Hypothalamic-pituitary hormones during critical illness: a dynamic neuroendocrine response

Systematic review and meta-analysis of serum total testosterone and luteinizing hormone variations across hospitalized Covid-19 patients

A growing body of evidence suggests the role of male hypogonadism as a possible harbinger for poor clinical outcomes across hospitalized Covid-19 patients. Accordingly, we sought to investigate the impact of dysregulated hypothalamic-pituitary-gonadal axis on the severity of the clinical manifestations for hospitalized Covid-19 patients matched with healthy controls through a systematic review and meta-analysis. Databases were searched from inception to March 2022. A standardized mean difference (SMD) meta-analysis focused on hospitalized Covid-19 patients and healthy controls was developed for studies who reported total testosterone (TT) and luteinizing hormone (LH) levels at hospital admission. Overall, n = 18 series with n = 1575 patients between 2020 and 2022 were reviewed. A significant decrease in SMD of TT levels in Covid-19 patients compared to paired controls was observed (- 3.25 nmol/L, 95%CI - 0.57 and - 5.93). This reduction was even more consistent when matching severe Covid-19 patients with controls (- 5.04 nmol/L, 95%CI - 1.26 and - 8.82) but similar for Covid-19 survivors and non-survivors (- 3.04 nmol/L, 95%CI - 2.04 and - 4.05). No significant variation was observed for serum LH levels across studies. Patient related comorbidities, year of the pandemic, and total lymphocyte count were associated with the observed estimates. TT levels may be a useful serum marker of poor outcomes among Covid-19 patients. These findings may support the development of ad-hoc clinical trials in the Covid-19 risk-group classification and subsequent disease monitoring. The interplay between TT and immune response should be evaluated in future researches.

Long-term impact of paediatric critical illness on the difference between epigenetic and chronological age in relation to physical growth

BACKGROUND

Altered DNA-methylation affects biological ageing in adults and developmental processes in children. DNA-methylation is altered by environmental factors, trauma and illnesses. We hypothesised that paediatric critical illness, and the nutritional management in the paediatric intensive care unit (PICU), affects DNA-methylation changes that underly the developmental processes of childhood ageing.

RESULTS

We studied the impact of critical illness, and of the early use of parenteral nutrition (early-PN) versus late-PN, on "epigenetic age-deviation" in buccal mucosa of 818 former PICU-patients (406 early-PN, 412 late-PN) who participated in the 2-year follow-up of the multicentre PEPaNIC-RCT (ClinicalTrials.gov-NCT01536275), as compared with 392 matched healthy children, and assessed whether this relates to their impaired growth. The epigenetic age-deviation (difference between PedBE clock-estimated epigenetic age and chronological age) was calculated. Using bootstrapped multivariable linear regression models, we assessed the impact hereon of critical illness, and of early-PN versus late-PN. As compared with healthy children, epigenetic age of patients assessed 2 years after PICU-admission deviated negatively from chronological age (p < 0.05 in 51% of bootstrapped replicates), similarly in early-PN and late-PN groups. Next, we identified vulnerable subgroups for epigenetic age-deviation using interaction analysis. We revealed that DNA-methylation age-deceleration in former PICU-patients was dependent on age at time of illness (p < 0.05 for 83% of bootstrapped replicates), with vulnerability starting from 6 years onwards. Finally, we assessed whether vulnerability to epigenetic age-deviation could be related to impaired growth from PICU-admission to follow-up at 2 and 4 years. Multivariable repeated measures ANOVA showed that former PICU-patients, as compared with healthy children, grew less in height (p = 0.0002) and transiently gained weight (p = 0.0003) over the 4-year time course. Growth in height was more stunted in former PICU-patients aged ≥ 6-years at time of critical illness (p = 0.002) than in the younger patients.

CONCLUSIONS

As compared with healthy children, former PICU-patients, in particular those aged ≥ 6-years at time of illness, revealed epigenetic age-deceleration, with a physical correlate revealing stunted growth in height. Whether this vulnerability around the age of 6 years for epigenetic age-deceleration and stunted growth years later relates to altered endocrine pathways activated at the time of adrenarche requires further investigation.

Endocrine Aspects of ICU-Hospitalized COVID-19 Patients

The unprecedented scale of the current SARS-CoV-2/COVID-19 pandemic has led to an extensive—yet fragmented—assessment of its endocrine repercussions; in many reports, the endocrine aspects of COVID-19 are lumped together in intensive care unit (ICU) patients and non-ICU patients. In this brief review, we aimed to present endocrine alterations in ICU-hospitalized patients with COVID-19. There are tangible endocrine disturbances that may provide fertile ground for COVID-19, such as preexisting diabetes. Other endocrine disturbances accompany the disease and more particularly its severe forms. Up to the time of writing, no isolated robust endocrine/hormonal biomarkers for the prognosis of COVID-19 have been presented. Among those which may be easily available are admission glycemia, thyroid hormones, and maybe (OH)₂₅-vitamin D3. Their overlap among patients with severe and less severe forms of COVID-19 may be considerable, so their levels may be indicative only. We have shown that insulin-like growth factor 1 may have prognostic value, but this is not a routine measurement. Possibly, as our current knowledge is expanding, the inclusion of selected routine endocrine/hormonal measurements into artificial intelligence/machine learning models may provide further information.

