Incidence of hypophosphataemia after ICU admission in mechanically ventilated patients and its relationship with risk factors for refeeding syndrome

OBJECTIVE

To describe the incidence of hypophosphatemia in patients admitted to the ICU who have required mechanical ventilation. To analyze the presence of risk factors and its relationship with nutritional practice.

DESIGN

Prospective observational study.

SETTING

Polyvalent ICUs of 2 University Hospitals.

PATIENTS OR PARTICIPANTS

Patients on invasive mechanical ventilation ≥72 h with normal level of phosphorus at admission.

INTERVENTIONS

None.

MAIN VARIABLES OF INTEREST

Electrolyte levels (phosphorus, magnesium, potassium) were determined on admission to the ICU and at 96 h. Risk categories on admission, caloric intake, insulin doses and acid-base status during the first 4 days of admission were recorded. Incidence was calculated as the number of patients who developed hypophosphataemia after admission. Univariate analysis was performed for between-group comparison and multivariate analysis of potential risk factors.

RESULTS

89 patients were included. The incidence of hypophosphataemia was 32.6%. In these patients phosphorus decreased from 3.57 ± 1.02 mmol/l to 1.87 ± 0.65 mmol/l (52.3%). The mean kcal/kg/24 h provided in the first 4 days was 17.4 ± 4.1, with no difference between the group that developed hypophosphataemia and the group that did not. Significant risk factors were insulin doses administered and pH and PaCO2 values.

CONCLUSIONS

The incidence of hypophosphataemia at 96 h from admission in mechanically ventilated patients is high and unrelated to the risk category and hypocaloric nutritional practice used. Insulin dosis and acid-base status are the main determinants of its occurrence.

Azathioprine dose tailoring based on pharmacogenetic information: Insights of clinical implementation

Azathioprine is commonly used as an immunosuppressive antimetabolite in the treatment of acute lymphoblastic leukemia, autoimmune disorders (such as Crohn's disease and rheumatoid arthritis), and in patients receiving organ transplants. Thiopurine-S-methyltransferase (TPMT) is a cytoplasmic trans-methylase catalyzing the S-methylation of thiopurines. The active metabolites obtained from thiopurines are hydrolyzed into inactive forms by the Nudix hydrolase 15 (NUDT15). The TPMT*2 (defined by rs1800462), *3A (defined by rs1800460 and rs1142345), *3B (defined by rs1800460), *3C (defined by rs1142345), *6 (defined by rs75543815), and NUDT15 rs116855232 genetic variant have been associated, with the highest level of evidence, with the response to azathioprine, and, the approved drug label for azathioprine and main pharmacogenetic dosing guidelines recommend starting with reduced initial doses in TPMT intermediate metabolizer (IM) patients and considering an alternative treatment in TPMT poor metabolizer (PM) patients. This study aims to assess the clinical impact of azathioprine dose tailoring based on TPMT genotyping studying the azathioprine toxicity and efficacy, treatment starts, and dose adjustments during follow-up, comparing TPMT IM/PM and normal metabolizer (NM) patients. It also studied the association of NUDT15 rs116855232 with response to azathioprine in patients receiving a tailored treatment based on TPMT and characterized the TMPT and NUDT15 studied variants in our population. Results show that azathioprine dose reduction in TPMT IM patients (TPMT*1/*2, *1/*3A, or *1/*3C genotypes) is related to lower toxicity events compared to TPMT NM (TPMT *1/*1 genotype), and lower azathioprine dose adjustments during follow-up without showing differences in the efficacy. The results support the hypothesis of existing other genetic variants affecting azathioprine toxicity.

Administration of intestinal mesenchymal stromal cells reduces colitis-associated cancer in C57BL/6J mice modulating the immune response and gut dysbiosis

BACKGROUND

Patients with inflammatory bowel disease (IBD) have a higher risk of developing colitis-associated colorectal cancer (CAC) with poor prognosis. IBD etiology remains undefined but involves environmental factors, genetic predisposition, microbiota imbalance (dysbiosis) and mucosal immune defects. Mesenchymal stromal cell (MSC) injections have shown good efficacy in reducing intestinal inflammation in animal and human studies. However, their effect on tumor growth in CAC and their capacity to restore gut dysbiosis are not clear.

