Ultrastructural mitochondrial alterations in Equine myopathies of unknown origin

Figures & data

Table 1. The onset of the disease, the clinical signs, treatment and outcome of five cases of equine myopathy of unknown origin.

Number	1	2	3	4	5
Onset	<One day	Six weeks	Six months	Four months	<One day
Clinical signs	Incoordination of the hind legs, lethargy, intention tremor and signs of cerebellar ataxia	Weakness of the hind legs, brown urine and progressive weight loss	Progressive weight loss, tottering pace and gluteal and femoral muscle atrophy	Difficult micturition, intermittent colic, muscle stiffness during work and atrophy of the back muscles	Training intolerance, muscle tremor, heavy sweating, pulse rate 100 bpm. and rectal temperature 41.7 °C
Treatment	Parenteral fluid therapy, dexamethason, antibiotics, vitamin E, KCl, NaHCO3, biotin and thiamin	Parenteral fluid therapy, vitamin E, selenium, sodium acid citrate and recovering training	Vitamin E and light workload	Vitamin E and rest	Parenteral fluid therapy, NaHCO3, NSAIDs, glucose, insulin and carnitine
Clinical course	Recovered	Recovered	Recovered	Euthanized	Died within hours

Table 2. Urine and blood analyses in five horses with myopathy of unknown origin.

Horse	1	2	3	4	5
Urine analysis	n.p.	Hemoglobinuria	n.p.	Normal	Glucosuria, hematuria, and proteinuria
Blood analysis
CK IU/L	n.p.	6695	n.p.	128	2410
LDH IU/L	706	3895	n.p.	262	1190
AST IU/L	335	9513	n.p.	220	230
Lactate mmol/L	26.3	n.p.	n.p.	n.p.	18.0
Glucose mmol/L	9.8	n.p.	n.p.	n.p.	16.5
Creatinine μmol/L	93	261	148	109	194
Other	Leukocytes 16.1 × 10^9/L				pH 7.18

Note: n.p., not performed.

Figure 1. Transmission electron microscopy of the vastus lateralis muscle in patient 1, a 17-year-old pony mare: small round to oval mitochondria line up between the myofibrils (a, arrows); scale 1a = 2 μm. Small mitochondria with few, simple cristae were seen, some presenting with brighter zones in the mitochondrial matrix (b, arrow) and zones with complete disruption of cristae (b, asterisk); scale 1b = 500 nm.

Figure 2. Transmission electron microscopy of the vastus lateralis muscle in patient 2, a five-year-old Quarter horse stallion: note extremely long and slender mitochondria with longitudinal cristae (a). Some mitochondria show an onion-shaped aspect on transverse section due to cristae forming concentric lamellae (b).

Figure 3. Transmission electron microscopy of the vastus lateralis muscle in patient 3, an eight-year-old Hanoverian mare: simultaneous presence of mitochondria of normal size and shape (a, small arrows) and large mitochondria (a, thick arrow) were seen. The right picture shows a detailed view of an extremely large mitochondrion with complex branching cristae (b).

Figure 4. Transmission electron microscopy of the vastus lateralis muscle in patient 4, an 11-year-old pony gelding: small round mitochondria with only few cristae were seen (a). Transmission electron microscopy of the vastus lateralis muscle in patient 5, a two-year-old Dutch Warmblood colt: subsarcolemmal accumulations of mitochondria were present (b).