Pain mechanisms in the transgender individual: a review

Specific Aim

Provide an overview of the literature addressing major areas pertinent to pain in transgender persons and to identify areas of primary relevance for future research.

Methods

A team of scholars that have previously published on different areas of related research met periodically though zoom conferencing between April 2021 and February 2023 to discuss relevant literature with the goal of providing an overview on the incidence, phenotype, and mechanisms of pain in transgender patients. Review sections were written after gathering information from systematic literature searches of published or publicly available electronic literature to be compiled for publication as part of a topical series on gender and pain in the Frontiers in Pain Research.

Results

While transgender individuals represent a significant and increasingly visible component of the population, many researchers and clinicians are not well informed about the diversity in gender identity, physiology, hormonal status, and gender-affirming medical procedures utilized by transgender and other gender diverse patients. Transgender and cisgender people present with many of the same medical concerns, but research and treatment of these medical needs must reflect an appreciation of how differences in sex, gender, gender-affirming medical procedures, and minoritized status impact pain.

Conclusions

While significant advances have occurred in our appreciation of pain, the review indicates the need to support more targeted research on treatment and prevention of pain in transgender individuals. This is particularly relevant both for gender-affirming medical interventions and related medical care. Of particular importance is the need for large long-term follow-up studies to ascertain best practices for such procedures. A multi-disciplinary approach with personalized interventions is of particular importance to move forward.

Addition of dexamethasone to prolong peripheral nerve blocks: a ChatGPT-created narrative review

Chat Generative Pre-trained Transformer (ChatGPT), an artificial intelligence chatbot, produces detailed responses and human-like coherent answers, and has been used in the clinical and academic medicine. To evaluate its accuracy in regional anesthesia topics, we produced a ChatGPT review on the addition of dexamethasone to prolong peripheral nerve blocks. A group of experts in regional anesthesia and pain medicine were invited to help shape the topic to be studied, refine the questions entered in to the ChatGPT program, vet the manuscript for accuracy, and create a commentary on the article. Although ChatGPT produced an adequate summary of the topic for a general medical or lay audience, the review that were created appeared to be inadequate for a subspecialty audience as the expert authors. Major concerns raised by the authors included the poor search methodology, poor organization/lack of flow, inaccuracies/omissions of text or references, and lack of novelty. At this time, we do not believe ChatGPT is able to replace human experts and is extremely limited in providing original, creative solutions/ideas and interpreting data for a subspecialty medical review article.

Cardiovascular risk in the elderly population of Spain. The EPICARDIAN risk score

BACKGROUND AND OBJECTIVES

Cardiovascular risk estimation in people over 70 years of age is problematic. Most scores have been created based on cohorts of middle-aged people, with an underrepresentation of older adults. The predictive power of classical cardiovascular risk factors declines with age. The aim of this work is to develop a specific score for estimating cardiovascular risk among the elderly population in Spain.

METHODS

This work is a population-based cohort established in 1995.

SETTING

Three geographical areas of Spain (Madrid, Ávila, and Lugo).

PARTICIPANTS

3,729 people older than 64 years with no cardiovascular diseases (CVD) at baseline.

MEASUREMENTS

Suspected fatal and nonfatal CVD (both coronary heart disease and stroke) were investigated annually and confirmed using the WHO-MONICA criteria. All participants were followed-up on until occurrence of a first CVD event, until death, or until December 31, 2015.

RESULTS

Age was the strongest predictor of CVD at 10 years in both men and women. In men, variables associated with CVD were high blood pressure treatment (HR: 1.35; 95% CI: 1.067-1.710), diabetes (HR: 1.359; 95% CI: 0.997-1.852), and smoking (HR: 1.207; 95% CI: 0.945-1.541) and in women, the variables were smoking (HR: 1.881; 95% CI: 1.356-2.609) and diabetes (HR: 1.285; 95% CI: 0.967-1.707). Total cholesterol did not increase the risk of CVD in men or women. However, total cholesterol levels >200 mg/dL were inversely associated with 10-year risk of CVD in men and women.

CONCLUSIONS

In elderly Spanish men, total CVD at 10 years is significantly increased by age, diabetes, and antihypertensive treatment and in elderly Spanish women by diabetes and smoking. Total cholesterol levels did not increase the risk of CVD, particularly in males.

Influence of the external cephalic version attempt on the Cesarean section rate: experience of a type 3 maternity hospital in France

PURPOSE

To define the effects of attempted external cephalic version (ECV) in a low-risk population for breech delivery in a maternity hospital where breech vaginal delivery is widely practiced.

