Experience With Elexacaftor/Tezacaftor/Ivacaftor in Patients With Cystic Fibrosis and Advanced Disease

INTRODUCTION

Elexacaftor/tezacaftor/ivacaftor (ETI) was used through the early access programme in Spain from December 2019 in cystic fibrosis (CF) patients with homozygous or heterozygous F508del mutation with advanced lung disease.

METHODOLOGY

Multicentre, ambispective, observational, study in which 114 patients in follow-up in 16 national CF units were recruited. Clinical data, functional tests, nutritional parameters, quality of life questionnaires, microbiological isolates, number of exacerbations, antibiotic treatments and side effects were collected. The study also compared patients with homozygous and heterozygous F508del mutations.

RESULTS

Of the 114 patients, 85 (74.6%) were heterozygous for F508del mutation, and the mean age was 32.2±9.96 years. After 30 months of treatment, lung function measured by FEV1% showed improvement from 37.5 to 48.6 (p<0.001), BMI increased from 20.5 to 22.3 (p<0.001), and all isolated microorganisms decreased significantly. The total number of exacerbations was also significantly reduced from 3.9 (±2.9) to 0.9 (±1.1) (p<0.001). All items in the CFQ-R questionnaire showed improvement, except for the digestive domain. Oxygen therapy use decreased by 40%, and only 20% of patients referred for lung transplantation remained on the active transplant list. ETI was well-tolerated, with only 4 patients discontinuing treatment due to hypertransaminemia.

CONCLUSIONS

ETI decreases the number of exacerbations, increases lung function and nutritional parameters, decrease in all isolated microorganisms, for 30 months of treatment. There is an improvement in the CFQ-R questionnaire score except for the digestive item. It is a safe and well-tolerated drug.

[Results of the Implementation of a Case-Finding Program for Alpha-1 Antitrypsin Deficiency in COPD Patients]

Objectives

Currently, the identification of new cases of alpha-1 antitrypsin deficiency (AATD) continues to be one of the great challenges facing the disease. The present study aims to perform an analysis of the results of the implementation of a systematic case detection program of AATD for patients with chronic obstructive pulmonary disease.

Material and methods

Cross-sectional observational study in which the results of AAT screening until December 2022 were analyzed. The cases studied were divided into three periods: (1) no systematic case detection until 2013; (2) systematic case detection of S and Z alleles for cases with AAT < 90 mg/dL until 2018, and (3) systematic case detection of 14 mutations for cases with AAT < 120 mg/dL since 2018.

Results

A total of 471 cases were studied, of which 306 (65.0%) were carriers of some mutation related to HAD. The number of detected cases of all mutations with their percentage against those studied in each period was respectively: 6 (100%), 48 (88.8%) and 253 (61.5%). If we limit to severe mutations (AAT < 57.2 mg/dL), the distribution by periods was respectively: 3 (50.0), 10 (18.5%) and 17 (4.1%).

Conclusions

The present study describes the changes in the detection of patients carrying DAAT-related alleles with three different case identification policies. The data support the use of systematic case detection system in the COPD patient population.

Nutriepigenomics and chronic obstructive pulmonary disease: potential role of dietary and epigenetics factors in disease development and management

Over recent decades, a number of studies have revealed the possible role of different types of diets, as well as the nutritional elements they are made up of, in the pathogenesis of chronic obstructive pulmonary disease (COPD). To date, dietary factors have been identified to play a role in the prevention of COPD, with evidence from antioxidant nutrients, vitamins, and fiber intake. Additionally, certain dietary patterns such as the Mediterranean diet, together with other Western diets, provide evidence of the influence on COPD development, promoting lung health through nutritional approaches, and giving us an opportunity for intervention. The effect of diet on COPD is conveyed by 3 mechanisms: regulation of inflammation, oxidative stress, and carbon dioxide produced/oxygen intake. Current advances have begun to highlight the possible role of diet in modifying gene expression in certain individuals that predisposes them to COPD through epigenetic modifications. The relation between dietary intake and epigenetic factors has therefore outlined nutriepigenomics as a possible missing link in the relation between environmental exposure to smoke and the appearance of a subsequent chronic bronchial obstruction. This review summarizes the evidence regarding the influence of dietary patterns and nutrients and epigenetic regulatory mechanisms on COPD development and prevention with the aim of encouraging clinical research on the impact of dietary modifications on COPD-related clinical outcomes. This review highlights the importance of proposing and carrying out future studies focused on the modulating effects of certain nutrients on epigenetic changes in patients with specific COPD phenotypes (bronchiectasis, emphysema, asthma/COPD, chronic bronchitis), and their individual responses to cigarette smoking, environmental pollution, or other noxious particles. The objectives of these future studies must be directed to the development of novel therapeutic approaches and personalized management of COPD.

