midazolam during myocardial IR-injury. Moreover, nobiletin treatment alone significantly reduced infarct sizes or Troponin I levels in wildtype but not in Per2-/- mice. Pharmacological studies on nobiletin like flavonoids revealed that only nobiletin and tangeritin, both found to enhance PER2, were cardioprotective in our murine model for myocardial IR-injury. CONCLUSION: We identified midazolam mediated downregulation of cardiac PER2 as an underlying mechanism for a deleterious effect of midazolam pretreatment in myocardial IR-injury. These findings highlight PER2 as a cardioprotective mechanism and suggest the PER2 enhancers nobiletin or tangeritin as a preventative therapy for myocardial IR-injury in the perioperative setting where midazolam pretreatment occurs frequently.

Circadian MicroRNAs in Cardioprotection.

The most dramatic feature of life on Earth is our adaptation to the cycle of day and night. Throughout evolutionary time, almost all living organisms developed a molecular clock linked to the light-dark cycles of the sun. In present time, we know that this molecular clock is crucial to maintain metabolic and physiological homeostasis. Indeed, a dysregulated molecular clockwork is a major contributing factor to many metabolic diseases. In fact, the time of onset of acute myocardial infarction exhibits a circadian periodicity and recent studies have found that the light regulated circadian rhythm protein Period 2 (PER2) elicits endogenous cardioprotection from ischemia. Manipulating the molecular clockwork may prove beneficial during myocardial ischemia in humans. MicroRNAs are small non-coding RNA molecules capable of silencing messenger RNA (mRNA) targets. MicroRNA dysregulation has been linked to cancer development, cardiovascular and neurological diseases, lipid metabolism, and impaired immunity. Therefore, microRNAs are gaining interest as putative novel disease biomarkers and therapeutic targets. To identify circadian microRNA-based cardioprotective pathways, a recent study evaluated transcriptional changes of PER2 dependent microRNAs during myocardial ischemia. Out of 352 most abundantly expressed microRNAs, miR-21 was amongst the top PER2 dependent microRNAs and was shown to mediate PER2 elicited cardioprotection. Further analysis suggested circadian entrainment via intense light therapy to be a potential strategy to enhance miR-21 activity in humans. In this review, we will focus on circadian microRNAs in the context of cardioprotection and will highlight new discoveries, which could lead to novel therapeutic concepts to treat myocardial ischemia.