Does hydrocortisone improve treatment of septic shock?

UCSF-led international study suggests treatment combination which may increase chances of patient survival

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA SAN FRANCISCO MEDICAL CENTER

Sepsis is a global health priority affecting 55 million patients worldwide and causing 11 million deaths annually. Treatment for sepsis may include prompt recognition, source control, antibiotics, fluids, vasopressors, and adjunctive therapies. Corticosteroids have been evaluated as adjunctive therapy for septic shock for more than 50 years. Despite this substantive body of research, uncertainty persists about the effects of corticosteroids on mortality.

In a study publishing May 22, 2023 in the New England Journal of Medicine: Evidence, an international team of researchers from UC San Francisco, Raymond Poincaré AP-HP Hospital, Versailles SQY University, Paris-Saclay University and Inserm, and the George Institute for Global Health in Sydney, studied the role of hydrocortisone in the management of adult patients with septic shock. They found that while the effect of hydrocortisone was modest in terms of overall survival, it was associated with a decrease in the need for vasopressor drugs and improvement in survival when used in combination with other corticosteroids.

The study, coordinated by first authors Romain Pirracchio, MD, MPH, PhD, UCSF Professor of Anesthesia, Djillali Annane, MD, PhD, and senior author Anthony Delaney, MBBS, MSc, PhD, was designed to evaluate the role of corticosteroids in the management of patients with septic shock and the contradictory effects on mortality as recorded in past research and treatment.

The research team performed a meta-analysis of the effect of hydrocortisone on patients with septic shock by pooling individual data from studies conducted between 1998 and 2019 including adult patients with sepsis or septic shock who received intravenous hydrocortisone at a maximum daily dose of 400 mg for at least 72 hours, or a placebo. Individual patient data were available for 17 studies, and 7 of these provided 90-day mortality data. The primary endpoint was 90-day all-cause mortality.

Secondary outcomes included mortality in ICU and discharge from hospital, at 28 and 180 days, and number of days without the need for vasopressor drugs to maintain cardiovascular function, without a ventilator, and the number of days without vital organ failure.

The researchers found that hydrocortisone was not associated with a significant reduction in mortality for patients with septic shock compared to placebo. Hydrocortisone was, however, associated with a significant increase, on average of 1.24 days, in the number of days without the need for vasopressor drugs.

The study also suggests that the association of fludrocortisone, a corticosteroid with a strong action on the regulation of water and sodium, with hydrocortisone might reduce mortality. 

“For the first time, the effects of hydrocortisone for the treatment of patients with septic shock could be studied by analyzing individual data from the main randomized trials published to date,” said Pirracchio. “This study shows that if the effect of hydrocortisone on the mortality of septic shock is modest, this treatment makes it possible to spare the exposure of patients to vasopressor drugs and to prevent their complications. The combination of fludrocortisone with hydrocortisone seems to provide a greater benefit in terms of survival.”

About UCSF Health: UCSF Health is recognized worldwide for its innovative patient care, reflecting the latest medical knowledge, advanced technologies and pioneering research. It includes the flagship UCSF Medical Center, which is a top-ranked specialty hospital, as well as UCSF Benioff Children’s Hospitals, with campuses in San Francisco and Oakland, Langley Porter Psychiatric Hospital and Clinics, UCSF Benioff Children’s Physicians and the UCSF Faculty Practice. These hospitals serve as the academic medical center of the University of California, San Francisco, which is world-renowned for its graduate-level health sciences education and biomedical research. UCSF Health has affiliations with hospitals and health organizations throughout the Bay Area. Visit https://ucsfhealth.org. Follow UCSF Health on Facebook or on Twitter.