Perspective: Drawing on Findings From Critical Illness to Explain Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

We propose an initial explanation for how myalgic encephalomyelitis / chronic fatigue syndrome (ME/CFS) could originate and perpetuate by drawing on findings from critical illness research. Specifically, we combine emerging findings regarding (a) hypoperfusion and endotheliopathy, and (b) intestinal injury in these illnesses with our previously published hypothesis about the role of (c) pituitary suppression, and (d) low thyroid hormone function associated with redox imbalance in ME/CFS. Moreover, we describe interlinkages between these pathophysiological mechanisms as well as “vicious cycles” involving cytokines and inflammation that may contribute to explain the chronic nature of these illnesses. This paper summarizes and expands on our previous publications about the relevance of findings from critical illness for ME/CFS. New knowledge on diagnostics, prognostics and treatment strategies could be gained through active collaboration between critical illness and ME/CFS researchers, which could lead to improved outcomes for both conditions.

Assessment of Neuroendocrine Changes and Hypothalamo-Pituitary Autoimmunity in Patients with COVID-19

SARS-CoV-2 may affect the hypothalamic-pituitary axis and pituitary dysfunction may occur. Therefore, we investigated neuroendocrine changes, in particular, secondary adrenal insufficiency, using a dynamic test and the role of autoimmunity in pituitary dysfunction in patients with COVID-19. The single-center, prospective, case-control study included patients with polymerase chain reaction (PCR)-confirmed COVID-19 and healthy controls. Basal hormone levels were measured, and the adrenocorticotropic hormone (ACTH) stimulation test was performed. Antipituitary (APA) and antihypothalamic antibodies (AHA) were also determined. We examined a total of 49 patients with COVID-19 and 28 healthy controls. The frequency of adrenal insufficiency in patients with COVID-19 was found as 8.2%. Patients with COVID-19 had lower free T₃, IGF-1, and total testosterone levels, and higher cortisol and prolactin levels when compared with controls. We also demonstrated the presence of APA in three and AHA in one of four patients with adrenal insufficiency. In conclusion, COVID-19 may result in adrenal insufficiency, thus routine screening of adrenal functions in these patients is needed. Endocrine disturbances in COVID-19 are similar to those seen in acute stressful conditions or infections. Pituitary or hypothalamic autoimmunity may play a role in neuroendocrine abnormalities in COVID-19.

Serum leptin level as a diagnostic and prognostic marker in infectious diseases and sepsis: A comprehensive literature review

BACKGROUND

Infections and sepsis are common causes of morbidity and mortality, with an increasing incidence worldwide. Leptin is involved in the inflammatory process and may modulate the cytokine production, immune cell proliferation and endothelial function. There are conflicting results regarding alterations of leptin levels in infectious diseases and the outcome from sepsis.The aim of the current article is to provide an overview of the medical literature on the correlations between variations of leptin levels and infectious diseases and sepsis.

METHODS

We performed an extensive literature search in PubMed and Google Scholar databases, using keywords to identify articles related to leptin in infectious diseases and sepsis. Searches were referenced using medical subject headings that included "leptin," "adipokines," "sepsis," "infectious diseases," "leptin deficiency," "leptin resistance" or "hyperleptinemia." The language of publication, journal, or country were not included as limitation criteria.Articles or abstracts containing adequate information, such as age, sex, anthropometric indices, clinical presentation, comorbidities, and management were included in the study, whereas articles with insufficient clinical and demographic data were excluded. We assessed the quality of the studies selected.The final review of all databases was conducted on June 18, 2020.

RESULTS

We find the results from the current review to be of great importance due to the possible therapeutic role of leptin analogs in states of leptin deficiency associated with infectious diseases or sepsis.In hyperleptinemia, a therapeutic plan for obtaining leptin neutralization also needs further investigations. This could lead to the reduction of proinflammatory responses.There is a need for further studies to demonstrate the specificity and sensitivity of leptin in the early diagnosis of sepsis and the need to measure serum leptin levels in routine evaluation of the critical patient.

CONCLUSION

The multiple effects of leptin are of growing interest, but further studies are needed to elucidate the role of leptin signalling in infectious diseases and sepsis. Because very few human studies are reported, we recommend the need for further research.Better understanding of the pathophysiology of sepsis and the implication of circulating total leptin in this process could help physicians in managing this life-threatening condition.

