Brain-Derived neurotrophic factor and inflammatory biomarkers are unaffected by acute and chronic intermittent hypoxic-hyperoxic exposure in geriatric patients: a randomized controlled trial

Figures & data

Figure 1. Flow chart of the study. BDNF_S: serum brain-derived neurotrophic factor; BDNF_P: plasma brain-derived neurotrophic factor; BDNF_S/P-ratio: brain-derived neurotrophic factor serum/plasma-ratio; CG: control group; COPD: chronic obstructive pulmonary disease; IG: intervention group.

Table 1. Patients’ characteristics at baseline split by group (intervention group (IG), control group (CG)). Values are presented as means ± standard deviations.

Characteristics	IG (n = 12)	CG (n = 12)
Age [years]	82.7 ± 4.3	83.5 ± 6.0
Women	n = 12 (100%)	n = 10 (83%)
Height [cm]	73.4 ± 9.4	160.3 ± 10.1
Weight [kg]	71.2 ± 11.9	68.8 ± 10.9
Body Mass Index [cm·kg^−²]	28.7 ± 2.4*	26.8 ± 3.7
Mini-Mental-State-Examination	16.9 ± 8.9	14.8 ± 8.0
Clinical Diagnosis [n (%)]
Alzheimer’s dementia	3 (25%)	6 (50%)
Vascular dementia	1 (8%)	0 (0%)
Mixed types of dementia	4 (33%)	5 (42%)
Hypertension	10 (83%)	10 (83%)
Diabetes mellitus type II	3 (25%)	5 (42%)
Hypothyreosis	2 (17%)	4 (33%)
Osteoporosis	3 (25%)	4 (33%)

* Differences between groups (d ≥ 0.5).

Figure 2. Acute and chronic effects of intermittent hypoxic-hyperoxic exposure (IHHE, intervention group) and sham-IHHE (control group) prior to aerobic cycling on (A) brain-derived neurotrophic factor serum blood concentration (BDNF_S), (B) brain-derived neurotrophic factor plasma blood concentration (BDNF_P), (C) brain-derived neurotrophic factor serum/plasma-ratio (BDNF_S/P-ratio), (D) interleukin-6 (IL-6), and (E) C-reactive protein (CRP). Values are presented as individual data points and medians (horizontal lines) with the 25th and 75th percentiles. * d > 0.50 vs. pre-exercise, # d > 0.50 vs. intervention group.

Table 2. Acute and chronic effects of intermittent hypoxic-hyperoxic exposure (IHHE, intervention group (IG)) and sham-IHHE (control group (CG)) prior to aerobic cycling on brain-derived neurotrophic factor serum blood concentration (BDNF_S), brain-derived neurotrophic factor plasma blood concentration (BDNF_P), brain-derived neurotrophic factor serum/plasma-ratio (BDNF_S/P-ratio), interleukin-6 (IL-6), and C-reactive protein (CRP). Values are presented as means ± standard deviations.

Outcome	Group	Pre-exercise	Post-exercise	ANCOVA			Post-training	ANCOVA
				Group × time interaction	Main group effect	Main time effect		Group × time interaction	Main group effect	Main time effect
BDNFS [pg/ml]	IG	31283.3 ± 13065.2	33358.3 ± 13396.4	F1,17 = 0.211, p = .652, ηp² = 0.01	F1,17 = 0.455, p = .509, ηp² = 0.03	F1,17 = 2.293, p = .148, ηp² = 0.12	22775.0 ± 4513.2	F1,17 = 0.666, p = .426, ηp² = 0.04	F1,17 = 0.021, p = .886, ηp² < 0.01	F1,17 = 0.279, p = .604, ηp² = 0.02
	CG	31058.3 ± 6095.5	32875.0 ± 10438.9				25845.5 ± 5439.2
BDNFP [pg/ml]	IG	1077.0 ± 111.0	935.0 ± 509.8	F1,17 = 0.016, p = .902, ηp² < 0.01	F1,17 = 0.053, p = .821, ηp² < 0.01	F1,17 = 1.616, p = .221, ηp² = 0.09	522.6 ± 308.7	F1,17 = 0.135, p = .718, ηp² < 0.01	F1,17 = 0.304, p = .588, ηp² = 0.02	F1,17 = 1.589, p = .223, ηp² = 0.09
	CG	1155.7 ± 1232.4	1060.7 ± 799.6				687.5 ± 706.8
BDNFS/P-ratio	IG	49.4 ± 47.5	50.2 ± 46.9	F1,17 < 0.001, p = .986, ηp² < 0.01	F1,17 = 0.021, p = .885, ηp² < 0.01	F1,17 = 0.286, p = .600, ηp² = 0.02	62.6 ± 43.9	F1,17 = 1.045, p = .321, ηp² = 0.06	F1,17 = 0.073, p = .459, ηp² = 0.03	F1,17 = 0.659, p = .428, ηp² = 0.04
	CG	50.5 ± 34.1	46.1 ± 27.1				105.3 ± 91.3
IL-6 [ng/l]	IG	5.29 ± 2.09	5.54 ± 2.26	F1,18 = 0.011, p = .917, ηp² < 0.01	F1,18 = 0.141, p = .712, ηp² < 0.01	F1,18 = 0.049, p = .827, ηp² < 0.01	4.91 ± 2.05	F1,19 = 0.003, p = .960, ηp² < 0.01	F1,19 = 0.010, p = .920, ηp² < 0.01	F1,19 = 2.237, p = .151, ηp² = 0.11
	CG	5.13 ± 1.85	5.23 ± 2.15				4.62 ± 1.90
CRP [mg/l]	IG	1.00 ± 1.18	1.83 ± 1.23	F1,18 = 0.810, p = .380, ηp² = 0.04	F1,18 = 1.173, p = .293, ηp² = 0.06	F1,18 = 0.094, p = .763, ηp² < 0.01	1.79 ± 1.28	F1,19 = 0.159, p = .695, ηp² < 0.01	F1,19 = 0.798, p = .383, ηp² = 0.04	F1,19 = 0.409, p = .530, ηp² = 0.02
	CG	2.22 ± 0.30	2.63 ± 2.06				3.23 ± 4.11

ANCOVA: analysis of covariance with repeated measures.

Data availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on reasonable request.