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JOURNAL

NEJM Evidence

DOI

10.1056/EVIDoa2300034 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Patient-Level Meta-Analysis of Low-Dose Hydrocortisone in Adults with Septic Shock

ARTICLE PUBLICATION DATE

22-May-2023

Study highlights long-term benefits of family-based care following institutional care

Peer-Reviewed Publication

AMERICAN PSYCHIATRIC ASSOCIATION

SAN FRANCISCO, May 22, 2023 – New research, published online today in the American Journal of Psychiatry, provides the most robust and comprehensive evidence to date that children exposed to early psychosocial deprivation benefit substantially from family-based care. Senior author Kathryn L. Humphreys, Ph.D., discussed this work today at a special briefing during the 2023 Annual Meeting of the American Psychiatric Association.

Results of research from the Bucharest Early Intervention Project, the first randomized controlled trial of foster care as an alternative to institutional (orphanage) care, found the positive effects of foster care persisted across nearly two decades of follow-up assessments. The researchers synthesized data from nearly 20 years of assessments to examine the impact on children’s development of high-quality family-based care following exposure to institutional care in early life.

The Bucharest Early Intervention Project is a collaboration between researchers at Tulane University, University of Maryland, Boston Children's Hospital, Harvard University, Bucharest University, Vanderbilt University, and UNC-Chapel Hill.  The study seeks to examine the impact of neglect and effective interventions, including high-quality foster care, that can have a positive impact on children’s long-term outcomes.

"Our study highlights the importance of investing in family-based interventions for children exposed to early institutional care. These interventions can have a profound and lasting impact, helping to improve children's cognitive, emotional, and social development," Humphreys said.

 

“This is a very important study as it provides critical findings that demonstrate the ability of family-based interventions, such as high-quality foster care, to mitigate the substantial effects of early life deprivation and neglect on brain development, cognitive function, and the risk to develop psychopathology,” said Ned H. Kalin, M.D., editor-in-chief of the American Journal of Psychiatry. 

Lead author Lucy S. King, Ph.D., with Tulane University School of Medicine (LA), and colleagues analyzed more than 7,000 observations from infancy through adolescence for 136 children residing in institutions in Bucharest, Romania. The children were aged 6-31 months when the study was initiated and were randomly assigned to either a newly created high-quality foster care intervention or care-as-usual (remaining in their institutional care placements). Because foster care was extremely limited when the study began, the researchers, in collaboration with Romanian officials, created a foster care network.

 

The children were assessed at ages 30, 42, and 54 months, and 8, 12, and 16-18 years. The study received ethics approval from the researchers’ institutional review boards and from the local child protection agency and the children’s legal guardians provided signed informed consent. 

The study found the foster care intervention had positive effects on IQ, physical growth, symptoms of disorders of social relatedness (reactive attachment disorder and disinhibited social engagement disorder), and internalizing symptoms. The impact of the intervention was apparent by age 30 months and sustained through late adolescence.

 

While the benefits of family-based care were consistent across development, outcomes differed based on developmental domain, how early in life children were placed in family-based care, and whether this care was stable across childhood and adolescence. Children who remained with their original foster families had better cognitive and physical outcomes and less severe mental health symptoms compared to children who experienced placement disruptions. The effect of having a stable family placement was largest in outcomes measured in adolescence.

 

The study provides “strong and conclusive causal evidence that children exposed to early deprivation benefit from high-quality family-based care, and, more broadly, that the nature of the early caregiving environment has an extensive and lasting impact on development,” the authors conclude. “Our findings indicate that providing high quality and stable family-based care, which includes biological, foster, or adoptive families, is critical for children’s wellbeing, and, in turn, the wellbeing of society.”

 

Humphreys notes, “The results of our research have significant policy implications for global efforts to address the public health crisis of abandoned and orphaned children. Family-based interventions ensure that these children receive the care and support they need to thrive."

 

In addition to King, the researchers included Katherine L. Guyon-Harris, Ph.D., Emilio A. Valadez, Ph.D., Anca Radulescu, Ph.D., Nathan A. Fox, Ph.D., Charles A. Nelson, Ph.D., Charles H. Zeanah, M.D., and Kathryn L. Humphreys, Ph.D.