Hypothesis: Mechanisms That Prevent Recovery in Prolonged ICU Patients Also Underlie Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)

Here the hypothesis is advanced that maladaptive mechanisms that prevent recovery in some intensive care unit (ICU) patients may also underlie Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Specifically, these mechanisms are: (a) suppression of the pituitary gland's pulsatile secretion of tropic hormones, and (b) a "vicious circle" between inflammation, oxidative and nitrosative stress (O&NS), and low thyroid hormone function. This hypothesis should be investigated through collaborative research projects.

Dynamics of testosterone levels in patients with newly detected glucose abnormalities and acute myocardial infarction

OBJECTIVE

Low testosterone has been associated with increased cardiovascular risk and glucose abnormalities. This study explored the prevalence of low testosterone, dynamics over time and prognostic implications in acute myocardial infarction patients with or without glucose abnormalities.

METHODS

Male acute myocardial infarction patients (n = 123) and healthy controls (n = 124) were categorised as having normal or abnormal glucose tolerance (impaired glucose tolerance or diabetes) by oral glucose tolerance testing. Testosterone was measured at hospital admission, discharge, 3 and 12 months thereafter in patients. Patients and controls were followed for 11 years for major cardiovascular events (cardiovascular death/acute myocardial infarction/stroke/severe heart failure).

RESULTS

At hospital admission, more patients had low testosterone (⩽300 ng/dl) and lower median levels than controls (64 vs 28%; p < 0.001 and 243 vs 380 ng/dl; p < 0.01). At the subsequent time points, testosterone had increased to 311, 345 and 357 ng/dl. Patients with abnormal glucose tolerance had the highest prevalence (75%) of low levels. In adjusted Cox regression models, neither total nor free testosterone predicted major cardiovascular events.

CONCLUSION

Low testosterone levels were common in male acute myocardial infarction patients in the acute phase, especially in the presence of abnormal glucose tolerance, but increased over time indicating that testosterone measured in close proximity to acute myocardial infarction should be interpreted with caution.

Impact of Thyroid Hormone Levels on Functional Outcome in Neurological and Neurosurgical Early Rehabilitation Patients

Background

Neurological and neurosurgical early rehabilitation (NNER) is a specialized treatment option for patients with severe neurological disorders. The present study investigated whether thyroid hormone levels on admission have an impact on the outcome of NNER patients.

Method

The study included 500 NNER patients who were admitted to the BDH-Clinic Hessisch Oldendorf between 2009 and 2010. Data such as age, sex, diagnoses, comorbidities, Glasgow Coma Scale score, length of stay, and thyroid hormone levels (obtained as part of clinical routine care) were analyzed retrospectively. Improvement in the Early Rehabilitation Barthel Index (ERBI) at the end of the NNER treatment was defined as outcome parameter.

Results

Most patients made functional progress during treatment, as reflected in significant enhancements of the ERBI. Approximately half of the patients were transferred to further rehabilitation treatment. Young age, early onset of NNER treatment, low functional impairment on admission, and, in particular, low total T3 levels were independently associated with a good outcome.

Conclusion

Age, severity of disease, and time between injury and admission are known to predict outcome. The present study confirms the influence of these general factors. In addition, an association between thyroid hormones and functional outcome was demonstrated for NNER patients.

Acute hormonal findings after aneurysmal subarachnoid hemorrhage - report from a single center

PURPOSE

The aim was to assess anterior pituitary hormone levels during the acute phase of aneurysmal subarachnoid hemorrhage (aSAH) and analyze the possible association with the clinical condition and outcome.

MATERIAL AND METHODS

Forty patients with aSAH whose aneurysm was secured by endovascular coiling were enrolled. Basal secretions of cortisol, testosterone, luteinizing hormone (LH), prolactin (PRL), and sex hormone binding globulin (SHBG) levels were measured up to 14 days after the incident.

RESULTS

The main finding was that hypocortisolism was rare whereas testosterone deficiency was common in male patients. Furthermore, various other hormone deviations were frequent and there was wide interindividual variability. We found no association between delayed cerebral ischemia (DCI), outcome of the patients or aneurysm location, and hormone abnormalities, while both Hunt & Hess and Fisher grade were associated with low PRL levels. Hunt & Hess 5 was associated with low PRL concentration when compared to grades 1 (OR = 4.81, 95% CI 1.15-20.14, p = 0.03), 3 (OR 7.73, 95% CI 1.33-45.01, p = 0.02), and 4 (OR = 6.86 95% CI 1.28-26.83, p = 0.02). Fisher grade 4 was associated with low PRL concentration when compared to grades 3 (OR 3.37, 95% CI 1.06-10.73, p = 0.03) and 2 (OR 9.71, 95% CI 1.22-77.10, p = 0.04).

