Provocative stimulation of growth hormone: a monozygotic twin study discordant for spinal cord injury

Risk of Low Energy Availability in National and International Level Paralympic Athletes: An Exploratory Investigation

(1) Background: The purpose of this study was to examine the symptoms of low energy availability (LEA) and risk of relative energy deficiency in sport (RED-S) symptoms in para-athletes using a multi-parameter approach. (2) Methods: National level para-athletes (n = 9 males, n = 9 females) completed 7-day food and activity logs to quantify energy availability (EA), the LEA in Females Questionnaire (LEAF-Q), dual energy X-ray absorptiometry (DXA) scans to assess bone mineral density (BMD), and hormonal blood spot testing. (3) Results: Based on EA calculations, no athlete was at risk for LEA (females < 30 kcal·kg⁻¹ FFM·day⁻¹; and males < 25 kcal·kg⁻¹ FFM·day⁻¹; thresholds for able-bodied (AB) subjects). Overall, 78% of females were “at risk” for LEA using the LEAF-Q, and 67% reported birth control use, with three of these participants reporting menstrual dysfunction. BMD was clinically low in the hip (<−2 z-score) for 56% of female and 25% of male athletes (4) Conclusions: Based on calculated EA, the risk for RED-S appears to be low, but hormonal outcomes suggest that RED-S risk is high in this para-athlete population. This considerable discrepancy in various EA and RED-S assessment tools suggests the need for further investigation to determine the true prevalence of RED-S in para-athlete populations.

GH deficiency in patients with spinal cord injury: efficacy/safety of GH replacement, a pilot study

Objective Growth hormone (GH) was shown to stimulate proliferation, migration and survival of neural cells in animal models. GH deficiency (GHD) was reported following traumatic brain lesions; however, there are not available data in spinal cord injury (SCI) patients. The aim of the study was to evaluate (1) the frequency of GHD in chronic SCI population; (2) the efficacy/safety of GH replacement in patients with SCI and suboptimal GH secretion. Design and methods Nineteen consecutive patients with chronic thoracic complete SCI (AIS-A) were studied. Patients with low GH secretion were randomized in a double-blind, placebo-controlled study to receive either subcutaneous placebo injections or GH combined with physical therapy, for 6 months. Baseline cranial MRI, AIS motor and sensory scale, quality of life (spinal cord impact measurement) and modified Ashworth spasticity scale, quantitative sensory testing and neurophysiological exploration were assessed at baseline, 1, 3 and 6 months following treatment. Results Thirteen had GH deficiency. Seven received GH, five placebo and one dropped out. Both groups were similar according to clinical and demographical data at baseline, except for greater GH deficiency in the GH treatment group. At 6th month, patients treated with GH showed a significant improvement in SCIM-III score and in electrical perception threshold up to the 5th level below SCI, on both sides compared to baseline. Conclusions GHD seems to be frequent in traumatic SCI and GH replacement is safe without side effects. GH combined with physical therapy can improve quality of life of SCI patients and, strikingly, the sensory perception below lesion level.

Growth Hormone (GH) and Gonadotropin-Releasing Hormone (GnRH) in the Central Nervous System: A Potential Neurological Combinatory Therapy?

This brief review of the neurological effects of growth hormone (GH) and gonadotropin-releasing hormone (GnRH) in the brain, particularly in the cerebral cortex, hypothalamus, hippocampus, cerebellum, spinal cord, neural retina, and brain tumors, summarizes recent information about their therapeutic potential as treatments for different neuropathologies and neurodegenerative processes. The effect of GH and GnRH (by independent administration) has been associated with beneficial impacts in patients with brain trauma and spinal cord injuries. Both GH and GnRH have demonstrated potent neurotrophic, neuroprotective, and neuroregenerative action. Positive behavioral and cognitive effects are also associated with GH and GnRH administration. Increasing evidence suggests the possibility of a multifactorial therapy that includes both GH and GnRH.

