Correlates of low testosterone in men with chronic spinal cord injury

Evaluating Sex Steroid Hormone Neuroprotection in Spinal Cord Injury in Animal Models: Is It Promising in the Clinic?

The primary mechanism of traumatic spinal cord injury (SCI) comprises the initial mechanical trauma due to the transmission of energy to the spinal cord, subsequent deformity, and persistent compression. The secondary mechanism of injury, which involves structures that remained undamaged after the initial trauma, triggers alterations in microvascular perfusion, the liberation of free radicals and neurotransmitters, lipid peroxidation, alteration in ionic concentrations, and the consequent cell death by necrosis and apoptosis. Research in the treatment of SCI has sought to develop early therapeutic interventions that mitigate the effects of these pathophysiological mechanisms. Clinical and experimental evidence has demonstrated the therapeutic benefits of sex-steroid hormone administration after traumatic brain injury and SCI. The administration of estradiol, progesterone, and testosterone has been associated with neuroprotective effects, better neurological recovery, and decreased mortality after SCI. This review evaluated evidence supporting hormone-related neuroprotection over SCI and the possible underlying mechanisms in animal models. As neuroprotection has been associated with signaling pathways, the effects of these hormones are observed on astrocytes and microglia, modulating the inflammatory response, cerebral blood flow, and metabolism, mediating glutamate excitotoxicity, and their antioxidant effects. Based on the current evidence, it is essential to analyze the benefit of sex steroid hormone therapy in the clinical management of patients with SCI.

Factors affecting sexual health in individuals with spinal cord injury: A systematic scoping review

PURPOSE

This study aims to review the literature to explore some factors affecting sexual and partnership adjustment in individuals with spinal cord injury (SCI).

METHODS

This study was based on the methodological framework of scoping reviews, including 3 methodological steps: (1) identifying relevant studies (searching for related studies); (2) selecting related studies; (3) collecting key findings, summarizing, and reporting the results. The electronic databases were searched including Medline (PubMed), Scopus, Web of Science, Embase, and Cochrane Library. Studies were included if they reported data about the related factors of sexual and partnership adjustment in individuals with SCI. No limitations were considered in terms of time or methodology of the search.

RESULTS

After the full-text screening, 52 studies were included from the year of 1978 - 2019 with various methodologies. The present review demonstrated that proper sexual health among individuals with SCI is related to several factors including the anatomical factor, level of the injury, completeness of the injury, psycho-social factor, socio-economic status, and type of relationship.

CONCLUSION

With consideration of factors affecting sexual and partnership adjustment in individuals with SCI, a better estimation of sexual health can be achieved in clinical to improve the relationship and quality of life.

Nitric oxide-induced lipophagic defects contribute to testosterone deficiency in rats with spinal cord injury

Introduction

Males with acute spinal cord injury (SCI) frequently exhibit testosterone deficiency and reproductive dysfunction. While such incidence rates are high in chronic patients, the underlying mechanisms remain elusive.

Methods and results

Herein, we generated a rat SCI model, which recapitulated complications in human males, including low testosterone levels and spermatogenic disorders. Proteomics analyses showed that the differentially expressed proteins were mostly enriched in lipid metabolism and steroid metabolism and biosynthesis. In SCI rats, we observed that testicular nitric oxide (NO) levels were elevated and lipid droplet-autophagosome co-localization in testicular interstitial cells was decreased. We hypothesized that NO impaired lipophagy in Leydig cells (LCs) to disrupt testosterone biosynthesis and spermatogenesis. As postulated, exogenous NO donor (S-nitroso-N-acetylpenicillamine (SNAP)) treatment markedly raised NO levels and disturbed lipophagy via the AMPK/mTOR/ULK1 pathway, and ultimately impaired testosterone production in mouse LCs. However, such alterations were not fully observed when cells were treated with an endogenous NO donor (L-arginine), suggesting that mouse LCs were devoid of an endogenous NO-production system. Alternatively, activated (M1) macrophages were predominant NO sources, as inducible NO synthase inhibition attenuated lipophagic defects and testosterone insufficiency in LCs in a macrophage-LC co-culture system. In scavenging NO (2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO)) we effectively restored lipophagy and testosterone levels both in vitro and in vivo, and importantly, spermatogenesis in vivo. Autophagy activation by LYN-1604 also promoted lipid degradation and testosterone synthesis.

Discussion

In summary, we showed that NO-disrupted-lipophagy caused testosterone deficiency following SCI, and NO clearance or autophagy activation could be effective in preventing reproductive dysfunction in males with SCI.

Independent association of hypovitaminosis d with non-alcoholic fatty liver disease in people with chronic spinal cord injury: a cross-sectional study

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) and hypovitaminosis D are highly prevalent in people with spinal cord injury (SCI) and could exert an unfavorable influence on cardiovascular profile and rehabilitation outcomes. We aimed to assess the independent association between low 25-hydroxy vitamin D (25(OH)D) levels and NAFLD in people with chronic (> 1 year) SCI.

METHODS

One hundred seventy-three consecutive patients with chronic SCI (132 men and 41 women) admitted to a rehabilitation program underwent clinical/biochemical evaluations and liver ultrasonography.

RESULTS

NAFLD was found in 105 patients (60.7% of the study population). They were significantly older and exhibited a poorer leisure time physical activity (LTPA) and functional independence in activities of daily living, a greater number of comorbidities and a higher prevalence of metabolic syndrome (MetS) and its correlates, including lower HDL and higher values of body mass index (BMI), systolic blood pressure, HOMA-index of insulin resistance and triglycerides. 25(OH)D levels were significantly lower in NAFLD (median: 10.6 ng/ml, range: 2.0-31.0) than in non-NAFLD group (22.5 ng/ml, 4.2-51.6). When all these variables were included in a multiple logistic regression analysis, a significant independent association with NAFLD only persisted for lower 25(OH)D levels, a greater number of comorbidities and a poorer LTPA. The ROC analysis revealed that 25(OH)D levels < 18.25 ng/ml discriminated patients with NAFLD with a sensitivity of 89.0% and a specificity of 73.0% (AUC: 85.7%; 95%CI: 79.6-91.7%). NAFLD was exhibited by 83.9% of patients with 25(OH)D levels < 18.25 ng/ml and by 18% of those with 25(OH)D levels ≥ 18.25 ng/ml (p < 0.0001).

