Diego Hidalgo

Elicitation, an Effective Strategy for the Biotechnological Production of Bioactive High-Added Value Compounds in Plant Cell Factories

Plant in vitro cultures represent an attractive and cost-effective alternative to classical approaches to plant secondary metabolite (PSM) production (the “Plant Cell Factory” concept). Among other advantages, they constitute the only sustainable and eco-friendly system to obtain complex chemical structures biosynthesized by rare or endangered plant species that resist domestication. For successful results, the biotechnological production of PSM requires an optimized system, for which elicitation has proved one of the most effective strategies. In plant cell cultures, an elicitor can be defined as a compound introduced in small concentrations to a living system to promote the biosynthesis of the target metabolite. Traditionally, elicitors have been classified in two types, abiotic or biotic, according to their chemical nature and exogenous or endogenous origin, and notably include yeast extract, methyl jasmonate, salicylic acid, vanadyl sulphate and chitosan. In this review, we summarize the enhancing effects of elicitors on the production of high-added value plant compounds such as taxanes, ginsenosides, aryltetralin lignans and other types of polyphenols, focusing particularly on the use of a new generation of elicitors such as coronatine and cyclodextrins.

New trends in biotechnological production of rosmarinic acid

Rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydroxyphenyl lactic acid, is widely distributed in the plant kingdom. Interest in it is growing due to its promising biological activities, including cognitive-enhancing effects and slowing the development of Alzheimer’s disease, cancer chemoprotection or anti-inflammatory activity, among others. In order to meet the increasing demand for this compound, several biotechnological approaches to its production based on plant cell and hairy root cultures have been developed. Empirical strategies are currently being combined with metabolic engineering tools to increase RA production in plant cell platforms in a more rational way. Discussed here are the latest advances in the field, together with recent trends in plant biotechnology, such as the application of single use technology and the use of biosensors in downstream processes.

Bipolar disorder in the elderly: a cohort study comparing older and younger patients.

The purpose of this study was to analyze differences in clinical and socio‐demographic characteristics between older and younger bipolar outpatients paying special attention to depressive symptoms in a large, naturalistic cohort.

Management of Adverse Effects of Mood Stabilizers

Mood stabilizers such as lithium and anticonvulsants are still standard-of-care for the acute and long-term treatment of bipolar disorder (BD). This systematic review aimed to assess the prevalence of their adverse effects (AEs) and to provide recommendations on their clinical management. We performed a systematic research for studies reporting the prevalence of AEs with lithium, valproate, lamotrigine, and carbamazepine/oxcarbazepine. Management recommendations were then developed. Mood stabilizers have different tolerability profiles and are eventually associated to cognitive, dermatological, endocrine, gastrointestinal, immunological, metabolic, nephrogenic, neurologic, sexual, and teratogenic AEs. Most of those can be transient or dose-related and can be managed by optimizing drug doses to the lowest effective dose. Some rare AEs can be serious and potentially lethal, and require abrupt discontinuation of medication. Integrated medical attention is warranted for complex somatic AEs. Functional remediation and psychoeducation may help to promote awareness on BD and better medication management.

Biotechnological production of centellosides in cell cultures of Centella asiatica (L) Urban

Centella asiatica (L.) Urban plants have been used since ancient times for their medicinal properties, and their extracts have proven antioxidant, wound healing, sedative, and neuroprotective activities, among others. The natural compounds responsible for C. asiatica bioactivity are triterpene saponins formed from the dammarene branch of the triterpene biosynthetic pathway, collectively known as centellosides, with madecassoside and asiaticoside and their aglycones, madecassic acid and asiatic acid being the most important. Several biotechnological approaches have been developed for the bioproduction of centellosides, based on cell, hairy root, and in vitro plant cultures. This review summarizes the main therapeutic properties of these compounds, as well as their biosynthetic pathways, referring to genetic studies that have identified genes involved in their formation. The biotechnological production of centellosides from a small scale to bioreactor level is also covered. Finally, we summarize the most effective strategies for increasing centelloside yield, including recent transcriptomic, proteomic, and metabolomic studies that have gained new insights into the centelloside biosynthetic pathway and its control.

Effectiveness of long-acting injectable risperidone versus oral antipsychotics in the treatment of recent-onset schizophrenia: a case-control study.

Long-acting injectable antipsychotics may offer a relevant improvement in treatment adherence in recent-onset psychosis, leading to a decreased rate of hospital readmission, a better rate of clinical remission and improved psychosocial adjustment. The aim of the study was to compare the clinical remission rates, number of hospital readmissions and personal and social functioning after 2 years between patients with recent-onset schizophrenia (<2 years) in treatment with risperidone long-acting injectable (RLAI) and patients with recent-onset schizophrenia receiving oral antipsychotics. This is a case–control study comparing patients with recent-onset schizophrenia who initiated RLAI treatment between 2004 and 2008 (n=26) with a control group matched for age and sex, diagnosed with recent-onset schizophrenia and treated with oral antipsychotics (n=26). Study assessments included sociodemographic variables, the Positive and Negative Syndrome Scale, the Personal and Social Functioning Scale, the number of hospital readmissions and the Andreasen remission criteria. To assess the effect of treatment on each dependent variable, separate generalized estimating equations models were constructed. After 2 years of treatment, and adjusting for educational level, the RLAI group showed a greater reduction in the Positive and Negative Syndrome Scale total scale [mean (SD)=47.7 (12.0) vs. 66.2 (18.5); mean difference =−17.56; 95% confidence interval (CI)=−27.11 to −8.00; P<0.001], as well as in the negative [mean (SD) 14.3 (6.1) vs. 19.4 (6.4); mean difference=−5.02; 95% CI=−8.28 to −1.77; P=0.002] and general psychopathology [mean (SD)=23.4 (6.3) vs. 32.7 (8.1); mean difference=−9.16; 95% CI=−13.3 to −5.03; P<0.001] subscales compared with the oral antipsychotic group. Personal and Social Functioning Scale scores were also higher in the RLAI group [mean (SD)=72.4 (14.8) vs. 59.7 (13.5); mean difference=13.41; 95% CI=5.65–21.18; P<0.001]. Although not statistically significant, there were fewer readmissions (adjusted odds ratio 0.28; 95% CI=0.06–1.35; P=0.114) and more illness remissions (adjusted odds ratio 3.24; 95% CI=0.20–11.93; P=0.077) in the RLAI group. Treatment with RLAI instead of oral antipsychotics in recent-onset schizophrenia might improve clinical symptoms and social functioning. The efficacy of RLAI treatment on remission and readmission rates should be researched further.

