Effect of Doxycycline on Clinical Outcomes in Patients with Ischemic Stroke

² Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran

³ Medicinal Plants and Natural Products Research Center, Hamadan University of Medical Sciences, Hamadan, Iran

⁴ Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran

*Corresponding author: Salman Khazaei, Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran. Email: salman.khazaei61@gmail.com

EXTENDED ABSTRACT

Background

Stroke is a common neurological cause of disability and death, particularly in older adults, and imposes substantial costs on patients and health systems [1,2]. Ischemic stroke accounts for approximately 85% of strokes [3] and occurs when partial or complete cerebral vascular occlusion reduces blood flow, oxygen, and nutrient delivery, potentially producing irreversible neuronal injury [4]. Rapid reperfusion can limit damage, but fibrinolytic treatment such as tissue plasminogen activator is constrained by a narrow therapeutic window, multiple contraindications, and cost, and therefore cannot be used routinely in all patients [5]. These limitations support investigation of safe adjunctive therapies that may target secondary injury pathways after cerebral ischemia.

Tetracyclines are primarily bacteriostatic antibiotics, but they also have clinically relevant anti-inflammatory actions [6]. Experimental studies cited in the article indicate that doxycycline and minocycline may exert neuroprotective effects in ischemic and hemorrhagic stroke and other neurological disorders [7]. Proposed mechanisms include inhibition of matrix metalloproteinases involved in ischemic tissue injury [8, 9], reduction of inflammatory cytokine release [10], and antioxidant activity that may reduce oxidative cellular damage [11]. On this basis, the present clinical trial evaluated whether short-term doxycycline, added to standard treatment, could improve neurological disability and functional outcome after acute ischemic stroke.

Methods

This randomized, double-blind clinical trial was conducted among patients with acute ischemic stroke admitted to the neurology ward of Besat Hospital, Hamadan, during the first six months of 1402 (2023). Patients were enrolled within the first 24 hours after stroke onset. The sample-size calculation was based on previously reported 30-day Modified Rankin Scale (mRS) findings with minocycline [12]. Seventy patients were initially randomized by block allocation to intervention and control groups (35 per group); 60 patients, 30 in each group, completed the study and were included in the analysis.

Eligibility criteria included age 18-85 years, a focal neurological deficit, clinical diagnosis of acute hemispheric ischemic stroke supported by CT or MRI findings, a National Institutes of Health Stroke Scale (NIHSS) score of 4-27, admission within 24 hours of stroke onset, no previous ischemic stroke, no concurrent inflammatory disease, and no use of antioxidant compounds during the preceding month. Pregnancy or lactation, intracranial hemorrhage or aneurysm, nonischemic etiologies, cognitive or behavioral impairment preventing cooperation, intolerance or hypersensitivity to doxycycline, clinically relevant adverse reactions, nonadherence, and use of nonstudy antioxidant products were among the exclusion criteria.

Both groups received standard stroke treatment. The intervention group additionally received doxycycline 100 mg every 12 hours for 7 days; the dose was selected on the basis of prior short-term doxycycline therapy described by Cerisano et al. [13]. The control group received a placebo solution containing starch and Avicel in water with an appearance similar to the active drug. A study nurse prepared and administered treatment and monitored correct intake. The person collecting outcome data and the person analyzing the study results were unaware of allocation codes. Neurological status was assessed at baseline and on days 7, 30, and 90 using the NIHSS and mRS. NIHSS quantifies neurological impairment on a 0-42 scale, while the mRS grades functional disability from 0 (no disability) to 6 (death). Quantitative variables were compared with Student t tests and categorical variables with chi-square or Fisher exact tests; repeated-measures analysis was used to assess longitudinal treatment effects. Analyses were performed with SPSS version 26 at a significance level of P<0.05. The study was approved by the Ethics Committee of Hamadan University of Medical Sciences (IR.UMSHA.REC.1401.317) and registered as IRCT20120215009014N432; written informed consent was obtained.

Results

The final analysis included 60 patients, 30 receiving doxycycline and 30 receiving placebo. Baseline characteristics were comparable. Mean age was 68.33 ± 12.15 years in the doxycycline group and 67.40 ± 9.99 years in the control group (P=0.75); body mass index was 27.04 ± 10.61 and 26.95 ± 10.87 kg/m², respectively (P=0.74), and the interval from symptom onset to emergency presentation was 11.50 ± 8.93 versus 11.70 ± 5.48 hours (P=0.93). Men constituted 63.3% of the intervention group and 43.3% of the control group (P=0.12). No significant baseline difference was observed in underlying diseases.

Table 1. Comparison of selected baseline variables in the doxycycline and control groups.