CONCLUSION

In people with chronic SCI, 25(OH)D levels < 18.25 ng/ml may represent a marker of NAFLD independent of MetS-related features. Further studies are warranted to define the cause-effect relationships of this association.

A comprehensive look at the psychoneuroimmunoendocrinology of spinal cord injury and its progression: mechanisms and clinical opportunities

Spinal cord injury (SCI) is a devastating and disabling medical condition generally caused by a traumatic event (primary injury). This initial trauma is accompanied by a set of biological mechanisms directed to ameliorate neural damage but also exacerbate initial damage (secondary injury). The alterations that occur in the spinal cord have not only local but also systemic consequences and virtually all organs and tissues of the body incur important changes after SCI, explaining the progression and detrimental consequences related to this condition. Psychoneuroimmunoendocrinology (PNIE) is a growing area of research aiming to integrate and explore the interactions among the different systems that compose the human organism, considering the mind and the body as a whole. The initial traumatic event and the consequent neurological disruption trigger immune, endocrine, and multisystem dysfunction, which in turn affect the patient's psyche and well-being. In the present review, we will explore the most important local and systemic consequences of SCI from a PNIE perspective, defining the changes occurring in each system and how all these mechanisms are interconnected. Finally, potential clinical approaches derived from this knowledge will also be collectively presented with the aim to develop integrative therapies to maximize the clinical management of these patients.

Early Changes in Androgen Levels in Individuals with Spinal Cord Injury: A Longitudinal SwiSCI Study

We aimed to explore longitudinal changes in androgen levels in individuals with spinal cord injury (SCI) within initial inpatient rehabilitation stay and identify clinical/injury characteristics associated with hormone levels. Linear regression analysis was applied to explore the association between personal/injury characteristics and androgen hormones (total testosterone, free testosterone, sex hormone-binding globulin (SHBG), dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEA-S)) at admission to rehabilitation. Longitudinal changes in androgen levels were studied using linear mixed models. Analyses were stratified by sex and by injury type. We included 70 men and 16 women with SCI. We observed a non-linear association between age, time since injury, and androgens at baseline. At admission to initial rehabilitation, mature serum SHBG (full-length, protein form which lacks the N-terminal signaling peptide) was higher, while DHEA and DHEA-S were lower among opioid users vs. non-users. Serum levels of total testosterone and DHEA-S increased over rehabilitation period [β 3.96 (95%CI 1.37, 6.56), p = 0.003] and [β 1.77 (95%CI 0.73, 2.81), p = 0.01], respectively. We observed no significant changes in other androgens. Restricting our analysis to men with traumatic injury did not materially change our findings. During first inpatient rehabilitation over a median follow up of 5.6 months, we observed an increase in total testosterone and DHEA-S in men with SCI. Future studies need to explore whether these hormonal changes influence neurological and functional recovery as well as metabolic parameters during initial rehabilitation stay.

Endocrinological and inflammatory markers in individuals with spinal cord injury: A systematic review and meta-analysis

Spinal cord injury (SCI) can lead to dramatic physiological changes which can be a factor in developing secondary health conditions and might be reflected in biomarker changes in this elevated risk group. We focused specifically on the endocrine and inflammation profile differences between SCI and able-bodied individuals (ABI). Our aim was to determine the differences in inflammatory markers and endocrine profiles between SCI and ABI. We systematically searched 4 electronic databases for relevant studies. Human observational (cross-sectional, cohort, case-control) studies that compared biomarkers of interest between SCI and ABI population were included. Weighted mean difference between SCI and ABI was calculated using random-effects models. Heterogeneity was computed using I² statistic and chi-squared test. Study quality was evaluated through the Newcastle-Ottawa Scale. The search strategy yielded a total of 2,603 studies from which 256 articles were selected for full-text assessment. Sixty-two studies were included in the meta-analysis. SCI individuals had higher levels of pro-inflammatory C-reactive protein and IL-6 than ABI. Creatinine and 25-hydroxyvitamin D₃ levels were lower in SCI than ABI. Total testosterone levels and IGF-1 were also found to be lower, while cortisol and leptin levels were higher in SCI when compared to ABI. Accordingly, meta-regression, subgroup analysis, and leave-one-out analysis were performed, however, they were only able to partially explain the high levels of heterogeneity. Individuals with SCI show higher levels of inflammatory markers and present significant endocrinological changes when compared to ABI. Moreover, higher incidence of obesity, diabetes, osteoporosis, and hypogonadism in SCI individuals, together with decreased creatinine levels reflect some of the readily measurable aspects of the phenotype changes in the SCI group. These findings need to be considered in anticipating medically related complications and personalizing SCI medical care.

Energy expenditure and nutrient intake after spinal cord injury: a comprehensive review and practical recommendations

Many persons with spinal cord injury (SCI) have one or more preventable chronic diseases related to excessive energetic intake and poor eating patterns. Appropriate nutrient consumption relative to need becomes a concern despite authoritative dietary recommendations from around the world. These recommendations were developed for the non-disabled population and do not account for the injury-induced changes in body composition, hypometabolic rate, hormonal dysregulation and nutrition status after SCI. Because evidence-based dietary reference intake values for SCI do not exist, ensuring appropriate consumption of macronutrient and micronutrients for their energy requirements becomes a challenge. In this compressive review, we briefly evaluate aspects of energy balance and appetite control relative to SCI. We report on the evidence regarding energy expenditure, nutrient intake and their relationship after SCI. We compare these data with several established nutritional guidelines from American Heart Association, Australian Dietary Guidelines, Dietary Guidelines for Americans, Institute of Medicine Dietary Reference Intake, Public Health England Government Dietary Recommendations, WHO Healthy Diet and the Paralyzed Veterans of America (PVA) Clinical Practice Guidelines. We also provide practical assessment and nutritional recommendations to facilitate a healthy dietary pattern after SCI. Because of a lack of strong SCI research, there are currently limited dietary recommendations outside of the PVA guidelines that capture the unique nutrient needs after SCI. Future multicentre clinical trials are needed to develop comprehensive, evidence-based dietary reference values specific for persons with SCI across the care continuum that rely on accurate, individual assessment of energy need.

