Future directions for the discovery of natural product-derived immunomodulating drugs: an IUPHAR positional review.

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology Sections, with contributions from a number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.

Chronic Lead Intoxication From Eating Wild-Harvested Game.

BACKGROUND: The purpose of this article is to determine if conversion from eating wild game harvested with lead-based ammunition to nonlead-based ammunition results in lower blood lead levels. Supersonic injection of toxin-leeching frangible projectiles into food is intuitively bad. As much as 95% of the ~13.7 million hunters in the United States choose shrapnel-inducing lead bullets to kill game; in addition, not harvesting meat is an incarcerable crime. A lead ammunition ban on certain federal lands was recently rescinded and the National Rifle Association refutes any risk from eating lead bullet-harvested game. METHODS: A patient subsisting solely on lead-shot meat was converted to non-lead ammunition and his blood lead level tracked. Concomitant with his conversion to nonlead ammunition, a controlled experiment was performed using the patient's bullets to determine his daily lead intake from lead-shot meat. RESULTS: While eating lead-shot meat, the patient was consuming 259.3 ± 235.6 µg of lead daily and his blood lead level was 74.7 µg/dL. Conversion to nonlead ammunition was associated with a reduced blood lead level. CONCLUSIONS: Unsafe blood lead levels can occur from eating game harvested with lead ammunition. Physicians should warn hunting patients of this potential risk and counsel them about the availability of nonlead ammunition alternatives.

The Ethnopharmacologic Contribution to Bioprospecting Natural Products.

Descriptions of the use of natural products in traditional medicine have served as starting points for new therapeutics. The details of the traditional use of these organisms can provide important information for future drug discovery and development efforts. Recent technologic advances provide the framework to leverage ethnopharmacologic data in the drug discovery process. Information on the traditional harvest, preparation, storage, and administration of the organisms, and the natural products they contain, provides valuable details regarding characteristics of the active compounds. Importantly, researchers can now rapidly analyze and identify the multiple, and often synergistic, compounds contained in these natural products. Although we are entering the acme of ethnopharmacology, where information regarding the traditional use of organisms can provide valuable natural product leads and accelerate the identification of new therapeutics, this ethnopharmacologic resource is threatened by the loss of traditional medicine knowledge and extinction of organisms.

Potential role of high-stress employment in hypertension.

We report a patient with a reduction in blood pressure through cessation of high-stress employment.

A prospective observational study assessing the feasibility of measuring blood lead levels in New Zealand hunters eating meat harvested with lead projectiles.

There is no safe level of lead exposure. Correlations suggest that hunters harvesting wild game with lead bullets may be at risk of lead exposure through eating minute lead particles from shrapnel in their wild game. This feasibility study will determine if it is possible to conduct an interventional controlled, blinded study to evaluate if there is a causal relationship between meat harvested with lead bullets and elevated blood lead levels in those who consume the meat. This is an observational case crossover study and the primary outcome is blood lead levels. Individuals will have blood lead levels measured 2-4 days after eating one serving of meat harvested with lead bullets. At three potential washout periods these same individuals will have a subsequent blood lead level analysis. This observational study will provide the data necessary to determine the washout period and sample size for a prospective interventional study to evaluate if meat harvested with lead bullets raises blood-lead levels in those who consume the meat. This study has been approved by the Health and Disabilities Ethics Committees of New Zealand. TRIAL REGISTRATION: NCT02775890.

Little risk of severe complications associated with Zika infection in New Zealand.

Zika virus infection has raised considerable concern in New Zealand, but the risks faced by most New Zealanders, while real, are quite small as New Zealand does not harbor the primary mosquito vector. Furthermore, in individuals with a competent immune system, the acute illness caused by Zika virus infection is generally mild. Serious complication associated with Zika virus infections include microcephaly and Guillain-Barré Syndrome. Pacific Island countries have reported cases of Zika virus infection and these climates support the mosquito vector. Thus, travelers to these areas are at risk of infection. New Zealand travelers returning from endemic areas have developed the illness associated with the virus, but the probability of autochthonous transmission in New Zealand is very small.

Neuroprotection mediated by inhibition of calpain during acute viral encephalitis.