CONCLUSION

Deviations from normal and huge interindividual differences are common in hormone levels during the acute phase of aSAH. Routine assessment of anterior pituitary function in the acute phase of aSAH is not warranted. During the follow-up in the outpatient clinic, hormone concentrations were not measured, which would have brought a more long-term perspective into our findings.

Effects of forced swimming stress on thyroid function, pituitary thyroid-stimulating hormone and hypothalamus thyrotropin releasing hormone expression in adrenalectomy Wistar rats

In order to study the impact that is imposed on the hypothalamic-pituitary-thyroid (HPT) axis of adrenalectomy male Wistar rats by stress caused by swimming, the blood level of triiodothyronine (T3), thyroxine (T4) and thyroid-stimulating hormone (TSH), the expression of TSHβ mRNA at the pituitary and thyrotropin releasing hormone (TRH) expression at the paraventricular nucleus (PVN) were measured. A total of 50 male Wistar rats of 6-8 weeks of age and with an average weight of 190-210 grams were randomly divided into the following two groups: The surgical (without adrenal glands) and non-surgical (adrenalectomy) group. These two groups were then divided into the following five groups, according to the time delay of sacrifice following forced swim (10 min, 2 h, 12 h and 24 h) and control (not subjected to swimming) groups. A bilateral adrenalectomy animal model was established. Serum TSH in the blood was measurement by chemiluminescent immunoassay, and cerebrum tissue were excised for the measurement of TRH expression using an immunohistochemistry assay. In addition, pituitaries were excised for the extraction of total RNA. Finally, reverse transcription-quantitative polymerase chain reaction was performed for quantitation of TSHβ. Following swimming, the serum T3, T4 and TSH, the TSHβ mRNA expression levels in the pituitary and the TRH expression in the PVN of the surgical group were gradually increased. In the non-surgical group, no significant differences were observed in the serum T3, T4 and TSH levels compared with the control group. The TSHβ mRNA expression at the pituitary showed a similar result. Furthermore, the TRH expression at PVN was gradually increased and stress from swimming could increase the blood T4, T3 and TSH levels, TSHβ mRNA expression at the pituitary and TRH expression at the PVN in adrenalectomy Wistar rats. Moreover, the index in the surgical group changed significantly compared with the non-surgical group. In conclusion, the results suggest that there is a positive correlation between stress from forced swimming and the variation of the HPT axis.

Testosterone and Cardiovascular Disease

Testosterone (T) is the principal male sex hormone. As men age, T levels typically fall. Symptoms of low T include decreased libido, vasomotor instability, and decreased bone mineral density. Other symptoms may include depression, fatigue, erectile dysfunction, and reduced muscle strength/mass. Epidemiology studies show that low levels of T are associated with more atherosclerosis, coronary artery disease, and cardiovascular events. However, treating hypogonadism in the aging male has resulted in discrepant results in regard to its effect on cardiovascular events. Emerging studies suggest that T may have a future role in treating heart failure, angina, and myocardial ischemia. A large, prospective, long-term study of T replacement, with a primary endpoint of a composite of adverse cardiovascular events including myocardial infarction, stroke, and/or cardiovascular death, is needed. The Food and Drug Administration recently put additional restrictions on T replacement therapy labeling and called for additional studies to determine its cardiac safety.

Occult endocrine dysfunction in patients of cerebrovascular accident

Background:

Cerebrovascular disorders are common conditions leading to significant morbidity and mortality in the population. Occult endocrine disorders also contribute to the morbidity and we studied the prevalence of endocrine dysfunction in patients of cerebrovascular accident (CVA).

Materials and Methods:

We evaluated 30 patients of CVA (aged 18-75, admission within 72 h of symptoms and positive neuroimaging) in this prospective, observational study. All subjects were assessed clinically and biochemically for hormonal dysfunction at admission and for mortality at the end of 1 month. The patients were divided into two groups: Group 1 (infarct, n = 20) and Group 2 (hemorrhage, n = 10) and the data were analyzed with appropriate statistical tests using GraphPad Prism Software, version 6.

Results:

The study participants (24M:6F) had a mean age of 60.7 ± 11.4 years and body weight of 67.2 ± 11.4 kg. Fourteen out of 30 patients showed results consistent with an endocrine disorder, including sick euthyroid syndrome (SES) and central hypothyroidism (n = 10), secondary hypogonadism (n = 3), subclinical hypothyroidism (n = 1), and growth hormone (GH) deficiency in two patients. The endocrine conditions did not differ significantly between both the groups and nine out of 30 patients succumbed to their illness within 1 month. None of the hormonal parameters studied, could predict the 30 day mortality.

Conclusion:

Endocrine disorders are common in acute stage of CVA and commonest finding is a SES. Hormonal dysfunction did not differ based on the etiology of the CVA. Long-term follow-up is essential to understand the morbidity contributed by the hormonal alterations.