Experiences of patients and their partners with sexual problems after spinal cord injury: A phenomenological qualitative study

Objective: This study aimed to examine the experiences of patients and their partners about their sexual lives after Spinal Cord Injury (SCI).Design: This qualitative study was based on Heidegger's hermeneutic phenomenological approach.Setting: The Physical Medicine and Rehabilitation Outpatient Clinic of a city hospital in the Central Anatolia Region in Turkey.Participants: The study consisted of seven female and six male patients with spinal cord injury and their partners.Outcome measures: The textual analysis was carried out in three stages: (1) a naive reading, (2) a structural analysis, and (3) a comprehensive understanding of the text including a discussion. The sample size was calculated by using the criterion sampling technique.Results: As a result of the in-depth interviews with individuals with SCI about their sexual experiences, five themes were derived: (1) first confrontation with SCI, (2) experienced sexual problems, (3) coping, (4) partners' views on sexual problems, and (5) other people.Conclusion: It was found that the sex life of individuals with SCI was negatively affected, they were left helpless in dealing with their problems, and that some patients had difficulties in coping with this condition.

Comparison of Various Indices in Identifying Insulin Resistance and Diabetes in Chronic Spinal Cord Injury

The purpose of this screening and diagnostic study was to examine the accord among indices of glucose metabolism, including the Homeostatic Model Assessment for Insulin Resistance (HOMA), HOMA2, Matsuda Index, Quantitative Insulin-sensitivity Check Index (QUICKI), hemoglobin A1C (HbA1C), and fasting plasma glucose (FPG) against intravenous glucose tolerance test-measured insulin sensitivity (Si) in individuals with chronic motor complete SCI. Persons with chronic (≥12-months post-injury) SCI (n = 29; 79% men; age 42.2 ± 11.4; body mass index 28.6 ± 6.4 kg/m2; C4-T10) were included. Measures were compared using adjusted R2 from linear regression models with Akaike information criterion (AIC, a measure of error). QUICKI had the greatest agreement with Si (adjusted R2 = 0.463, AIC = 91.1, p = 0.0001), followed by HOMA (adjusted R2 = 0.378, AIC = 95.4, p = 0.0008), HOMA2 (adjusted R2 = 0.256, AIC = 99.7, p = 0.0030), and the Matsuda Index (adjusted R2 = 0.356, AIC = 95.5, p = 0.0004). FPG (adjusted R2 = 0.056, AIC = 107.5, p = 0.1799) and HbA1C (adjusted R2 = 0.1, AIC = 106.1, p = 0.0975) had poor agreement with Si. While HbA1C and FPG are commonly used for evaluating disorders of glucose metabolism, QUICKI demonstrates the best accord with Si compared to the other measures.

Erectile Dysfunction Is the Main Correlate of Depression in Men with Chronic Spinal Cord Injury

Depression is the most prevalent psychological issue after a spinal cord injury (SCI) and is associated with noticeable disability, mortality and health expenditure. As SCI mainly occurs in sexually active men at a young age, and can lead to them suffering from an organic neurogenic erectile dysfunction (ED), we supposed that ED could be a major correlate of depressive status in men with SCI. As documented by a Beck Depression Inventory-II (BDI-II) score ≥14, depression was reported in 17 out of 57 men with a chronic SCI (29.8%). They exhibited a significantly higher prevalence of ED and a more severe bowel and bladder dysfunction when compared to the group without depression. At the multiple logistic regression analysis, depression showed a significant independent association with ED (OR = 19.0, 95% CI: 3.1, 203.3; p = 0.004) and, to a lesser extent, with a severe impairment of bowel and bladder function (OR = 0.84; 95% CI: 0.72, 0.94; p = 0.01). Depression was observed in 43.7% of men with ED and only in 12.0% of those without ED (p = 0.002). In conclusion, healthcare providers should give the right level of importance to the management of ED in men with SCI, as this represents a major independent correlate of depression, which, in turn, might hinder physical rehabilitation and exacerbate physical health issues related to SCI.

Relationship of Vitamin D status with testosterone levels: a systematic review and meta-analysis

PURPOSE

Despite a biological plausibility of a direct link between low vitamin D and androgen deficiency, the association remains inconclusive in epidemiological studies. Therefore, this systematic review and meta-analysis of case-control studies aim to assess whether and in what populations such an association can be demonstrated.

METHODS

A systematic search was performed in PubMed, EMBASE, Cochrane Library, Web of science, Science Direct, and CINAHL. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) in total testosterone (TT) levels between men with 25-hydroxyvitamin D (25(OH)D) <20 and ≥20 ng/mL were combined using random-effects models. Funnel plot and trim-and-fill analysis were used to assess publication bias. Heterogeneity source was explored by a sub-group analysis according to health-related characteristics of the study populations.

RESULTS

Eighteen included studies collectively gave information on 9892 men with vitamin D deficiency and 10,675 controls. The pooled SMD revealed a slight, albeit just significant, positive association between 25(OH)D and TT (pooled SMD: -0.23, 95% CI: -0.45 to -0.01; P = 0.04) with a large between-study heterogeneity (I² = 98%, P_{for heterogeneity} < 0.00001). At the sub-group analysis, a significant positive association, along with noticeable decrease in heterogeneity, could only be demonstrated in studies of patients with frailty states (pooled SMD: -0.19; 95% CI: -0.27, -0.10,  P < 0.0001; I² = 51%, P_{for heterogeneity} = 0.06). A sensitivity analysis revealed a high stability of the result and the trim-and-fill adjustment for publication bias did not affect pooled estimate.