Step-Up and Step-Down Treatment Approaches for COPD: A Holistic View of Progressive Therapies

Recent advances in inhaled drugs and a clearer definition of the disease have made the task of managing COPD more complex. Different proposals have been put forward which combine all the available treatments and the different clinical presentations in an effort to select the best therapeutic options for each clinical context. As COPD is a chronic progressive disease, the escalation of therapy has traditionally been considered the most natural way to tackle it. However, the notion of COPD as a constantly progressing disease has recently been challenged and, in specific areas, this points to the possibility of a de-escalation in treatment. In this context, the clinician requires simple, specific recommendations to guide these changes in treatment in their daily clinical practice. To accomplish this, the first step must be a correct evaluation and an accurate initial preliminary diagnosis of the patient's condition. Thereafter, the first escalation in therapy must be introduced with caution as the disease progresses, since clinical trials are not designed with clinical decision-making in mind. During this escalation, three possibilities are open to change the current treatment for a different one within the same family, to increase non-pharmacological interventions or to increase the pharmacological therapies. Beyond that point, a patient with persistent symptoms represents a complex clinical scenario which requires a specialized approach, including the evaluation of different respiratory and non-respiratory comorbidities. Unfortunately, there are few de-escalation studies available, and these are mainly observational in nature. The debate on de-escalation in pharmacological treatment, therefore, involves two main discussion points: the withdrawal of bronchodilators and the withdrawal of inhaled steroids. Altogether, the scheme for modifying treatment must be more personalized than just adding molecules, and the therapeutic response and its conditioning factors should be evaluated at each step before proceeding further.

Predictors of Single Bronchodilation Treatment Response for COPD: An Observational Study with the Trace Database Cohort

Chronic obstructive pulmonary disease (COPD) patients constitute a heterogeneous population in terms of treatment response. Our objective was to identify possible predictive factors of response to treatment with single bronchodilation monotherapy in patients diagnosed with COPD. The Time-based Register and Analysis of COPD Endpoints (TRACE; clinicaltrials.gov NCT03485690) is a prospective cohort of COPD patients who have been attending annual visits since 2012. Patients who were kept on a single bronchodilator during the first year of follow-up were selected. The responders were defined according to all of the following variables: any improvement in morning post-dose forced expiratory volume in 1 s or deterioration <100 mL, no change or improvement in dyspnea score, and no occurrence of exacerbations. Significant and plausible variables were analyzed using a proportional hazard Cox regression for single bronchodilator responders. We analyzed 764 cases, of whom 128 (16.8%) were receiving monotherapy with one bronchodilator. Of these, 85 patients (66.4%) were responders. Factors affecting responder status were: female gender (hazard ratio (HR) 0.276; 95% confidence interval (CI) 0.089–0.858), dyslipidemia (HR 0.436; 95%CI 0.202–0.939), not performing regular exercise (HR 0.523; 95%CI 0.254–1.076), active smoking (HR 0.413; 95%CI 0.186–0.920), and treatment adherence (HR 2.527; 95%CI 1.271–5.027). The factors associated with a single bronchodilation response are mainly non-pharmacological interventions and comorbidities.

Deconstructing Phenotypes in COPD: an Analysis of the TRACE Cohort

OBJECTIVES

In a clinical phenotype-based management strategy for COPD, it would be preferable to at least assign all patients to a phenotype, but to a single phenotype only. The aim of this study was to evaluate whether all patients are assigned to one and only one phenotype using the Spanish COPD guidelines (GesEPOC) and to evaluate the criteria that define these categories.

METHOD

The Time-based Register and Analysis of COPD Endpoints study (TRACE; clinicaltrials.gov NCT03485690) is a prospective cohort of COPD patients attending annual visits since 2012, which collects GesEPOC phenotypes. Although the GesEPOC recommends that patients considered to be at low risk are not phenotyped, an analysis of the criteria for identifying high- and low-risk phenotypes was performed, comparing the distribution of phenotypes and the criteria applied between these 2 groups.