American Psychiatric Association
The American Psychiatric Association, founded in 1844, is the oldest medical association in the country. The APA is also the largest psychiatric association in the world with more than 38,000 physician members specializing in the diagnosis, treatment, prevention and research of mental illnesses. APA’s vision is to ensure access to quality psychiatric diagnosis and treatment. For more information, please visit www.psychiatry.org.

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JOURNAL

American Journal of Psychiatry

DOI

10.1176/appi.ajp.20220672 

METHOD OF RESEARCH

Randomized controlled/clinical trial

SUBJECT OF RESEARCH

People

ARTICLE TITLE

A Comprehensive Multilevel Analysis of the Bucharest Early Intervention Project: Causal Effects on Recovery From Early Severe Deprivation

ARTICLE PUBLICATION DATE

22-May-2023

COI STATEMENT

Supported by NIH (grants F32HD105385 and R01MH091363), the John D. and Catherine T. MacArthur Foundation, the Palix Foundation, and the Jacobs Foundation (grant 2017-1261-05). Dr. Zeanah has received grants from the Irving Harris Foundation, the Lumos Foundation, the National Heart, Lung, and Blood Institute, NIMH, and the Substance Abuse and Mental Health Services Administration, and he has received royalties from Elsevier, Guilford Press, and Harvard University Press. Dr. Humphreys has received research funding from the Brain and Behavior Research Foundation, the Caplan Foundation, the Jacobs Foundation, the National Science Foundation, NIH, the Vanderbilt Institute for Clinical and Translational Research, the Vanderbilt Kennedy Center, and Vanderbilt University; she has received honoraria from the Journal of Clinical Child and Adolescent Psychology Future Directions Forum, Learning Grove, the University of Iowa, the University of Texas at Austin, and ZERO TO THREE. The other authors report no financial relationships with commercial interests

New method reveals bacterial reaction to antibiotics in five minutes

Peer-Reviewed Publication

KAROLINSKA INSTITUTET

“We are confident and hope that this can be one of many tools that doctors need to tackle antibiotic resistance, which is a serious and growing problem,” says principal investigator Vicent Pelechano, associate professor at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.

The method is called 5PSeq, is simple to use, and is based on sequencing the messenger RNA (mRNA) that the bacteria break down as they synthesise proteins. The measurements reveal how the bacteria are affected by different environmental factors, such as antibiotic treatments and other types of stress.

Rapid test for clinical use

The researchers tested the method on a total of 96 bacterial species from different phyla in complex clinical samples taken, for example, from faecal matter and the vagina, but also in compost samples. After only a matter of minutes, they were able to see whether or not the bacteria responded to antibiotic treatment; the effect was most salient after about half an hour.

3N Bio is a company that Dr Pelechano and some of his colleagues have started up in the KI Innovations incubator to develop the method and create a rapid molecular test for clinical use. They have now received financing from the Swedish Research Council to demonstrate proof of concept for such a test in collaboration with the Karolinska University Hospital.

“It’s crucial that doctors can quickly find the right antibiotics for seriously ill patients with bacterial infections to reduce the unnecessary use of antibiotics,” says Dr Pelechano. “Current methods of testing antibiotic resistance can take hours or even days, but often treatment needs to be given more promptly than that to avoid serious consequences for the patient. Because of this, a broad-spectrum antibiotic is often prescribed, which increases the risk of resistance.”

Examine how bacteria interact

Apart from measuring antibiotic resistance, the method can be used to help researchers understand how bacteria handle stress and interact with each other and with their hosts. The researchers will continue to study complex gut samples to examine how the bacterial communities interact in our gut and contribute to health and disease.

The research was financed by the Ragnar Söderbergs foundation (Swedish Foundations’ Starting Grant), the Swedish Research Council, the Knut and Alice Wallenberg Foundation (a Wallenberg Academy Fellowship), EU’s Horizon 2020, among others. See the scientific article for a complete list. 3N Bio was co-founded by Vicent Pelechano and the two first authors of the paper, Susanne Huch and Lilit Nersisyan.