CONCLUSIONS

Both hypovitaminosis D and androgen deficiency should be regarded as markers of a poor health status, sharing common underlying aetiologies and risk factors.

Recurrent priapism in spinal cord injury: A case report

Context: Recurrent priapism is characterized by repetitive episodes of erections which are unrelated to sexual interest or stimulation. It is extremely rare in patients with spinal cord injury (SCI). There are a number of conservative agents used in the treatment.Findings: We describe the case of a 20-year-old male with cervical-5 American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade A tetraplegia as a result of a diving accident 2 years ago. He declared that the recurrent penile erections occurred up to 15-20 times day and night every day and lasted up to 20 min each time unrelated to sexual interest or stimulation. He was prescribed baclofen 10 mg, twice daily. The frequency and duration of erections decreased to 3-5 times/day lasting for about 5 min each and the patient reported a high treatment satisfaction.Conclusion: The presentation of this case is to remind clinicians this rare but distressing condition of recurrent priapism seen in men with complete spinal cord lesions and to summarize the use of medications, most commonly baclofen, to alleviate the condition.

Testosterone, level of the lesion and age are independently associated with prostate volume in men with chronic spinal cord injury

PURPOSE

Although men with spinal cord injury (SCI) exhibit a prostate volume significantly smaller compared to age-matched able-bodied men, the independent association of lower prostate volume with its putative determinants has never been analyzed in this population. This study was designed to identify variables independently associated with prostate volume in men with chronic SCI.

METHODS

In this cross-sectional study, prostate volume of 138 men with chronic (> 1 years) SCI, aged 54.5 (25th-75th percentile: 36.0-66.0) years, was evaluated with trans-rectal ultrasonography. All patients underwent a complete neurological exam, as well as biochemical and hormonal assessment, including total testosterone (TT) levels. Free testosterone levels were calculated (cFT) by the Vermeulen formula.

RESULTS

The median prostate volume was 23.4 mL. At the univariate analysis, a larger prostate volume was associated with higher TT (p = 0.00001) and cFT (p = 0.001), SCI level below T12 (p = 0.007), more advanced age (p = 0.04), lower body mass index (p = 0.04), higher functional independence score (p = 0.06), higher values of prostate-specific antigen (p = 0.12) and shorter duration of the injury (p = 0.21). However, at the multiple regression analyses, an independent and positive association only persisted between the prostate volume with either TT or cFT levels, and, to a lesser extent, with age and a level of spinal lesion below T12. A prostate volume below the median value was observed in 91.4% (32/35) of patients with both androgen deficiency (TT < 264 ng/dL) and spinal lesion level ≥ T12, but only in 16.5% (2/12) of patients with both normal androgen levels and spinal lesion level below T12 (p < 0.001).

CONCLUSIONS

Our data indicate that lower testosterone levels and, to a lesser extent, a younger age and a spinal lesion level ≥ T12 represent the only variables exhibiting an independent association with a smaller prostate volume in men with SCI.

Considerations for Studying Sex as a Biological Variable in Spinal Cord Injury

In response to NIH initiatives to investigate sex as a biological variable in preclinical animal studies, researchers have increased their focus on male and female differences in neurotrauma. Inclusion of both sexes when modeling neurotrauma is leading to the identification of novel areas for therapeutic and scientific exploitation. Here, we review the organizational and activational effects of sex hormones on recovery from injury and how these changes impact the long-term health of spinal cord injury (SCI) patients. When determining how sex affects SCI it remains imperative to expand outcomes beyond locomotor recovery and consider other complications plaguing the quality of life of patients with SCI. Interestingly, the SCI field predominately utilizes female rodents for basic science research which contrasts most other male-biased research fields. We discuss the unique caveats this creates to the translatability of preclinical research in the SCI field. We also review current clinical and preclinical data examining sex as biological variable in SCI. Further, we report how technical considerations such as housing, size, care management, and age, confound the interpretation of sex-specific effects in animal studies of SCI. We have uncovered novel findings regarding how age differentially affects mortality and injury-induced anemia in males and females after SCI, and further identified estrus cycle dysfunction in mice after injury. Emerging concepts underlying sexually dimorphic responses to therapy are also discussed. Through a combination of literature review and primary research observations we present a practical guide for considering and incorporating sex as biological variable in preclinical neurotrauma studies.

Independent Association of Erectile Dysfunction and Low Testosterone Levels With Life Dissatisfaction in Men With Chronic Spinal Cord Injury

BACKGROUND

The loss of global functional independence, along with bladder, bowel, and sexual dysfunctions, may contribute to psychological distress and life dissatisfaction after spinal cord injury (SCI).

AIM

To explore the relationship of erectile function and androgenic status with life satisfaction, independently from confounders recognizable in spinal cord-injured men.

METHODS

100 consecutive men (49 ± 17 years) admitted to a rehabilitation program because of chronic SCI (≥1 year) underwent clinical/biochemical evaluations, including the assessment of life and sexual satisfaction using the Life-Satisfaction Questionnaire-9 (LiSat-9), erectile function using the International Index of Erectile Function-5 (IIEF-5), global and bowel-bladder functional independence using the Spinal Cord Independence Measure (SCIM) and measurement of total testosterone (TT) levels. The free testosterone level was calculated using the Vermeulen formula.

OUTCOMES

The outcomes include the relationship between sexual health and life satisfaction in men with SCI.

RESULTS

A LiSat-9 score <4, suggestive for life dissatisfaction, was exhibited by 49% of men. When compared with the life-satisfied group, a significantly higher percentage of them had sexual dissatisfaction and erectile dysfunction (ED); they also exhibited significantly lower levels of TT and calculated free testosterone (cFT) and a more severe impairment of bowel-bladder function. The life satisfaction degree correlated with sexual satisfaction degree, IIEF-5 score, TT, cFT, and bowel-bladder function degree. At the logistic regression model, including sexual LiSat-9 subscore and bowel-bladder SCIM subscore, only the former exhibited a significant negative association with life dissatisfaction. In a further logistic regression model, including the putative key determinants of sexual satisfaction, erectile function, and cFT levels, a higher odd of life dissatisfaction was independently associated both with a lower IIEF-5 score (OR: 0.93; 95% CI: 0.88, 0.98) and lower cFT levels (OR: 0.98; 95% CI: 0.98, 0.99).