RESULTS

The cohort included 970 patients with a confirmed diagnosis of COPD, divided into 427 (44.02%) low-risk and 543 (55.9%) high-risk patients. The most frequent phenotype was the non-exacerbator (44.9% of high-risk patients). Overall, 20.6% of low-risk patients met criteria for asthma-COPD overlap syndrome, while 9.2% of the cohort did not meet the diagnostic criteria for any phenotype, and 19.1% met the criteria for 2 phenotypes, with no differences between risk groups.

CONCLUSIONS

Our data highlight some of the weaknesses of the current clinical phenotype strategy, revealing overlapping categories in some cases, and patients to whom no phenotype was assigned.

Ten Research Questions for Improving COPD Care in the Next Decade

With the 60th anniversary of the CIBA symposium, it is worth evaluating research questions that should be prioritized in the future. Coming research initiatives can be summarized in 10 main areas. (1) From epidemiology the impact of new forms of electronic cigarettes on prevalence and mortality of COPD will be sought. (2) The study of the disease endotypes and its relationship phenotypes will have to be unraveled in the next decade. (3) Diagnosis of COPD faces several challenges opening the possibility of a change in the definition of the disease itself. (4) Patients' classification and risk stratification will need to be clarified and reassessed. (5) The asthma-COPD overlap dilemma will have to be clarified and define whether both conditions represent one only chronic airway disease again. (6) Integrating comorbidities in COPD care will be key in a progressively ageing population to improve clinical care in a chronic care model. (7) Nonpharmacological management have areas for research including pulmonary rehabilitation and vaccines. (8) Improving physical activity should focus research because of the clear prognostic impact. (9). Pharmacological therapies present several challenges including efficacy and safety issues with current medications and the development of biological therapy. (10) The definition, identification, categorization and specific therapy of exacerbations will also be an area of research development. During the next decade, we have a window of opportunity to address these research questions that will put us on the path for precision medicine.

Status of and strategies for improving adherence to COPD treatment

Despite the wide application of adherence as a concept, the definition, evaluation and improvement of the adherence to treatment by patients with chronic obstructive pulmonary disease (COPD) still present some challenges. First, it is necessary to clearly define the concepts of treatment adherence, compliance and persistence. Second, it is critical to consider the various methods of evaluating and quantifying adherence when interpreting adherence studies. In addition, the advantages and disadvantages of the different ways of measuring treatment adherence should be taken into account. Another subject of some debate is the number of variables associated with COPD treatment adherence. Adherence is a complex concept that goes beyond the dosage or the use of inhalation devices, and a number of variables are involved in determining adherence, from the clinical aspects of the disease to the patient's confidence in the doctor's expertise and the level of social support experienced by the patient. Notably, despite these challenges, the importance of adherence has been well established by clinical trials and routine clinical practice. The available evidence consistently shows the substantial impact that a lack of adherence has on the control of the disease and its long-term prognosis. For these reasons, the correct evaluation of therapeutic adherence should be a key objective in clinical interviews of patients. In recent years, various initiatives for improving adherence have been explored. All these initiatives have been based on patient education. Therefore, health care professionals should be aware of the issues pertaining to adherence and take the opportunity to educate patients each time they contact the health care system.

Using the Social-Local-Mobile App for Smoking Cessation in the SmokeFreeBrain Project: Protocol for a Randomized Controlled Trial

Background

Smoking is considered the main cause of preventable illness and early deaths worldwide. The treatment usually prescribed to people who wish to quit smoking is a multidisciplinary intervention, combining both psychological advice and pharmacological therapy, since the application of both strategies significantly increases the chance of success in a quit attempt.

Objective

We present a study protocol of a 12-month randomized open-label parallel-group trial whose primary objective is to analyze the efficacy and efficiency of usual psychopharmacological therapy plus the Social-Local-Mobile app (intervention group) applied to the smoking cessation process compared with usual psychopharmacological therapy alone (control group).