Neurologic complications associated with viral encephalitis, including seizures and cognitive impairment, are a global health issue, especially in children. We previously showed that hippocampal injury during acute picornavirus infection in mice is associated with calpain activation and is the result of neuronal death triggered by brain-infiltrating inflammatory monocytes. We therefore hypothesized that treatment with a calpain inhibitor would protect neurons from immune-mediated bystander injury. C57BL/6J mice infected with the Daniel's strain of Theiler's murine encephalomyelitis virus were treated with the FDA-approved drug ritonavir using a dosing regimen that resulted in plasma concentrations within the therapeutic range for calpain inhibition. Ritonavir treatment significantly reduced calpain activity in the hippocampus, protected hippocampal neurons from death, preserved cognitive performance, and suppressed seizure escalation, even when therapy was initiated 36 hours after disease onset. Calpain inhibition by ritonavir may be a powerful tool for preserving neurons and cognitive function and preventing neural circuit dysregulation in humans with neuroinflammatory disorders.

Hippocampal protection in mice with an attenuated inflammatory monocyte response to acute CNS picornavirus infection.

Neuronal injury during acute viral infection of the brain is associated with the development of persistent cognitive deficits and seizures in humans. In C57BL/6 mice acutely infected with the Theiler's murine encephalomyelitis virus, hippocampal CA1 neurons are injured by a rapid innate immune response, resulting in profound memory deficits. In contrast, infected SJL and B6xSJL F1 hybrid mice exhibit essentially complete hippocampal and memory preservation. Analysis of brain-infiltrating leukocytes revealed that SJL mice mount a sharply attenuated inflammatory monocyte response as compared to B6 mice. Bone marrow transplantation experiments isolated the attenuation to the SJL immune system. Adoptive transfer of B6 inflammatory monocytes into acutely infected B6xSJL hosts converted these mice to a hippocampal damage phenotype and induced a cognitive deficit marked by failure to recognize a novel object. These findings show that inflammatory monocytes are the critical cellular mediator of hippocampal injury during acute picornavirus infection of the brain.

Apoptosis of hippocampal pyramidal neurons is virus independent in a mouse model of acute neurovirulent picornavirus infection.

Many viruses, including picornaviruses, have the potential to infect the central nervous system (CNS) and stimulate a neuroinflammatory immune response, especially in infants and young children. Cognitive deficits associated with CNS picornavirus infection result from injury and death of neurons that may occur due to direct viral infection or during the immune responses to virus in the brain. Previous studies have concluded that apoptosis of hippocampal neurons during picornavirus infection is a cell-autonomous event triggered by direct neuronal infection. However, these studies assessed neuron death at time points late in infection and during infections that lead to either death of the host or persistent viral infection. In contrast, many neurovirulent picornavirus infections are acute and transient, with rapid clearance of virus from the host. We provide evidence of hippocampal pathology in mice acutely infected with the Theiler's murine encephalomyelitis picornavirus. We found that CA1 pyramidal neurons exhibited several hallmarks of apoptotic death, including caspase-3 activation, DNA fragmentation, and chromatin condensation within 72 hours of infection. Critically, we also found that many of the CA1 pyramidal neurons undergoing apoptosis were not infected with virus, indicating that neuronal cell death during acute picornavirus infection of the CNS occurs in a non-cell-autonomous manner. These observations suggest that therapeutic strategies other than antiviral interventions may be useful for neuroprotection during acute CNS picornavirus infection.

Aloin induces apoptosis in Jurkat cells.

Aloe is widely used as a dietary supplement. However, there are continuing concerns over the toxicity and the purity of aloe-based products. The primary class of compounds responsible for aloe-induced toxicity are anthraquinones. One of these, aloe-emodin, has been extensively investigated for apoptosis inducing effects. Conversely, the precursor to aloe-emodin, aloin, has been subjected to only minimal investigation of any cytotoxic effects. Jurkat T cells, an established model for the study of compound toxicity, were used to evaluate the effect of aloin on cell viability. Cells were analyzed using flow cytometry and microscopy for cell size and granularity, cell membrane integrity, mitochondrial membrane potential, and cell cycle profile. Treatment with aloin resulted in a reduction in cell size, compromised membrane integrity, and loss of mitochondrial membrane potential in a dose-dependent manner. Additionally, treatment with aloin resulted in alteration of the cell cycle, specifically a block at G2/M phase. Importantly, the loss of cell membrane integrity was preceded by a loss of mitochondrial membrane potential, suggesting a mitochondrial-dependent pathway for aloin-induced apoptosis. These observations provide insight into the potential mechanisms of aloin-induced toxicity and thus, perhaps, aloe preparation-induced toxicity. Furthermore, because of the concern over the safety of aloe-based supplements, this work suggests that aloe supplements not containing aloin may be safer than aloe supplements containing aloin, and that aloin should be considered in addition to concentrations of aloe-emodin.