Publication: “Atlas of mRNA translation and decay for bacteria”, Susanne Huch, Lilit Nersisyan, Maria Ropat, Donal Barrett, Mengjun Wu, Jing Wang, Valerie D Valeriano, Nelli Vardazaryan, Jaime Huerta-Cepas, Wu Wei, Juan Du, Lars M Steinmetz, Lars Engstrand, Vicent Pelechano. Nature Microbiology, online 22 May 2023, doi: 10.1038/s41564-023-01393-z.

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JOURNAL

Nature Microbiology

DOI

10.1038/s41564-023-01393-z 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

Atlas of mRNA translation and decay for bacteria

ARTICLE PUBLICATION DATE

22-May-2023

Public aware of and accept use of bacteria-killing viruses as alternative to antibiotics, study shows

Peer-Reviewed Publication

UNIVERSITY OF EXETER

The public are in favour of the development of bacteria-killing viruses as an alternative to antibiotics – and more efforts to educate will make them significantly more likely to use the treatment, a new study shows.

The antimicrobial resistance (AMR) crisis means previously treatable infections can kill. This has revitalised the development of antibiotic alternatives, such as phage therapy, which was first explored over a century ago but abandoned in many countries in favour of antibiotics.

The study shows public acceptance of phage therapy is already moderately high, and priming people to think about novel medicines and antibiotic resistance significantly increases their likelihood of using it.

There is a higher acceptance of phage therapy when described without using perceived harsh words, such as “kill” and “virus” but instead “natural bacterial predator”.

Those who took part in the survey had a high awareness of antibiotic resistance – 92 per cent had heard of antibiotic resistance, but only 13 per cent reported that they had heard about phage therapy prior to the survey.

Success and side effect rate, treatment duration, and where the medicine has been approved for use, influenced their treatment preferences.

The study was conducted by Sophie McCammon, Kirils Makarovs, Susan Banducci and Vicki Gold from the University of Exeter.

Dr Banducci said: “While phage therapy remains poorly understood by the UK public our research suggests there is extensive acceptance and support for its development. Exposure to only very limited information about antibiotic resistance and alternative treatments to antibiotics greatly increases the public acceptance of phage therapy.”

Dr Gold said: “Those involved in the research wanted to know more about phage therapy and were inspired to research this topic after completing our survey. Exposure to only a very limited amount of information about phage therapy significantly increases acceptance.”

Researchers held a workshop with experts and a review of phage research. They also fielded a survey assessing the UK public’s acceptance, opinions and preferences regarding phage therapy. A total of 787 people completed the survey, distributed in December 2021.

One group was given two scenarios; in the first they presented with a minor infection, and in the second they presented with an infection that did not respond well to antibiotics for three months. In each scenario, the group ranked the selected attributes based on their importance in deciding whether to accept a treatment or not.

Participants were randomly assigned one of four descriptions of phage therapy and then surveyed to assess their acceptance of the treatment. The acceptance of phage therapy was high across the board. However, describing phage therapy using perceived harsh words, such as “kill and “virus”, resulted in lower acceptance rates than alternative descriptions. Additionally, participants who had recent exposure to information about antibiotic resistance and alternative treatments were more accepting of phage therapy.

From the 787 participants who completed the survey, 213 left written responses expressing their opinions on the potential of phage therapy. Of this group, 38 per cent showed a specific interest in phage therapy development, while a further 17 per cent supported the development of antibiotic alternatives generally.

Sophie McCammon said: “An advantage of phage therapy is often the minimal side effects. Emphasising this through education and marketing may increase public acceptance of phage therapy.

“Even though phage therapy may be some years away from routine clinical use in the UK, increasing pressures from the AMR crisis require evaluation of the UK public’s acceptance of alternative treatments.

“The public desire for increased education is apparent. Expanding schemes which are interactively involving children in phage research not only generates excitement for the therapy now, but also promotes awareness in the generation likely to be treated with antibiotic alternatives.”