Methods

The target population consists of adult smokers (both male and female) attending the Smoking Cessation Unit at Virgen del Rocío University Hospital, Seville, Spain. Social-Local-Mobile is an innovative intervention based on mobile technologies and their capacity to trigger behavioral changes. The app is a complement to pharmacological therapies to quit smoking by providing personalized motivational messages, physical activity monitoring, lifestyle advice, and distractions (minigames) to help overcome cravings. Usual pharmacological therapy consists of bupropion (Zyntabac 150 mg) or varenicline (Champix 0.5 mg or 1 mg). The main outcomes will be (1) the smoking abstinence rate at 1 year measured by means of exhaled carbon monoxide and urinary cotinine tests, and (2) the result of the cost-effectiveness analysis, which will be expressed in terms of an incremental cost-effectiveness ratio. Secondary outcome measures will be (1) analysis of the safety of pharmacological therapy, (2) analysis of the health-related quality of life of patients, and (3) monitoring of healthy lifestyle and physical exercise habits.

Results

Of 548 patients identified using the hospital’s electronic records system, we excluded 308 patients: 188 declined to participate and 120 did not meet the inclusion criteria. A total of 240 patients were enrolled: the control group (n=120) will receive usual psychopharmacological therapy, while the intervention group (n=120) will receive usual psychopharmacological therapy plus the So-Lo-Mo app. The project was approved for funding in June 2015. Enrollment started in October 2016 and was completed in October 2017. Data gathering was completed in November 2018, and data analysis is under way. The first results are expected to be submitted for publication in early 2019.

Conclusions

Social networks and mobile technologies influence our daily lives and, therefore, may influence our smoking habits as well. As part of the SmokeFreeBrain H2020 European Commission project, this study aims at elucidating the potential role of these technologies when used as an extra aid to quit smoking.

Trial Registration

ClinicalTrials.gov NCT03553173; https://clinicaltrials.gov/ct2/show/record/NCT03553173 (Archived by WebCite at http://www.webcitation.org/74DuHypOW).

International Registered Report Identifier (IRRID)

PRR1-10.2196/12464

Results of the Andalusian Cystic Fibrosis Neonatal Screening Program, 5 Years After Implementation

INTRODUCTION

Cystic fibrosis neonatal screening (CFNS), based on double determination of immunoreactive trypsinogen ([IRT] [IRT1/IRT2]), has been available in Andalusia since May 2011. If screening is positive, a sweat test is performed, and if that is positive or inconclusive, genetic testing is requested.

OBJECTIVE

To analyze CFNS, based on results from the first 4.5 years of the program.

MATERIALS AND METHODS

Prospective descriptive study of neonates undergoing CFNS. IRT levels, sweat chloride, and mutations were recorded. Statistical analysis was performed using SPSS 12.0.

RESULTS

Between May 2011 and December 2016, 474,953 neonates underwent CFNS. Of these, 1,087 (0.23%) had elevated IRT2. Since CFNS was introduced, 73 cases of cystic fibrosis were diagnosed; 60 were diagnosed by positive CFNS, and 13 were diagnosed by other means. In one case, the patient developed a typical clinical picture of cystic fibrosis, but had not undergone CFNS at the decision of the parents; the remaining 12 had a negative CFNS (false negatives). Of these, one patient was diagnosed before symptoms developed, as his twin brother had a positive CFNS result; another had chloride at the upper limit of normal, and was subsequently diagnosed with genetic testing before symptoms appeared; and 10 patients developed clinical signs and symptoms. Excluding patients with meconium ileus, sensitivity and specificity of the CFNS program were 85.71% and 99.78%, respectively. The incidence of the disease in Andalusia is 1/6,506 live births.

CONCLUSION

These results are a basis for reflection on possible areas for improvement of the CFNS algorithm, and thought may be given to the introduction of genetic studies to increase sensitivity and reduce false positives.

Current controversies in the stepping up and stepping down of inhaled therapies for COPD at the patient level

The implementation of potential new step-up or step-down treatment recommendations in response to current guidelines is one of the main challenges currently faced in actual daily practice settings. In the present narrative review, we aim to discuss the relevance of these step-up and step-down proposals at the patient level in daily clinical practice. In particular, we aim to review the challenges associated with inhaled maintenance therapy for chronic obstructive pulmonary disease (COPD) in four clinical scenarios. First, we discuss the step up from single to double bronchodilation, including current controversies regarding the addition of a second bronchodilator versus initial treatment with two bronchodilators. Second, we discuss the step up from double bronchodilation to triple therapy while challenging current indications for inhaled steroid therapy and discussing triple therapy designs. Third, we discuss the step down from triple therapy to double bronchodilation while evaluating the effect of this downshift in risk categories on the patient according to the new classifications. Finally, we discuss the step down from double to single bronchodilation, with a special focus on safety. We believe this review will help to highlight the most relevant discussion points regarding the treatment of COPD in a manner that will stimulate and guide related clinical research.