MATERIALS AND METHODS

Retrospective exposed-unexposed study including 204 patients presented with a live singleton fetus breech presentation on third-trimester ultrasound and who delivered at Reims University Hospital between January 1st, 2013 and July 1st, 2018.

RESULTS

121 patients received ECV. Cesarean section rate was lower (OR with no adjustment 0.42 [0.24-0.76] p = 0.004) but without significant difference in the exposed patients after adjustment. This difference was significant between exposed and unexposed patients in the subgroup of 51 primiparous (OR = 0.14 [0.04-0.52] p = 0.002) and 51 multiparous (OR = 0.26 [0.08-0.89] p = 0.028) but not in the subgroup of 102 nulliparous. There was no difference in fetal impact other than neonatal management in the delivery room, which is less needed in exposed primiparous women. Attempted ECV significantly decreased the breech rate (72.5 vs 100%, p < 0.001). There were 7 (5.79%) complications. Three factors favored success: high uterine height (p = 0.011), a non-elevated BMI (p = 0.006) and an earlier term at ECV (p = 0.003).

CONCLUSION

The attempt of ECV in the Reims University Hospital does not significantly reduce the Cesarean section rate and has no effect on neonatal status.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Long-term psychopathology changes among the injured and members of the community after a massive terrorist attack

Background and aim

To document long-term prevalence trends and changes in Post-Traumatic Stress Disorder (PTSD), Current Major Depression (MD), Agoraphobia, Generalized Anxiety Disorder (GAD), and Panic Disorder, in two groups of people with different levels of exposure to a massive terrorist attack.

Methods

Cohort study. Two random samples of people exposed to a terrorist attack, the injured (n = 127) and community residents (n = 485) were followed and assessed, 2 and 18 months after the event.

Results

Among the injured, 2 and 18 months after the attack, the prevalences were respectively, PTSD: 44.1% and 34%, MD: 31.5% and 23.7%, Agoraphobia: 23.8% and 20.7%, GAD: 13.4% and 12.4% and Panic Disorder: 9.4% and 11.3%. The corresponding figures among residents were PTSD: 12.3% and 3.5%, MD: 8.5% and 5.4%, Agoraphobia: 10.5% and 8.7%, GAD: 8.6%, and 8.2% and Panic Disorder 2.1% and 2.7%.

Conclusions

Two months after the event, the prevalence of mental disorders among both injured and residents was higher than expected levels at baseline conditions. Eighteen months after the event, psychopathological conditions did not change significantly among the injured but returned to the expected baseline rates among community residents.

Posttraumatic stress disorder in victims of the March 11 attacks in Madrid admitted to a hospital emergency room: 6-month follow-up

Purpose:

To determine the change in prevalence of posttraumatic stress disorder (PTSD) symptoms in victims of the March 11 attacks and their relatives, 1 and 6 months after the attacks.

Subjects and methods

Evaluation of PTSD symptoms using the Davidson Trauma Scale (DTS) and General Health Questionnaire (GHQ) in a sample of 56 patients admitted to an emergency room of a general hospital, and assessment of PTSD symptoms in relatives of the patients.

Results:

At Month 1, 41.1% of patients (31.3% of males and 54.2% of females) presented with PTSD. At Month 6, this figure was 40.9% (30.4% of males and 52.4% of females). There was a significant improvement in perception of health among females between Month 1 and Month 6. Relatives presented similar DTS scores at baseline and at 6 months.

Discussion:

We verified that rates of PTSD did not vary substantively between the two evaluations. PTSD symptoms positively correlated with psychological health involvement. This correlation points out that both PTSD symptoms and subjective general health involvement are part of the psychological response to trauma.

Conclusion:

The prevalence of PTSD symptoms was high and remained stable between Month 1 and Month 6, while subjective perception of health improved significantly.

P757Methamphetamine-associated cardiomyopathy: a case-controlled study of clinical characteristics, management and outcomes

Background

Methamphetamine-associated cardiomyopathy (MAC) is an increasingly diagnosed condition with poor prognosis, and there remains paucity of literature including how MAC differs from other cardiomyopathies. We compared the characteristics and outcomes MAC patients with non-ischaemic cardiomyopathy controls at our centre.

Methods

Clinical profile, management and outcomes were prospectively assessed in consecutive patients with MAC at our hospital from 2006–2018. They were compared with randomly chosen controls with non-ischaemic dilated cardiomyopathy of similar age-group (20–65 year).