METHODS

The outcome of systemic administrations of in vitro expanded human intestinal MSCs (iMSCs) on tumor growth in vivo was evaluated using the AOM/DSS model of CAC in C57BL/6J mice. Innate and adaptive immune responses in blood, mesenteric lymph nodes (MLNs) and colonic tissue were analyzed by flow cytometry. Intestinal microbiota composition was evaluated by 16S rRNA amplicon sequencing.

RESULTS

iMSCs significantly inhibited colitis and intestinal tumor development, reducing IL-6 and COX-2 expression, and IL-6/STAT3 and PI3K/Akt signaling. iMSCs decreased colonic immune cell infiltration, and partly restored intestinal monocyte homing and differentiation. iMSC administration increased the numbers of Tregs and IFN-γ+CD8+ T cells in the MLNs while decreasing the IL-4+Th2 response. It also ameliorated intestinal dysbiosis in CAC mice, increasing diversity and Bacillota/Bacteroidota ratio, as well as Akkermansia abundance, while reducing Alistipes and Turicibacter, genera associated with inflammation.

CONCLUSION

Administration of iMSCs protects against CAC, ameliorating colitis and partially reverting intestinal dysbiosis, supporting the use of MSCs for the treatment of IBD.

Gut Microbiota Composition Can Predict Colonization by Multidrug-Resistant Bacteria in SARS-CoV-2 Patients in Intensive Care Unit: A Pilot Study

The SARS-CoV-2 infection has increased the number of patients entering Intensive Care Unit (ICU) facilities and antibiotic treatments. Concurrently, the multi-drug resistant bacteria (MDRB) colonization index has risen. Considering that most of these bacteria are derived from gut microbiota, the study of its composition is essential. Additionally, SARS-CoV-2 infection may promote gut dysbiosis, suggesting an effect on microbiota composition. This pilot study aims to determine bacteria biomarkers to predict MDRB colonization risk in SARS-CoV-2 patients in ICUs. Seventeen adult patients with an ICU stay >48 h and who tested positive for SARS-CoV-2 infection were enrolled in this study. Patients were assigned to two groups according to routine MDRB colonization surveillance: non-colonized and colonized. Stool samples were collected when entering ICUs, and microbiota composition was determined through Next Generation Sequencing techniques. Gut microbiota from colonized patients presented significantly lower bacterial diversity compared with non-colonized patients (p < 0.05). Microbiota in colonized subjects showed higher abundance of Anaerococcus, Dialister and Peptoniphilus, while higher levels of Enterococcus, Ochrobactrum and Staphylococcus were found in non-colonized ones. Moreover, LEfSe analysis suggests an initial detection of Dialister propionicifaciens as a biomarker of MDRB colonization risk. This pilot study shows that gut microbiota profile can become a predictor biomarker for MDRB colonization in SARS-CoV-2 patients.

Intestinal mesenchymal cells regulate immune responses and promote epithelial regeneration in vitro and in dextran sulfate sodium-induced experimental colitis in mice

AIM

Disruption of the intestinal mucosal tolerance, that is, the immunological unresponsiveness to innocuous food antigens and the commensal microbiota, in the colon is associated with several chronic diseases including inflammatory bowel disease (IBD). Understanding the mechanisms responsible for intestinal mucosal tolerance has potential translational value for its therapy and management. Human intestinal mesenchymal cells (iMCs) play important roles in colonic mucosal tolerance, but further studies on their tissue regenerative and immunomodulatory capacities are necessary in order to fully understand their function in health and disease.

METHODS

In this study, we have isolated and analysed the capacity of human iMCs to promote wound healing and modulate immune responses in vitro and in vivo, using the dextran sulfate sodium (DSS)-induced colitis model.

RESULTS

Cultured iMCs were CD45^- CD73⁺ CD90⁺ CD105⁺ and accelerated the wound closure in a normal colon mucosa (NCM) 356 human epithelial cell wound healing assay. Furthermore, iMCs blocked the LPS-mediated induction of TNF-α in THP-1 macrophages and inhibited the proliferation of peripheral blood mononuclear cells, partly through the induction of indoleamine-2,3-dioxygenase. In DSS colitic mice, iMCs administration reduced the disease activity index and ameliorated intestinal tissue damage and permeability. Furthermore, iMCs reduced intestinal inflammation, evidenced by a decreased mRNA expression of pro-inflammatory cytokines, reduced IL-1β secretion by intestinal explants and inhibited colonic iNOS protein expression.