Estudio no invasivo de las venas cerebrales y los senos durales: comparación de dos técnicas de angiografía con resonancia magnética

OBJECTIVE

To evaluate MR venography with bolus injection of intravenous contrast and elliptical filling of the K space, using three-dimensional fast spoiled gradient-echo (3D-FSPGR) sequences, and to compare it to the technique most frequently employed in the study of cerebral veins and dural sinuses, which is two-dimensional time-of-flight (2D-TOF) MR venography.

MATERIAL AND METHODS

Source images, multiplanar reconstructions, and maximum intensity projections (MIP) were obtained using both 2D-TOF venography and contrasted-enhanced 3D-FSPGR venography in 20 healthy volunteers. Two radiologists independently evaluated both techniques for the visualization of twenty-one predefined venous structures, classifying the depiction as completely visible, partially visible, or not visible.

RESULTS

The predefined venous structures were completely visible in 795 of 840 (94.6%) of the evaluations of contrast-enhanced 3D-FSPGR images versus 682 of 840 (81.1%) evaluations of 2D-TOF venography images. In the major dural sinuses, visualization was complete in 99.4% of the readings of contrast-enhanced 3D-FSPGR images versus 81% in the readings of the 2D-TOF images.

CONCLUSION

3D-FSPGR with elliptical filling of the K space and bolus injection of contrast material provides higher quality images of the intracranial venous system than those obtained using 2D-TOF sequences.

[Adult congenital anomalies of the coronary arteries described over 31 years of angiographic studies in the Asturias Principality: main angiographic and clinical characteristics]

OBJECTIVE

The aim of this study was to determine the incidence of adult congenital anomalies of the coronary arteries over 31 years of angiographic studies, describing their angiographic and clinical characteristics. The results have been compared with the main series published.

METHODS

The diagnostic angiographic reports done in the Principado de Asturias from 1968 to 1999 are reviewed. In those in which a congenital anomaly was diagnosed, the clinical report and the angiography were studied. The initial course of the anomaly was defined following angiographic criteria.

RESULTS

Thirteen thousand five hundred reports were reviewed describing 75 patients with 75 anomalies (0.5%) including: anomalous origin of the left circumflex coronary artery (n = 24), coronary artery fistulae (n = 21), both coronary arteries arising from the left coronary sinus (n = 15), single coronary arteries (n = 6), both coronary arteries arising from the right coronary sinus (n = 2), separated origin of anterior descending and left circumflex coronary arteries (n = 3), anterior descending artery arising from the right coronary sinus (n = 2), and others (n = 1). Angiographic studies were done because of: angina (59%), dysnea (25%), atypical chest pain (7%), syncope (3%), dizziness (3%) and palpitations (3%). The initial course was retroaortic in all the circumflex arteries, interarterial in the right coronaries, anterior in the anterior descending arteries and retroaortic, septal and combined, in the left coronaries.

CONCLUSIONS

Adult congenital anomalies of the coronary arteries are not very common and are usually casual findings of diagnostic angiographic studies. Left circumflex coronary artery anomalies are the most frequently diagnosed.

In vivo bromodeoxyuridine (BrdU)-labelling index of rat thymus: influence of different BrdU doses and exposure times as analyzed both in tissue sections and in single cell suspensions

Tissue sections and single cell suspensions of rat thymus were analyzed by flow and image cytometry to study the effects of different doses of bromodeoxyuridine (BrdU) (10, 50 and 100 mg/kg and different labelling periods (15, 30 and 60 min) on the BrdU-labelling index. The proportions of BrdU-labelled cells, as analyzed by flow cytometry, were similar in the different groups of our study. However, the quality of the results was not exactly the same, since when the BrdU dose decreased, the separation between BrdU-positive S-phase cells and both the G0/G1 and the G2/M BrdU-negative cells on a DNA/BrdU histogram became less clear. On the other hand, the proportion of BrdU-labelled cells in tissue sections was greater in the groups of animals that received doses of 100 mg/kg and were killed 15, 30 or 60 min later than in the sections obtained from the remaining groups. Our results show that both dose and exposure time to BrdU may influence the final results when cell proliferation is assessed, the variations obtained clearly depending on the technique used for the immunological detection of BrdU-positive S-phase cells.