Results

Both groups had 62 patients followed for 3.0±2.9 years. MAC patients were younger, with higher proportion of Maori ethnicity, unemployment and cardiogenic shock during index admission and lower proportion of Pacific ethnicity, cardiovascular risk factors and atrial fibrillation. MAC patients also had higher peak NT-proBNP, lower ejection fraction, and lower attendance rate to outpatient appointments. There was no index admission mortality in both groups. MAC had higher mortality and trend to higher heart failure re-admissions rates during follow-up (Figure 1). Amongst MAC patients, baseline left ventricular end diastolic diameter and failure of improvement in right ventricular systolic function by one category during follow-up were independent predictors of mortality, while failure of improvement of left ventricular ejection fraction by one category predicted heart failure readmission.

Figure 1

Conclusions

MAC patients were younger but sicker on presentation, with higher mortality and trend towards higher heart failure readmission rates during medium-term follow-up than controls. Adherence to therapy and attendance to appointments may improve cardiac systolic function over time to reduce adverse clinical endpoints.

Gynecology-obstetric resident surgery training: a national evaluation

OBJECTIVES

The main objective of this study was to evaluate surgery training and evaluation of French gynecology-obstetrics residents. The second objective was to evaluate using simulation during residency.

STUDY DESIGN

This national descriptive study, utilized a questionnaire to survey all interns in French gynecology and obstetrics. At the end of a study, 129 responses of residents were analyzed.

RESULTS

The participation rate was 12%. The majority of residents were women (84%) and the highest response rate was from the Ile-de-France region (36%). The lowest rate was from the Southern region. The majority of residents were in the eighth semester (20%). Residents reported surgical and obstetric orientations in 53% (n = 68) and 44% (n = 57) of cases, respectively. Registration for cancer oncology was reported by 22% (n = 28) of respondents. Evaluation of oncologic surgery training was mostly considered "good" by the surgical group and "passable" by the obstetrics group. Access to simulators was usually restricted and most often utilized the pelvitrainer. Sessions were typically not mandatory and numbered between zero and five per semester. Three types of simulators were accessible in the Ile-de-France, North-West, West and Rhône-Alpes. The North-East did not have access to animal models, and the South-West did not have access to corpses. Surgical classes were more common in the Rhône-Alpes, North-East, Ile-de-France and North-West regions. To improve their training in oncological surgery, 64% (n = 18) of residents planned to do an inter-university exchange and 54% had completed additional specialized training. Measures that were most expected to improve training were increased training in surgery (96% of respondents, n = 27) and more intensive coaching (96%, n = 27).

CONCLUSIONS

Companionship is a pillar of residents training, but its effectiveness is variable. One solution could be to implement better use of simulation methods.

Associations between sleep duration and sleep debt with insulin sensitivity and insulin secretion in the EGIR-RISC Study

AIM

Extremes in sleep duration play an important role in the development of type 2 diabetes. We examined the associations between sleep duration and sleep debt with estimates of insulin sensitivity and insulin secretion.

METHODS

Data were derived from the European multi-centre EGIR-RISC study. Sleep duration and sleep debt were derived from a sleep questionnaire asking about sleeping time during the week and during the weekend. Insulin sensitivity and insulin secretion were estimated from a 2-hour Oral Glucose Tolerance Test, with samples every 30 minutes. Associations between sleep duration and sleep debt with insulin sensitivity and insulin secretion, were analysed by multiple linear regression models corrected for possible confounders.

RESULTS

Sleep data were available in 1002 participants, 46% men, mean age 48 ± 8 years, who had an average sleep duration of 7 ± 1 hours [range 3-14] and an average sleep debt (absolute difference hours sleep weekend days minus weekdays) of 1 ± 1 hour [range 0-8]. With regard to insulin sensitivity, we observed an inverted U-shaped association between sleep duration and the Stumvoll MCR in (mL/kg/min), with a corrected β (95% CI) of 2.05 (0.8; 3.3) and for the quadratic term -0.2 (-0.3; -0.1). Similarly, a U-shaped association between sleep duration and log HOMA-IR in (µU/mL), with a corrected βs of -0.83 (-1.4; -0.24) and 0.06 (0.02; 0.10) for the quadratic term. Confounders showed an attenuating effect on the associations, while BMI mediated 60 to 91% of the association between sleep duration and insulin sensitivity. No significant associations were observed between sleep duration with insulin secretion or between sleep debt with either insulin sensitivity or insulin secretion.