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JOURNAL

PLoS ONE

DOI

10.1371/journal.pone.0285824 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Phage therapy and the public: Increasing awareness essential to widespread use

ARTICLE PUBLICATION DATE

18-May-2023

TARGETING PHAGE THERAPY WORLD

 CONGRESS WILL BRING PHAGE

THERAPY UP TO ANOTHER LEVEL

 WITH MORE THAN 70

 COMMUNICATIONS

Meeting Announcement

MITOCHONDRIA-MICROBIOTA TASK FORCE

NEWS RELEASE 22-MAY-2023

 

IMAGE: 25+ MAJOR SPEAKERS WILL PRESENT OUTSTANDING COMMUNICATIONS DURING TARGETING PHAGE THERAPY 2023 view more 

CREDIT: TARGETING PHAGE THERAPY

The 6th World Congress on Targeting Phage Therapy 2023, being held on June 1-2 in Paris, will include more than 70 communications highlighting the most recent advances in phage and phage therapy. 

150+ attendees will gather to discuss the future potential of phage therapy. The most strategic question to discuss is: “how to bring phage therapy up to a new level?”.

Targeting Phages 2023 will address how phages play a strategic role to combat infection and antibiotic resistance. A special session will also be dedicated to how phages and phage therapy can modulate gut microbiota.

Get access to the final agenda and speakers.

 

Supporters

Armata Pharmaceuticals and BiomX will share the results of their latest clinical trials

Mina Pastagia, Armata Pharmaceuticals, USA

Safety, Pharmacokinetics, and Antibacterial Activity of AP-PA02 Multi-phage Cocktail in Patients with Cystic Fibrosis and Chronic Pulmonary Pseudomonas aeruginosa Infection (SWARM-P.a. Clinical Trial)

Iddo Nadav Weiner, VP of Research at BiomX, Israel

A Phase 1b/2a Randomized, Double-blind, Placebo-controlled Study Evaluating Nebulized Phage Therapy in Cystic Fibrosis Subjects with Chronic Pseudomonas Aeruginosa Pulmonary Infection

 

Cellexus will present the use of their CellMaker system in GMP production

Adam Ostrowski, Cellexus, United Kingdom

Implementating GMP Manufacturing for Phage Therapy

 

More than 25 posters will be presented by academics and industrials

Efficiency of innovative bacteriophage products: Bafacol®, Bafasal® and Bafador® in improving animals health in poultry farming and aquaculture

Proteon Pharmaceuticals (Poland)

Hierarchical classifier of 171 bacteriophage genera with related families and orders

Proteon Pharmaceuticals (Poland)

Selection of bacteriophages with therapeutic potential based on complete genome sequence analysis

JSC Biochimpharm (Georgia)

Propagation and purification of S. epidermidis-specific phage COP-80B for preclinical mouse model study

COBIK (Slovenia)

Check the list of posters of Phage Therapy 2023.

 

Come and Network with 150+ Attendees

Industrial participants: Phiogen (USA), Armata Pharmaceuticals (USA), BiomX (Israel), Cellexus (UK), , Aparon (UK), AusHealth (Australia), Biochimpharm JSC (Georgia), BIOCODEX (Paris), BIOMERIEUX SA (France), COBIK (Slovenia), ERYTECH Pharma (France), H Venture Partners (USA), Intralytix, Inc. (USA), MB Pharma s.r.o. (Czech Republic), Microbiotix Inc. (USA), Optipharm Inc. (Republic of Korea), Phage Consulting, Phagos (France), Pherecydes Pharma (France), Proteon Pharmaceuticals S.A. (Poland), R.E.D. Laboratories (Belgium), Resistell (Switzerland), Rime Bioinformatics (France), SET Medikal (Turkey), Vésale Bioscience (Belgium), Vitalis Phage Therapy (India), and others.