Bioconversion of stilbenes in genetically engineered root and cell cultures of tobacco

It is currently possible to transfer a biosynthetic pathway from a plant to another organism. This system has been exploited to transfer the metabolic richness of certain plant species to other plants or even to more simple metabolic organisms such as yeast or bacteria for the production of high added value plant compounds. Another application is to bioconvert substrates into scarcer or biologically more interesting compounds, such as piceatannol and pterostilbene. These two resveratrol-derived stilbenes, which have very promising pharmacological activities, are found in plants only in small amounts. By transferring the human cytochrome P450 hydroxylase 1B1 (HsCYP1B1) gene to tobacco hairy roots and cell cultures, we developed a system able to bioconvert exogenous t-resveratrol into piceatannol in quantities near to mg L−1. Similarly, after heterologous expression of resveratrol O-methyltransferase from Vitis vinifera (VvROMT) in tobacco hairy roots, the exogenous t-resveratrol was bioconverted into pterostilbene. We also observed that both bioconversions can take place in tobacco wild type hairy roots (pRiA4, without any transgene), showing that unspecific tobacco P450 hydroxylases and methyltransferases can perform the bioconversion of t-resveratrol to give the target compounds, albeit at a lower rate than transgenic roots.

Antipsychotic switching in schizoaffective disorder: A systematic review

Objectives. To systematically review the evidence about the switching of antipsychotics in SZA in acute and maintenance treatment. Methods. A systematic review following the PRISMA statement identifying studies specifically conducted on, or including, SZA patients. Results. One analysis considered uniquely a SZA population, 13 more studies including an adequate SZA subsample were considered. Most of the studies were aimed at switching antipsychotic treatments to improve tolerability issues. Despite the absolute lack of trials specifically conducted on SZA populations, we found limited evidence on the use of aripiprazole, lurasidone, and, to a lesser extent, risperidone and ziprasidone as possible agents to substitute previous treatments whereas efficacy or, more frequently, tolerability issues arise. Evidence supports also the switch to risperidone long-acting injectable when the adherence to oral treatment may be a concern. Conclusions. Antipsychotic switching in SZA is a neglected topic that would need better profiling. Clinicians should keep in mind the receptor binding characteristics of drugs in order to optimize transitions. Evidence supports the switch to aripiprazole and lurasidone, less strongly to risperidone and ziprasidone. The switch to risperidone long-acting injectable is supported, especially in patients with limited treatment adherence to oral therapy.

An optimized biotechnological system for the production of centellosides based on elicitation and bioconversion of Centella asiatica cell cultures

Centella asiatica is a herbaceous plant of Asian traditional medicine. Besides wound healing, this plant is recommended for the treatment or care of various skin conditions such as dry skin, leprosy, varicose ulcers, eczema, and/or psoriasis. Triterpene saponins, known as centellosides, are the main metabolites associated with these beneficial effects. Considering the interest in these high value active compounds, there is a need to develop biosustainable and economically viable processes to produce them. Previous work using C. asiatica plant cell culture technology demonstrated the efficient conversion of amyrin derivatives into centellosides, opening a new way to access these biomolecules. The current study was aimed at increasing the production of centellosides in C. asiatica plant cell cultures. Herein, we report the application of a new elicitor, coronatine, combined with the addition of amyrin‐enriched resins as potential sustainable precursors in the centelloside pathway, for a positive synergistic effect on centelloside production. Our results show that coronatine is a powerful elicitor for increasing centelloside production and that treatments with sustainable natural sources of amyrins enhance centelloside yields. This process can be scaled up to an orbitally shaken CellBag, thereby increasing the capacity of the system for producing biomass and centellosides.

Biotechnological production of recombinant tissue plasminogen activator protein (reteplase) from transplastomic tobacco cell cultures

Transplastomic plants are a system of choice for the mass production of biopharmaceuticals due to the polyploidy of the plastid genome and the low risk of pollen-mediated outcrossing because of maternal inheritance. However, as field-grown plants, they can suffer contamination by agrochemicals and fertilizers, as well as fluctuations in yield due to climatic changes and infections. Tissue-type plasminogen activator (tPA), a protein used to treat heart attacks, converts plasminogen into plasmine, which digests fibrin and induces the dissolution of fibrin clots. Recently, we obtained transplastomic tobacco plants carrying the K2S gene encoding truncated human tPA (reteplase) with improved biological activity, and confirmed the presence of the target protein in the transgenic plant leaves. Considering the advantages of plant cell cultures for biopharmaceutical production, we established a cell line derived from the K2S tobacco plants. The active form of reteplase was quantified in cultures grown in light or darkness, with production 3-fold higher in light.