CONCLUSIONS

Short and long sleep duration are associated with a lower insulin sensitivity, suggesting that sleep plays an important role in insulin resistance and may provide the link with development of type 2 diabetes.

Molecular Evidence of Genome Editing in a Mouse Model of Immunodeficiency

Genome editing is the introduction of directed modifications in the genome, a process boosted to therapeutic levels by designer nucleases. Building on the experience of ex vivo gene therapy for severe combined immunodeficiencies, it is likely that genome editing of haematopoietic stem/progenitor cells (HSPC) for correction of inherited blood diseases will be an early clinical application. We show molecular evidence of gene correction in a mouse model of primary immunodeficiency. In vitro experiments in DNA-dependent protein kinase catalytic subunit severe combined immunodeficiency (Prkdc scid) fibroblasts using designed zinc finger nucleases (ZFN) and a repair template demonstrated molecular and functional correction of the defect. Following transplantation of ex vivo gene-edited Prkdc scid HSPC, some of the recipient animals carried the expected genomic signature of ZFN-driven gene correction. In some primary and secondary transplant recipients we detected double-positive CD4/CD8 T-cells in thymus and single-positive T-cells in blood, but no other evidence of immune reconstitution. However, the leakiness of this model is a confounding factor for the interpretation of the possible T-cell reconstitution. Our results provide support for the feasibility of rescuing inherited blood disease by ex vivo genome editing followed by transplantation, and highlight some of the challenges.

Insulin resistance and β-cell function in smokers: results from the EGIR-RISC European multicentre study

AIMS

Tobacco smoking is known to increase the long-term risk of developing Type 2 diabetes mellitus, but the mechanisms involved are poorly understood. This observational, cross-sectional study aims to compare measures of insulin sensitivity and β-cell function in current, ex- and never-smokers.

METHODS

The study population included 1246 people without diabetes (mean age 44 years, 55% women) from the EGIR-RISC population, a large European multicentre cohort. Insulin sensitivity was measured using a hyperinsulinaemic, euglycaemic clamp and the homeostatic model assessment - insulin resistance (HOMA-IR) index. Two β-cell function parameters were derived from measures during an oral glucose tolerance test: the early insulin response index and β-cell glucose sensitivity. Additionally, the areas under the curve during the oral glucose tolerance test were calculated for glucose, insulin and C-peptide.

RESULTS

According to smoking habits, there were differences in insulin sensitivity, which was lower in women who smoked, and in β-cell glucose sensitivity, which was lower in men who smoked, but these associations lost significance after adjustment. However, after adjustment, the areas under the glucose and the C-peptide curves during the oral glucose tolerance test were significantly higher in men who smoked.

CONCLUSIONS

Smoking habits were not independently associated with insulin sensitivity or β-cell function in a healthy middle-aged European population. Health-selection bias, methodological shortcomings or a true lack of causal links between smoking and impaired insulin sensitivity/secretion are possible explanations. The mechanisms behind the observed increased glucose and C-peptide areas under the curve during the oral glucose tolerance test in male smokers need to be further evaluated.

[French residents' training in instrumental deliveries: A national survey]

OBJECTIVES

To evaluate French residents in Obstetrics and Gynaecology's training in instrumental deliveries in 2015.

PATIENTS AND METHODS

We conducted a national descriptive survey among 758 residents between December 2014 and January 2015. Respondents were invited by email to specify their University Hospital, their current university term, the number of instrumental deliveries performed by vacuum extractor, forceps or spatulas, and whether they made systematic ultrasound exams before performing the extraction.

RESULTS

Response rate was 34.7 % (n=263). There were important differences between regions in terms of type of instruments used. Vacuum extractor was the most commonly used instrument for instrumental deliveries by French residents (56.9 %), more than forceps (25.2 %) and spatulas (17.9 %). At the end of the residency, all the residents had been trained in instrumental deliveries with at least two instruments.

CONCLUSION

The training of difficult techniques as well as their perfect control is required for instrumental deliveries. Yet, we are forced to note that there are substantial differences in the French residents' training in instrumental deliveries depending on their region. So, teaching at least two techniques seems essential as well as improving the training capacities and standardizing practices. A greater systematization of the teaching of the mechanics and obstetric techniques might be a solution to be considered too.