Academic participants: Adam Mickiewicz University, Agricultural University of Athens, Amrita University, Azabu University, Bacteriophage.news, Baylor College of Medicine, Bhabha Atomic Research Centre, Biological Research Centre, Szeged,Campus Universitaire de Maubeuge, Centre International de Recherche en Infectiologie, Chungnam Natl. Univ., Comenius University, Food and Drug Administration (FDA), Fundação Universidade Aberta Da Terceira,Fundación AZTI, G. Eliava Institute of Bacteriophages, microbiology and virology, Geneva University Hospitals, German Center for Infection Research (DZIF), German Federal Institute for Risk Assessment, Helmholtz Center Munich, Hirszfeld Institute of Immunology and Experimental Therapy, Hôpitaux Unversitaires de Genève, Hospices Civils de Lyon, IDADE, IIBR ,Ilia state university, INSERM, Institut Pasteur, Instituto de Biología Integrativa de Sistemas (I2SysBio) Universitat de València-CSIC, Kyorin University, Laboratoire ERRMECe, Laboratoire M2iSH, Lesaffre International,Louvain University, Masaryk University, Max Planck Institute for Medical Research, Medical center Francesc Macia, MPI, National Taiwan University, North-West Unversity, Pediatric Infectious Diseases Research Center, Phage Consulting,Phage Directory, Pharmabiotic Research Institute (PRI),Polish Academy of Sciences, Prof. Waclaw Dabrowski Institute of Agricultural and Food Biotechnology – State Research Institute, Queen Astrid Military Hospital, Queen Astrid Military Hospital, Burn Wound Centre, LabMCT, Brussels, Belgium, Sofia University, Stockholm University, TailΦr Labs, Baylor College of Medicine, and others.

 

Industrial Participation

25+ Industries will be present at Targeting Phage Therapy 2023 this June in Paris

CREDIT

Targeting Phage Therapy

Contributing partner

PHAGE Therapy, Applications, and Research Journal is the Official Partner of Targeting Phage Therapy 2023.

Attendees will have the chance to network with the Editor in Chief, Martha Clokie, during Targeting Phage Therapy 2023 and discuss about future collaboration.

 

For more information about the conference program, speakers, venue and more: www.phagetherapy-site.com

 

More about PHAGE: Therapy, Applications, and Research

PHAGE: Therapy, Applications, and Research is the only peer-reviewed journal dedicated to fundamental bacteriophage research and its applications in medicine, agriculture, aquaculture, veterinary applications, animal production, food safety, and food production. Under the distinct leadership of Editor-in-Chief Martha Clokie, PhD, University of Leicester, United Kingdom, the Journal showcases groundbreaking research, reviews, commentaries, opinion pieces, profiles, and perspectives dedicated to defining the roles of phages in all facets of microbiology and microbial ecology and exploring their potential to manipulate bacterial communities and treat infection.

PHAGE is the critical resource for molecular biologists, microbiologists, bacteriologists, bioengineers, immunologists, clinicians, and translational biologists, and aims to unify this evolving cluster of innovative researchers, industry leaders, clinicians, and policy makers. The Journal also advances knowledge and development in this re-emerging area of research and opens doors for new ideas and funding opportunities for researchers and clinicians in the field.

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LA REVUE GAUCHE - Left Comment: Search results for BACTERIOPHAGE 

LA REVUE GAUCHE - Left Comment: Search results for PHAGE 

How a drought affects trees depends on what’s been holding them back

In cold, harsh environments, drought can actually benefit the trees by extending the growing season

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SANTA BARBARA

 

IMAGE: WHITEBARK PINES GROWING IN COLD, HIGH ELEVATION REGIONS GREW MORE DURING DROUGHTS, WHICH LENGTHENED THEIR GROWING SEASON. view more 

CREDIT: JOAN DUDNEY

(Santa Barbara, Calif.) — Droughts can be good for trees. Certain trees, that is.

Contrary to expectation, sometimes a record-breaking drought can increase tree growth. Why and where this happens is the subject of a new paper in Global Change Biology.

A team of scientists led by Joan Dudney at UC Santa Barbara examined the drought response of endangered whitebark pine over the past century. They found that in cold, harsh environments — often at high altitudes and latitudes — drought can actually benefit the trees by extending the growing season. This research provides insights into where the threats from extreme drought will be greatest, and how different species and ecosystems will respond to climate change.