CONCLUSIONS

Our data show that human iMCs isolated from the noninflamed intestine possess tissue-regenerative and immunomodulatory capacities that could potentially be harnessed/restored in order to reduce IBD severity.

The Beneficial Effects of Lippia Citriodora Extract on Diet-Induced Obesity in Mice Are Associated with Modulation in the Gut Microbiota Composition

SCOPE

Obesity is characterized by a dysfunction in the adipose tissue and an inflammatory subclinical state leading to insulin resistance and increased risk of cardiovascular diseases. It is also associated with intestinal dysbiosis that contributes to inflammation development. Lippia citriodora (LCE) contains high levels of polyphenolpropanoids and has shown promising results in obesity. The aim of this study is to investigate a well-characterized extract of LCE in a model of metabolic syndrome in mice, focusing on its effects on metabolic tissues, endothelial dysfunction, and microbiome.

METHODS

Mice are fed a high fat diet (HFD) for six weeks and treated daily with LCE (1, 10, and 25 mg kg^-1 ). Glucose and lipid metabolism is investigated. The inflammatory state in the metabolic tissues and the intestinal microbiota composition are characterized, as well as the endothelium-dependent vasodilator response to acetylcholine.

RESULTS

LCE reduces fat accumulation and improves plasma glycemic and lipid profiles, as well as the inflammatory process and vascular dysfunction. Moreover, LCE lessens intestinal dysbiosis, as it reduces the Firmicutes/Bacteroidetes ratio and increases Akkermansia abundance in comparison with untreated HFD mice.

CONCLUSION

The antiobesity therapeutic properties of LCE are most probably mediated by the synergic effects of its bioactive compounds.

Long-term resveratrol administration reduces metabolic disturbances and lowers blood pressure in obese Zucker rats

Resveratrol is a natural polyphenolic stilbene derivative found in several human diet components that possess important and wide-ranging effects in biological systems including anticancer, anti-inflammatory, antioxidant, cardio-protective, and anti-ageing actions and beneficial properties against metabolic diseases. This study addresses the effects of long-term administration of resveratrol on several functional alterations arising from the metabolic syndrome experimental model of obese Zucker rats, and the possible mechanisms involved. The high plasma concentrations of triglycerides, total cholesterol, free fatty acids, insulin and leptin found in obese Zucker rats were reduced in obese rats that received resveratrol. Furthermore, the elevated hepatic lipid content was significantly lower in obese rats treated with resveratrol, an effect which was related to the increased phosphorylation of 5'-AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) in the liver of these animals. Resveratrol treatment also improved the inflammatory status peculiar to this model, as it increased the concentration of adiponectin and lowered tumor necrosis factor-alpha production in the visceral adipose tissue (VAT) of obese Zucker rats. Moreover, chronic intake of resveratrol enhanced VAT eNOS expression among obese Zucker rats. These effects parallel the activation of AMPK and inhibition by phosphorylation of ACC in this tissue. The raised systolic blood pressure and reduced aortic eNOS expression found in obese Zucker rats were significantly improved in the resveratrol-treated obese rats. In conclusion, resveratrol improved dyslipidemia, hyperinsulinemia, hyperleptinemia and hypertension in obese Zucker rats, and produced anti-inflammatory effects in VAT, effects that seem to be mediated by AMPK activation.

Quercetin ameliorates metabolic syndrome and improves the inflammatory status in obese Zucker rats

The aim of this study was to analyze the effects of chronic administration of high doses of quercetin on metabolic syndrome abnormalities, including obesity, dyslipidemia, hypertension, and insulin resistance. For this purpose, obese Zucker rats and their lean littermates were used. The rats received a daily dose of quercetin (2 or 10 mg/kg of body weight) or vehicle for 10 weeks. Body weight and systolic blood pressure (SBP) were recorded weekly. At the end of the treatment, plasma concentrations of triglycerides, total cholesterol, free-fatty acids (FFAs), glucose, insulin, adiponectin, and nitrate plus nitrite (NOx) were determined. Tumor necrosis factor-alpha (TNF-alpha) production, inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS) protein expression were analyzed in visceral adipose tissue (VAT). The raised SBP and high plasma concentrations of triglycerides, total cholesterol, FFA, and insulin found in obese Zucker rats were reduced in obese rats that received either of the doses of quercetin assayed. The higher dose also improved the inflammatory status peculiar to this model, as it increased the plasma concentration of adiponectin, reduced NOx levels in plasma, and lowered VAT TNF-alpha production in obese Zucker rats. Furthermore, chronic intake of the higher dose of quercetin enhanced VAT eNOS expression among obese Zucker rats, whereas it downregulated VAT iNOS expression. In conclusion, both doses of quercetin improved dyslipidemia, hypertension, and hyperinsulinemia in obese Zucker rats, but only the high dose produced antiinflammatory effects in VAT together with a reduction in body weight gain.