CLINICAL IMPLICATIONS

In men with chronic SCI, assessment of erectile function and testosterone levels can help to predict life satisfaction.

STRENGTHS & LIMITATIONS

This is the first demonstration of the independent association of androgen deficiency and ED with life satisfaction in men with SCI. Prospective studies are warranted to clarify the cause-effect relationships.

CONCLUSIONS

In men with SCI, ED and low testosterone levels exhibit a significant independent association with life dissatisfaction; longitudinal intervention studies could explore possible effects of their treatment in improving sexual and life satisfaction in this population. D'Andrea S, Minaldi E, Castellini C, et al. Independent Association of Erectile Dysfunction and Low Testosterone Levels With Life Dissatisfaction in Men With Chronic Spinal Cord Injury. J Sex Med 2020;17:911-918.

Lifestyle modifications and pharmacological approaches to improve sexual function and satisfaction in men with spinal cord injury: a narrative review

STUDY DESIGN

A narrative review describing various components of sexual dysfunction in men with spinal cord injury (SCI), as well as addressing potential therapeutic approaches.

OBJECTIVES

Restoration of sexual function is considered one of the most important health priorities for individuals with SCI. The purpose of this review is to provide information regarding the factors that are less appreciated when considering changes to sexual function in men with SCI. We also propose therapeutic approaches, with a focus on lifestyle modifications, which have been shown to improve sexual function.

METHODS

A literature search was performed and limited evidence for therapeutic approaches in individuals with SCI was supplemented by consistent findings from the able-bodied population.

RESULTS

We evaluated the less addressed factors known to contribute to sexual dysfunction in men with SCI, including hormonal influences (i.e., testosterone deficiency, thyroid hormone, and cortisol), psychological factors (i.e., pain, fatigue, depression, and body image), and secondary SCI complications (i.e., urinary tract infection, pressure sores, and autonomic dysreflexia). To address these factors beyond standard medical treatments for sexual dysfunction, options include physical activity/exercise, diet, and specific medications for symptom relief (i.e., testosterone replacement therapy and selective serotonin reuptake inhibitors for depression).

CONCLUSIONS

Physical activity's potential application, efficacy across multiple aspects of sexuality, and the lack of side effects, suggests that long-term exercise is a viable solution to directly or indirectly improve sexual function in males with SCI. Diet and supplemental medications may further promote body composition changes, which more broadly affect sexuality.

Risk of prostate cancer in men with spinal cord injury: A systematic review and meta-analysis

A lower risk of prostate cancer has been reported in men with spinal cord injury (SCI) as compared to that observed in able-bodied subjects. As injury-related consequences can have opposite effects on prostate pathophysiology, this meta-analysis aimed to (1) establish the existence/quantify the extent of decreased prostate cancer risk following SCI and (2) find out if there is any statistically significant difference in prostate-specific antigen (PSA) levels between SCI and able-bodied subjects. MEDLINE, Cochrane Library, Scopus, CINAHL, and ScienceDirect databases were used. Only studies reporting a prostate cancer diagnosis and/or PSA levels following SCI and in able-bodied controls were included. Five studies provided information about prostate cancer on 35 293 subjects with SCI and 158 140 controls. Six studies were included in PSA analysis which reported information on 391 men with SCI and 1921 controls. Pooled estimates indicated that SCI reduced the prostate cancer risk by approximately 50% as compared to controls, whereas differences in PSA levels were not statistically significant. Funnel plots suggested the presence of publication bias only in PSA analysis. Between-study heterogeneity was established and when, according to meta-regression models, analysis was restricted to studies including men with mean age over 55 years, prostate cancer risk in SCI decreased up to 65.0% than that in controls with no heterogeneity (P = 0.33, I² = 9%). In conclusion, in men over 55 years old, SCI decreases the prostate cancer risk up to 65.0% than that in controls. The large between-study heterogeneity on PSA confirms its poor reliability as a screening tool for prostate cancer in SCI.

Chronic Spinal Cord Injury Reduces Gastrin-Releasing Peptide in the Spinal Ejaculation Generator in Male Rats

Spinal cord injury (SCI) causes sexual dysfunction, including anejaculation in men. Likewise, chronic mid-thoracic contusion injury impairs ejaculatory reflexes in male rats. Ejaculation is controlled by a spinal ejaculation generator (SEG) comprised of a population of lumbar spinothalamic (LSt) neurons. LSt neurons co-express four neuropeptides, including gastrin-releasing peptide (GRP) and galanin and control ejaculation via release of these peptides in lumbar and sacral autonomic and motor nuclei. Here, we tested the hypothesis that contusion injury causes a disruption of the neuropeptides that are expressed in LSt cell bodies and axon terminals, thereby causing ejaculatory dysfunction. Male Sprague Dawley rats received contusion or sham surgery at spinal levels T6-7. Five to six weeks later, animals were perfused and spinal cords were immunoprocessed for galanin and GRP. Results showed that numbers of cells immunoreactive for galanin were not altered by SCI, suggesting that LSt cells are not ablated by SCI. In contrast, GRP immunoreactivity was decreased in LSt cells following SCI, evidenced by fewer GRP and galanin/GRP dual labeled cells. However, SCI did not affect efferent connections of LSt, cells as axon terminals containing galanin or GRP in contact with autonomic cells were not reduced following SCI. Finally, no changes in testosterone plasma levels or androgen receptor expression were noted after SCI. In conclusion, chronic contusion injury decreased immunoreactivity for GRP in LSt cell soma, but did not affect LSt neurons per se or LSt connections within the SEG. Since GRP is essential for triggering ejaculation, such loss may contribute to ejaculatory dysfunction following SCI.

Correlation between thyroid function, testosterone levels, and depressive symptoms in females with spinal cord injury

Study Design

Prospective case series.