Nanowired Delivery of Growth Hormone Attenuates Pathophysiology of Spinal Cord Injury and Enhances Insulin-Like Growth Factor-1 Concentration in the Plasma and the Spinal Cord

Previous studies from our laboratory showed that topical application of growth hormone (GH) induced neuroprotection 5 h after spinal cord injury (SCI) in a rat model. Since nanodelivery of drugs exerts superior neuroprotective effects, a possibility exists that nanodelivery of GH will induce long-term neuroprotection after a focal SCI. SCI induces GH deficiency that is coupled with insulin-like growth factor-1 (IGF-1) reduction in the plasma. Thus, an exogenous supplement of GH in SCI may enhance the IGF-1 levels in the cord and induce neuroprotection. In the present investigation, we delivered TiO2-nanowired growth hormone (NWGH) after a longitudinal incision of the right dorsal horn at the T10-11 segments in anesthetized rats and compared the results with normal GH therapy on IGF-1 and GH contents in the plasma and in the cord in relation to blood-spinal cord barrier (BSCB) disruption, edema formation, and neuronal injuries. Our results showed a progressive decline in IGF-1 and GH contents in the plasma and the T9 and T12 segments of the cord 12 and 24 h after SCI. Marked increase in the BSCB breakdown, as revealed by extravasation of Evans blue and radioiodine, was seen at these time points after SCI in association with edema and neuronal injuries. Administration of NWGH markedly enhanced the IGF-1 levels and GH contents in plasma and cord after SCI, whereas normal GH was unable to enhance IGF-1 or GH levels 12 or 24 h after SCI. Interestingly, NWGH was also able to reduce BSCB disruption, edema formation, and neuronal injuries after trauma. On the other hand, normal GH was ineffective on these parameters at all time points examined. Taken together, our results are the first to demonstrate that NWGH is quite effective in enhancing IGF-1 and GH levels in the cord and plasma that may be crucial in reducing pathophysiology of SCI.

Low-dose baclofen therapy raised plasma insulin-like growth factor-1 concentrations, but not into the normal range in a predictable and sustained manner in men with chronic spinal cord injury

OBJECTIVE

To evaluate, whether once-daily oral baclofen administration increases and/or sustains plasma insulin-like growth factor-1 (IGF-1) concentration in 11 men with chronic spinal cord injury (SCI) and IGF-1 deficiency (i.e. <250 ng/ml).

DESIGN

Prospective, open-label, dose titration study. Baclofen was administered at 20 mg/day for 8 weeks; then increased to 40 mg/day for another 8 weeks. Plasma IGF-1 and self-reported side effects were measured at baseline and every other week for the duration of the study.

RESULTS

The subjects were 43 ± 12 years old, had duration of injury of 20 ± 12 years; eight subjects had a complete motor injury, and eight had paraplegia. Nine of 11 subjects completed the 20 mg/day treatment and 5 subjects completed the 40 mg/day treatment. Plasma IGF-1 levels improved with each baclofen dose; however, only one subject increased from baseline and remained above the targeted physiological range of 250 ng/ml throughout treatment. A significant increase in IGF-1concentration was observed between baseline and week 2 (154 ± 63 vs. 217 ± 69 ng/ml; P < 0.05), weeks 8 and 10 (188 ± 95 vs. 228 ± 93 ng/ml; P < 0.05), and weeks 8 and 16 (188 ± 95 vs. 259 ± 92 ng/ml; P < 0.05). No serious side effects were observed at 20 mg/day; the 40 mg/day dose was less well tolerated.

CONCLUSION

Baclofen was not effective at sustaining plasma IGF-1 concentrations in the physiological range in men with chronic SCI.

Traumatic and non-traumatic spinal cord-injured patients in Quebec, Canada. Part 2: biochemical profile

STUDY DESIGN

Community-based, cross-sectional study.

OBJECTIVES

This study aimed at examining and comparing biochemical profiles (blood and urine) of traumatic and non-traumatic spinal cord-injured patients (TSCIs vs NTSCIs).

SETTING

The Interval Rehabilitation Center, Trois-Rivieres, Province of Quebec, Canada.

METHODS

Medical records from a cohort of 175 chronic spinal cord-injured patients (94 TSCI and 81 NTSCI individuals) were thoroughly studied.