Systolic and diastolic blood pressure decreased significantly from day 1 to day 3 within both groups (P<0.001), but there was no significant between-group difference at either time point. The main neurological outcomes showed no significant early between-group difference. Baseline NIHSS scores were 19.13 ± 4.46 in the doxycycline group and 20.27 ± 4.22 in the control group (P=0.322), and day-7 scores were 16.87 ± 3.78 and 18.43 ± 3.90 (P=0.07). By day 30, however, NIHSS was significantly lower with doxycycline (8.97 ± 3.63 vs 11.17 ± 2.20; P=0.007), and this difference was larger at day 90 (2.28 ± 2.19 vs 5.33 ± 3.86; P<0.001).

Functional outcome followed a similar pattern. Baseline mRS scores were 3.30 ± 0.92 and 3.70 ± 0.80 in the intervention and control groups, respectively (P=0.07), and on day 7 they were 3.03 ± 0.81 and 3.07 ± 0.64 (P=0.97). At day 30, mean mRS was significantly lower in the doxycycline group (1.70 ± 0.75 vs 2.17 ± 0.70; P=0.009), and at day 90 it remained lower (0.47 ± 0.51 vs 1.24 ± 0.63; P<0.001). Repeated-measures analysis showed a significant intervention effect (P=0.022) and time-by-intervention interaction (P<0.001) for NIHSS. For mRS, the intervention effect was also significant (P=0.003), with a significant time-by-intervention interaction (P<0.001). Thus, neurological impairment and disability declined over time in both groups, but improvement was greater in patients receiving doxycycline.

Table 3. Mean NIHSS and mRS scores in the doxycycline and control groups according to assessment time.

Figure 1. Change in mean mRS and NIHSS scores over 90 days in the doxycycline and control groups.

Treatment was generally tolerated. Dyspepsia occurred in 3 patients (10%) and diarrhea in 2 patients (6.7%) receiving doxycycline. The article reported no major treatment-limiting adverse effects. The delayed separation of NIHSS and mRS trajectories, becoming significant at one and three months rather than at day 7, was consistent with the study conclusion that short-term doxycycline was associated with better subsequent neurological and functional recovery.

Conclusion

In patients with acute ischemic stroke, adding doxycycline 100 mg every 12 hours for 7 days to standard treatment was associated with lower NIHSS and mRS scores at 30 and 90 days without prominent adverse effects. The findings indicate reduced neurological impairment and improved functional outcome during one- to three-month follow-up. Within the conditions of this 60-patient double-blind trial, short-term doxycycline appeared to be a potentially useful adjunct to standard ischemic stroke management.