Changes in hypothalamic met-enkephalin levels of rats induced by painful stimulation and morphine treatment

The possible influence of painful stimulation and morphine analgesia on hypothalamic met-enkephalin levels, and the possible correlation between this biochemical parameter and animal behaviour was studied. The results indicate that both painful stimulation and morphine treatment induce an increase in hypothalamic metenkephalin. On the other hand, naloxone did not cause any variation. In animals submitted to painful stimulus, morphine treatment induced a decrease in hypothalamic met-enkephalin levels. Finally, when both morphine and naloxone were administrated before nociceptive stimulation, much higher levels were measured. There was no correlation between the level of hypothalamic met-enkephalin and the pain rating.

Immunohistochemical localization of epidermal growth factor and its receptor during odontogenesis in the rat

The expression of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFr) in developing teeth has been immunohistochemically studied in rat embryos (E-16 to E-21). Both EGF and EGFr showed a similar pattern of distribution. A very weak immunostaining was observed in the dental germ cells during the bud, cap, and bell teeth stages, as well as in few ectomesenchymal cells. In developed, but not erupted teeth, a moderate immunoreactivity for EGF and EGFr was present in the odontoblasts, in the ameloblasts and in the internal epithelial cells, but it was stronger in the dentine. In addition, the presence of EGF/EGFr was also observed in the intercalated ducts of salivary glands, primarily the submaxillary gland, in the maxillary bone cells, and in the cells of the peripheral and central nervous system. These results suggest that EGF has little or no effect during the early periods of tooth differentiation, whereas it is probably involved in the production of dentine. Moreover, EGF/EGFr seem to participate in the maturation and differentiation of other embryonic tissues such as tissues of the nervous system and bone.

Ultrastructural, immunocytochemical and morphometric studies of pituitary prolactin cells after chronic administration of met-enkephalin

The effects of chronic administration of met-enkephalin (40 micrograms/day, for 20 days) on the pituitary prolactin cells of Wistar male rats were studied at the light (PAP-immunohistochemical for PRL demonstration technique) and electron microscopy levels. The D. CIRCLE (mean diameter), D. MAX (maximum diameter) and FORM PE (circular factor of form; irregularity degree) form secretory granules, as well as their percent distribution, were also evaluated. The cellular alterations were variable. Most prolactin cells showed an increase in immunohistochemical reaction. At the electron microscope level the prolactin cells showed an enlargement and swelling of the RER and Golgi apparatus. The secretory granules were bigger and more spherical in experimental than in untreated and control animals. A number of cells showed a variable number of cytoplasmic vacuoles or a large central vacuole formed from dilated RER-cisternae. The authors discuss the possible mechanism whereby met-enkephalin exerts a control on prolactin cells.

Vasoactive intestinal polypeptide (VIP)-like immunoreactivity in intraprostatic neurons and major pelvic ganglia in the rat

VIP-like immunoreactive neurons have been found within the prostate and major pelvic ganglia of the male rats; they are of two different sizes. Moreover many VIP-like nerve fibers were found around the perikarya. On the basis of present data it is suggested that VIP-like prostatic nerves arise from both pelvic ganglia and intraprostatic neurons.

[Microscopic innervation of the spermatic ducts and testis. I. Vas deferens]

The microscopic innervation of the vas deferens in the rat was studied both in light and electron microscope. The nerve fibres form perivascular, intramuscular and subepithelial plexuses. Inside the connective tissue surrounding the vas deferens both isolated nerve fibres and sensory corpuscles (glomerular and Ruffine-like types) were observed. The varicosities and endings of nerve fibres contain synaptic vesicles of different sizes and electron characteristics. These varicosities were closely related to the smooth muscle cells and some of them lacked of Schwannian sheath. The nervous fibres were not in direct contact with the epithelial cells.

[An experimental pain model: the formaldehyde test]

Some papers have been published in relation to alternative models of experimental pain in animals. In this work, with the aim of proving the validity, safety, reproducibility and objectivity of this model, we have compared the behaviour of the animal under the formaldehyde test before and after the intracerebroventricular administration of morphine, proving itself as an ideal model for the study of chronic pain caused by an excess of nociception.