Many factors can constrain tree growth, including temperature, sunlight and the availability of water and nutrients. The threshold between energy-limited and water-limited systems turns out to be particularly significant. Trees that try to grow in excessively cold temperatures — often energy-limited systems — can freeze to death. On the other hand, too little water can also kill a tree, particularly in water-limited systems. Over time, many tree species have adapted to these extreme conditions, and their responses are broadly similar. They often reduce growth-related activities, including photosynthesis and nutrient uptake, to protect themselves until the weather improves.

“Interestingly, the transition from energy- to water-limited growth can produce highly unexpected responses,” explained Dudney, an assistant professor in the Bren School of Environmental Science & Management and the Environmental Studies Program. “In cold, energy-limited environments, extreme drought can actually increase growth and productivity, even in California.”

Dudney and her colleagues extracted 800 tree cores from whitebark pine across the Sierra Nevada, comparing the tree rings to historical records of climate conditions. This climate data spanned 1900 to 2018, and included three extreme droughts: 1959–61, 1976–77, and 2012–15. They recorded where tree growth and temperature showed a positive relationship, and where the relationship was negative.

The authors found a pronounced shift in growth during times of drought when the average maximum temperature was roughly 8.4° Celsius (47.1° Fahrenheit) between October and May. Above this threshold, extreme drought reduced growth and photosynthesis. Below this temperature, trees grew more in response to drought.

“It’s basically, ‘how long is the growing season?’” Dudney said. Colder winters and higher snowpack often lead to shorter growing seasons that constrain tree growth. Even during an extreme drought, many of the trees growing in these extreme environments did not experience high water stress. This surprised the team of scientists, many of whom had observed and measured the unprecedented tree mortality that occurred at slightly lower elevations in the Sierra Nevada.

Dudney was curious whether drought impacts growth in just the main trunk, or the whole tree. Without more data, the trends they saw could be a result of disparate processes all responding to the drought differently, she explained. Fortunately, whitebark pine retains its needles for roughly eight years. This provided additional data that could address this question.

The researchers shifted their attention from dendrology to chemistry. Atoms of the same element can have different weights, or isotopes, thanks to the number of neutrons they contain. Several aspects of a plant’s metabolism can influence the relative abundance of heavy, carbon-13 and light, carbon-12 in tissues such as their leaves and needles. These changes provide a rough guide to the amount of water stress a tree experienced during drought. This was a boon for the researchers, because isotopic data from the pine needles spanned drought and non-drought years.

Analyzing needle growth, carbon and nitrogen isotopes revealed that the whole tree was affected by the threshold between water-limited and energy-limited systems. Trunk growth, needle growth, photosynthesis and nutrient cycling responded in opposite directions to drought above and below the threshold between energy- and water-limited systems.

The future of whitebark pine is highly uncertain. The species — recently listed as threatened under the Endangered Species Act — faces many threats, including disease, pine beetle infestation and impacts from altered fire regimes. It’s clear from this research that drought and warming will likely exacerbate these threats in water-limited regions, but warming may be beneficial for growth in energy-limited environments. “This research can help develop more targeted conservation strategies,” said Dudney, “to help restore this historically widespread tree species.” Indeed, the pine’s range encompasses a diverse region, stretching from California to British Columbia, and east to Wyoming.

The findings also have implications more broadly. Approximately 21% of forests are considered energy limited, and an even higher percentage can be classified as water limited. So transitions between these two climatic regimes likely occur around the globe. What’s more, the transition seems to have an effect on nitrogen cycling. Trees in water-limited environments appeared to rely less on symbiotic fungi for nitrogen, which is critical for tree growth in harsh, energy-limited environments.

“Droughts are leading to widespread tree mortality across the globe,” Dudney said, “which can accelerate global warming.” 

Deciphering the many ways trees respond to drought will help us better predict where ecosystems are vulnerable to climate change and how to develop more targeted strategies to protect our forests.