RESULTS

Augmentations over time of red blood cell (erythrocyte), hematocrit and hemoglobin levels were generally found after spinal cord injury (SCI), specifically in NTSCI patients (late vs early chronic). In contrast, although leukocyte levels generally decreased over time after SCI, higher lymphocyte levels were detected only in NTSCI patients (late vs early chronic). Higher total cholesterol, triglyceride, high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C), protein and albumin serum levels were generally found over time after SCI, again, specifically in chronic NTSCI patients (late vs early chronic), whereas increased (twofold) nitrite and decreased (twofold) ubilirogen urine levels were found specifically in TSCI individuals (late vs early chronic).

CONCLUSION

Clear differences were reported between subgroups of SCI patients strongly supporting the idea that therapeutic approaches aimed to treat these problems should be specifically designed for each type of patients (that is, NTSCI vs TSCI or early vs late chronic patients).

Sublesional spinal vertebral bone mineral density correlates with neurological level and body mass index in individuals with chronic complete spinal cord injuries

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

Our aim was to find out the factors influencing the bone mineral density (BMD) change of sublesional spinal vertebrae in spinal cord injury (SCI) individuals.

SUMMARY OF BACKGROUND DATA

In individuals with SCI, the BMD of sublesional extremities dramatically decreases to fracture threshold because of unloading. In contrast, the BMD of sublesional spinal vertebrae is reported to be preserved. The etiology of the discrepancy is unknown.

METHODS

This study was performed in a university tertiary referral medical center. A total of 62 men with traumatic and neurologically complete SCI attending a special SCI clinic attached to the medical center from 2000 to 2003. Participants were prescreened using lumbosacral roentgenography to rule out heterotopic ossification and early-onset spinal degeneration. The BMD was then evaluated with dual energy radiograph absorptiometry at the thoracic spine and lumbar spine, using anteroposterior and lateral scout images.

RESULTS

The mean age was 27.3 +/- 8.3 years and mean injury duration was 11.7 +/- 6.8 years. Lumbar spine BMD did not increase or decrease significantly after SCI. Lumbar spine BMD correlated significantly with body mass index. Thoracic and lumbar spine BMDs were significantly higher if the injury level was below T6. There were no correlations with postinjury duration, age of the subject, or level of physical activity.

CONCLUSION

In men with chronic complete SCI, the long-term sublesional spinal vertebrae BMDs are significantly lower if injury levels are at T6 or above, suggesting the role of neurologic control on bone metabolism.

Impact of exercise on neuroplasticity-related proteins in spinal cord injured humans

The present study investigated the effects of exercise on the serum concentrations of brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), prolactin (PRL) and cortisol (COR) in 11 chronically spinal cord-injured athletes. In these subjects BDNF concentration at rest was sixfold higher compared with the concentrations reported earlier in able-bodied persons, while IGF-1, PRL and COR were within normal range. Ten minutes of moderate intensity handbiking (54% of the maximal heart rate) during a warm-up period (W) induced an increase (P<0.05) of BDNF of approximately 1.5-fold from basal level at rest, while a decrease to basal level was found after an immediately succeeding handbiking time trial (89% of the maximal heart rate) over the marathon distance of 42 km (M). An increase (P<0.01) of serum IGF-1 was found after W and this levels remained elevated (P<0.01) until the end of M. W had no significant effects on the serum PRL and COR, however, M induced an increase (P<0.01) of both hormones. This is the first study showing elevated BDNF concentrations at rest in spinal cord-injured athletes. Furthermore, short moderate intensity handbiking but not immediately following long lasting high intensity handbiking further increases serum BDNF concentrations. IGF-1 response to exercise differs to BDNF response as this neuroplasticity-related protein remains elevated during the long lasting physical demand with high intensity. The augmented PRL concentration suggests that a possible mechanism by which exercise promotes neuroplasticity might be the activation of neural serotonergic pathways as 5-HT is the main PRL releasing factor. Elevated COR concentrations after M are unlikely to be deleterious to neuroplasticity as COR concentrations remain within the physiological range. The present study suggests that exercise might be beneficial to enhance neuroprotection and neuroplasticity, thereby improving recovery after spinal cord injury.