Objective

Investigate the association of testosterone and thyroid-stimulating hormone (TSH) levels with depressive symptoms in women after spinal cord injury (SCI).

Setting

Community SCI clinic.

Methods

Twenty-seven participants were enrolled in this study. Total testosterone (Total T) and TSH levels as well as the Center for Epidemiological Studies Depression Scale (CES-D) survey and monthly sexual activity were obtained from only 20 participants. Pearson's correlations were used to assess the relationship between age, time from injury, Total T level, TSH level, and CES-D total score. Follow-up analyses investigating the role of monthly sexual activity was also explored.

Results

Participants' average age and time from injury was 44.4 ± 12.7 years old and 11.7 ± 8.89 years, respectively. Low Total T was observed in four participants and one of those participant's presented with low TSH as well. Nine women were classified as "at risk for clinical depression" on the CES-D (total score >15). Pearson's correlations revealed a significant association between time from injury and TSH (r = .536, p = .015), as well as CES-D total score (r = -.547, p = .013). Total T was associated with CES-D total score (ρ = -.541, p = .02).

Conclusions

This study provides preliminary results on abnormal hormone levels and depressive symptoms in women after SCI. Twenty percent of this sample presented with low Total T, which was associated with increased depressive symptoms after accounting for time from injury. Further research is needed to investigate the impact of SCI on hormone function and mental health in women post SCI.

Sponsorship

Sally Rynne National Association of Women's Health Quality Award 2002.

B Cell-Activating Factor Is Associated with Testosterone and Smoking Status in Non-Ambulatory Men with Chronic Spinal Cord Injury

B cell-mediated autoimmunity may contribute to poor neurological outcomes after spinal cord injury (SCI). B cell-activating factor (BAFF) is a key cytokine involved in B cell development, proliferation, activation, and survival whose expression is elevated in men with chronic SCI. The aim of this study was to assess factors associated with circulating BAFF in non-ambulatory males with chronic SCI. We assessed the association between clinical and demographic factors, health habits, and circulating BAFF levels in a convenience sample of 43 non-ambulatory men with chronic spinal cord injury (≥ 1 year post-injury). Serum BAFF and total testosterone levels were quantified by enzyme-linked immunosorbent assay. Body composition was determined by whole body dual-energy X-ray absorptiometry. In multivariable models, active smokers had significantly greater BAFF levels than former/nonsmokers (871 pg/mL vs. 665 pg/ml, p = 0.002). BAFF decreased 36 ± 11.1 pg/mL for every 1 ng/mL increase in total testosterone (p = 0.002). This model explained 41% of the variation in circulating BAFF levels (model p < 0.0001). Our findings suggest that modifiable health habits may be associated with elevated BAFF levels in men with non-ambulatory chronic SCI. Further, the significant and independent negative association between testosterone levels and BAFF would suggest a link between androgen deficiency and autoimmunity observed in SCI via modulation of BAFF and B cell numbers. This points toward BAFF as a potential biomarker of injury severity and a target of therapies designed to reduce neuroinflammation and improve neurological outcomes after SCI.

Sex Differences and Role of Gonadal Hormones on Glutamate LevelAfter Spinal Cord Injury in Rats: A Microdialysis Study

Introduction:

Sex differences in outcomes of Spinal Cord Injury (SCI) suggest a sex-hormone-mediated effect on post-SCI pathological events, including glutamate excitotoxicity. This study aimed to investigate the importance of gonadal hormones on glutamate release subsequent to SCI in rats.

Methods:

After laminectomy at T8–T9, an electrolytic lesion was applied to the spinothalamic tracts of male and female rats. Using spinal microdialysis, we assessed glutamate levels at the site of lesion in both intact and gonadectomized rats for 4 hours. In this way, we examined the sex differences in the glutamate concentrations.

Results:

The peak retention time of glutamate level was 10.6 min and spinal glutamate concentration reached a maximum level 40 min following SCI. In male SCI rats, gonadectomy caused a significant elevation of glutamate level (P<0.001) following injury which was maximum 40 min post-SCI as well. However, no significant alterations were seen in gonadectomized female rats.

Conclusion:

The significant differences in glutamate levels between both intact and gonadectomized SCI male and female rats show the sex-hormone-related mechanisms underlying the molecular events in the second phase of SCI. It seems that the role of male gonadal hormones to prevent glutamate excitotoxicity is more prominent. The exact mechanisms of these hormones on the functional recovery after SCI should be clarified in further studies.

Can the positive association of osteocalcin with testosterone be unmasked when the preeminent hypothalamic-pituitary regulation of testosterone production is impaired? The model of spinal cord injury

PURPOSE

Osteocalcin (OCN), released from the bone matrix during the resorption phase, in its undercarboxylated form, stimulates testosterone (T) biosynthesis in mouse and a loss-of-function mutation of its receptor was associated with hypergonadotropic hypogonadism in humans. Nevertheless, when population-based studies have explored the OCN-T association, conflicting results have been reported. Hypothesizing that the evidence of a positive association between OCN and T could have been hindered by the preeminent role of a well-functioning hypothalamus-pituitary axis in promoting T biosynthesis, we explored this association in men with chronic spinal cord injury (SCI), exhibiting high prevalence of non-hypergonadotropic androgen deficiency.

METHODS

Fifty-five consecutive men with chronic SCI underwent clinical/biochemical evaluations, including measurements of total T (TT), OCN and 25(OH)D levels. Free T (FT) levels were calculated by the Vermeulen formula. Comorbidity was scored by Charlson comorbidity index (CCI).

RESULTS

A biochemical androgen deficiency (TT < 300 ng/dL) was observed in 15 patients (27.3%). TT was positively correlated with OCN, 25(OH)D and leisure time physical activity and negatively correlated with age, BMI and CCI. OCN was also positively correlated with calculated FT and negatively correlated with BMI and HOMA-IR. At the multiple linear regression analyses, a positive association of OCN with TT and calculated FT persisted after adjustment for confounders.