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JOURNAL

Global Change Biology

Allowing financial trading in California’s wholesale electricity market significantly reduced volatility of prices, electricity production costs, carbon emissions

Peer-Reviewed Publication

CARNEGIE MELLON UNIVERSITY

Forward markets—over-the-counter marketplaces that set the price of a financial instrument or asset—are used to trade a variety of instruments, including securities and commodities. In a new study, researchers measured the extent to which forward prices and spot prices (the current market price at which a given asset can be bought or sold for immediate delivery) agreed in markets with transaction costs in California, studying time periods before and after the state introduced financial trading to its wholesale electricity market in 2011.

The study found that allowing trading in this market led to a reduction in the implicit cost of trading day-ahead/real-time price differences, the volatility of these price differences, and the volatility of real-time prices. In addition, operating costs and fuel use fell on days after the introduction of purely financial participation.

The study, by researchers at Carnegie Mellon University (CMU) and Stanford University, is published in American Economic Journal: Economic Policy.

“Our results have important implications for the design of wholesale electricity markets with large shares of intermittent renewable resources,” says Akshaya Jha, assistant professor of economics and public policy at CMU’s Heinz College, who led the study.

Forward markets are believed to aggregate information about future spot prices and reduce the cost of producing the commodity. But it has been difficult to link increases in forward market liquidity to reductions in production costs due to the long time period over which most commodities are produced and traded. To examine changes in forward-spot price convergence after the implementation of financial trading, researchers measured the 24-dimensional vector of hourly average day-ahead prices at a location in the transmission network versus the 24-dimensional vector of hourly average real-time prices at the same location.

Using this model, they computed two measures of implied transaction costs using hourly, location-specific data on day-ahead and real-time prices from April 1, 2009, to November 30, 2012, before and after financial trading began at most pricing locations in California. The California Independent System Operator introduced financial participation on February 1, 2011, to reduce differences between day-ahead and real-time prices at more than 4,000 locations in the state’s transmission network.

The study found that both measures fell substantially after California introduced purely financial participation. In addition, both measures fell more at locations where trading was restricted prior to the introduction of financial trading. This suggests that allowing financial trading resulted in day-ahead prices that better reflect real-time conditions.

The study’s findings also suggest that physical market outcomes improved as a consequence of the better information encapsulated in day-ahead prices after financial trading. Namely, they show that residualized fuel cost per megawatt hour (MWh) of gas-fired output and input fuel use per MWh of gas-fired output fell after financial trading was introduced on days when the complexity of the real-time market-clearing problem was high but not on days when complexity was low–again, indicative of the importance of improved day-ahead information. The results remained similar regardless of whether complexity was measured using daily total demand, the daily standard deviation across locations and hours in real-time prices, or the total number of daily starts. The study’s authors estimated that fuel costs per MWh fell 2% after the introduction of financial trading on high-demand days relative to low-demand days. This would result in an average $16.6 million reduction in annual total fuel costs.

As the share of electricity demand in a region grows, system operators are often required to impose more operating constraints on day-ahead and real-time markets to maintain the balance between supply and demand throughout the day. Controllable generation resources with positive startup costs are also likely to fluctuate more frequently because intermittent renewables can start and stop producing with very little notice. Rising transmission network constraints are also likely to bind as the percentage of electricity production from wind and solar resources distributed across the grid increases.

“The location-specific bids and offers submitted by purely financial participants can reduce day-ahead/real-time price differences caused by uncertainty in intermittent renewable output,” explains Frank Wolak, professor of economics at Stanford University, who coauthored the study. “These financial bids and offers can also ensure that the least-cost combination of controllable resources is available to compensate for fluctuations in real-time output from intermittent renewables on high-complexity days.”

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JOURNAL

American Economic Journal Economic Policy

DOI

10.1257/pol.20200234 

ARTICLE TITLE

Can Forward Commodity Markets Improve Spot Market Performance? Evidence from Wholesale Electricity