Diversity among clinical isolates of penicillin-resistant Streptococcus mitis: indication for a PBP1-dependent way to reach high levels of penicillin resistance

A total of 12 non-epidemiologically related clinical isolates of Streptococcus mitis that showed different levels of resistance to penicillin were studied. Membrane-protein profiles and penicillin-binding protein (PBP) patterns showed a great polymorphism; and patterns of 4-7 PBPs, with sizes that ranged from approximately 101 kDa to approximately 40 kDa, were detected in each strain. No association could be found between PBP pattern and resistance level to penicillin among these isolates. Arbitrarily primed PCR confirmed the genetic diversity among this group of streptococci. One of the isolates of intermediate level of resistance to penicillin, which showed a PBP pattern similar to that of the high-resistance strains, was used as a laboratory model to analyse the mechanism underlying high-resistance acquisition by these strains. A 14-fold increase in penicillin resistance was obtained after a single selection step, which resulted in a decrease in penicillin affinity for PBP1. The size of this PBP (92 kDa) and the differences in PBP profiles of the penicillin-resistant clinical isolates suggest the existence in S. mitis of PBP-mediated mechanisms to acquire high-level resistance to penicillin, among which alterations in PBP1 seem to play a main role, in contrast to the PBP2X mediated mechanism described for other streptococci.

New genus-specific primers for the PCR identification of members of the genus Saccharomonospora and evaluation of the microbial diversity of wild-type isolates of Saccharomonospora detected from soil DNAs

Members of the genus Saccharomonospora are isolated infrequently, probably due to the low occurrence of these actinomycetes in the environment. Although members of this genus can easily be identified by micromorphological criteria, the extensive chemotaxonomic characterization of each new isolate is a time-consuming task which cannot always be undertaken when handling large numbers of strains as is the case in natural products screening programmes. In this work, the design of one set of genus-specific oligonucleotides which allows rapid detection of members of the genus Saccharomonospora by means of PCR-specific amplification is presented. The genus specificity of these primers was validated on a wide range of collection and wild-type strains, and subsequently applied to evaluate the presence of representatives of this taxon directly from soil DNAs. Partial 16S rDNA sequencing of representative wild-type strains was used to validate their genus assignment. Further analyses of PCR fingerprinting patterns and 16S-23S internal transcribed spacer sequences were used to determine the diversity of wild-type isolates obtained from soils. This study shows the usefulness of the application of these primers for the direct identification of members of this genus and in assessment of its occurrence within natural microbial habitats.

New genus-specific primers for the PCR identification of members of the genera Pseudonocardia and Saccharopolyspora

Members of the family Pseudonocardiaceae are difficult to identify on the basis of their micromorphology only. The biochemical characterization of each new isolate is a painstaking and time-consuming task which cannot always be undertaken when handling large numbers of strains as is the case in natural product screening programmes. In this study, two sets of genus-specific oligonucleotides were designed which allow rapid detection of members of the genera Pseudonocardia and Saccharopolyspora by means of PCR-specific amplification. The genus specificity of these primers was validated on a wide range of collection strains and the primers were subsequently used to study a group of 106 wild-type isolates that possessed morphological characteristics of the family. Out of this group, 51 strains could be identified as members of the genus Pseudonocardia and only nine isolates could be assigned to the genus Saccharopolyspora. The diversity indicated by whole-cell fatty acid profiles of both wild-type and reference strains was compared with that identified using the oligonucleotide primers. The partial 16S rDNA sequencing of representative wild-type strains was used to validate their genus assignment by PCR-specific amplification. This study shows the industrial usefulness of the application of these direct identification tools as well as the complementary use of two sources of data, PCR-specific amplification results and fatty acid composition, to assess the diversity of a microbial population.