CONCLUSIONS

The positive association here found between OCN and T levels in men with chronic SCI reinforces the notion that a bone-testis axis is also functioning in humans and suggests that it can be unmasked when the preeminent hypothalamic-pituitary regulation of T production is impaired.

Serum testosterone levels may influence body composition and cardiometabolic health in men with spinal cord injury

Study Design:

Cross-sectional study

Objective

To establish the association between serum testosterone (T) levels, biomarkers of cardiometabolic health and regional body composition variables after spinal cord injury (SCI).

Setting:

Medical research center

Methods

Metabolic and body composition measurements were collected from thirty-six men with chronic motor complete SCI. Serum T, carbohydrate and lipid profiles were measured after an overnight fast. Body composition was measured using anthropometrics, dual energy x-ray absorptiometry and magnetic resonance imaging. Participants were evenly classified into tertiles based on their serum T levels into low, mid-normal and normal ranges.

Results

Low, mid-normal and normal range serum T were 288.8 ± 84.9ng/dL, 461.0 ± 52.5ng/dL and 648.0 ± 53.5ng/dL, respectively. Low range serum T group had greater total (9.6%, P= 0.04) percentage fat mass and visceral adipose tissue (VAT) area (72%, P= 0.01) compared to normal range serum T group. Serum T was related to the absolute whole thigh muscle area (r= 0.40, P< 0.05) after controlling for body mass index. Serum T was negatively related to fasting plasma glucose (r= −0.46, P= 0.006) and insulin (r= −0.42, P= 0.01), HbA1c (r= −0.39, P= 0.02) and triglycerides (r= −0.36, P= 0.03).

Conclusion

Men with low serum T have more unfavorable body composition and cardiometabolic health outcomes after SCI. Testosterone replacement therapy may serve as a potential strategy in preventing cardiometabolic disorders after SCI.

Spinal cord injury and male infertility-a review of current literature, knowledge gaps, and future research

Spinal cord injury (SCI) affects nearly half a million new patients worldwide, with 17,700 in the US each year, and disproportionately impacts young males of reproductive age. Almost every aspect of male reproduction is affected by SCI, resulting in: erectile, endocrine and sexual dysfunction, decreased sperm motility despite an often-normal count, and abnormal semen emission and ejaculation. The aim of this review is to focus on how SCI impacts testicular spermatogenesis, sperm function, semen quality, and overall fecundity while discussing what is not known, and future avenues for research.

The influence of level of spinal cord injury on adipose tissue and its relationship to inflammatory adipokines and cardiometabolic profiles

OBJECTIVE

Level of injury (LOI) and the role of adipose tissue and its proinflammatory adipokines in cardiometabolic dysfunction following spinal cord injury (SCI) remains poorly understood. We aim to examine the influence of LOI on adipose tissue and its relationship to proinflammatory adipokines and cardiometabolic profiles following SCI.

DESIGN

Cross sectional and correlational study.

SETTING

Clinical hospital and academic setting.

PARTICIPANTS

Forty-seven individuals with chronic motor complete SCI (age 43.8±11.5 y, BMI: 27.3±5.3) were classified as having tetraplegia (TSCI; n=12) or paraplegia (PSCI; n=35).

INTERVENTION

Non applicable.

OUTCOME MEASURES

Visceral (VAT) and subcutaneous (SAT) adipose tissue volumes were measured using magnetic resonance imaging. Proinflammatory adipokines (tumor neurosis factor-α, interleukin-6 (IL-6), plasminogen activatable inhibitor-1, thrombin-activatable fibrinolysis inhibitor, and high-sensitivity c-reactive protein) and cardiovascular, carbohydrate, and lipid profiles were assessed according to standard techniques.

RESULTS

VAT volume was greater in TSCI versus PSCI (p=0.042); however, after covarying for age this significance was lost (p>0.05). IL-6 was significantly elevated in TSCI (p<0.05), while other markers of inflammation generally were elevated, but did not reach statistical significance (p>0.05). Systolic blood pressure and total cholesterol were significantly lower in TSCI (p<0.05), while fasting glucose was significantly lower in PSCI (p<0.05). A number of proinflammatory adipokines and cardiometabolic markers significantly correlated with adipose tissue depots by LOI (p<0.05).

CONCLUSION

The results show that LOI does not influence the distribution of adipose tissue, but does influence proinflammatory adipokines and cardiometabolic profiles following SCI. Further research is needed to evaluate impact of lean body mass on these findings.

Impact of bladder, bowel and sexual dysfunction on health status of people with thoracolumbar spinal cord injuries living in the community

OBJECTIVE

The disruption of autonomic function following a spinal cord injury (SCI) is common and can negatively affect quality of life. The objective of this study was to describe the prevalence of bladder/bowel incontinence and sexual dysfunction in community-dwelling individuals with a thoracolumbar SCI and examine the impact on general physical and mental health status.

METHODS

Participants who sustained a traumatic SCI to the thoracolumbar region of the spinal cord and classified as American Spinal Injury Association Impairment Scale (AIS) A to D were recruited. Demographic, injury data, MRI classification and neurological data were collected on admission. At follow-up, the neurological data, a questionnaire collecting participant-reported secondary health conditions (SHCs) (e.g. bladder incontinence, depression etc.) following SCI and health status measured by Short Form-36 were obtained. Regression models determined the association of health status with demographic/injury-related data, types and number of SHCs.

RESULTS

Of the 51 participants, 58.8% reported bladder incontinence, 54.0% bowel incontinence, 60.8% sexual dysfunction and 29.4% had all three. The regression models demonstrated that age at injury, bowel incontinence, sexual dysfunction, presence of pain, motor score at follow-up and the number of SHCs were significant predictors of health status. The number of SHCs was more predictive than all other demographic and injury variables for health status.

CONCLUSION

Results highlight the high prevalence of self-reported bowel/bladder incontinence and sexual dysfunction in the traumatic thoracolumbar SCI population and support the need for standardized assessments. Several demographic, injury-related and SHCs impacted health status and should be considered for the management of individuals living in the community.