Pituitary Adenylate Cyclase Activating Polypeptide, A Potential Therapeutic Agent for Diabetic Retinopathy in Rats: Focus on the Vertical Information Processing Pathway

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurotrophic and neuroprotective peptide that has been shown to exert protective effects in different neuronal injuries, such as retinal degenerations. Diabetic retinopathy (DR), the most common complication of diabetes, affects the microvasculature and neuronal architecture of the retina. We have proven earlier that PACAP is also protective in a rat model of DR. In this study, streptozotocin-induced DR was treated with intravitreal PACAP administration in order to further analyze the synaptic structure and proteins of PACAP-treated diabetic retinas, primarily in the vertical information processing pathway. Streptozotocin-treated Wistar rats received intravitreal PACAP injection three times into the right eye 2 weeks after the induction of diabetes. Morphological and molecular biological (qRT-PCR; Western blot) methods were used to analyze retinal synapses (ribbons, conventional) and related structures. Electron microscopic analysis revealed that retinal pigment epithelium, the ribbon synapses and other synaptic profiles suffered alterations in diabetes. However, in PACAP-treated diabetic retinas more bipolar ribbon synapses were found intact in the inner plexiform layer than in DR animals. The ribbon synapse was marked with C-terminal binding protein 2/Bassoon and formed horseshoe-shape ribbons, which were more retained in PACAP-treated diabetic retinas than in DR rats. These results are supported by molecular biological data. The selective degeneration of related structures such as bipolar and ganglion cells could be ameliorated by PACAP treatment. In summary, intravitreal administration of PACAP may have therapeutic potential in streptozotocin-induced DR through maintaining synapse integrity in the vertical pathway.

Urocortin 2 treatment is protective in excitotoxic retinal degeneration

Urocortin 2 (Ucn 2) is a corticotrop releasing factor paralog peptide with many physiological functions and it has widespread distribution. There are some data on the cytoprotective effects of Ucn 2, but less is known about its neuro- and retinoprotective actions. We have previously shown that Ucn 2 is protective in ischemia-induced retinal degeneration. The aim of the present study was to examine the protective potential of Ucn 2 in monosodium-glutamate (MSG)-induced retinal degeneration by routine histology and to investigate cell-type specific effects by immunohistochemistry. Rat pups received MSG applied on postnatal days 1, 5 and 9 and Ucn 2 was injected intravitreally into one eye. Retinas were processed for histology and immunocytochemistry after 3 weeks. Immunolabeling was determined for glial fibrillary acidic protein, vesicular glutamate transporter 1, protein kinase Cα, calbindin, parvalbumin and calretinin. Retinal tissue from animals treated with MSG showed severe degeneration compared to normal retinas, but intravitreal Ucn 2 treatment resulted in a retained retinal structure both at histological and neurochemical levels: distinct inner retinal layers and rescued inner retinal cells (different types of amacrine and rod bipolar cells) could be observed. These findings support the neuroprotective function of Ucn 2 in MSG-induced retinal degeneration.

Examination of calcium-binding protein expression in the inner ear of wild-type, heterozygous and homozygous pituitary adenylate cyclase-activating polypeptide (PACAP)-knockout mice in kanamycin-induced ototoxicity

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with diverse biological effects. It also occurs and exerts protective effects in sensory organs; however, little is known about its effects in the auditory system. Recently, we have shown that PACAP protects cochlear cells against oxidative-stress-induced apoptosis and homozygous PACAP-deficient animals show stronger expression of Ca(2+)-binding proteins in the hair cells of the inner ear, but there are no data about the consequences of the lack of endogenous PACAP in different ototoxic insults such as aminoglycoside-induced toxicity. In this study, we examined the effect of kanamycin treatment on Ca(2+)-binding protein expression in hair cells of wild-type, heterozygous and homozygous PACAP-deficient mice. We treated 5-day-old mice with kanamycin, and 2 days later, we examined the Ca(2+)-binding protein expression of the hair cells with immunohistochemistry. We found stronger expression of Ca(2+)-binding proteins in the hair cells of control heterozygous and homozygous PACAP-deficient mice compared with wild-type animals. Kanamycin induced a significant increase in Ca(2+)-binding protein expression in wild-type and heterozygous PACAP-deficient mice, but the baseline higher expression in homozygous PACAP-deficient mice did not show further changes after the treatment. Elevated endolymphatic Ca(2+) is deleterious for the cochlear function, against which the high concentration of Ca(2+)-buffers in hair cells may protect. Meanwhile, the increased immunoreactivity of Ca(2+)-binding proteins in the absence of PACAP provide further evidence for the important protective role of PACAP in ototoxicity, but further investigations are necessary to examine the exact role of endogenous PACAP in ototoxic insults.