Keywords: Clinical Outcome, Doxycycline, Ischemic Stroke

REFERENCES

1. Murphy SJ, Werring DJ. Stroke: causes and clinical features. Medicine. 2020;48(9):561-6. PMID: 32837228 DOI: 10.1016/j.mpmed.2020.06.002
2. Feigin VL, Norrving B, Mensah GA. Global burden of stroke. Circulation Research. 2017;120(3):439-48. DOI: 10.1161/CIRCRESAHA.116.308413
3. Runchey S, McGee S. Does this patient have a hemorrhagic stroke?: clinical findings distinguishing hemorrhagic stroke from ischemic stroke. JAMA. 2010;303(22):2280-6. DOI: 10.1001/jama.2010.754
4. Pandya RS, Mao L, Zhou H, Zhou S, Zeng J, Popp AJ, Wang X. Central nervous system agents for ischemic stroke: neuroprotection mechanisms. Cent Nerv Syst Agents Med Chem. 2011;11(2):81-97. PMID: 21521165 DOI: 10.2174/187152411796011321
5. Adeoye O, Hornung R, Khatri P, Kleindorfer D. Recombinant tissue-type plasminogen activator use for ischemic stroke in the United States: a doubling of treatment rates over the course of 5 years. Stroke. 2011;42(7):1952-5. DOI: 10.1161/STROKEAHA.110.612358
6. Weinberg JM. The anti-inflammatory effects of tetracyclines. Cutis. 2005;75(4 Suppl):6-11. PMID: 15916224
7. Domercq M, Matute C. Neuroprotection by tetracyclines. Trends in pharmacological sciences. 2004;25(12):609-12. DOI: 10.1016/j.tips.2004.10.001
8. Samartzis EP, Fink D, Stucki M, Imesch P. Doxycycline reduces MMP-2 activity and inhibits invasion of 12Z epithelial endometriotic cells as well as MMP-2 and-9 activity in primary endometriotic stromal cells in vitro. Reprod Biol Endocrinol. 2019;17(1):1-10. DOI: 10.1186/s12958-019-0481-z
9. Smith CJ, Heal C, Vail A, Jeans AR, Westendorp WF, Nederkoorn PJ, et al. Antibiotic class and outcome in post-stroke infections: an individual participant data pooled analysis of VISTA-Acute. Front Neurol. 2019;10:504. DOI: 10.3389/fneur.2019.00504
10. Bostanci N, Akgül B, Tsakanika V, Allaker R, Hughes F, McKay I. Effects of low-dose doxycycline on cytokine secretion in human monocytes stimulated with Aggregatibacter actinomycetemcomitans. Cytokine. 2011;56(3):656-61. DOI: 10.1016/j.cyto.2011.08.039
11. Clemens DL, Duryee MJ, Sarmiento C, Chiou A, McGowan JD, Hunter CD, et al. Novel antioxidant properties of doxycycline. Int J Mol Sci. 2018;19(12):4078. DOI: 10.3390/ijms19124078
12. Lampl Y, Boaz M, Gilad R, Lorberboym M, Dabby R, Rapoport A, et al. Minocycline treatment in acute stroke: an open-label, evaluator-blinded study. Neurology. 2007;69(14):1404-10. DOI: 10.1212/01.wnl.0000277487.04281.db
13. Cerisano G, Buonamici P, Valenti R, Sciagra R, Raspanti S, Santini A, et al. Early short-term doxycycline therapy in patients with acute myocardial infarction and left ventricular dysfunction to prevent the ominous progression to adverse remodelling: the TIPTOP trial. European heart journal. 2014;35(3):184-91. DOI: 10.1093/eurheartj/eht420
14. Widerøe M, Havnes MB, Morken TS, Skranes J, Goa PE, Brubakk AM. Doxycycline treatment in a neonatal rat model of hypoxia–ischemia reduces cerebral tissue and white matter injury: a longitudinal magnetic resonance imaging study. European Journal of Neuroscience. 2012;36(1):2006-16. DOI: 10.1111/j.1460-9568.2012.08114.x
15. Fathy HA, Soliman AM, Lotfy SM. The Role of Serum Matrix Metalloproteinase-9 as a Prognostic Biomarker for Short-Term Outcome in Acute Ischemic Stroke. Zagazig University Medical Journal. 2023;29(6):1506-14. DOI: 10.21608/zumj.2023.222211.2823
16. Modheji M, Olapour S, Khodayar MJ, Jalili A, Yaghooti H. Minocycline is more potent than tetracycline and doxycycline in inhibiting MMP-9 in vitro. Jundishapur Journal Of Natural Pharmaceutical Products. 2016;11(2). Link
17. Axisa B, Loftus IM, Naylor AR, Goodall S, Jones L, Bell PR, et al. Prospective, randomized, double-blind trial investigating the effect of doxycycline on matrix metalloproteinase expression within atherosclerotic carotid plaques. Stroke. 2002;33(12):2858-64. DOI: 10.1161/01.STR.0000038098.04291.F6
18. Pires PW, Rogers CT, McClain JL, Garver HS, Fink GD, Dorrance AM. Doxycycline, a matrix metalloprotease inhibitor, reduces vascular remodeling and damage after cerebral ischemia in stroke-prone spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol . 2011;301(1):H87-97. DOI: 10.1152/ajpheart.01206.2010
19. Clark WM, Lessov N, Lauten JD, Hazel K. Doxycycline treatment reduces ischemic brain damage in transient middle cerebral artery occlusion in the rat. J Mol Neurosci. 1997;9:103-8. DOI: 10.1007/BF02736854
20. Reasoner DK, Hindman BJ, Dexter F, Subieta A, Cutkomp J, Smith T. Doxycycline reduces early neurologic impairment after cerebral arterial air embolism in the rabbit. The Journal of the American Society of Anesthesiologists. 1997;87(3):569-76. DOI: 10.1097/00000542-199709000-00017
21. Jiang Y, Zhu J, Wu L, Xu G, Dai J, Liu X. Tetracycline inhibits local inflammation induced by cerebral ischemia via modulating autophagy. PloS one. 2012;7(11):e48672. DOI: 10.1371/journal.pone.0048672
22. Fan X, Lo EH, Wang X. Effects of minocycline plus tissue plasminogen activator combination therapy after focal embolic stroke in type 1 diabetic rats. Stroke. 2013;44(3):745-52. DOI: 10.1161/STROKEAHA.111.000309
23. Seleem M. Benefit of Doxycycline Therapy in Acute St segment Elevation myocardial Infarction with Left Ventricular Dysfunction treated with primary percutaneous coronary intervention (PPCI). American Journal of Research Communication. 2015;3(11):55-68. Link
24. Wang Q, Wu ZY, Tang HL, Yi ZM, Zhai SD. The efficacy and safety of prophylactic antibiotics for post‐acute stroke infection: A systematic review and meta-analysis. Br J Clin Pharmacol. 2023;89(3):946-55. DOI: 10.1111/bcp.15646
25. Shelat V, Seah M, Lim K. Doxycycline induced acute erosive oesophagitis and presenting as acute dysphagia. J Assoc Physicians India. 2011;59(1):57-9. Link
26. Holmes NE, Charles PG. Safety and efficacy review of doxycycline. Clinical Medicine Therapeutics. 2009;1:CMT.S2035. DOI: 10.4137/CMT.S2035