Lower Vitamin D Levels Are Associated With Depression in People With Chronic Spinal Cord Injury

OBJECTIVES

To determine (1) whether the serum concentration of 25-hydroxy vitamin D (25(OH)D₃) was associated with depression levels in people with chronic spinal cord injury (SCI) and (2) whether any observed association was independent of potential confounders.

DESIGN

Cross-sectional study.

SETTING

Rehabilitation institute.

PARTICIPANTS

Patients with chronic SCI (N=100) recruited consecutively.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Patients underwent clinical and biochemical evaluations, including assessment of 25(OH)D₃ levels and the presence and severity of depressive symptoms, by using the interviewer-assisted self-report Beck Depression Inventory-II (BDI-II).

RESULTS

Depression (BDI-II score ≥14) was observed in 15 of 28 women (53.6%) and 18 of 72 men (25.0%) of the study population. They exhibited significantly lower 25(OH)D₃ levels, lower functional independence degree in performing activities of daily living, poorer engagement in leisure time physical activity, and higher body mass index. Lower 25(OH)D₃ levels were associated with higher BDI-II scores as well as with the occurrence of depression. These associations persisted after adjustment for all significant predictors of the BDI-II score that were selected, as possible confounders, by univariate analysis. In receiver operating characteristic analysis, a 25(OH)D₃ level of <9.99ng/mL had the highest accuracy in discriminating patients with depression.

CONCLUSIONS

In people with chronic SCI, an inverse association exists between serum 25(OH)D₃ levels and depressive symptoms, widely independent of potential confounders, especially those, peculiar to this population, that can mediate the effects of depression on vitamin D levels.

Low testosterone and non-alcoholic fatty liver disease: Evidence for their independent association in men with chronic spinal cord injury

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) has been claimed as a liver phenotype of metabolic syndrome, which in turn is associated with male hypogonadism. We assessed whether an independent association between NAFLD and androgen deficiency could be revealed in men with chronic spinal cord injury (SCI), who exhibit a high prevalence of biochemical androgen deficiency and a combination of risk factors for metabolic syndrome.

DESIGN

Fifty-five consecutive men with chronic SCI admitted to a rehabilitation program underwent clinical/biochemical evaluations and liver ultrasonography.

RESULTS

NAFLD was diagnosed in 27 patients (49.1%). Men with NAFLD were older and exhibited significantly higher body mass index, Homeostatic model assessment of insulin resistance, triglycerides and gamma-glutamyl transpeptidase values, lower total and free testosterone levels and they were engaged in a significantly poorer weekly leisure time physical activity (LTPA). At the multiple logistic regression analysis, only total and free testosterone levels exhibited a significant independent association with NAFLD. The risk of having NAFLD increased indeed of 1% for each decrement of 1 ng/dL of total testosterone and of 3% for each decrement of 1 pg/mL of free testosterone, after adjustment for confounders. In men with total testosterone < 300 ng/dL (36.4%) the prevalence of NAFLD reached 85%: they had a risk of having NAFLD significantly higher (∼12-fold) than those with total testosterone ≥ 300 ng/dL, after adjustment for confounders.

CONCLUSION

The evidence of an independent association between NAFLD and low testosterone is strongly reinforced by its demonstration in men with chronic SCI, in spite of the many confounders peculiar to this population.

Association between 25(OH)-vitamin D and testosterone levels: Evidence from men with chronic spinal cord injury

OBJECTIVE

As an independent linear association between 25-hydroxyvitamin D (25(OH)D) and testosterone levels is controversial, this study aimed to explore this topic in men with chronic spinal cord injury (SCI), who exhibit a high prevalence of both androgen and vitamin D deficiency.

DESIGN

Forty-nine men with chronic SCI consecutively admitted to a rehabilitation program underwent clinical/biochemical evaluations.

RESULTS

Deficiency of 25(OH)D (<20 ng/mL) was found in 36 patients (73.5%). They exhibited significantly lower total testosterone and free testosterone levels, higher parathyroid hormone (PTH) and HOMA-IR, a poorer functional independence degree, and were engaged in poorer weekly leisure time physical activity (LTPA). Significant correlates of 25(OH)D levels were: total testosterone, free testosterone, PTH, functional independence degree and weekly LTPA. At the linear regression models, lower 25(OH)D levels were associated with both lower total and free testosterone after adjustment for age, smoking, alcohol consumption, comorbidities and HOMA-IR. However, after full adjustment, also including functional independence degree, BMI and LTPA, only the association of lower 25(OH)D with lower free testosterone was still significant.

CONCLUSION

In men with SCI, 25(OH)D correlates with total and free testosterone and exhibits an independent linear association with free testosterone. Regardless of this independent link, hypovitaminosis D and androgen deficiency are markers of poor health, sharing common risk factors to take into account in the rehabilitative approach to patients with SCI.

Independent Association of Vitamin D With Physical Function in People With Chronic Spinal Cord Injury

OBJECTIVE

To explore the relation between vitamin D and physical function outcomes in people with spinal cord injury (SCI).

DESIGN

Cross-sectional study.

SETTING

Rehabilitation institute.

PARTICIPANTS

Consecutive patients (N=100; 72 men and 28 women) with chronic SCI admitted to a rehabilitation program.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Functional independence in activities of daily living (ADL) and leisure time physical activity (LTPA) were assessed as measures of physical function.

RESULTS

Vitamin D deficiency (<20ng/mL) was found in 78 patients: they exhibited a significantly higher body mass index, lower functional independence in ADL, and were engaged in a significantly poorer weekly LTPA. At the linear multiple regression analysis, lower 25-hydroxyvitamin D levels showed significant independent associations with poorer functional independence in ADL (β=.59; 95% confidence interval, .36-.82; P<.0001) and with poorer LTPA (β=2.35; 95% confidence interval, 0.77-3.94; P=.004), after adjustment for other predictors of physical function outcomes selected by univariate analyses.

CONCLUSIONS

In people with chronic SCI, a low vitamin D level represents an independent predictor of poor physical function.