Taking small steps towards targets - perspectives for clinical practice in diabetes, cardiometabolic disorders and beyond

Big changes are hard. When trying to achieve guideline targets in diabetes and cardiometabolic disorders, patients can lack commitment or suffer despondency. It is much easier to make small changes in lifestyle or treatment, which are less noticeable and easier to manage long-term. Obesity is central to the cardiometabolic disorders, and even small weight losses of 2-5% can improve the cardiometabolic risk profile and substantially reduce the risk of developing type 2 diabetes. Likewise, small increases in physical activity, such as 15-30 min of brisk walking per day, can cut the risk of heart disease by 10%. Lifestyle or treatment changes that lead to small improvements in metabolic parameters also impact patient outcome - for example, a 5 mmHg decrease in blood pressure can translate into significant reductions in the rates of myocardial infarction and cardiovascular mortality. Benefits of small changes can also be seen in health economic outcome models. Implementing change at an individual versus a population level has different implications for overall benefit and patient motivation. Even very small steps taken in trying to reach guideline targets should represent a positive achievement for patients. Patient engagement is essential - only when patients commit themselves to change can benefits be maintained, and physicians should recognise their influence. Small changes in individual parameters can result in significant beneficial effects; however, a major impact can occur when small changes are made together in multiple parameters. More research is required to elucidate the full impact of small changes on patient outcome.

Associations between surrogate measures of insulin resistance and waist circumference, cardiovascular risk and the metabolic syndrome across Hispanic and non-Hispanic white populations

AIMS

We evaluated the relations between surrogate indices of insulin resistance and waist circumference, metabolic syndrome and coronary heart disease risk across Hispanic and non-Hispanic white populations.

METHODS

The study was a cross-sectional analysis of participants without diabetes in the San Antonio Heart Study, Mexico City Diabetes Study and Spanish Insulin Resistance Study. We evaluated commonly used indices of insulin resistance, including homeostasis model assessment, McAuley's index, Gutt's insulin sensitivity index, Avignon's insulin sensitivity index and the Stumvoll index with and without demographics, the modified Matsuda index and the product of the triglycerides and glucose index. The metabolic syndrome was defined by American Heart Association/National Heart, Lung, and Blood Institute criteria and coronary heart disease risk by Framingham risk scores.

RESULTS

The Stumvoll index with demographics and the Avignon's insulin sensitivity index had the strongest correlations with waist circumference across populations. The triglycerides and glucose and McAuley's indices had the most robust correlations with Framingham risk score. The triglycerides and glucose index had the greatest ability to detect individuals with the metabolic syndrome and ≥ 10% coronary heart disease risk. Some indices display significant variability in the strength of the relationship with adiposity and coronary heart disease risk across populations.

CONCLUSIONS

There are significant differences between insulin resistance indices regarding the ability to detect the metabolic syndrome and coronary heart disease risk across populations. Studies may need to consider the index of insulin resistance that best suits the objectives.

Mice deficient in pituitary adenylate cyclase activating polypeptide (PACAP) are more susceptible to retinal ischemic injury in vivo

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuroprotective peptide exerting protective effects in neuronal injuries. We have provided evidence that PACAP is neuroprotective in several models of retinal degeneration in vivo. Our previous studies showed that PACAP treatment ameliorated the damaging effects of chronic hypoperfusion modeled by permanent bilateral carotid artery occlusion. We have also demonstrated in earlier studies that treatment with PACAP antagonists further aggravates retinal lesions. It has been shown that PACAP deficient mice have larger infarct size in cerebral ischemia. The aim of this study was to compare the degree of retinal damage in wild type and PACAP deficient mice in ischemic retinal insult. Mice underwent 10 min of bilateral carotid artery occlusion followed by 2-week reperfusion period. Retinas were then processed for histological analysis. It was found that PACAP deficient mice had significantly greater retinal damage, as shown by the thickness of the whole retina, the morphometric analysis of the individual retinal layers, and the cell numbers in the inner nuclear and ganglion cell layers. Exogenous PACAP administration could partially protect against retinal degeneration in PACAP deficient mice. These results clearly show that endogenous PACAP reacts as a stress-response peptide that is necessary for endogenous protection against different retinal insults.